I TA L I A N H A B I TAT S
Italian habitats
24
Italian habitats
Italian Ministry of the Environment and Territorial Protection / Ministero dell’Ambiente e della Tutela del
Territorio e del Mare
Friuli Museum of Natural History / Museo Friulano di Storia Naturale · Comune di Udine
I TA L I A N H A B I TAT S
Scientific coordinators
Alessandro Minelli · Sandro Ruffo · Fabio Stoch
Editorial committee
Aldo Cosentino · Alessandro La Posta · Carlo Morandini · Giuseppe Muscio
“Italian habitats · Expression of biodiversity”
edited by Fabio Stoch
Texts
Edoardo Biondi · Ferdinando Boero · Benedetta Brecciaroli · Eugenio Duprè · Lucio Eleuteri ·
Simonetta Fraschetti · Giuseppe Giaccone · Thalassia Giaccone · Alessandro La Posta · Laura Pettiti ·
Fabio Stoch · Nicoletta Tartaglini · Corrado Venturini
In collaboration with
Carlo Blasi
English translation
Elena Calandruccio · Alison Garside · Gabriel Walton
Illustrations
Roberto Zanella
Italian habitats
Graphic design
Furio Colman
Expression of biodiversity
Photographs
Nevio Agostini 97 · Archive Museo Friulano di Storia Naturale, 55, 64/1, 64/2, 73, 77, 100, 131/1· Archive
Ministero dell’Ambiente e della Tutela del Territorio e del Mare (Pandaphoto, F. Di Domenico) 174/2 · Archive
Naturmedia 69 · Archive Unione Speleologica Bolognese (E. Altara) 99 · Andrea Artoni 22 · Mauro Arzillo 187 ·
Paolo Audisio 58, 59/2 · Flavio Bacchia 174/1, 177 · Pietro Baccino 61 · Carlo Nike Bianchi 159/1 · Edoardo
Biondi 47, 48, 49, 59/1, 63, 72, 76/2, 81, 82 · Alessandro Biscaccianti 191 · Ferdinando Boero 137, 150, 151,
162/2, 171, 183 · Enrico Lana 91 · Francesco Luigi Cinelli 132, 133 · Carlo Corradini 13 · Corrado Venturini 17 ·
Adalberto D’Andrea 109, 110/1, 110/2, 193 · Vitantonio Dell’Orto 6, 7, 9, 11, 12, 24, 46, 56, 60, 74, 78, 80, 88,
104/1,104/2, 105, 186, 188, 189, 190, 194 · Helmut Deutsch 127 · Dario Ersetti 8, 54, 79 · Anna Flagiello 98 ·
Gabriele Fiumi121/3 · Fulvio Gasparo 131/2 · Luciano Gaudenzio 122 · Giuseppe Giaccone 134 · Google Maps
10, 42 · Giuliano Mainardis 89, 119/2, 121/1 · Giuseppe Muscio 33, 41 · Francesco Orsino 76/1 · Ivo Pecile 44,
52, 62, 66, 67, 68, 70/1, 70/2, 71, 83/1, 83/2, 84, 85, 86, 116, 196 · Giuseppe Lucio Pesce 168 · Arnaldo Piccinini
103, 111 · Marco Relini 185 · Roberto Sauli 112 · Pino Sfregola 75 · Margherita Solari 50 · Fabio Stoch 57, 65,
87, 93, 106/1, 106/2, 107, 114, 119/1, 120, 123, 125, 126/1, 126/2, 128, 129, 144, 154, 158/2, 160, 180, 184,
192 · Luca Lapini 116/1 · Antonio Todaro 172/1 · Egidio Trainito 135, 136, 138, 139/1, 139/2, 140, 141, 142,
143, 145, 146, 147, 148, 149, 152, 153, 155, 158/1, 159/2, 162/1, 165/1, 172/2, 178, 181, 182, 197, 43 · Damiano
Vagaggini 115/1, 115/2 · Augusto Vigna Taglianti 101 · Francesco Zaramella 165/2 · Roberto Zucchini 121/2, 156
© 2009 Museo Friulano di Storia Naturale, Udine, Italy
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or
transmitted in any form or by any means, without the prior permission in writing of the publishers.
ISBN 88 88192 47 6
ISSN 1724-6539
Cover photo: Lagoon of Marano with Julian Alps in the background (Friuli, photo: U. Da Pozzo)
M I N I S T E R O D E L L’ A M B I E N T E E D E L L A T U T E L A D E L T E R R I T O R I O E D E L M A R E
M U S E O F R I U L A N O D I S T O R I A N AT U R A L E · C O M U N E D I U D I N E
Contents
Italian habitats
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Alessandro Minelli · Sandro Ruffo · Fabio Stoch
The dynamic landforms of Italy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Corrado Venturini
1
Caves and
karstic
phenomena
2
Springs and
spring
watercourses
3
Woodlands
of the Po
Plain
4
Sand dunes
and beaches
5
Mountain
streams
6
The
Mediterranean
maquis
Terrestrial and freshwater habitats: vegetation. . . . . . . . . . . . . . . . . . . . . 47
Edoardo Biondi
Terrestrial and freshwater habitats: fauna . . . . . . . . . . . . . . . . . . . . . . . . . 89
Fabio Stoch
7
Sea cliffs and
rocky
coastlines
8
Brackish
coastal lakes
9
Mountain
peat-bogs
10
Realms of
snow and ice
11
Pools, ponds
and
marshland
12
Arid
meadows
Marine habitats: vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Thalassia Giaccone · Giuseppe Giaccone
Marine habitats: fauna and ecology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Ferdinando Boero · Simonetta Fraschetti
Conservation of biodiversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Alessandro La Posta · Eugenio Dupré · Lucio Eleuteri · Laura Pettiti ·
Benedetta Brecciaroli · Nicoletta Tartaglini
13
Rocky slopes
and screes
19
Seagrass
meadows
14
High-altitude
lakes
15
16
Beech forests The pelagic
of the
domain
Apennines
20
21
Subterranean Rivers and
waters
riverine
woodlands
17
Volcanic
lakes
22
23
Marine bioLagoons,
constructions estuaries
and deltas
18
Mountain
conifer forests
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
List of species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
24
Italian
habitats
Introduction
ALESSANDRO MINELLI · SANDRO RUFFO · FABIO STOCH
The Italian peninsula extends for one
thousand kilometres from north to
south, the high mountainous chain of
the Alps clearly separating it from
central Europe.
Italy splits the Mediterranean Sea into
two large, distinct basins, and has a
variety of environments unparalleled in
the entire European continent. The
islands of Sicily, Sardinia, Elba, and the
many others that surround Italy and
are part of it, all contribute towards
making this country unique.
The great variety of environments is
evident from the different types of
vegetation, which range from imposing
fir and beech stands to the more
Spring flowers in a hay meadow
discreet, newly formed pioneering
vegetation growing in volcanic soil,
near Alpine glaciers and along the snowline. Although travellers to Italy
immediately appreciate this multitude of habitats, they may not be equally
aware of the extraordinary, albeit less conspicuous, diversity of animal
forms.
This is not only because these populations are small in numbers, but also
because most of the animals in question, especially the invertebrates, are
small and elusive.
Visitors who are not provided with special equipment meet an even greater
challenge if they wish to observe the diversity of organisms living underwater,
both inland (streams, rivers, ponds and lakes, caves and springs) and in the
sea, which even in a limited stretch along the coastline contains a large
number of species representing the Mediterranean animal and plant
populations.
Small waterfalls in a mountain stream
7
8
Knowledge of the organisms living in
Italy and its seas is still incomplete,
and every year new species are
added to the list of Italy’s fauna and
flora. These may not only be the first
Italian sightings of species which are
known to live in other countries, or
alien species introduced into Italy
deliberately or by mistake: very often
they are newly discovered species
still unknown to science.
The great efforts made towards
improving our knowledge is supported
by the fact that, in recent years, plant
species of “popular” genera like Primula
(primrose) and Gentiana (gentian) have
been found in Italy.
The coast of Salento (Apulia)
Similarly, the list of Italian reptile and
amphibian species has radically changed in past decades, after research
showed that what were originally thought to be the Italian representatives of
species already known to live in other parts of Europe, were in fact specific to
Italy.
The extraordinary importance of Italian biodiversity is not only due to the
57,000 known animal species, 6,700 vascular plants and several thousands of
species belonging to various groups of living organisms, especially fungi and
algae. There are also large numbers of endemics, species whose habitats are
limited to Italy, sometimes even small areas within the country. Indeed, many
of the recently discovered species live in areas no larger than one mountain
range or one river. The percentage of endemic flowering plants is 13%, and
that of the entire Italian fauna is estimated to be more than 10%, which is
expected to increase in the future with the discovery of further species with
restricted distribution.
These are among the highest percentages in Europe, and may be explained by
the complex palaeo-geographical events that took place in Italy in the course
of its geological evolution, over millions of years: endemic species are
irreplaceable witnesses of these ancient events, and represent one of the
largest “open-air museums” of Italian history.
Just as the value of such a rich, diversified natural heritage is easy to
comprehend, it is equally easy to understand that, precisely because of its
richness, the survival of this heritage has often been dramatically put in
jeopardy. Over the centuries, plants, animals and, more generally, habitats,
have had to come to terms with the presence of man, who has not only altered
the landscape to make room for cities and crops, but has also felled whole
forests to satisfy his need for wood for heating and timber for building. In the
recent past, man has resorted to destructive activities which have profoundly
affected fragile ecosystems like coastlines, peat bogs and springs.
The “Habitat Series” has been the tool by means of which the Italian Ministry
for the Environment aims at promoting knowledge of Italy’s natural heritage,
and of the most important environmental situations in the country. Each of
these habitats has been examined in a monographic volume describing the
characteristics of its geography, geology and climate, and its animal and
plant populations.
Lastly, the twenty-four volumes in the series examine the changes man has
introduced, and provide a series of indications on how these environments
should be managed and protected. The series ends with this volume, which
analyses the main environmental differences in Italy. It invites readers to begin
a journey which, on one hand, takes them to unique habitats with very
distinctive animal and plant populations. On the other, it will arouse their
awareness of the need to ensure that these ecosystems are protected and
managed responsibly and sensibly by competent administrators.
Spring river (Sile, Veneto)
9
The dynamic landforms of Italy
CORRADO VENTURINI
■ A concise geological introduction
The great variety of landscapes and
habitats in Italy is not only due to the
orography, latitude and climate of the
country, but also to the distribution of
the main types of rocks and sediments
that contribute to this multiplicity.
This introduction provides a short
overall view of Italy, its geological
evolution, ancient rocks and recent
sediments, and their age, deformation
and distribution. It also explains the
incredible shape of this peninsula
resulting, as it does, from the
combined effects of several dynamic
and sedimentary events.
Monviso and the Po springs (Piedmont)
■ A fascinating profile
I am sure that many of you, as schoolchildren, were pleasantly surprised and
amused at discovering that Italy is shaped exactly like a boot, right down to the
tiniest detail. In the early 1960s, I still remember the effort I made when drawing
the profile of Italy, thinking how dull the shape of other European countries was
in comparison.
My satisfaction was complete when my geographical skills extended further
than Europe: indeed, my “boot” was unmatched in the whole world! By then,
surprise was mingled with the sense of pride I felt when my favourite football
team won. A few years later, satellite images confirmed the aesthetically unique
position of Italy with respect to the rest of the world.
In the meantime I was growing up, and the feelings I had once had were fading
and were replaced by subtle curiosity. My questions as to why, how and when
Italy achieved its shape after a series of often spectacular geological events
11
12
now required answers. As is often the case, my desire to know soon turned into
a passion, which turned to study first and a job later. As a geologist, I finally
understood the complex chain of causes and effects that had produced the
particular shape of the Italian peninsula as we see it today: a shape that derives
from the evolution and distribution of mountain chains, large and small plains,
unstable, fractured portions of the Earth’s crust mixed with stable and solid
ones, uplift and subsidence, areas of magma effusion and those accumulating
sediments, coherent rocks and loose sediments, resistant and easily erodible
rocks, river flow and erosion by glaciers.
All these events developed both in space and over time, as their roles
changed to adapt to unbelievable scripts which, with slow, inexorable
determination, involved and overturned that great three-dimensional stage on
which we are now moving. We, human beings, play a double role: as guests
in environments created by geological events, and as modifying and
disrupting forces of natural scenery, which we have sometimes turned into
man-made landscapes.
In order to describe in a few pages the complex geological steps that have
given the Italian peninsula - and its islands - their present shape and geological
setting, some examples and brief analyses are required. Let us imagine that we
are watching the long film describing the geological evolution of Italy, which
began more than 500 million years ago, shown as a trailer with breathtaking
Mont Blanc seen from Val Ferret (Val d’Aosta)
fast-forward stills. Then the narrator’s
story could well begin as follows.
We are taken back to the distant
Palaeozoic, about half a billion years
ago. For over 200 million years,
lithospheric plates of various shapes
and sizes have interacted, drifting,
sliding past each other, colliding.
Each time these plates pull away from
Distribution of land and sea about 300 million
each other, new, dense, thin oceanic
years ago
crust forms, covered by slowly
expanding oceans.
At points of convergence, the Earth’s
crust becomes thicker and lighter, and
emerges from - or is barely covered by shallow seas.
About 250 million years ago, the
Palaeozoic was coming to an end. The
most frequent phenomenon between
the emerging, mobile continental plates
Palaeozoic rocks outcropping along the
was subduction (see later), which
Sardinian coast
systematically destroyed the oceanic
crust separating them.
One of the characteristics of the Earth that fascinates all geologists was coming
into being: the super-continent Pangaea - one great block of emerged
continental crust, a gigantic land mass surrounded by water and oceanic crust.
If seen from the moon, Pangaea must have looked like a huge ochre bubble
emerging from the vast, deep blue ocean called Panthalassa. An expanding
layer of green quickly covered Pangaea’s surface.
The great collision that unified so many land masses gave rise to outcrops at
converging boundaries between plates of continental crust. These formed a
corrugated range 5,000 km long: the Hercynian (or Variscan) orogenic
(mountain-building) belt. In the meantime, the rocks thrust to great depths by
subduction became metamorphic, i.e., were reworked at depth by great heat
and enormous pressure, becoming crystalline.
It is from that precise geological moment that the story of the Italian peninsula
becomes interesting and detailed. Unceasing evolution, made up of
continuous changes that took hundreds of millions of years, gave Italy its
present-day shape.
13
14
The geological toolbox: all you need to build a small planet
When describing geological evolution to
those who are not knowledgeable in this
field, geologists often take for granted
concepts that average readers know
nothing about. Basic geological
information is therefore required for better
understanding of the following chapters.
The Earth’s entire land surface is
subdivided into what are known as
lithospheric or tectonic plates, formed
by the crust and the upper portion of the
mantle. There are ten or twelve major
tectonic plates, each ranging in thickness
between 40 and less than 200 km.
The boundary between two plates may
often lie in the middle of an ocean,
in which case it coincides with spreading
ridges (divergent boundaries). These are
narrow fractures along the ocean floor
from which magma, escaping from deep
within the Earth’s mantle (asthenosphere),
continually pushes upwards. As it rises, it
solidifies at the edges of ridges, producing
new crust, which is denser, and therefore
lowerer (oceanic crust). The two edges of
the ridge are continually drifting apart,
allowing for potential new escape of
From top to bottom: opening of a plate following
the creation of an oceanic ridge
magma. The speed of this process is at
most 10-14 cm a year, practically the
same as that of our nails and hair! This is
how land masses made up of continental
crust - which are, after all, the emerged,
visible portions of tectonic plates gradually drift for thousands of miles.
We must remember, however, that, in
many cases, they move still connected
to the portions of oceanic crust, and
which we cannot see because they
are underwater. Together they can
form one whole lithospheric plate.
We may compare a very large plate Pangaea, for example - with a thick layer
of ice forming on the surface of the sea.
Let us now imagine that the ice layer
splits down the middle, giving rise to two
“continental” ice portions that soon pull
away from each other. As this
phenomenon occurs, at the bottom of the
newly formed central ridge, water freezes
and - only to serve the purpose of our
metaphor - forms a new layer of ice that
is thinner and denser than that of the two
drifting portions. The original single plate
is now divided into two distinct plates
separated by a central fracture that does
not heal. From underneath the ridge, water
forms new, thinner and denser “oceanic”
ice, which crystallises as it adheres to the
icy edges of the fracture. This type of thin
crust initially develops by attaching itself
to the thick, light and icy “continental”
crust, with which it now forms a single
mass. From this point onwards, they
move together as two different portions
firmly attached to one another.
Another new concept must be introduced
here: subduction. Physics requires
equilibrium so, just as new oceanic crust
is continually formed from magma rising
along the 40,000 km of the Earth’s seafloor
ridges, in other parts of the planet there
Corrado Venturini
must be ancient crust that in some way
sinks deeply into the mantle. This occurs
along what are known as subduction
zones, where plates converge.
As they do so, one of the two slabs is
thrust downwards and towards the
mantle, and is assimilated by it. If, for
whatever reason, underneath the ice of
our example sea currents change
direction, the two plates may stop drifting
apart, and even start converging again.
In the meantime, higher up, “snow”
(debris of all kinds) has gradually been
falling and has covered the surface
of the two plates. Several layers of new
material have accumulated on both the
thin, dense ice of the lower central area
and the “continental” plates. Convergence
now changes the shape of the plates,
shortening the distance between them.
Portions of recent, thin “oceanic” ice
break easily, due to their different
thickness and density. They bend, warp,
and slowly sink (subduct) beneath the
mass of “continental” ice, where they
melt, becoming incorporated in the mass
of water. During collision and subduction,
layers of lightweight, new snow may
separate from the “oceanic” ice and float,
break and overlap like tiles or cards
against the mass of “continental” ice.
In our metaphor, the layers of soft snow
are the mainly clayey sediments settled
on basalt and gabbro, which in geological
reality form the ocean floor.
The collision may compress, deform or
make oceanic sediments overlap
together with part of the underlying thin,
dense ice (magmatic rock), driving
everything to thrust over the large
“continental” ice plate. This process is
called obduction, and is contemporary
with - although opposed to - subduction.
As the collision continues, what remains
of the “oceanic” ice sinks into the Earth’s
depths. When all the “oceanic” ice with
its snow cover has been subducted (or
obducted), two masses of thicker though
lighter “continental” ice are left facing
each other once again: the “continental”
ice and some of the obducted “oceanic”
ice, together with their snow covers, will
form an orogenetic (mountain) chain.
In reality, one of the two plates slowly
bends and sinks underneath the other,
making miles of bent, broken, warped,
shrunken and imbricate folded rocks
overlap like tectonic “tiles” or “slabs”.
In representations of deformed orogenic
systems, the limits between these lowangle thrust faults are indicated by a
typical symbol: a continuous line with
triangles along the top, overlapping the
slabs. The end-result of orogenesis,
in this case a collision between two
continental ice plates - is a mountain
chain. In the example given here, it is a
compact series of layers of imbricate ice
and snow slabs. In what was to become
Italy, it is the huge deformed shape of
the Alpine and Apennine chains.
O
C
O
C
O
C
C
Lithosphere
Asthenosphere
The subduction process (o: oceanic crust; c: continental crust)
15
25
65
milion years
CENO
ZOIC
Neogene
Palaeogene
■ A Rubik cube - or rather, “sphere”
MESOZOIC
From the geological point of view, the
circum-Mediterranean sector is one of
145
the most geologically complex areas
Jurassic
of the entire planet, and Italy is its
205
active centre. This complexity is due to
Triassic
250
the coexistence of phenomena such
Permian
as crustal compression, distension,
290
opening and drifting, which also occur
Carboniferous
360
at the same time in nearby, sometimes
overlapping areas. In addition, some
Devonian
410
of these areas have a diabolical habit
Silurian
440
of changing roles over time, from
Ordovician
510
compressive to distensive and vice
Cambrian
versa, sometimes without warning:
570
meanwhile, individual tectonic plates
Geological time: list of the main geological
subdivisions and relative ages in million of
drift independently, although logically,
years (for the last 570 million years)
on the Earth’s molten core. Some
sectors are deformed, uplifted and eroded, and their products, in various forms
- river gravel, sand, silt, but also gigantic underwater mudslides - flow towards
valleys, deltas, seas and oceans. The tectonic plates continue to drift, collide,
spread and subduct, adding further variables to an already very complex system
in which climate also plays an important role. Further details could be added. As
today, as in the past 300 million years ago, the circum-Mediterranean sector
contains areas in which new crust is still forming (e.g., underwater), and others in
which ancient crust subducts and melts in the mantle underneath
(asthenosphere). Still other areas, at this precise moment, are being compressed
and uplifted, and one of the results will soon be devastating earthquakes.
This description is very like that of a “Rubik cube”: indeed, this section of Italian
Habitats makes extensive use of various similes and metaphors in order to
explain geological phenomena. The difference between the original supercontinent of Pangaea and the situation today could be compared with a “Rubik
cube”, one of those complex games on sale in toy shops, and the disordered
appearance of such cubes when they are not completed. However, there are
substantial differences between the Earth and a Rubik cube - or rather, sphere,
because the metaphor we use here changes that cube into the spherical shape
of our planet. In the case of Rubik cubes, the infinite possible combinations are
the result of random choices; in the circum-Mediterranean context, all events
PALAEOZOIC
16
Cretaceous
are regulated by an admirable series of
causes and effects, the origins of which
lie deep within the Earth’s crust - in
those slow movements of dense yet
fluid mantle material that crushes,
drags and modifies the overlying
plates, which are colder and more rigid
(see pp. 14-15).
In over a century of research, first
geologists and then geophysicists have
been able to understand the intricate
Mediterranean and, more specifically,
Italian jigsaw puzzle. In the following
section, we shall examine the main
evolutionary steps of Italy’s geological
history. Most of the Italian peninsula
today is composed of bedrock which, in
The Devonian succession of Monte Coglians,
north flank (Carnian Alps, Friuli Venezia
the past - as sediments and magmatic
Giulia)
products - accumulated on the seafloor
and anticipated the formation of the present-day Mediterranean Sea. The
surface rocks now visible are the products of particular surface conditions
triggered by crustal dynamics, i.e., drifting plates. The same still happens today.
The whole cycle is continually repeating itself in apparently random modes.
Let us take another example from our everyday world. Let us imagine that a
certain area is served by trains, which run along tracks, stop at stations, and
follow a timetable. But we have never seen them and cannot obtain direct
information about them. Our only source of information comes from passengers
leaving the stations who, however, never speak of the train they have just got off
or the one they are about to take - they only talk about themselves and the
reasons why they chose that particular train. We have to imagine the rest. In this
example, the passengers are the rocks and sediments of the Earth, and the
trains represent the drifting plates. Now we need to go back in time by about 300
million years, to the beginning of our train journey, to Pangaea and the broad gulf
of Tethys that arched along the eastern coasts. From there, we shall make our
way to the Present. In order to simplify our journey, we divide it into seven
evolutionary steps, seven magnificent geological moments whose effects overlapping in rocky masses representing the three-dimensional rendering of
time - explain the present distribution of the outcrops, mountains, plains,
sediments and seas surrounding Italy, as well as its peculiar shape.
17
18
Pangaea
■ Geological evolution of Italy
1. The disintegration of Pangaea
and the Piedmont-Liguria Ocean.
Pangaea had now acquired the status
Panthalassa
of a true super-plate. This occurred
about 300 million years ago, in the
Carboniferous, and resulted from the
Pangaea
casual assembly of large and small
Pangaea and Panthalassa: the two great
plates which, colliding, had created
protagonists of a massive crustal scenario of
mountain chains in those areas where
300 million years ago
their respective edges had come into
contact. The resulting mega-continent combined Antarctica, Australia, India
and South America in a single block, firmly attached to North America, Europe
and Asia. All this enormous area of land was surrounded by the Panthalassa
Ocean.
The last collision that allowed Pangaea to come into being had also formed a
vast collisional mountain belt stretching transversally across North America (the
Appalachians), north-western Spain, France, Germany and Italy (northern Italy,
Sardinia and Calabria, which at the time occupied very different positions from
their present-day ones). These were the Hercynian (or Variscan) ranges. Here,
sedimentary successions were transformed into metamorphic rocks. After
partial exhumation and erosion, these rocks formed a large supporting wedge,
on top of which initially Late Carboniferous, then Permian and Mesozoic
deposits accumulated. A great sea gulf expanding eastwards formed in the
Late Palaeozoic and Early Mesozoic, the Tethys. Expanding, it flooded plains
and stretched to the west and south. Limestone banks accumulated in layers a
few thousand metres thick, in shallow to moderately deep sea environments.
These deposits - which today form part of the Alpine range - are typically found
in the Triveneto Alps and Pre-Alps (Dolomites, Carnia and Tarvisio) and, to a
lesser degree, in Lombardy.
In the meantime, the present-day regions of Emilia-Romagna, Tuscany,
Umbria, Marches and Apulia, and the areas now occupied by the Adriatic Sea
were evaporitic marine environments, with salt, sulphate and carbon
deposits. They were similar to the western coastline of today’s Sahara, dotted
with large inland lagoons that were periodically flooded by the sea. Those
deposits, which have been part of the Apennines for over ten million years,
seldom outcrop and then only for short stretches, although they have been
found as a result of deep-sea drilling.
Adr
ia
In the Late Triassic, a few narrow strips
of deep sea in the Lombard and
Ligurian areas started showing signs of
1
Adr
ia
2
the radical change that was to occur a
Tethys
few million years later - a split second
in geological terms - and which was to
India
overturn the geological evolution of
1 Piedmont-Liguria Ocean
Pangaea in general and future Italy in
2 Atlantic Ocean
particular. What might so far have
The opening of the Atlantic Ocean 180 million
represented “added value” for
years ago gave rise to the formation of the
Pangaea - the imposing Mesozoic Gulf
Piedmont-Liguria Ocean
of Tethys - in the Lower Jurassic (about
200 million years ago) turned out to be a powerful geological "wedge" that
would accelerate the disintegration of the super-continent.
Precisely in the Jurassic, generalised instability of the crust, which had
developed in the mid-Triassic, produced a series of gigantic strains. Its effects
were disastrous for the survival of Pangaea. The land surface, from today’s
Florida in the south to Newfoundland in the north, started sinking along a
narrow strip thousands of miles long. This process has continued unceasingly
to this day, at a speed of 2-3 cm a year.
The central-northern Atlantic Ocean was forming and, with it, the boundary
between two new plates: the North American and Eurasian (Laurasia) on one
side, and Africa - still joined to South America, India, Antarctica and Australia,
known collectively as Gondwana - on the other. Underwater basalt effusions
from the N-S-running mid-oceanic fracture added thin, dense, newly formed
oceanic crust to the newborn plates, while the African plate gradually started
drifting eastwards.
The Atlantic was not the only ocean to open and widen. Another stretch of sea
underwent the same process when a deep crustal fracture opened and new
oceanic crust began pouring out. Analysis of the geographical position in which
the rocks that formed its floor lie today, reveal the presence of a smaller sound,
called the Piedmont-Liguria Ocean. It goes without saying that, since this
ocean disappeared about 40 million years ago, it could only be identified by its
remains, i.e., the typical rocks of oceanic crust that it produced (ophiolites),
which are today incorporated in the Apennine and Alpine ranges.
This new situation produced two new tectonic plates that began to pull away
from each other. The northern, the North American plate - was still joined to
Europe and Asia - and the southern one, made up of Africa and South America,
also contained a small, albeit important area called the Adria plate. It was either
19
20
a sort of northern protuberance of the African continent or, according to a
different theory, a small plate separated from the African block by extensive
vertical fractures and a narrow, deep sea corridor. In both theories, it was made
up of the same African continental crust.
Independently of its definition - protuberance or micro-plate - from the midCretaceous onwards, the role of the Adria plate was to act as a buffer between
Africa and Europe, a sort of shock-absorber blunting the force of the physical
collisions between these two geological giants. It careened the northern side of
the African plate and, as such, was exposed to potentially intense, complex
deformation phenomena that soon occurred.
There is another aspect worthy of analysis here, for its importance in future
evolutionary developments. Sardinia and Corsica were not part of the Adria
plate. They clung to present-day Provence, in the area between Nice and
the Gulf of Lions, and were part of the southern margin of the Euro-Asiatic
plate. The Adria plate lay on the other side, separated by Sardinia and
Corsica (and their vast inland territory) through the widening PiedmontLiguria Ocean.
In the Lower Jurassic-Cretaceous (about 135 million years ago), the Adria plate
had moved to inter-tropical latitudes, and was almost completely covered by
shallow seas. It probably looked rather like today’s Caribbean. One hundred
EUROPEAN
PLATE
P-L OCEAN
A
EUROPE
RI
AD
AFRICAN
PLATE
ADRIA
Lombardy
Friuli
Adria is the small northern portion of the African plate: the section shows separation from the European
plate and the development of new oceanic crust (Atlantic and Piedmont-Liguria Oceans)
million years after their genesis,
Insubric
line
Mesozoic deposits accumulated in the
Piedmont-Liguria Ocean and, on the
Lombardy
Fr
basin
iul
Adria plate, formed part of the Alps and
i
pla an-i
tfo stri
Apennines.
rm an
In the meantime, the Piedmont-Liguria
Umbro-marchigian
basin
Ocean belt, which formed about 180
Ion
ian
ba
million years ago, was gradually
Ap
sin
uli
an
pla
expanding and deepening, eventually
tfo
rm
reaching 2500 m.
Large amounts of basalt in the form of
pillow lava were extruded on to its floor
and, deeper down, basic magma
(gabbro) also rose, giving rise to new
oceanic crust. In addition, thick layers
of clay and stratified flintstone (jasper)
accumulated as sediments in deep
Quite deep seas (basins) and platforms
(lagoons and reefs) during the Mesozoic in
seas. As they drifted away from the
Italy: map shows present-day distribution
oceanic zone and moved towards the
Adria plate, these underwater terrains changed from average deep (Lombardy)
to shallow (Friuli).
If we had been able to cross these areas, we would have found water
extending for hundreds of miles, dotted with several white limestone sand
islands of green land on which dinosaurs lived. There were many tropical
lagoons that were crossed by these gigantic beasts, as we can see today
from the fossil tracks, still visible at low tide, which they created in the
limestone mud. These deposits are made of thick, coarse fossiliferous
limestone of bio-constructed organogenic banks and the generally muddy,
thinly layered limestone of lagoons. These deposits accumulated to form
layers thousands of metres thick. They are typically found in two large areas
of the Adria plate: that comprising central-southern Friuli together with
southern Veneto, Venezia Giulia, Istria and the Croatian belt and, further
south, another making up almost all Apulia and part of Basilicata. They were
divided by a stretch of sea of average depth, occupying the area of the
present-day Adriatic.
Although in the Lower Cretaceous (approx. 135 million years ago) the Alps
and Apennines could not have been foreseen, most of the rocks composing
them were already in place, and another titanic series of events was about to
take place.
21
22
2. The Alps form in the vice-like grip
of two great plates: Europe and Africa.
In the late Lower Cretaceous (about
100 million years ago), a mighty event
occurred, producing the results that
are nowadays visible to all of us. It
turned an ocean almost 3000 m deep and, with it, all the shallow marine
environments that surrounded it and
the corresponding magmatic and
sedimentary successions - into
mountain ranges more than 4 km high.
Once again, the agent responsible for
dramatic changes in the area which
was going to become Italy with its
mountains was, improbably, the Atlantic
Ocean. Although indirectly, the ocean
Serpentinites at the Apennine chain margin: are
the remains of the ancient Piedmont-Liguria
turned what was expanding and
Ocean (Castello di Roccalanzona, Parma)
opening into something restraining and
closing. The first victim was the Piedmont-Liguria Ocean, which had been in a
phase of indefinite expansion, like the coeval central-northern Atlantic Ocean.
Until the Lower Cretaceous, the mid-Atlantic fracture was still located in the
present-day area of Florida and the Caribbean, and started drifting south
about 130 million years ago. Consequently, the South American and African
plates also began to separate. As usual, new oceanic crust started to form
between them - a still ongoing process. Until this point, it does not seem that
the situation would cause any changes to the area of the Adria plate. However,
the new crustal opening did not favour the ongoing eastward drift of the
African block. In fact, it conferred upon it a drift towards the north-east and
north, setting Africa and Europe on a collision route. The most visible result of
this movement was the genesis of the Alps. In the area of the Adria plate, drift
turned into convergence.
If you imagine clapping your hands in slow motion, you can understand how,
almost 200 million years previously, in the Carboniferous, two gigantic rocky
hands had come together in a clap, becoming a single unit. Later, after the
collision and the first noisy clap, they drifted apart again symmetrically. Now
they were about to converge and come together again. In this metaphor, the
movement of the second clap coincided with a new phase of crustal collision,
of which the rise of the Alpine range was its apex.
Let us examine very briefly the space
and time successions of the main
events that caused the deformation of
the Alps, and which culminated in the
mid-Cenozoic, between the Eocene
and the Miocene (approx. 50 to 5
million years ago). Simplifying, we note
1
that crustal convergence produced an
extensive fracture along the southeastern margin of the Piedmont-Liguria
Ocean. Its oceanic crust, which by then
was up to 1000 km wide and made up
of basic magmatic rock (gabbro and
basalt) with clayey and flintstone
2
sedimentary deposits, began to sink
obliquely beneath the Adria plate.
Part of this slab did not melt at depth,
The Earth 130 million years ago (2): the South
Atlantic Ocean opened and Africa rotated
but was intensely metamorphosed,
counterclockwise toward NE
flattened by the Adria plate and
squeezed into gigantic flakes, first against and then on to the great European
block that was gradually approaching.
For a better understanding of what happened between the Upper Cretaceous
and the Miocene, let us use another metaphor and imagine the European
continental block as a thick phone book - the Yellow Pages, for instance - and
the African block as another phone book. If we place them on the floor and put,
say, a city map between the two, the pages of the map may well represent the
thin oceanic crust of the Piedmont-Liguria Ocean. Now, if we remove the
covers of both books to make their contents easier to fold, and push the Adria
plate-phone book towards the Yellow Pages of Europe, the upper sheets of the
city map will easily fold and deform. In the end, the Adria plate-phone book will
overlap the Ocean-city map, crushing and creasing all its upper pages.
In the meantime, its lower pages will slide beneath the Adria plate-phone book
(subduction). When all the Ocean-city map is completely squeezed between
the two books - its lower pages completely subducted beneath the Adria platephone book - the two larger blocks will collide. This was the crucial moment of
a titanic clash. We can see the Adria plate-phone book marching against
Europe-Yellow pages holding the creased, greatly deformed belt of Ocean-city
map up in front of it, like a shield. In the clash, the Adria plate-phone book is
literally thrust onto Europe-Yellow pages, overwhelming it. Between the two
23
24
The Triassic rocks in Sass della Luesa in the Dolomites (Trentino-Alto Adige)
fallen blocks, one on top of the other,
Alpine chain
is the Ocean-city map in a greatly
section
mutilated condition.
EUROPEAN
This is how the central and northern
PLATE
parts of the present-day Alps came into
Adria
ain
being. In the collision, the fault edifice
e ch
Alpin
(the Adria plate) and its shield (Ocean)
migrated and, like tectonic plates,
AFRICAN PLATE
overlapped one another towards
Alpine chain
EUROPEAN
Austria, Switzerland and France
Adria
PLATE
(Europe). The two original continental
blocks (the two phone books) can still
P-L
be distinguished: all you need to do is
to read their pages! More evident still,
This is the structure of the Alpine chain about
50 million years ago, before the Apennines
thanks to their rocks which are typical
formed: the collision between the Adria and
ocean floor basalts, are the pages of
European plates formed a sandwich containing
“slices” of Piedmont-Liguria Ocean (P-L)
the Piedmont-Liguria Ocean-city map.
Today, its rocks, which underwent metamorphism during the Alpine
deformation process, make up the large range of the Maritime Alps between
Genoa and Ventimiglia (Italy), and continue in the Western Alps (Cottian, Graian,
Pennine and Lepontine Alps).
The deformational history of Italy described so far cannot be considered as over,
as we are still in the Oligocene (about 30 million years ago). The Alpine range of
faults folding north and north-west had just formed as a result of the extensive
south and south-eastern subduction of the European block that accompanied
crustal collision. The so-called "Italian" portion of the Alpine edifice in its true
sense., i.e., the Southern Alps, had not yet formed. That point between Lombardy
and Friuli which today borders south with the Insubric Line (Periadriatic
lineament), the most ancient and important fault of the Southern Alps.
The development of the true Cretaceous-Eocene Alpine range is easier to
describe than the layout of today’s Alps, including the Southern Alps. This is
because, in those times, the Alpine range was far more regularly distributed
than it is today. It was a little more than 100 km wide: south of western Liguria
it bent slightly SW towards Corsica, and proceeded west of Sardinia. The
bend was only very slight because Corsica and Sardinia were still attached to
southern France at that time.
From this geological moment onwards, Sardinia and Corsica, which so far had
been attached and made up the western margin of the European continent,
became true protagonists.
25
Alp
aric
Din
ine
c
ha
in
3. Rotation of the Sardinia-Corsica
EUROPEAN
PLATE
block and opening of the Tyrrhenian.
About 40 years ago, some of us who
were interested in both physics and
Balearic
opening
games, used to keep a peculiar object
on our desks: it was called “Newton’s
Adria
cradle”. It was made up of a series of
steel balls, threaded on wire, one after
Apulia
the other. If you pulled the first ball of the
AFRICAN
row towards you and suddenly released
PLATE
it, "special effects" were created. The
ball that had been pulled out of position,
Rotation of the Sardinia-Corsica block marked
the early genesis of the future Apennines
like a pendulum, returned to its original
position and transmitted its movement
to the last ball in the row. To our great amusement, as soon as the first ball
touched the row, the last one in the sequence sprang away.
Although this is a somewhat far-fetched metaphor, this device can help us in
understanding crustal movements. These still ongoing effects began about 30
million years ago in the area between the southern European margin and the
Adria plate. In the Oligocene, fractures and crustal subduction were active along
the side of the European plate. A little later, a plate fragment became detached
from the Provence area and started drifting away. It included Corsica and
Sardinia, together with a portion of the newly formed Alpine range, most of which
had formed underwater and had made up its south-eastern boundary. This
drifting movement was curved, occurred at a faster pace for Sardinia, and its
fulcrum was the centre of future Liguria. The crustal block may be compared to a
sort of geological pendulum that stopped along a north-south line only about 12
million years later, after rotating counterclockwise by more than 40°. This rotation
of the Sardinia-Corsica block was caused by the opening of the Algeria-Provence
Basin between the block itself and Provence (Balearic opening): it was a sinking
triangular section gradually becoming an ocean. For the circum-Mediterranean
sector, these events marked the beginning of the complications that today,
millions of years later, beset those who try to understand and explain this
situation. The Cretaceous-Oligocene Alpine chain had overlapped to the NW on
to Corsica and had developed west of Sardinia, mostly underwater. The chain
formed a single block together with Sardinia-Corsica and, with it, started to
rotate counterclockwise. Millions of years later, one fragment of that
underwater Alpine chain that formed off Sardinia became today’s Calabria (and
eastern Sicily), after drifting for about one thousand kilometres.
lle
He
nan
cha
in
Alp
Ap
ine
enn
ch
ine
ain
cha
in
26
At the time - during the Sardinia-Corsica drift, about 30-18 million years ago,
between the Oligocene and the Miocene - the first land emerging to the east
was the Balkan area which, together with Venezia Giulia, had already been
folded and uplifted. South of the Genoa-Trieste join, what was to become the
future Italian peninsula was still all underwater, and some sedimentary
successions that today form the outer parts of the northern Apennines still had
to be deposited. It was the counterclockwise drift of the Sardinia-Corsica block
that changed the situation, as it prepared the ground for the development of the
Italian “boot”, then unimaginable. Like a gigantic bulldozer, the drifting
Sardinia-Corsica block compressed and piled up in front of itself what
remained of the oceanic crustal deposits of the previous Piedmont-Liguria
Ocean. Before this rotation, along the Sardinia-Corsica margin, the European
plate was subducting south and south-east.
Things changed when the Sardinia-Corsica block detached itself from the
Provence and started drifting counterclockwise. At that point, southward
subduction stopped. Since the collision with the Adria plate meant that one
portion had to sink, another subduction event began in a slightly different
position and, more importantly, in the opposite direction. This time it was the
Adria plate, with part of the Piedmont-Liguria ocean floor, which was
subducted beneath Corsica and Sardinia. Evidence of this inversion in
subduction is provided by the large quantities of vulcanites that poured out
along the western margin of Sardinia during this counterclockwise rotation.
Alpine chain
EUROPEAN PLATE
Adria
?
?
future fault
Alpine chain
Corsica
EU
Apennine chain
Adria
Rotation of
Balearic opening Sardinia-Corsica
Adria plate subducts
Alpine chain
EU
Balearic opening
stops
Apennine chain
Corsica
Adria
Opening of
Tyrrhenian Sea
Adria plate subducts
Between 50 and 10 million years ago, the Mediterranean was like a chessboard on which the pieces
gradually increased in number and made reciprocal moves
27
28
EUROPEAN
PLATE
Insubric
line
na
lpi
aA
n
e
t
ain
e ch
in
Alp
Ca
Today’s
EUROPEAN
PLATE
Alp
n
ther
Sou
Apennin
e front
ain
ch
Alps
t
fron
Tod
a
y’s A
pen
ine
Alp
nine
Emilia
line
fron
t
ch
Emilia
in
e cha
Apenn
in
Adria
Marches
Umbria
nt
ain fro
front o
f
ine ch
Latium
n
rrenea
the Ty
AFRICAN
PLATE
15 Ma
g of
Umbria
ain
Tuscany
Apenn
ch
Adria
in
Open
ine
Alp
ain
Romagna
Romagna
25 Ma
ine
Insubric
Sea
AFRICAN
PLATE
The opening of the northern Tyrrhenian Sea separated the Alps from the embryonic Apennines,
triggering their counterclockwise rotation (ma: million of years)
They were produced by melting crust which, due to prolonged crustal
compression, had started to sink to the west, beneath Sardinia and Corsica.
As a further consequence, enormous blocks of oceanic material (the Ligurian
Units) started accumulating along the margins of the Adria plate. These were
the first signs of the Apennines, which were still underwater. In the meantime,
sand and mud were forming by erosion from the emerged areas of Sardinia and
Corsica (with their Hercynian successions and Palaeozoic granite), and
accumulated to the east, forming deep-sea turbiditic successions. Over time,
these too were uplifted and juxtaposed on the margin of the Adria plate,
contributing to the formation of the Apennines.
The processes regulating surface events often take place at depth. Southsoutheasterly Alpine subduction in the Sardinia-Corsica block finally ceased. At
the same time, the Adria plate, which was still compressed by the crustal rotation
of Sardinia and Corsica, started to bend. Its western boundary began to dip
downwards, like a rubber mattress pushed against a wall. This occurred at the
expense of the remains of the Piedmont-Liguria Ocean, parts of which had already
overthrust the European boundary (Corsica) and now, with the drifting of the
Sardinia-Corsica block, were squeezed between this block and the Adria plate. It
is at this point that our metaphor of the steel balls on a wire becomes clear.
About 18 million years ago (Lower Miocene), the Sardinia-Corsica pendulum
stopped along a north-south line. It is still stable in that position, as the total
lack of earth tremors and other seismic activity in the area confirms. Twenty
million years ago, off the coasts of Sardinia and Corsica, in a narrowing stretch
of shallowing sea, the Apennines (in their "youth") and the Alps (in their "teens")
were being heaped one on top of the other. Soon afterwards (15-10 million
years ago, in the mid-Miocene), the fledgling northern Apennines started
rotating counterclockwise, just as the Sardinia-Corsica block had done before,
like a steel ball now still. This time, however, the reason for the
counterclockwise motion must be sought elsewhere, i.e., in the sinking and
opening of the northern Tyrrhenian Sea, which only began forming then. By
sinking and opening, the Tyrrhenian divided the newly deformed underwater
territory into two sections, the Alps and the Apennines, of which the incipient
Apennine chain corresponded to the eastern portion. The Apennine block also
began drifting, and, in so doing, gradually rotated east and north-east. Over
time, its drift and counterclockwise motion incorporated larger and more outer
portions of land, slowly turning them into a truly emerged range.
A few million years later (4.5 million years ago), the Tyrrhenian crustal opening
moved southwards, producing the southern Tyrrhenian Sea. At first, spreading
only favoured the settling of small magmatic masses (a typical example is the
plutonic granite of the island of Elba). In the southern Tyrrhenian Sea, spreading
was so extensive that the seafloor was lowered to a depth of -3500 m. Great
quantities of basaltic lava poured out of the crustal fractures, producing new
oceanic crust. Thus, the spreading and opening of the Tyrrhenian - still an
ongoing process in its southernmost sector - had several different effects on
the circum-Mediterranean area. Some of these were:
● centrifugal migration of the Apennine deformation, which moved towards the
present-day Po valley, the Adriatic and the Ionian Seas at the same time;
● division of the "Mediterranean" Apennine range into segments separated by
faults, which drifted away from each other for distances of up to a thousand
kilometres, and as far as Calabria and eastern Sicily;
● formation of new oceanic crust in the southern Tyrrhenian, starting 6-4.5
million years ago (Lower Pliocene).
All these events happened in the middle of the Mediterranean Sea. In the
meantime, Africa and Europe had been continuing their march towards collision.
Although initially, when the southern Atlantic had opened, Africa’s drift had been
north-easterly, it had now decisively changed course and began to move north.
This occurred in the mid-Miocene, about 15 million years ago. However, 5 million
years ago, in another process that is still ongoing, the direction of the drift
changed yet again, this time to the north-north-west. Although several events
took place in the middle of the Mediterranean - spreading, ocean formation,
block rotation and deformation - the great Alpine deformations: the event that
more generally influenced was the Africa northward drift.
29
30
4. The Southern Alps rise from the plains and the Apennines from the sea.
Between the end of the Eocene and throughout the Oligocene (35-25 million
years ago), the Alps underwent a spreading phase. Along the extensive Insubric
Line and nearby, large localised magmatic bodies associated with lava
spreading rose to the surface. But these events represented only a moment of
quiet before the storm. In fact, in the following Miocene, crustal compression
recommenced along the Alpine chain. However, this time the most affected
area was the Italian territory south of the Insubric Line. Under the influence of
the new African thrust, its rock successions folded and piled up on top of each
other, forming a series of “tectonic slabs”, this time thrusting southwards. The
new series of imbricate rocks, each of which was hundreds of metres or
sometimes even some kilometres thick, extended for great distances. These
tectonic slabs overlapped at low angles, thrusting towards the future Po and
Veneto-Friuli plains, i.e., the non-deformed area (the Adria plate in this case)
known in geological terms as foreland. This deformation caused the land to
become shorter by a third of its original area.
Initially, the successions involved were mainly calcareous and dolomitic
Palaeozoic and Mesozoic rocks, including the more ancient Palaeozoic
successions at the base: they were almost completely made up of
metamorphic rocks, except those of Carnia, which still preserve ancient fossils
in rocks dating back 450 million years.
Except for a few local variations, the genesis and development of deformations
was always the same, and each new fold and overlap formed in front of the
previous one, as in the Apennines. Each new compressive structure involved
areas that until then had been part of the foreland, i.e., sediments and rocks that
had been left undisturbed because they were located at the margins of the chain.
The reason for Alpine deformation with tectonic imbricates (slabs) that thrust
towards Africa rather than Europe - as geologically expected for the Alps - may
once again be explained by events occurring at great depths. Subduction of
EUROPEAN PLATE
Southern
Alps
Adria plate
P-L
The Alpine chain becomes more complex as the southern margin of the great sandwich structure sags
and overthrusts forming the Southern Alps
Insubric line
Alps
31
Southern
Alps
ex P-L Ocean
CRUST
EUROPEAN
PLATE
AFRICAN
PLATE
CRU
ST
MANTLE
MANTLE
50 km
Mechanism of crustal underthrust, as shown by recent deep crustal “X-rays”, which explains the
genesis of the Italian flank of the Alps, known as the Southern Alps
the European margin continued southwards (and is still continuing). It must be
recalled that the northern African margin - once again represented by the
headlands of the Adria plate - had started overthrusting on the European plate
millions of years before. In the collision, it had formed huge but still regularly
shaped tectonic slabs that thrust north-west and north. The less rigid deposits
between the two continental blocks and the floor of the late Piedmont-Liguria
Ocean had literally been crushed between the two.
In the Miocene, the thrusting movement of the tectonic slabs towards Europe
met with some resistance. All the imbricate tectonic “shavings” or “flakes”
started a folding motion that penetrated the oceanic sediments that had
already been crushed by previous compressions.
In the meantime, subduction of the Adria plate (the African “shock-absorber”)
continued. Folding gave rise to sagging, which favoured further penetration by
the Adriatic plate. This plate, precisely like an enormous wedge, sank deep
beneath the huge fold. The southern part of the fold - the one facing the Po plain
- also began to break into slabs which, this time, thrust southwards. This was
due to internal resistance by crustal masses to the powerful thrust northwards.
The volume of rock involved was immense: the entire Southern Alps, a
succession about 15 km thick and covering an area of about 500 x 150 km. In
their reciprocal movements, the rocky peaks crowded together, shortening the
original extension of deposits which, in the meantime, overlapped, moving along
slightly inclined fault surfaces. The Southern Alps came into being, although
32
their formation was not particularly
complex when compared with what
Delta
was happening along the Apennines at
the same time.
Along the external margin of the
Foreland
Apennine
Apennines, which were deforming as
(undeformed
chain front
area)
Foredeep
they moved north-east, a phenomenon
(sinking area)
was taking place that was similar to the
one wich had occurred a few million
The Apennine foredeeps were mainly filled in
years before (in the Eocene) in Venezia
by material from the Alps, crumbled and
Giulia, and which had produced the
eroded by Alpine rivers
Dinaric range. As the most advanced
slab was forming, the area in front of it was sinking dramatically, due to load
subsidence and the pull of subduction. The sinking area was parallel to the
rising one, and was a few dozen kilometres wide. These subsiding belts similar in shape to very large, long bathtubs - are called foredeeps, i.e.,
depressions forming in front of a forward-moving mountain range and which
migrate with it. They are generated both by the mighty weight of the moving
chain that can bend the area ahead of it downwards, and by the subducting
foreland margin sinking beneath the chain.
In the Apennines - as in Venezia Giulia millions of years before - these were
deep marine depressions which, as such, easily collected turbiditic sediments.
In the Miocene, the best-known Apennine foredeep was filled by a turbiditic
succession 4 kilometres thick. As the chain continued to move forwards, it was
later incorporated in the deformation. The depression of this foredeep ran along
the Apennine margin of the time, which was between 50 and 100 kilometres
behind the present-day one. Southwards, beyond Romagna, it split up into
various parts of different ages but of similar geological significance. The marine
foredeep, which had formed in front of the advancing Apennines, collected
sand and mud from the demolition of the Western Alps and, partly, from the
emerging Apennines.
It was certainly a very particular scene for the future western Po area: short, but
fast-flowing Miocene Alpine rivers drove gravel, sand and mud as far as a
series of deltas, presumably located between the present-day cities of Milan
and Alessandria. These deltaic deposits then periodically collapsed into the
southern Po gulf, the great Apennine "pool". Large amounts of sand flowed
directly into the deltas and accumulated at the bottom, where they turned into
turbiditic successions. Slipping was due to frequent earthquakes. At the time we are now speaking of 20-10 million years ago - the Apennines were slowly
Alpine Chain
emerging from the sea. For the time being, if we had been able to view the
situation from above, we would have seen a wreath of islands arranged NNWSSE, i.e., the tips of the most advanced slabs, but also the embryonic stage of
the future “boot”.
Later, in the Pliocene, foredeep deposits were incorporated into the advancing
range. They now formed large marl-sandstone nappes arranged in the regular,
continuous flat parallel layers outcropping in extensive areas: typical turbiditic
successions. Today, they are found in the middle section of the Apennines, in
Romagna, the Marches highlands and, further south, between L’Aquila and
Frosinone, alternating with large Mesozoic and Cenozoic limestone areas. Still
further south, similar deposits outcrop extensively between Isernia and Vasto,
narrowing as they cross Molise and closing near Melfi (Basilicata). The whole
structure is 500 km long and is made up of Miocene deposits.
The genesis of the Apennines continued, alternating slow and fast periods of
forward motion. Nappes of rocky successions, like gigantic playing cards as
thick as mountains, continued to overthrust each other, collecting the flattened,
planed material from what was left of the Piedmont-Liguria Ocean floor and the
mainly carbonatic Mesozoic successions that formed the Adria plate. The result
was a tectonic slab structure which, even today, shows signs of the ancient
Piedmont-Liguria Ocean in the form of ophiolites, together with large amounts of
ancient oceanic clay (today turned into mountains), and the mainly limestone
Marl-sandstone formation of Miocene age outcropping extensively in the northern Apennines
33
34
nappes uprooted along the margins of the Adria plate. Today, the oceanic clay
that turned into the Apennines (a huge mass of thousands of cubic kilometres)
does not only contain gigantic pieces of basalt and gabbro (ophiolites). There is
also something else, as we shall see.
While the chain was forming and was still underwater, some sectors - such as
the northern Apennines and part of the central-southern ones - contained large
amounts of oceanic clay with blocks of magmatic rocks and jasper (flintstone).
Once these were crushed, uplifted and thrust over the top of the Adria plate,
clay - owing to its plasticity - moved forwards as a huge, extremely slow
underwater flow. Over time, it produced the Argille Scagliose. The movement of
these gravitational nappes was due to compression. They later became the
Ligurian Units of the Apennines, so-called in memory of the Piedmont-Liguria
Ocean that had contributed to their formation.
To complicate the situation even further, another event was taking place.
Hundreds of metres of stratified sediments, often of shallow seas, accumulated
on the surface of these gigantic flows which, in addition to being pushed NE by
compression, also slid gravitationally. Tectonic movements then also involved
these new successions (called the Epiligurian Units, because they formed on the
surface of the Ligurian ones), which started moving, supported - rather flimsily by the underlying clay. This instability caused them to break into enormous rocky
“rafts” gliding on clay masses. The Rock of Bismantova, as well as the steep
rocky relief forming most of the present-day Republic of San Marino and the
crest-like steep ridge of San Leo nearby, are examples of these rafts.
What we have learnt so far about the formation of the Apennines and its rocky
successions is only a small part of the complex evolution of this mountain range.
Describing the characters of the Apennines, their development and distribution
over time and space, can complete the elaborate Italian geological puzzle.
SW
NE
Foreland
Foredeep
1
2
3
Apennine chain front
New foredeep
1
2
3
4
Apennine chain front
The northern and central Apennine chain may be likened to a bulldozer making its way north-east
5. The Apennines: a gigantic wave.
In the Pliocene (5-2 million years ago),
deformation in the northern Apennines
Distensive faults
FI
accelerated. To visualise this mountainOverthrusts
building process better, let us imagine
PG
a very slow, gigantic wave crossing
Fluvial deposits
the mass of rocky successions by
AQ
arching and overriding them.
Marine deposits
In the Apennines, the crest of the
The large tectonic spreading of inner portions
wave, with its steep, deformed flank,
of the Apennines gave rise to the landscapes
was gradually moving north-east and
of present-day Tuscany and Umbria, which
feature flat, narrow belts alternating with
rotating counterclockwise at the
mountainous areas
same time. As the mass of water of a
wave collapses after its peak has passed, so in the Apennines extensive
stretching occurred behind the front of the chain. In the Lower Pliocene the
deformation front in the northern Apennines was rapidly moving towards its
present-day position. In the Late Miocene, behind the advancing chain, in
the entire area of what is now Tuscany, large rectangular areas bordered with
spreading faults had already subsided.
Similar events occurred in nearby Umbria, because the spreading belt was
moving together with the range front, just like a gigantic wave.
The Tuscan depressions were filled with shallow marine sediments, and the
inland ones of Umbria and Abruzzi by river and lake sediments. In both
locations, these materials (sand, silt and gravel) may still be seen today, as
they occupy almost one-third of the total area of Tuscany and Umbria, which
preserve the flat morphology of the past.
Today, the compression front, which in the course of time continued to move
north-east, has stopped just beyond the Po plain (in fact, right beneath it). In
the meantime, the typical spreading of back-chain belts has moved parallel to
the advancing deformed front. They can now be found in areas near the
morphological ridge of the northern Apennines (near Mugello). The wave
effect continues to this day, as the recent "spreading" earthquakes in the area
of L’Aquila confirm.
In addition, to complicate still further the general picture of Apennine
evolution, in the last 600,000 years of the Miocene (5.9 to 5.3 million years
ago), the Mediterranean first repeatedly dried up and then filled with water
again, turning into a sort of large lake. The tendentially dry climate favoured
the precipitation of salts - mainly sulphates, like gypsum - in the evaporitic
lakes active during the first phase. These gypsum deposits, which were about
35
36
150 m thick, can still be found in some areas (Romagna, Marches, Calabria
and Sicily) and are now part of the Apennines. In the Lower Pliocene, as the
Strait of Gibraltar opened due to tectonic collapse, the Mediterranean sector
returned to its usual marine condition.
The great Pliocene Po Gulf - an underwater copy of the future Po plain opened between the well-structured Alps (Southern Alps) and the new-born
Apennines. Thick layers of Pliocene clay, produced by erosions of the
emerging areas, were deposited on its floor. Along the Alpine and Apennine
coastlines, fine sediments were replaced by sand and gravel of deltaic and
coastal origin.
In the meantime, the deformed flanks of the Southern Alps and the Apennines
continued to move at alternating stages towards the Po and the Adriatic
which, thanks to the emerging Apeninnes, was now beginning to look like an
independent body of water.
In the northern areas of the Alps, deformation and its outermost tectonic
slabs had reached Turin and collided with the deformations of the Southern
Alps, whose southward movement had gradually slowed down. The same
happened near Piacenza, an area today covered by the alluvial deposits of
the Po. In both areas, just below the surface of the plain, seismic profiles
show how the Alpine and Apennine structures collided.
In addition, in Emilia Romagna, the
outer flank of the Apennines does not
coincide with the boundary between
plain and reliefs, as it spreads beneath
the plain beyond Pavia, Parma,
Reggio and Modena, as far as Ferrara
and Ravenna, although the results of
seismic research are needed as
evidence. Near Ferrara, only 50
metres of Po alluvial deposits cover
the furthest slabs of the entire EmiliaRomagna Apennine sector. Today,
although these structures are buried
under alluvial deposits, they often
show some signs of activity, as
revealed by the weak frequent tremors
with their epicentres concentrated
In the early Pliocene (5.3 million years ago), the
beneath the plain in Reggio and
return of the Mediterranean Sea produced an
early outline of the Italian “boot”
Modena areas. These epicentres are
S
N
Apennine chain
River Po
Margin of Alpine chain
River Adda
NE
SW
Ferrara
Bologna
River Po
3-2 Ma
65-3 Ma
Foreland
> 65 Ma
Buried front of
Apennine chain
The Alps and the Apennines are now in contact with each other under the thin western Po Plain (top);
below Ferrara, a thin section of the plain covers the most advanced portion of the Apennine chain
(bottom) (ma: million years)
located along the faults of the most advanced overthrusting slabs of the
Middle-Upper Pliocene.
Moving south towards the Marches sector, the most advanced deformations
are not found along the coastline but in the sea, 30 km off the coast. Instead,
further south, the outer deformation front returns inland, between Basilicata
and Apulia, along the Bradanic Trough. Apulia, together with most of the
Adriatic floor, the peninsula of Istria, the ancient rocks covered by the FriuliVeneto plain, the Euganean Hills and the Lessini Mountains (partly of magmatic
origin), and a belt of rocks buried under the central-eastern Po plain, make up
the still non-deformed portion of the Adriatic, or Apulian, plate.
Apulia, with its 5000 metres of rocky successions lying on a very ancient
metamorphic base and culminating with Jurassic-Cretaceaous limestone, is
the easternmost Italian portion of the Adria plate. As such, it may be considered
a foreland of the Apennine chain, i.e., the land in front of the advancing range.
The region is squeezed between the forward-moving Apennines on one side
and, symmetrically, by the Dinaric-Hellenic range on the other. The Southern
Alps are also squeezing the region from the north.
In the meantime, the foot of the Italian “boot” was also taking up its presentday position. The role was perfect for Calabria, a fragment of the Alpine chain
37
38
Aeolian islands
Alpine
deformations
39
European crust
in Alpine chain
Calabria
Apennine
deformations
ex Piedimont-Ligurian ocean
(megabreccias and ophiolites)
Eastern Alps
rn
ste
We
UPPER MANTLE
s
Alp
Recent rock on African
crust in Alpine chain
rn Alps
Southe
African crust (Adria)
in Apennine chain
African crust (Adria),
undeformed
Tyrrhenian Sea
opens
p
d
lan ria
re Ad
Fo ed
tic rm
ria fo
Ad nde
U
An “X-ray” of Calabria provides a clearer view of its geological evolution
e
lat
Apennine
migrations
ain
e ch
Alpin
Br
ad
an
ic
Fo
re
d
ee
Alpine chain
Tyrrhenian Sea
opens
p
dr
lab
ria
Ca
that once flanked Sardinia. About 6 million years ago, as the southern
Tyrrhenian begun opening, it was pushed far away, towards the southern tip
of the peninsula. Its movement - centrifugal with respect to the Tyrrhenian
opening - made new deformations overthrust the rocks of the mobile Calabria
nappe. Typical Apennine deformations were thus produced, i.e., slabs
thrusting towards the African plate.
Deformations were not the only phenomena affecting the Calabria crustal
mass. As they moved, Apennine deformations overlapped Alpine ones and
thrust in the opposite direction.
These movements had begun even before the Sardinia-Corsica nappe started
its rotation, in the initial phase when Africa and Europe were still attached, in the
Cretaceous. In addition to this, the ancient Palaeozoic successions forming
most of the Calabria reliefs - before being deformed by Apennine thrusts, and
even before that by Alpine ones - had been deformed by Hercynian thrusts
(more than 300 million years ago), which had caused considerable
metamorphic activity in the area.
All these events speak for the high price paid - in terms of geological stress so that a perfectly shaped boot could come into being. Calabria made an
incredible effort and was greatly damaged by its movement; it also carried
along the Peloritani Mountains of north-eastern Sicily, which underwent
similar geological events.
Foredeeps, which are still found today, formed both along the Bradanic and
Hyblean deformational fronts, and are due both to the load of thrusting slabs
and to the dipping of subducting plates.
ifts
Sardinia
Hyblean
foredeep
Apennine chain front
s
ide
b
hre
g
Ma
A concise geological picture of Italy, emphasising the centrifugal movements responsible for the
formation of the Apennines and caused by the opening and “oceanisation” of the Tyrrhenian Sea
40
5. Subduction, oceanisation and volcanism: causes and effects.
This Italian geological panorama outlined by the great geodynamic processes
that caused its evolution, although concise, is not complete without
examining recent volcanism. Volcanic products do not only cover extensive
areas with lava and pyroclastic deposits (lapilli and ash); their chemical
composition may also provide interesting information on the geodynamic
conditions that caused their development (e.g., extension, oceanisation,
compression, subduction, etc.).
In addition to the well-known volcanoes of Mt Etna and Vesuvius, a quick
glance at the map of Italy also reveals other eruptive edifices, now extinct,
which produced extensive lava and pyroclastic flows. Proceeding
southwards along the western Italian coast, we find Monte Amiata in lower
Tuscany, and the volcanic lakes of Bolsena, Vico, Bracciano, Nemi and
Albano in Latium. All of them remind us of the numerous volcanic calderas
(collapsed craters) which, in the course of time, turned into natural lakes.
Further south are the islands of Ponza and Ventotene, off Monte Circeo and
the Gulf of Gaeta, and then the Vesuvian volcanic district with Vesuvius, the
Amiata
Bolsena
Bracciano
Vesuvius
Vulture
Vavilov
Marsili
Aeolian
islands
Quaternary extension
Pliocene extension
Oceanic crust
Etna
Quaternary compression
Pliocene compression
Pantelleria
Oligocene-Miocene compression
Cenozoic volcanismo: each deposit is where it is and has the age it has for a precise geological reason
41
Volcanic activity in the Solfatara of Pozzuoli (Campania)
island of Ischia, and the Phlaegrean Fields. All of them form an almost
continuous belt of eruptive edifices, 400 km long and 40 km wide, along the
interior side of the Apennines. Most of them are younger than 2 million years
(Pleistocene), and are associated with the subduction of the Adria plate
beneath the Apennine chain. The Adria plate, which passively dipped (and
dips) downwards due to the NE movement of the Apennines, bent at a high
angle, reaching depths and temperatures that caused its partial melting. The
lighter, melted portions made their way upwards through the numerous
spreading faults that make up the inner, most ancient part of the chain. They
gave rise to explosive eruptions typical of magma produced in a subductive
setting when continental crust is involved.
Further south, the next volcanic district is that of the Aeolian Islands. It
includes Stromboli, the only continually erupting European volcano. Although
at first sight these volcanoes may seem small and scattered, if we take a
closer look underwater, we realise that they actually occupy an area of about
4000 km2, larger than the entire region of Valle d’Aosta.
The genesis of the Aeolian Islands is also due to crustal subduction, with
deep melting and eruption of highly explosive materials. This time, it was the
floor of the Ionian Sea that subducted at depth and melted. This floor is
formed of part of one of the most ancient oceanic crusts in the whole world,
almost 180 million years old. The subduction was not only due to the
42
movement of the Calabria nappe, which the opening of the southern
Tyrrhenian continued to thrust south-east against and on to the Ionian
seabed, but also to the north-north-westerly drift of the African plate and its
Adriatic protuberances. The Sicilian volcanic basin also includes Mt Etna, the
island of Ustica off Palermo, Pantelleria and the Pelagic Islands (Linosa and
Lampedusa), south of Trapani. They are all recent basalt effusions due to
crustal spreading that affected the Strait of Messina as well as the Sicilian
Channel, the sea stretch between Sicily itself and Tunisia. This stretching is
explained as a secondary effect of the Ionian crust dragged by subduction
under the Calabrian arc.
There were also vast lava flows in the southern Tyrrhenian, although none of
them ultimately emerged as islands. Starting 6 million years ago, they
created true underwater mountains which, in some cases - the Vavilov and
Marsili seamounts - are between 2 and 3 km high, and only a few hundred
metres underwater. The bulk of the Vavilov seamount cone - 200 km off the
coast of Naples and Ischia - produces an underwater basin formed
exclusively of volcanic products that are generating new oceanic crust. The
eastern portions of Marsili, which is still active off the Cilento coast, has
various kinds of volcanic products, due alternately to the ascent of melts
associated with crustal extension and oceanisation processes, and to SWdipping subduction of the Adria plate.
To close this section on recent volcanism and its geodynamic importance,
mention must be made of Sardinia, which is rich in Cenozoic effusive
products emitted over the past 40 million years and extensive Palaeozoic
granite blocks in its north-eastern part. The chemical composition and
features of the Cenozoic effused rocks enable reconstruction of the main
geodynamic processes that produced them. For instance, volcanites emitted
between 30 and 18 million years ago (Oligocene and Miocene) and
distributed along the western half of the island were positioned there, as
already mentioned, during the rotation of the Sardinia-Corsica block. They
make up the products of melting and magma ascent caused by collision with
the margin of the Adria plate subducting westwards, as it dipped beneath
Sardinia itself. At the same geological time, remember the underwater
embryo of the Apennine chain was forming off the Sardinia-Corsica block,
due to crustal rotation and compression.
In Sardinia, another noteworthy cycle of effusions dates back to the PlioceneQuaternary (from 5 million years ago to the Present) - its most recent
products are only 100,000 years old. They are scattered and generally found
in the central and north-western areas of the island. Their thick basalt layers
show that their formation was due to the generalised, ongoing process of
crustal opening, the active fulcrum of which lies in the southern Tyrrhenian
Sea, reaching as far as Sardinia.
The volcano of Stromboli (Aeolian Islands, Sicily)
Lava field on the western slopes of Mt Etna (Sicily)
43
44
7. Glaciers, rivers, plains and deltas:
dynamic landforms mould Italy.
We have seen how the slow, complex
depositional
and
deformational
processes of Italy’s geological history
started more than half a billion years
ago. The Italian territory, which is
enclosed and protected by the Alps,
gradually became larger thanks to the
The Ortles glacier (Trentino-Alto Adige)
Apennines. As they slowly rose from the
Mesozoic and Cenozoic seas, these
mountains were unceasingly attacked by erosion that produced new material.
Incoherent (loose), non-deformed and generally recent sediments form little
more than 20% of the emerged territory of Italy. These are the plains, produced
by the accumulation of fluvial, fluvial-glacial, deltaic and littoral (beach)
deposits. The broad Po Plain, including its Veneto-Friuli and Romagna portions,
stretches for almost 50,000 km2, over a total 65,000 km2 of all Italian plains.
The Po Plain may be viewed as a container of sediments, or as a superficial
landform that derived from recent accumulation of sediments. In the former
case, Italy’s geological history may, once again, provide useful indications in
understanding how the immense Po Plain filled up. Most of the plain belongs to
the northernmost undeformed sector of the Adria microplate. Geologically, the
plain is squeezed by the southward advance of the Southern Alps and by the
north-north-eastward movement of the northern Apennines. For a few million
years, the two chains have exerted - and still exert - great force on the
respective margins of the Adria plate, causing it to bend.
Going back to foredeeps and forelands (see p. 32), the Po Plain may be seen as
the foredeep/foreland of both the Southern Alps and the Apennines. The marine
and continental sediments that have been filling it up since the Pliocene reveal a
considerable difference in thickness between sediments accumulating along the
Apennine front and those on the opposite Alpine front. Those on the Alpine side
are less than 1000 m thick, but those on the Apennine side are between 3000
and 7000 m. In order to find, in the Alps, thicknesses similar to those of the
Apennines, we must go north, to the other side of the chain, to Switzerland and
Germany. There, along the outermost Alpine deformation front, sediments of
Oligocene age may be up to 4000 m thick. Thickness is reduced along the Italian
Alpine front (Southern Alps) because there is no northward subduction there.
This means that the plate does not dip downwards and without this effect, the
load exerted on the foredeep area has bent the crust to a lesser extent.
If we consider the Po Plain simply as a landform in itself, we must take into
account its more recent additions, the topmost 100 metres. Analysis of these
sediments reveals not only that surface water powerfully and unceasingly
eroded the Alps and Apennines in the Upper Pleistocene (approx. the last
100,000 years). As we approach the Alpine range, we also see the contribution
of ice provided by the Würm glaciation, the last and most intense Alpine event.
Fluvioglacial deposits were produced by tongues of ice that crossed the large
moraines that still border the inside of the plain, like the cirque moraines of
Dora Riparia, Ivrea, the lakes Maggiore, Lugano, Como, d’Iseo and Garda, and
the rivers Piave and Tagliamento.
As the sea level fell by as much as 130 metres due to retention of water in the
form of ice, the fluvial and glacial deposits of the time covered the whole
northern and central Adriatic Sea, which had turned into a large alluvial plain.
In the last glacial stage and until the peak of the great Alpine deglaciation 20,000 years ago (Upper Pleistocene), the Po flowed into the Tagliamento, and
together they formed a delta whose coastline was just north of the line joining
present-day Pescara in Italy to Split (Croatia).
The sudden fall in sea level caused the outline of the Italian peninsula - which
had by now, over only a few hundred thousand years, achieved the shape of a
perfect boot - to be completely transformed. It swelled dramatically, and was
perhaps irredeemably and essentially compromised. However, the melting of the
glaciers enabled the return of the status
quo. From then onwards, and for the
following 20,000 years, the influences of
rivers on one hand and sea storms on
the other restored a certain balance,
adding to, removing from, and otherwise
refining the Italian coastline and the
magical profile of the peninsula.
With relatively little extra effort,
everything went back to its original
position - sea-level uplift had already
done much of the work - just in time for
modern man to appear on Earth.
And with him came geology, mapping
and satellite imaging which, together,
celebrate the wonderful landforms and
Italy during the Quaternary glacial phases (the
evolution of this unique, “booted”
last peak occured about 20,000 years ago;
beige: emerged land)
peninsula called Italy.
45
Terrestrial and freshwater habitats: vegetation
EDOARDO BIONDI
■ Flora and vegetation
Botanists interpret the Earth’s plant
cover - or part of it - in terms of flora
and vegetation. Both flora and
vegetation are the subjects of a littleknown, albeit ancient discipline,
geobotany, which analyses plant life in
relation to the environment in which it
grows.
The main objectives of geobotany are
analysis of habitats and plant diversity
Yellow pheasant’s eye (Adonis vernalis)
at all levels. It also deals with the
creation of functional vegetational,
bioclimatic and biogeographical macro- and micro-models with predictive
capacity, easy and practical to use, and aimed at planning suitable
environmental conservation and management. To achieve these targets,
geobotany is divided into subdomains: floristics, biogeography or chorology,
bioclimatology, and phytosociology.
Flora is defined as the list of plants (species, subspecies and varieties) found in
a certain area and in which they naturally reproduce. The concept of flora is
associated with both a geographical area and a precise period, as its
components vary over time, for natural and anthropic reasons (man’s
introduction of exotic species, modifications of species and environment).
Vegetation is the integration of plants in the different environments in which
they live in relation to local ecological and anthropic factors, giving rise to
several kinds of plant communities. Thus, the word flora describes the
qualitative aspect of the plant cover of a particular geographical area, and the
word vegetation represents its quantitative and associative aspects, made up
of woodlands, grasslands, etc.
The flora and vegetation of a given area are also indirect manifestations of
environmental diversity. This is because areas with great variations in soil and
Turkey oak forest (Bosco di Montepiano, Piccole Dolomiti Lucane, Basilicata)
47
48
climate conditions host particularly rich
flora which, in turn, produces varying
vegetational aspects. By contrast,
uniform areas of monotonous plains
are colonised by much poorer flora and
types of vegetation.
When comparing the importance of the
flora of differing geographical areas,
their richness should be assessed
more in relative than absolute terms for example, by means of the index
of floristic diversity, which is the
Blue anemone (Anemone apennina)
relationship between the area of a
territory in square kilometres and the
number of entities found in it. Flora is therefore the list of all the entities (species
and subspecies) known in the geographic area in question, indicated by their
scientific bi- or trinomials. This list may be associated with a dichotomic
analytical key identifying single entities and their descriptions. Well-known
examples of past works are “Flora d’Italia” (Italian Flora) by Pignatti, published
in 1982, and the previous volumes on Italian vascular plants by Adriano Fiori
(1923-1929).
More recent checklists have also been drawn up, i.e., lists of entities in which
simple descriptors like chorological elements and biological forms are added
to scientific names. According to the latest Italian checklist, issued in 2005,
Italian flora has 7634 entities, 136 of which are pteridophytes, 34 are
gymnosperms and 7464 are angiosperms. This rich floristic wealth is variously
represented in the flora of the Italian regions, the richest of which are those
with the greatest environmental diversity, like Piedmont (3510 species),
Tuscany (3435), Friuli Venezia Giulia (3335), Veneto (3295), Abruzzi (3232) and
Latium (3228).
The “value” of floristic diversity depends on natural and anthropic factors as
well as on the wealth of regional information, so that a given list does not
necessarily express the true floristic diversity at regional level. Unfortunately,
although in many other countries floristic studies are enhanced, in Italy, training
of young graduates in this sector is deteriorating.
A long tradition is thus being lost, better understanding of Italian flora is slowing
down and, as a recent survey on present knowledge revealed, many important
areas of Italy are still “almost unknown” or “barely known through basic
information”.
■ Vegetational habitats
The Habitats Directive (92/43/EEC) marked a radical change in perspectives
focused on safeguarding biodiversity in the European Union, mainly because it
indicates that conservation is aimed not only at animal and plant species (listed
in Annex II), but also at ecosystems identified through habitats (Annex I). The
Directive defines natural habitats as giusta: “terrestrial or aquatic areas
distinguished by geographic, abiotic and biotic features, whether entirely natural
or semi-natural”. This endows the conservation of species with significance, as
proper management of the ecosystems in which they live safeguards them. The
habitats marked by an asterisk in the Directive have priority, as they are seriously
threatened with extinction within the European Union.
A committee of experts has drawn up the “Interpretation Manual of European
Union Habitats”, which provides scientific guidance for the application of the
Directive. Habitats are divided into nine macro-categories: coastal and
halophytic habitats; coastal sand dunes and inland dunes; freshwater habitats;
temperate heath and scrub; sclerophyllous scrub (matorral); natural and seminatural grassland formations; raised bogs and mires and fens; rocky habitats
and caves; and forests. In view of the importance of the Habitats Directive at
European level, the following short description of Italian terrestrial habitats and
inland bodies of water follows the format of Annex I.
Beech wood (Prati di Tivo, Abruzzi)
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The bioclimate
The climate, i.e., the result of average
meteorological conditions in a certain
place, influences living beings and as
such contributes to their distribution on
Earth.
In 1807, in his “Essay on the geography
of plants”, Friedrich von Humboldt first
recognised that plants form associations
according to their physiological
requirements, and therefore that the
distribution of plant communities forming
various types of vegetation are strongly
influenced by different types of climate.
Humboldt’s pioneering work marked the
beginning of bioclimatology, which deals
with the relationship between climate
and the distribution of organisms; it is
called phytoclimatology when it focuses
specifically on the relationship between
climate and plants. Classification systems
of bioclimates by means of different
parameters and indexes have given rise
to various bioclimatic interpretations.
Over the past 15 years, research by
the Spanish school of phytosociology
has resulted in a classification of the
Earth’s bioclimate based on bioclimatic
indexes and parameters divided
into macrobioclimates, bioclimates,
bioclimatic variants, bioclimatic levels
and bioclimatic horizons.
The Earth has five macrobioclimates:
tropical, Mediterranean, temperate, boreal
and polar. In Italy, the climate is of two
types, Mediterranean and temperate.
The search for boundaries between these
macrobioclimates in Italy has been the
aim of many researchers who have
provided very different interpretations, as
the Italian peninsula is - in a certain sense
- a sort of long, narrow bridge between
Africa and Europe, along which the
temperate macroclimate gradually turns
into a the Mediterranean one.
Edoardo Biondi · Carlo Blasi
Mediterranean maquis with thyme and everlasting flower
The idea of a Mediterranean climate, as
defined by the Spanish school, outside
tropical areas, has a dry summer period
of at least two consecutive months.
Arid months are those during which
average monthly precipitation is less than
double the average monthly temperature.
According to the amount of precipitation,
the structure of the potential
Mediterranean vegetation may be of
many different types: closed deciduous
or evergreen woods, open woods,
scrub, open semi-desert areas, desert,
and hyper-desert areas.
Another fundamental characteristic of this
classification is that the high-mountain
bioclimate (oroclimate) is not considered
as a separate category or bioclimatic
area, because it is closely associated
with that of pedemontane areas.
The differences lie in temperature and
precipitation, which represent the vertical
zonation of flora and vegetation in
successive altitudinal bioclimatic planes.
In a study to define the types of Italian
phytoclimates recently carried out by
the Italian Ministry of the Environment
and Territorial Protection, monthly data
regarding maximum and minimum
temperatures and precipitation taken by
400 thermo-pluviometric stations in the
period 1955-85 were processed, and
identified 28 climatic classes. Once each
station had been assigned to each of the
classes, the experts could draw up a map
of the Italian phytoclimate. According to
this map, the Mediterranean zone
includes the entire Tyrrhenian flank except for the eastern Riviera Ligure - and
the Italian large and small islands, and
continues along the Ionian flank and
northwards up the Adriatic as far as
Pescara. Obviously, along the Adriatic
coast as far as Monte Conero, the
Mediterranean climatic region covers a
narrow stretch that extends to the
southern flank of the Conero Promontory.
The temperate climatic zone is made up
of northern Italy, the Apennines, and the
high-altitude areas of the larger Italian
islands. A more concise map (based on
the continentality Index) limits the number
of bioclimatic classes to nine:
Temperate-oceanic in the Alps,
high-altitude areas of the
Apennines and of Sicily.
Temperate semicontinental
in Alpine valleys and inland
valleys of the central-northern
Apennines along the Adriatic coast.
Temperate oceanic-semicontinental
in the central and eastern Pre-Alps, hilly
areas along the mid-Adriatic coast and
inland Apennine valleys, as far as
Temperate oceanic
Temperate semicontinental
Temperate oceanic-semicontinental
Temperate subcontinental
Temperate semicontinental-subcontinental
Transitional temperate-oceanic
Temperate oceanic-semicontinental
Mediterranean oceanic
Transitional Mediterranean-oceanic
Basilicata along the Tyrrhenian coast
and, locally, some areas in Sardinia.
Temperate subcontinental, typically
in the Po Plain from Piedmont to the
Po Delta.
Temperate semicontinentalsubcontinental, south of the river Po, in
central Pre-Alpine morainic valleys and in
eastern alluvial plains in northern Italy.
Transitional temperate-oceanic, in the
valleys at the foot of the Apennines along
the Tyrrhenian and Ionian flanks and in
several areas of the large Italian islands.
Temperate-oceanic-semicontinental,
in the valleys and lower hills of the midto low Adriatic and Ionian; also in inland
areas of the Madonie (Sicily) and Sardinia.
Mediterranean oceanic all along
peninsular Italy, from Liguria to Abruzzi,
and extending to the coasts of the large
Italian islands.
Transitional
Mediterraneanoceanic, along the
coasts of the midand high Tyrrhenian
localised in the low
Tyrrhenian, in
Sicily and in hilly
inland areas
of Sardinia.
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52
Landscape phytosociology
The landscape is understood as an
ensemble of interacting ecosystems
that are always repeated in similar
conditions. The landscape is therefore
produced by an eco-mosaic of
different areas identified by particular
characteristics making up a complex
system in which the basic physical
and biological components have been
transformed by human activities.
The landscape, as the Italian poet
Giacomo Leopardi realised, is deeply
“humanised”, and any analysis of it
must therefore include man, who
cannot be viewed as an invader.
Analysis of vegetation and its
transformations enables phytosociologists
to identify, qualify and quantify man’s
interventions and their effects on the
natural characteristics of landscapes. It is
therefore essential to know the potential
of the environment to understand the
dynamics of ecosystems affected by
human activities, and to monitor their
impact by means of vegetation. Hence,
landscape phytosociology is based on the
assumption that plant associations are
good bioindicators. Various relationships
may arise within associations - for
instance, of dynamic type when they
represent successive steps of the same
evolutionary or regressive processes
defined by the vegetational sere (or
sigmetum) or contact relationships
(chains). In vegetational seres (or series),
one plant association turns into another
one, e.g., abandoned grazing grassland
becomes a scrub association, which
in turn may later evolve into a forest
association.
Vegetational seres are made up of all
the associations (communities) linked
together by dynamic relationships,
found in the same area with the same
Edoardo Biondi · Carlo Blasi
The mosaic of the Dolomite landscape
vegetational potential, called tesserae
or tessellae, i.e., the biogeographicalenvironmental units used in mosaic work.
The number of associations making up
vegetational seres may vary considerably,
due to both natural conditions and the
actual use made of the area. There are
quasi-natural communities like woods;
stable, semi-natural communities like
perennial grasslands, which maintain their
characteristics for as long as they are
managed in the same way; unchanging or
unstable semi-natural communities, and
short-lived, rapidly evolving communities,
as when weeds infest fields of crops.
Most evolving vegetational dynamics
occur when agricultural activities and
forestry are abandoned. The dynamic
process starts from the ecotone
(transitional space) between forest
and grassland, occupied by intricate
vegetation of shrubs and lianas,
preceded by grassy formations.
When man’s activities come to a halt,
these phytocoenoses expand, invading
grasslands.
In landscape phytosociology, vegetational
seres play the same role as associations
in classic phytosociology. A further
distinction may be made between climatic
seres, which grow on soil benefiting
exclusively from precipitation; edaphic
seres, which develop on soil benefiting
from its own properties; and edaphoxerophytic areas, which occur in
particularly dry conditions compared
with local average conditions.
The model used for the definitions is a
valley on whose flanks the climatic sere is
found. In areas where the soil is poor or
has been eroded to reveal the underlying
bedrock, we find the edapho-xerophytic
sere and, in the central area, down in
the valley where streams flow and the
substrate is in any case moister than in
other areas of the system, the edaphohygrophytic sere.
This type of analysis defines a landscape
unit called geosigmetum or geosere,
meaning sequences of vegetational seres
found in areas having the same edaphic
and climatic characteristics, like valleys,
mountains and coastlines.
Vegetational seres and geoseres
are models which may be
integrated with various
environmental aspects essentially physiographical
ones, like geomorphological
characteristics, types of rocks,
exposure to sunlight, gradient, altitude
and soil characteristics. They offer
integrated methods that outline dynamic
schemes representing a complex, multidimensional way of studying the vegetal
landscape through elements
interacting completely with each other.
The Vegetation Map of Italy is a
monographic collection drawn up by
more than 100 researchers who have
contributed at regional levels, all of
them using the same methods to classify
the area hierarchically. On the map,
small-scale homogeneous areas are
defined through a deductive process,
superimposing climatic, lithological
and morphological thematic maps.
This process has identified areas that
are homogeneous in their physical
characteristics (tesserae), vegetational
seres corresponding to a well-defined
climax vegetation. Here, the
heterogeneous elements are typical of the
vegetational seres to which they belong.
The deductive process of map
overlapping is integrated with an inductive
one that identifies and defines single
ecological models (plant associations)
so as to gather together all floristic,
ecological and biogeographical
information.
The project for the Vegetation Map of Italy
(scale: 1:250,000) funded by the Italian
Ministry for the Environment and Territory
Protection, identifies 258 forestry seres,
92% of which are endemic
to Italy, 23 scrub
seres, 15 grass and
chamaephyte seres
(Alpine and oroMediterranean), 4
hydrophytic, aquatic
seres, and 4
psammophilous
coastal seres.
Landscape:
Agricultural
Natural
Composite
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Vegetation of freshwater and terrestrial habitats
Coastal habitats. In Italy, marine and
coastal environments are particularly
important, because the country has 7300
kilometres of coastline, 60% of which is
flat and sedimentary; the rest is generally
composed of high, rocky cliffs with a
small percentage of low coastline.
This imposing coastal development is
concentrated in the Mediterranean
macrobioclimatic area, except for the
northern sections of the peninsula, i.e.,
the northern Tyrrhenian and northern
Adriatic. In the former area, eastern
Liguria interrupts the Mediterranean
macrobioclimatic area which continues
in western Liguria. The temperate
macrobioclimatic area of the northern
Adriatic is far more extensive, as the
Mediterranean macrobioclimatic area ends
near Pescara and resumes in a narrow
strip ending on the Conero Promontory.
In addition to these particular bioclimatic
conditions, there are geological,
geomorphological and sedimentological
situations which produce an incredible
variety of environments, so that even very
small areas may contain very important
microhabitats, thanks to the diversity of
plants and animals they contain (Habitat
1130 “Estuaries”).
Unfortunately, the Italian coastline is also
the worst affected by man - with his cities,
roads, railways, bridges and airports, their
infrastructures, factories and extensive
tourist facilities - all of which have had
devastating consequences on the delicate
balances influencing the ecology of
coastal systems. The most badly
damaged and remodelled coastal areas
are river mouths, which always involve
several different environments due to the
mixture of marine and fresh waters and
the sedimentation of the material carried
by the rivers themselves. River mouths
produce sandy, silty and gravelly
substrates that sometimes give rise to
large intertidal areas. Here, cormophytic
vegetation (plants with stems and roots)
brackish lentic (still) water, which
undergoes considerable seasonal
variations in salinity and depth. Brackish
areas with silty-clayey soil that are flooded
in winter and dry up completely in
summer, leaving a layer of salt on their
surface, are colonised by halophilic
vegetation with annual and/or perennial
plants (Habitat 1310 “Salicornia and other
annuals colonising mud and sand”).
These are usually paucispecific
vegetational types. In view of their high
level of specialisation, which allows them
to live on salty soils. Indeed, their very
presence in one spot or another can
indicate the various degrees of salinity.
Saltwort (Salicornia) annuals are all
River mouth (Adriatic coast of Apulia)
may either be totally absent, due to the
type of sediments and the alternation of
the tides, or very heterogenous,
according to ecological gradient. There
may be typically marine formations, like
those with Zostera noltii, as well as
associations growing in brackish
lagoons, like Ruppietum maritimae.
There are also more halophilic annual
and/or perennial Salicornia formations
with small cord-grass (Spartina maritima).
Coastal lagoons (Habitat 1150* “Coastal
lagoons”) contain shallow, salty or
Salicornia veneta
members of the genus Salicornia, and
in Italy there are species which are
diploid (having the basic number of
chromosomes doubled) and tetraploid
(having that number multiplied by four).
The only known diploid species in Italy
is Salicornia patula, which forms
communities of the association SuaedoSalicornietum patulae. It normally grows
in higher positions than tetraploid
saltworts, that is, in soil that dries up
more quickly and contains more salt.
Among tetraploid saltworts, the most
common species is S. emerici, found in
salt-pans, pools of stagnant water even
in autumn, and in those parts of lagoons
which open towards the sea. Salicornia
veneta, another tetraploid, is found in the
upper Adriatic, and was originally thought
to be an endemic species before it was
found in two Sardinian locations and
south of the Gargano promontory on the
Adriatic. S. dolichostachya is also a
tetraploid of Atlantic distribution which,
in Italy, lives in the Circeo National Park
near Rome, the Stagno di Santa Gilla
(Cagliari, Sardinia) and was recently
even found at the mouth of the river
Candelaro (Gargano).
Among perennial saltworts growing in
Italy, there are glasswort (Sarcocornia
fruticosa) and glaucous glasswort
(Arthrocnemum macrostachyum) which,
although their populations are becoming
rarer, are still found in several locations.
Very rare is Halocnemum strobilaceum,
which is known to live in only four
locations: the Stagno di Santa Gilla
(Sardinia), the mouth of the Ombrone
(Tuscany), and the Sacca di Bellocchio
and Salina di Comacchio (parts of the
Po Delta in Emilia Romagna).
The upper Adriatic hosts small cordgrass (Spartina maritima), an Atlantic
plant that is only found in this area of the
Mediterranean as only here are there
great tidal variations (more than one
metre). Meadows of small cord-grass
also contain Limonium narbonense and
Puccinellia festuciformis ssp.
festuciformis, both considered to be able
to dfferentiate Adriatic phytocoenoses
[Habitat 1320 “Spartina swards
(Spartinion maritimae)”].
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56
In less salty inland areas, rushes mark
the transition towards freshwater
hygrophilous formations [Habitat 1410
“Mediterranean salt meadows (Juncetalia
maritimi)”]. Starting from areas closest
to the coast, the sea rush (Juncus
maritimus) forms almost pure
phytocoenoses sometimes mixed with
perennial Salicornia (glasswort) in saltier
areas. Otherwise, further inland, where
the substrate is quite dry and contains
less salt, Plantago crassifolia, Carex
estensa, Agropyron elongatum and
Juncus acutus grow, the last tending to
become dominant. These species are
followed by those living in freshwater:
large grass or sedge communities, like
Ravenna grass (Erianthus ravennae),
common reed (Phragmites australis) and
great fen sedge (Cladium mariscus)
which dominate in communities ranging
from freshwater to subhalophilic. The
club-rush (Bolboschoenus maritimus) is
Sand dunes (Apulia)
generally found along river banks, often
associated with common reed. Near river
mouths, in brackish water, it grows in
paucispecific populations made up of
dense communities with compact
inflorescences (Bolboschoenus maritimus
fo. compactus). These are useful
bioindicators, although most floristic
experts consider them insignificant,
because they represent individual stages.
Coastal sand dune and inland dune
habitats. Understanding the
characteristics of beaches means
interpreting biological phenomena and
ecological gradients all along coastlines,
avoiding the artificial separations
between submerged and emerged
environments.
Many of the factors regarding the
geomorphological stability and the
development of communities along the
seashore depend on phenomena that
originate in the sea. The submerged
areas of beaches host seagrass
meadows - unfortunately becoming
dramatically ever more restricted - that
play extremely important roles as both
ecosystem constructors and seabed
stabilisers. With their dense canopies,
these communities have the task of
reducing the effects of wave motion,
weakening erosion, and favouring the
accumulation of sand by means of their
well-developed root apparatuses, which
develop inside the seabed [Habitat
1120* “Posidonia beds (Posidonion
oceanicae)”].
The rhizomes of Posidonia oceanica, also
known as Neptune grass, can grow both
horizontally and vertically and, over time,
they combat progressive silting up by
creating tiered formations called mattes,
which protect the seabed against
erosion. The frayed leaves of Neptune
grass, stranded by waves, produce
Shore dunes and Posidonia banquettes (Latium)
typical sea balls or aegagropilae. Coastal
bays overlooking seabeds containing
Neptune grass are also filled with large
quantities of leaves, making up
banquettes, those large banks of foulsmelling, slowly decaying organic
matter that repel swimmers.
Other seagrasses that produce meadows
(like Cymodocea nodosa, Zostera noltii,
Z. marina) play an essential role in
stabilising seabeds, and live in seabed
areas differentiated by particle size
and depth.
The emerged portion of the beach and
its dunes make up a group of microenvironments that are particularly
inhospitable for plant life. The wind
makes the sand move, causing erosion,
it nebulises seawater turning it into
aerosol, and also affects the water
regimen by varying the quantity
of water available to plants. The species
that colonise these coastal areas are
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therefore highly specialised in occupying
specific ecological niches - generally
extremely limited, as the gradients of the
most important ecological factors are
subjected to great variations in just a
few metres. On sandy shores - the area
generally wetted by waves (aphytal zone)
- the substrate does not host higher
plants. Organic matter that is washed
ashore decomposes where it is, releasing
substances that enrich the sandy
substrate. Here, halo-nitrophilous annual
communities grow (Habitat 1210 “Annual
vegetation of drift lines”) and along most
of the Mediterranean coast, the most
common of which is the association
Salsolo kali-Cakiletum maritimae, made
up of sea rocket (Cakile maritima), prickly
Sea rocket (Cakile maritima)
saltwort (Salsola kali), purple spurge
(Euphorbia peplis) and sea knotgrass
(Polygonum maritimum). Slightly further
inland, the first mounds of sand form the so-called embryonic dunes (Habitat
2110 “Embryonic shifting dunes”), which
are still affected by the wind and are
occasionally nebulised by seawater.
Embryonic dunes are generally formed
by sand couch (Agropyron junceum
subsp. mediterraneum=Elytrigia juncea
subsp. juncea=Elymus farctus ssp.
farctus), a truly psammophilous plant
whose adaptations enable it to withstand
or even to counteract the accumulation
of sand carried by the wind. Its aerial
part is smaller than its hypogeal
(underground) part, whose densely
entwined, branched rhizomes send
down deep strong roots.
On most Italian beaches, the plant
association to which sand couch gives
origin is Echinophoro spinosaeElymetum farcti, which sometimes
includes another beach grass,
Sporobolus pungens, a creeping species
found at the foot of embryonic dunes
in areas seldom sprayed by water.
Other species that contribute to the
formation of these first sand mounds
are sea parsnip (Echinophora spinosa),
cottonweed (Otanthus maritimus),
sea medick (Medicago marina),
sea bindweed (Calystegia soldanella)
and sea holly (Eryngium maritimum).
The vegetation of embryonic dunes in
Sardinia is composed of the association
Sileno corsicae-Elytrigetum juncae, with
the Sardinian-Corsican endemite Silene
corsica, a psammophilous species with
fleshy, hairy leaves capable of capturing
grains of sand.
On higher shifting dunes [Habitat 2110
“Shifting dunes along the shoreline with
Ammophila arenaria (white dunes)”] that
follow embryonic dunes proceeding
inland, vegetation is dominated by
marram grass (Ammophila arenaria
subsp. arundinacea), a psammophilous
grass with feathery inflorescences that is
well adapted to withstand the wind
and sand accumulation, thanks to its
resistant rhizomes that develop very
similarly to those of sand couch.
The best-distributed Italian association is
Echinophoro spinosae-Ammophiletun
arundinaceae, which is made up of sea
parsnip, sea holly, sea spurge (Euphorbia
paralias) and sea daffodil (Pancratium
maritimum). In Sardinia, the same
association replaces Echinophora
spinosa with Silene corsica.
On the landward side of dunes, living
conditions are very different, as microenvironments are protected from salty
winds and therefore have less mobile
sand and more favourable conditions
for plant life. This is the area with more
stable, semi-fixed dunes colonised by
small shrubs and chamaephytes, among
which, in the areas with a Mediterranean
bioclimate, the most frequently found is
maritime crosswort (Crucianella maritima)
(Habitat 2110 “Crucianellion maritimae
fixed beach dunes”). It is generally
associated with everlasting absolute
(Helichrysum stoechas), curry plant
(H. italicum), southern birdsfoot trefoil
(Lotus cytisoides) and sometimes
Mediterranean thyme (Coridothymus
capitatus). In Sardinia, Sicily and
and pink thrift (Armeria pungens).
Greatly diversified therophytes insinuate
themselves amongst perennial
psammophilous vegetation, giving
rise to an exceptional mosaic effect.
This short-lived vegetation, composed
of tiny plants, together with that which
colonises maquis and garrigue clearings,
belongs to the class Tuberarietea which,
as part of ephemeral dune vegetation,
is classified in the order Malcolmietalia
(Habitat 2230 “Malcolmietalia dune
grasslands”). It is rich in species,
including Malcolmia ramosissima,
Maresia nana, and many species
of the genera Cutandia, Matthiola,
Silene and Ononis.
Sand restharrow (Ononis variegata)
Dunes in Piscinas (Sardinia): garrigue with
prickly juniper
Calabria, there is also joint fir (Ephedra
distachya) and, only in Sardinia, also
dog figwort (Scrophularia ramosissima)
The area of the so-called “grey dunes”,
with chamaephyte vegetation of the
alliance Crucianellion maritimae mixed
with therophytes of the order
Malcolmietalia, is found in dunes which
are more likely to be affected by human
activities. This is why in Italy and in the
Mediterranean basin in general, its
floristic characteristics are greatly
restricted and in some cases have even
been completely destroyed, due to
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mechanical remodelling of dune systems
to attract tourists or to accommodate,
however inappropriately, exotic shrub
and tree species. Inland, further dune
consolidation gives rise to the formation
of the juniper maquis typical of coastlines
(Habitat 2250* “Coastal dunes with
Juniperus spp.”). Among the plants
found here is prickly juniper (Juniperus
oxycedrus subsp. macrocarpa) with its
plump, reddish-orange cones, which
dominates the maquis, colonising the
seaward side of Italian coastal dunes
with a Mediterranean bioclimate.
The maquis on the other side of the
dunes is dominated by Phoenician juniper
(Juniperus phoenicia subsp. turbinata)
with larger oval cones. In inland areas far
from the sea in Sardinia and Sicily, this
type is replaced by a more highly evolved
and very rare maquis with Kermes oak
(Quercus calliprinos). Along northern
Adriatic coasts with a temperate
bioclimate, maquis hosts common juniper
(Juniperus communis) and sea buckthorn
(Hippophae rhamnoides ssp. fluvialis)
of the endemic association Junipero
communis-Hippophaetum fluviatilis
(Habitat 2160* “Dunes with Hippophae
rhamnoides”), which grows on the
continental side of dune systems or in
interdunal depressions far from the sea
along the northern Adriatic coast between
Venice and Ravenna. Dunes may also host
pine woods made up of thermophilic
Mediterranean species (Pinus halepensis, P.
pinea, P. pinaster), which grow on the more
stable landward side of dune systems.
They are seldom natural formations, like
some of the relict ones in Sardinia and
Sicily and, although they are often
completely artificial, the Habitats Directive
deems them worthy of preservation if they
are found in climax areas of holm oak
(Habitat 2270 “Wooded dunes with Pinus
pinea and/or Pinus pinaster”).
The Pineta Granducale (Tuscany) is the result of Pinus pinea reafforestation along the Tyrrhenian coast
Reafforested stands along low sandy
Italian coasts do not always have positive
effects in terms of ecological quality and
habitat protection, because they have
often accelerated erosion rather than
slowing it down. Therefore, protection of
reafforestation stands on sand should
only regard those species indicated in the
Habitats Directive, i.e., excluding from
protection all those stands found further
inland from dune systems, where typical
psammophilous formations should
develop instead. Management of coastal
pine forests should ensure the right
balance between pines and natural
species corresponding to the potential
of the site in question.
Sea cliffs and shingle or stony beach
habitats. Rocky coasts are particularly
hostile environments to the life of plants
which, nonetheless, manage to colonise
them by exploiting very small ecological
niches. The areas closest to the sea are
not usually colonised by higher plants
but by algae, due to the fact that they
are frequently wetted by waves.
The areas just above, which constantly
receive marine aerosol, are colonised
by pioneering chasmophytic, halophilic
reef vegetation, mainly rock samphire
(Crithmum maritimum) and by endemic
Rock samphire (Crithmum maritimum)
and micro-endemic species of the genus
Limonium, whose great diversity
is associated with their asexual
reproduction (apomixis) and low
dispersion of propagules (Habitat 1240
“Reefs with Mediterranean coastal
vegetation with endemic Limonium
spp.”). When cliffs are high or exposure
to sea winds changes, salinity falls and
intermediate cliff vegetation appears:
more or less halophilic and halo-tolerant
plants now grow in the community
Anthyllidion barbae-jovis, the name
deriving from silver bush (Anthyllis
barba-jovis), a shrub exceeding one
metre in height, with pretty white flowers.
On cliff tops, where the gradient of the
coastline is less steep, there are garrigue
chamaephytes growing in little soil, with
associations made up of different types
of everlasting (Helichrysum italicum, H.
italicum sp. microphyllum, H. stoechas,
H. siculum, H. rupestre).
These associations include the
vegetation widely distributed on granite
in northern Sardinia with the plant known
as “faded jeans” or euphorbia (Euphorbia
pithyusa) (Habitat 5320 “Low formations
of Euphorbia close to cliffs”).
In inland areas not affected by marine
aerosol, this type of vegetation is
replaced by other plants, which grow in
more highly evolved soil, like those of the
Mediterranean maquis and secondary
garrigue, the aftermath of fires.
Rocky and sandy coasts may also host
exotic species, some of which are very
invasive and have gaudy flowers, like the
succulent perennial sally-my-handsome
(Carpobrotus acinaciformis), a plant
of South African origin, whose leaf
parenchyma stores great quantities
of water.
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Alpine watercourse with a narrow bed (Arzino river, Carnian Prealps, Friuli Venezia Giulia)
Freshwater habitats. Rivers host several
phytocoenoses that reveal the great
ecological specialisation of plants in this
environment. Near springs and upstream
areas, there are few higher plants: here
we find algae and mosses that adhere to
stones and boulders. Rocky riverbeds
do not allow the development of river
vegetation due to the scarce quantity of
alluvial deposits. However, pioneering
shrubby willows do grow among the
rocks of the sandy-gravelly banks of
streams and fast-flowing rivers. In the
Alps and central-northern Apennines, this
type of vegetation is mainly composed
of the most common willow, rosemary
willow (Salix eleagnos) (Habitat 3240
“Alpine rivers and their ligneous
vegetation with Salix eleagnos”). In siltymuddy substrates, this phytocoenosis
sporadically grows in contact with the
rare German tamarisk (Myricaria
germanica). Together with young
populations of Salix eleagnos, they
produce communities of the association
Salici-Myricarietum germanicae (Habitat
3230 “Alpine rivers and their ligneous
vegetation with Myricaria germanica”).
There is also sea buckthorn growing
among the shrubs in very small dry areas.
Alluvial deposits that gradually formed
from eroded material carried by rivers
are arranged in terraces degrading
towards the present riverbed, and are
gravelly, gravelly-sandy and gravelly-silty
formations alternating with sandy and
clayey-silty banks. The riverbank
woodland that colonises the most recent
terraces is identified as a potential
phytocoenosis with very different
ecological characteristics. As it is
strategically important for the
conservation of biodiversity, it must be
protected and reconstituted over time
[Habitat 91EO “Alluvial forests with Alnus
glutinosa and Fraxinus excelsior (AlnoPadion, Alnion incanae, Salicion albae)”].
Vegetation growing on the present
terrace, the closest to the river, with
a sandy, sandy-pebbly substrate, is
dominated by white willow (Salix alba).
White willow (Salix alba) dominates the
vegetation of river terraces
This type of woodland can withstand
frequent flooding - in non-stagnant water,
in hydromorphic soil, with hardly any
humus - due to the accumulation
of alluvial material that blocks its
paedogenic evolution. White willow
stands have typical pioneering
characteristics, like anemochore (wind)
seed dispersal and a great capacity for
vegetative regeneration.
This type of forest, most of which grows
in central and southern Europe, belongs
to the association Salicetum albae,
and includes similar phytocoenoses
in northern Italy. In central Italy, the
association is replaced by Rubo ulmifoliiSalicetum albae, which has a number of
Mediterranean and Euro-Mediterranean
species. In southern Italy, these woods
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host the shrubby sandbar willow (Salix
pedicellata) (maximum height 8 m) of the
association Salicetum albae-pedicellatae
(Habitat 92A0 “Salix alba and Populus
alba galleries”). Willow woodland found
on terraces above rivers is followed by
black alder woodland (Alnus glutinosa)
Alder (Alnus glutinosa)
which, in Italy, grows along the Apennine
streams in the association Aro italiciAlnetum glutinosae, and is replaced by
the association Euphorbio-Alnetum
glutinosae in more southerly parts of the
Apennines.
Stands of white poplar (Populus alba) of
the association Populetum albae, grow
on higher terraces than willow woodland,
where flooding is less frequent, lasts a
shorter time, and the water table never
rises. This community, which develops
along the intermediate and lower
stretches of rivers, has been greatly
damaged by human activities, and today
is seldom found in northern Italy.
The association Salici albae-Populetum
nigrae includes black poplar (Populus
nigra) and white willow, which grow on
limestone in some areas of northern Italy,
where they colonise recent terraces
drawing water not from the stream but
from the water table. Pioneering stands
with black poplar and grey poplar
(Populus canescens) on mixed, pebbly
substrates, have been found in southern
Italy and are attributed to the association
Roso sempervirentis-Populetum nigrae.
Riparian woods dominated by oriental
plane (Platanus orientalis) are particularly
rare. They are generally found along the
banks of rivers in Greece, and in Italy
they take on particular biogeographical
importance. They grow along perennial
streams flowing in the narrow valley
of north-eastern Sicily, near Catanzaro
(eastern Calabria) and in Cilento
(Campania) [Habitat 92C0 “Platanus
orientalis and Liquidambar orientalis
woods (Platanion orientalis)”]. Some
alluvial areas in the plains still host
residual meso-hygrophilous woods with
Caucasian ash (Fraxinus oxycarpa subsp.
Caucasian ash (Fraxinus o. angustifolia)
angustifolia), which seasonally tend to
become marshy due to the higher water
table. These rare formations have been
found in associations in several areas of
Italy in general and in Friuli Venezia Giulia
in particular.
In the Po Plain and in northern Italy,
riverbeds with silty-pebbly substrates of
the so-called braided type - wide,
shallow channels separated by shingle
banks or shoals emerging from the water
during periods of drought - are colonised
by a type of vegetation belonging to the
association Polygono lapathifoliiXanthietum italici. This nitrophilous
vegetation is due to the great quantities
of organic pollutants generally found in
streams and which are more evident in
summer, at the peak of the dry season,
when rivers are at their lowest.
Muddy-silty substrates flooded for long
periods over the year host dense hygronitrophilous formations, most of which
belong to the association BidentiPolygonetum mitis. River banks are
dominated by dense populations of
watercress (of the association
Nasturtietum officinalis) followed by fool’s
watercress (Helosciadetum nodiflori),
which often completely colonises the
beds of channels and small streams
flowing into the main river (Habitat 3270
“Rivers with muddy banks with
Chenopodion rubri p.p. and Bidention
p.p. vegetation”).
Fast-flowing streams in southern Italy
often have wide pebbly shores (called
fiumare in Calabria and Sicily),
sometimes also found in Sardinia and
Tuscany. In periods of drought, the
pebbly beds of these streams, seldom
reached by water, unless the river is in
spate, host chamaephytic vegetation.
Among the colonising plants are species
of the genus Helichrysum (H. italicum,
H. stoechas), Artemisia (A. campestris,
A. variabilis, A. alba) and Santolina
(S. insularis, S. etrusca). In the various
phytogeographical areas, the
phytocoenoses they produce have been
attributed to several associations
extending from the Po Plain to Sicily
(Habitat 3250 “Constantly flowing
Mediterranean rivers with Glaucium
flavum”).
River bends that remain isolated in
periods of drought, leaving pools behind
as the water level falls, may contain
floating and submerged hydrophytic
rooting mats.
Among these are the paucispecific
associations of common duckweed
of the Lemnetum minoris and
Common duckweed (Lemna minor)
Lemnetum gibbae associations.
Submerged hydrophytes generally
form monospecific, sometimes
compenetrating phytocoenoses, like
those with broad-leaved pondweed and
fennel pondweed (Potamogeton natans
and P. pectinatus), which are more
closely associated with stagnant water.
Loddon pondweed and lesser pondweed
(P. nodosus and P. pusillus) are frequently
found in flowing water.
The margins of river bends and the
banks of streams and channels host
formations of large helophytes like
bulrush and lesser bulrush (Typha
latifolia, T. angustifolia, Schoenoplectus
lacustris and S. tabernaemontani), and,
in areas closest to the banks, especially
near river mouths, common reed
(Phragmites australis).
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Raised bogs, and mires and fens.
Bogs are humid areas of exceptional
environmental importance. Their
vegetation is mostly made up of
sphagnum moss and mosses which,
over time, accumulate to form large
quantities of peat, dead organic matter
associated with the vital activity of bogs.
Bogs are defined as active when peat
production is ongoing, and dead when
the same process is over. They are
traditionally divided into raised bogs, flat
bogs and transition mires.
In raised bogs, sphagnum mosses make
up the bulk of the vegetation. These
bryophytes can radically modify the
substrate in which they live, as their tips
grow while their older lower portions
progressively die, decomposing very
slowly due to the anaerobic
environment. This process produces
peat, which gradually accumulates,
raising the living layer of sphagnum
Peat-bog (Valle Aurina, Trentino-Alto Adige)
moss, which ends up being higher than
the level of groundwater. At this point,
the roots of these plants can no longer
reach the water, and the only sources of
nutrients for their living parts are rain
and snow.
Flat bogs are fed by springs, and their
vegetation is generally composed of
higher plants like grasses and sedges.
Transition mires are a mixture of the two
above types, as they contain a layer of
sphagnum moss and other typical
species of raised bogs, together with
higher plants. Habitat 7110* “Active
raised bogs” therefore refers to bogs
rich in sphagnum mosses, like
Sphagnum magellanicum, S. imbricatum
and S. fuscum, which are associated
with several species of sedges, like
Carex nigra (= C. fusca), C. limosa,
C. echinata and C. pauciflora. There are
also many carnivorous plants of the
genus Drosera (sundew), such as
D. anglica, D. intermedia and D.
obovata, and of the genus Utricularia
(bladderwort), like U. intermedia, U.
minor and U. ochroleuca.
The vegetation of raised bogs of the
order Sphagnetalia medii interlocks
with transition mires of the order
Schneuchzerietalia palustris (Habitat
7140 “Transition mires and quaking
bogs”) and with flat bogs of the order
Caricetalia fuscae [Habitat 7130
“Blanket bogs” (*if active bog)].
Sphagnum bogs are often marked by
degraded areas due to both human
activities and natural conditions. These
are colonised by pioneering vegetation
that produces sedge meadows, the
most common of which are those of the
genus Rhynchospora (R. alba, R fusca),
together with other species, like the
above-mentioned Drosera (Habitat
7150 “Depressions of peat substrates
of the Rhynchosporion”).
Most Italian sphagnum bogs are found
in the Alps and, to a lesser degree, in
the northern Apennines. In centralsouthern Italy and on the islands, these
bogs are extremely rare and often
contain impoverished sphagnum
populations, like those on Monte
Limbara (Sardinia) and in the Madonie
mountains (Sicily).
The greatest threats to bogs come from
modifications in their water supply,
reclamation operations, excavations for
peat and, occasionally, the creation of
small lakes. Unfortunately, these are
very often created in protected areas in line with a far from clear interpretation
of environmental protection laws - to
favour populations of ducks, generally
composed of species distributed
worldwide.
Natural and semi-natural grasslands,
screes and rocky cliffs.
In high-altitude mountain areas, plants
gradually become smaller, and trees
cannot grow high due to the harsh
climate, which is unsuitable for the
production of large tree biomasses,
as the warm season necessary for
photosynthesis is much shorter.
Therefore, forest vegetation turns into
scrubland in most of the sub-Alpine area,
which becomes primary grassland in the
Alpine area. At even higher altitudes,
vegetation is scarce and disappears
completely above the snowline. This is
where plants with simple structures live,
like cryptogams, extraordinary living
forms including lichens, symbiontic
organisms which can produce organic
matter at even extremely low
temperatures sometimes well below zero.
Actually, even in these areas, made up of
screes and rocks alternating with
permanent ice in extreme living
conditions, some cormophytes with
particular adaptations manage to survive.
Among them is the glacier buttercup
(Ranunculus glacialis), the species living
Glacier buttercup (Ranunculus glacialis)
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at the highest European altitudes. It is
also found in the Italian Alps, above 4000
m (4200 on Mt Cervino), in environments
where the season suitable for its
vegetative development lasts no longer
than three months. This is a very short
period, considering that the weather is
changeable and conditions are not
consistently favourable. In order to
overcome these difficulties, plants
adapted to these extreme conditions
have greater photosynthetic efficiency
and grow in positions where the
microclimate is warmer.
In addition to the glacier buttercup, the
Alps also host yarrow (Achillea atrata),
dwarf Alpine yarrow (A. nana), endemic
Alpine rock-jasmine (Androsace alpina)
and saxifrage-like rock-jasmine
(A. vandellii) which, on the snow deserts
of the Gran Sasso and Majella, is
replaced by Mathilda’s rock-jasmine
(A. mathildae). Another endemic plant of
the central Apennines, Thomas’s
chickweed (Cerastium thomasii), together
with whitlow grass (Draba aspera) and
Alpine rockcress (Arabis alpina ssp.
alpina) colonises the highest Apennine
peak, the Corno Grande (2912 m) of the
Gran Sasso d’Italia massif, forming the
association Arabido alpinae-Cerastietum
thomasii. Alpine vegetation is also
influenced by harsh climatic conditions,
which force it to grow in geomorphological
depressions, also known as snow valleys,
with better edaphic conditions. In these
areas, the long-lasting snow cover
favours plant survival, as it insulates
them from plummeting temperatures. In
addition, its slow thawing gives rise to
different conditions in relation to the
gradients of the main ecological factors.
Extraordinary willows grow here, like
dwarf willow (Salix herbacea), a small
arctic-Alpine shrub with creeping,
partially underground shoots. In Italy,
Grassland growing on scree (Val Venosta, Trentino-Alto Adige)
it is found in the Alps and in the central
Apennines (from the Monti della Laga to
the Gran Sasso and Maiella). In the Alps,
the association the dwarf willow
produces is Salicetum herbacea
which, in the Gran Sasso, is replaced
by Armerio majellensis-Salicetum
herbaceae, with Armeria majellensis,
Carex kitaibeliana and Graphalium
hoppeanum ssp. majellensis. In the
Gran Sasso, the association Carici
kitaibelianae-Salicetum retusae contains
vegetation with blunt-leaved willow
(Salix retusa), another willow with
partially creeping shoots that form dense
mats in the wettest areas of the
mountain flanks. The Habitats Directive
does not indicate a specific habitat for
these formations, although they may be
found in Habitat 6170 “Alpine and
subalpine calcareous grasslands”.
Vertical rocky cliffs host a great variety
of plants adapted to several microconditions. Most of them are
chasmophytes, whose roots creep into
rock cracks. Chomophytes are plants
colonising bare rock: they require only
very small amounts of the soil that
manages to accumulate in the tiny spurs
of rock jutting out of the near-vertical
surface (esochomophytes) or in cracks
(chasmo-chomophytes).
True lithophytes like algae, mosses and
lichens literally grow on bare rock.
The gaudiest vegetation growing on highaltitude cliffs is associated with the order
Potentilletalia caulescentis, which
combines the chasmophytic communities
living in cracks in alkaline calcareous
slopes with temperate and Mediterranean
microclimates. In the Alps, these
communities belong to the alliance
Potentillion caulescentis, which contains
some of the most beautiful and
important species of Alpine endemics.
The communities living on rocky slopes
of the Maritime and Apuan Alps belong
to the alliance Saxifragion lingulatae.
On the calcareous Apennines, as far as
Sicily, the alliance is Saxifragion australis,
which replaces the Alpine Potentillion
caulescentis.
The communities of limestone-poor
slopes are part of the order
Androsacetalia vandellii, and colonise
non-carbonatic rocks with the alliances
Androsacion vandellii of silicate Alpine
Saxifrage-like rock-jasmine (Androsace vandellii)
rocks and Asplenion serpentini of
serpentine cliffs. In the Mediterranean
basin, the order Asplenietalia glandulosi
includes communities of chasmophytic
vegetation on calcareous slopes of the
alliance Asplenion glandulosi of
Mediterranean distribution, found in the
north-western Mediterranean and, in
Italy, only on the highest Sardinian peaks.
Other important communities of the
island are the Centaureo filiformiMicromerion cordatae of the central
calcareous mountains. The many
associations found in southern Italy,
along the Tyrrhenian and Ionian Calabrian
coasts and in Sicily, belong to the
limestone-loving alliance Dianthon
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rupicolae. The order CentaureoCampanuletalia and the alliance
Centaureo kartschianae-Campanulion
pyramidalis belong to amphi-Adriatic
communities found in the Italian Karst.
In the Gargano peninsula on the
Adriatic, the endemic alliance is
Asperulion garganicae. Vegetation of
calcareous cliffs is described in Habitat
8210 “Calcareous rocky slopes with
chasmophytic vegetation”, and that
of siliceous slopes in Habitat 8220
“Siliceous rocky slopes with
chasmophytic vegetation”.
The alluvial cones found at the foot of
rocky slopes are also colonised by
specialised plants which, in different
stages, manage to stop rock fragments
from sliding down flanks and make them
gradually more stable. Vegetation finds it
difficult to colonise limestone screes with
large boulders. But, once again, several
plants are well adapted, like round-leaved
pennycress (Thlaspi rotundifolium),
“Calcareous and calcschist screes of
the montane to alpine levels (Thlaspietea
rotundifolii)”].
These plants, mostly grasses and
sedges, have stolons that stabilise
calcareous and dolomitic alluvial cones,
producing meadows of blue moorgrass
(Sesleria caerulea) and evergreen sedge
(Carex sempervirens). They initially form
grassy clumps that later turn into thick
grassland rich in species, covering the
warmest and sunniest areas, from the
oro-temperate to the cryo-temperate
levels, with the association SeslerioSemperviretum.
This is one of the most important Alpine
primary grasslands and shows different
aspects in relation to its development.
It may contain Alpine pasque flower
(Pulsatilla alpina), narcissus anemone
(Anemone narcissiflora), buckler mustard
(Biscutella laevigata), and several other
typical species of Alpine meadows like
edelweiss (Leontopodium alpinum),
Round-leaved pennycress (Thlaspi rotundifolium)
Edelweiss (Leontopodium alpinum)
which gives its name to the class
Thlaspietea rotundifolii containing
communities living on calcareous screes
in the Alps and Apennines.
Although in silicate mountains screes are
much more stable, they too contain
specialised flora [Habitat 8120
the symbol of Alpine flora. Higher
altitudes and peaks between 2000 and
3000 m host the Firmetum (meadow of
Caricetum firma), pioneering vegetation
that withstands cold and ice, and which
typically looks like a tussock meadow.
In this type of grassland, pioneering
species play a fundamental role,
examples being blue saxifrage (Saxifraga
caesia) which, together with blue sedge
(Carex firma) forms the basis of these
cushion-shaped formations associated
with vigorous creeping blunt-leaved
willow (Salix retusa) and net-leaved
willow (S. reticulata), which keep the
grassy clumps together and stabilise
them. Permanent populations of
mountain avens (Dryas octopetala) play
an important role in the formation of the
Mountain avens (Dryas octopetala)
Firmetum, as this plant colonises
clearings and then evolves with the later
growth of colonial bentgrass (Agrostis
alpina). In occasional flatter areas with
deeper soil, there are continuous
formations of Bellardi bogsedge
(Kobresia myosuroides=Elyna
myosuroides=E. bellardi), a plant of Asian
origin which, together with a group of
similar species, spread to Antarctica and
the European mountains during
glaciations. Bogsedge produces
brownish steppe meadows covering wellevolved soil on flat or slightly sloping
surfaces, unlike the Seslerietum and
Curvuletum that live on steep surfaces.
In the central Apennines, bogsedge
meadows of the cryo-temperate level
belong to the association Leontopodio
nivalis-Elynetum myosuroidis, which
contains European edelweiss
(Leontopodium nivale), a subendemic
species of the central Apennines and
Montenegro, moss campion (Silene
acaulis ssp. brypoides), Erigeron
epiroticus and Alpine gentian (Gentiana
nivalis). On silicate mountains, primary
grasslands are generally composed of
poor, acidophilic matgrass (Nardus
striata), a caespitose grass with typical,
dark purple unilateral spikes.
Floristically speaking, these meadows
are poorer than those described above,
and less important because cattle do
not feed on them.
In the Alps, there are two types of
matgrass meadows: the CurvuloNardetum between 2200 and 2500 m, a
transitional stage before the Curvuletum,
in which this species mixes with those of
the Aveno-Nardetum at lower altitudes
(1800-2000 m), containing more ArcticAlpine species. At even lower altitudes,
there is secondary Nardetum associated
with almost flat hay meadows.
The best distributed association in the
Alps and northern Apennines is the Geo
montani-Nardetum strictae, which
includes continuous grassland on flat or
slightly inclined surfaces deriving from
the destruction of beech woods and their
transformation into grazing land. This
Nardetum belongs to the alliance Nardion
strictae which, in the central Apennines,
is replaced by the Ranunculo pollinensisNardion strictae, containing more
endemics, including Pollino crowfoot
(Ranunculus pollinensis) and spiked
wood-rush (Luzula italica=L. spicata ssp.
italica). It is frequent and sometimes
extensive where geolithological
conditions are suitable, as in the Monti
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della Laga. In the calcareous central
Apennines, their distribution is
associated with particular
geomorphological conditions, like the
bottom of dolinas, flat areas with deep
lye soil with acid pH [Habitat 6230*
“Species-rich Nardus grasslands, on
silicious substrates in mountain areas
(and submountain areas in continental
Europe”)]. The most widespread
secondary grasslands in Italy belong to
the class Festuco-Brometea. This
includes hemi-cryptophytic and mesoxerophilous vegetation growing in deep,
alkaline soil found in Euro-Siberian and
Mediterranean areas in humid and subhumid locations with deep soil that
retains greater amounts of water.
The class has three distinct orders:
Festucetalia vallesiacae, ScorzoneroChrysopogonetalia and Brometalia
erecti. The first is steppe-like, with
chamaephytes and shrubs growing in
Grazing land
shallow soil with a thin layer of humus,
often near windy, exposed locations in
mountain valleys with continental climate
(Habitat 6240* “Sub-Pannonic steppic
grasslands”). Those of the order
Scorzonero-Chrysopogonetalia are xeric
formations found in north-eastern Friuli,
along the southern margin of the Alps, as
far as Lake Garda (Scorzonerion villosae
and Satureijon subspicatae) and, in
south-eastern Italy, in the Gargano and
upper Murgia (Hippocrepido glaucaeStipion austroitalicae). The more
mesophilous communities of the
Brometalia erecti grasslands belong to
the alliance Bromion erecti, and produce
meso-eutrophic grassland of grasses
growing in the deep, non-hydromorphic
soil of the mesotemperate and
supratemperate bioclimates of the Alps
and Apennines. In the latter, it contains
the sub-alliance Polygalo mediterraneaeBromenion erecti.
However, the vegetation with the greatest
biodiversity is made up of the
xerophilous and semi-mesophilous
grasslands of the alliance Phleo ambiguiBromion erecti, endemic to the
calcareous Apennines and the Madonie
in Sicily. It is divided into three suballiances: Phleo ambigui-Bromenion
erecti, which is typical and widespread in
mesotemperate and meso-subMediterranean bioclimates of the central
Apennines; Brachypodenion genuensis,
of supratemperate, at times
orotemperate bioclimates of the centralnorthern Apennines; and Sideridenion
italicae of the supra-Mediterranean and
sub-Mediterranean bioclimates of the
central-southern Apennines.
The Habitats Directive also aims at
preserving the biodiversity introduced by
centuries-old human activities, like the
traditional agriculture, forestry and
breeding of cattle on grazing land, which
have created an extraordinary variety of
environments and caused the expansion
of the ecological niches of many species.
Examples are the populations of orchids,
which have developed extensively in
secondary grasslands and which
presumably, in natural conditions, would
have found their habitats only on the
natural grassy crests of cliffs. It is
therefore necessary to find ways in which
human beings can coexist compatibly
with their environment. In particular,
interruption in the exploitation of
extensive secondary grasslands has
triggered spontaneous processes of
vegetational growth that will later form
scrub and pre-forests, and eventually new
woodland. Man’s activities will thus cause
the destruction of an entire heritage of
biodiversity, the selfsame heritage the
Directive intends to protect with Habitat
6210 “Semi-natural dry grassland and
scrubland facies on calcareous substrates
(Festuco-Brometalia) (*important orchid
sites)”. The asterisk indicating the priority
Toothed orchid (Orchis tridentata), found on dry
grassland
given to this habitat refers to orchids, as
this category only includes sites that host
rich cortèges of these species, or even
only one such population which, however,
is important at EU level.
The survival of these beautiful plants is
partly due to their high level of
specialisation, thanks to their symbiosis
with mycorrhizal fungi and their intense
collaboration with pollinating moths.
All these biological conditions give rise
to extreme precariousness, and cause
orchid populations to rarefy and
eventually disappear. Their conservation
requires careful management of the
territory with interventions aimed at
combating processes giving rise to
natural scrub and at reafforestation of
abandoned grasslands, by exploiting
traditional agricultural practices, mainly
re-creating grazing land for livestock
and meadows of hay.
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The Bosco della Zelata in the Ticino Natural Park (Lombardy)
Forests, woods, and maquis.
The virgin forest that still occupied
extensive areas of the Italian peninsula
in Roman times has been variously
modified over the centuries and has
consistently been reduced also due to
demographic events and socio-economic
conditions. Examining only the period
after the Unification of Italy (1861) - which
was when the true development of Italian
industry began - in northern Italy great
woodland areas were destroyed to make
room for crops. The last great forests of
the plains and most of those of the hills
were thus depleted.
In the South, unproductive large estates
were expropriated and sold to private
owners. In a few years, an area one-third
the size of the whole country was turned
to agricultural use. The development of
the railways produced an increased
demand for wood used to build tracks,
which led to the further destruction of
woodland, especially oak stands. The
consequences of all these interventions
were great territorial degradation and
hydro-geological damage. In the early
1900s, reafforestation and the creation of
laws to protect Italian forests were
deemed necessary. Forestry law
no. 2367, to protect the hydro-geological
heritage and dating back to 1923, was a
turning-point in woodland management,
and imposed a series of limitations and
checks that proved to be extremely
useful. However, reafforestation was only
truly carried out in the 1950s, at a time
when the population abandoned large
areas in the Italian mountains. This
caused a true expansion of green growth,
as woodland independently recuperated
and occupied larger and larger areas.
In the meantime, the population’s
sensitivity towards environmental issues
increased, speculation regarding natural
areas diminished, and migration from the
mountains towards the coast led to
unbearable urban pressure.
The present Italian situation shows good
forest cover - 8,675 ha, i.e., 28.8% of the
Italian territory - 6,436 ha of which are
woods (2,577 ha of mountain forest
and 858 ha of common woods) and
2,240 ha of scrubland, woodland and
Mediterranean maquis. However, the
forest cover/population ratio shows an
Holm oak (Quercus ilex)
average amount of less than 2,000 m2
per head of the population, which is
insufficient, especially in southern Italy,
where the figure is even smaller. It is
therefore absolutely necessary to allow
for woodland expansion and
improvements in forestry management,
emphasising not only economic functions
but also environmental defence and
conservation of the great biodiversity
value that woods and forests potentially
have. In short, forestry choices must be
made that apply “systemic forestry”
aiming at ensuring the survival of
woodland and guaranteeing its
biological functions and biodiversity.
The woodland vegetation of the
Mediterranean bioclimate is composed
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of shrubs and trees of the class
Quercetea ilicis, both in the warm, dry
thermo-Mediterranean areas and in
the more humid ones of the mesoMediterranean area. In the former area,
sclerophyllous maquis formations prevail,
the order being Pistacio-Rhamnetalia
alaterni with the alliances OleoCeratonion, which occupies evolved soil,
and Juniperion turbinatae, generally
found on sandy substrates.
The North-African alliance Periplocion
angustifoliae is only found on the islands
off the north-east coast of Sicily near the
Channel of Sicily. The alliance OleoCeratonion includes brushwood and
thermo-xerophilous maquis with thermoMediterranean species like wild olive
(Olea europea var. sylvestris), carob tree
(Ceratonia siliqua), mastic tree (Pistacia
lentiscus), dwarf palm (Chamaerops
humilis), Italian buckthorn (Rhamnus
Palma nana (Chamaerops humilis)
alaternus), Mediterranean prasium
(Prasium majus), Asparagus albus and
tree spurge (Euphorbia dendroides).
The characteristics of the alliance
Juniperion turbinatae have already been
described; the alliance Periplocion
angustifoliae contains species that are
rare in Italy, like silkvine (Periploca
laevigata ssp. angustifolia), which is
only found on the islands of the Channel
of Sicily, and joint pine (Ephedra fragilis)
angustifolia), laurustinus (Viburnum tinus),
terebinth (Pistacia terebinthus) and myrtle
(Myrtus communis). Lianas are also
widespread, examples being rough
bindweed (Smilax aspera), wild madder
(Rubia peregrina var. longifolia) and
virgin’s bower (Clematis flammula, C.
cirrhosa). In addition to these species,
which are typically found along
Mediterranean coasts, Italian-Illyrian
holm oak woods always contain
flowering ash (Fraxinus ornus) and bay
laurel (Laurus nobilis).
Joint pine (Ephedra fragilis)
(Habitat 9320 “Olea and Ceratonia
forests”).
Holm oak forests, which are widely
distributed in Italy and its islands,
occupy the Italo-Tyrrhenian, ApennineBalkan and Adriatic bio-geographical
provinces, acting as boundaries
between the Tyrrhenian in the west and
the Adriatic in the east. Their floristic
composition emphasises these
biogeographical conditions, as these
areas are rich in oriental species, with a
few western infiltrations, especially in
Liguria and Sardinia. According to the
latest taxonomic revisions, Italian holm
oak forests belong to the alliance Fraxino
orni-Quercion ilicis, with two suballiances: Fraxino orni-Quercion ilicis
along the Italian peninsula and in Sicily,
and Clematido cirrhosae-Quercenion
ilicis in Sardinia (and Corsica) (Habitat
9340 “Quercus ilex and Quercus
rotundifolia forests”).
The woods of this alliance contain a great
variety of evergreen shrubs like mock
privets (Phillyrea media, P. latifolia, P.
Bay laurel (Laurus nobilis)
The presence of other tree species
indicates that some associations are
more mesophilous: they include
European hop-hornbeam (Ostrya
carpinifolia) and Italian maple (Acer
obtusatum), together with subMediterranean and Mediterranean semideciduous oaks like Italian pubescent
oak (Quercus virgiliana) and Balkan
durmast (Quercus dalechampii).
The undergrowth generally hosts spring
sowbread (Cyclamen repandum) along
the Tyrrhenian side, and ivy-leaved
sowbread (C. hederifolium) in the eastern
part of Italy and Sicily. Sicily also hosts
thermophilic, limestone-loving
associations with a large number of
species of the order Pistacio-Rhamnetalia
alaterni, like dwarf palm, wild olive,
tree spurge and tree germander
(Teucrium fruticans). Sardinian holm oak
woods contain a large number of
distinguishing species, like arum pictum
(Arum pictum ssp. pictum), Corsican
hellebore (Helleborus lividus ssp.
corsicus), foxglove (Digitalis purpurea
var. gyspergerae) and Paeonia morisii.
Mesophilous and xerophilous deciduous
woods in areas with temperate
macrobioclimate belong to the class
Querco-Fagetea, are distributed in
mesotemperate and supratemperate
bioclimates, and sometimes penetrate
areas with a Mediterranean
macroclimate. In the Italian peninsula and
its islands, these forests have recently
been analysed thoroughly, especially
those of the order Quercetalia
pubescentis. Their phytocoenoses, mixed
with thermophilic broadleaves with great
biodiversity, show a close floristic
association with similar forests in the
Balkans. These analogies have led to the
identification of the Balkan alliance
Carpinion orientalis, due to the presence
of oriental hornbeam (Carpinus orientalis)
over most of the peninsula, except for its
southernmost section. Oak woods
dominated by species of the group
Quercus pubescens s.l. are widespread
in Italy, including those with Italian
pubescent oak, sometimes mixed with
Q. pubescens s. str. and Balkan durmast,
which have recently been found in some
central-southern Italian regions, from
Tuscany to Molise, where they are
edaphic-xerophilous formations. In
central Italy, where the Apennines are
divided into calcareous ranges,
subcontinental inland areas also contain
pubescent oak, although with a different
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78
Beech wood (Forca d’Acero, Abruzzo)
flora, which has led to their division into
several associations. Only recently has
the Habitats Directive taken into account
pubescent oak woods, thanks to the
addition of Romania and Bulgaria to the
European Union, and has included them
in priority habitats (Habitat 91AA*
“Eastern white oak woods”).
Mediterranean and sub-Mediterranean
oak woods are greatly degraded by
grazing and excessive felling of timber,
and require good management if their
forest characteristics are to be
recovered. Deciduous Turkey oak woods
(Quercus cerris), sometimes mixed with
Italian oak (Quercus frainetto), like those
with pubescent oak, grow on both the
Italian and Balkan peninsulas (Habitat
9280 “Quercus frainetto woods”).
In Italy, they are ascribed to the alliance
endemic to the central-southern
Apennines Teucrio siculi-Quercion
cerridis, which includes several
associations found in the hills,
Apennines, and sub-coastlines on
sandstone, marl-sandstone and
sometimes even trachytic substrates.
Italian oak woods have very similar
characteristics to those of Turkey oak.
Italian oak, which grows in many
locations of the Tyrrhenian side in
central-southern Italy, from Tuscany
to Calabria, is found in several wood
associations.
Hill and mountain broadleaf woods also
contain the alliance Pino calabricaeQuercion congestae, on the
southernmost tip of Italy, Sicily and
Sardinia.
In Apulia, which is considered the most
typical oak region for its richness in
species, there are two oriental types:
Macedonian oak (Quercus trojana) and
Valonia oak (Quercus macrolepis = Q.
ithaburensis ssp. macrolepis). The former
Valonia oak (Quercus macrolepis)
is closely associated with the area of
the Murge (central-western Apulia and
southern Basilicata) (Habitat 9250
“Quercus trojana woods”). In Italy,
Valonia oak forms a monospecific type of
forest, unfortunately considerably altered,
in Tricase, on the Salento peninsula.
In other woods of the same location,
it occasionally mixes with holm oak
(Habitat 9350 “Quercus macrolepis
forests”).
In the eastern Alps, from Friuli Venezia
Giulia to eastern Lombardy, there are
beech woods belonging to the IllyrianApennine alliance Aremonio-Fagion,
distinguished into several sub-alliances
[Habitat 91K0 “Illyrian Fagus sylvatica
forests (Aremonio-Fagion)”].
In the central-northern Apennines, these
beech woods are part of the sub-alliance
Cardamino kitaibelIi-Fagenion sylvaticae,
which may be found as far as the
calcareous reliefs of the Abruzzi
Apennines.
The Habitats Directive considers
Apennine beech woods important
because they contain holly (Ilex
aquifolium) and yew (Taxus baccata).
Southern Italian beech woods belong
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to the endemic alliance Geranio
versicoloris-Fagion, with two suballiances distinguishing the lower and
upper mesotemperate bioclimates.
The former contains the sub-alliance
Doronico orientalis-Fagenion, which
includes beech woods of the Umbria
Forest, a large forest in the Gargano. The
latter has the sub-alliance Lamio flexuosiFagenion, with microthermal beech
woods of the southern Apennines of
Calabria and Molise (Habitat 9210*
“Apennine beech forests with Taxus and
Ilex”). A particularly interesting Apennine
habitat is 9220* (“Apennine beech forests
with Abies alba and beech forests with
Abies nebrodensis”): it has been defined
heterogeneously because it also hosts
relict populations of Sicilian fir, mixed
with large, well-structured populations of
beech and European silver fir covering
extensive areas of the Apennines,
although greatly influenced by human
activities. As regards the first aspect of
this habitat, woods containing beech and
European silver fir grow in a patterned
fashion from the Tuscan-Emilian
Apennines to the Aspromonte, in areas
with a temperate macrobioclimate with
supratemperate, occasionally
mesotemperate thermotypes. These
woods, especially in the southern
Apennines, host an endemic subspecies
of European silver fir, Abies alba subsp.
apennina, which has only recently been
described. In addition, there are large
numbers of orophilous species,
considered relicts of the orophilous
Tertiary flora that remained isolated on
these Mediterranean mountains after
glaciations.
In the southern Apennines, European
silver fir forests are very interesting
(Habitat 9510* “Southern Apennine Abies
alba forests”) and have been found on
uplands potentially occupied by beech
The Montepiano wood (Tuscany) with holly (Ilex aquifolium)
woods of the Geranio versicoloris-Fagion
association. European silver fir forests in
Calabria have been ascribed to two
different associations: the Junipero
hemisphaericae-Abietetum apenninae, on
hills, rocky cliffs and steep mountain
slopes between 1400 and 1800 m, is a fir
forest with open tree canopies and a
Bearberry (Arctostaphylos uva-ursi)
thick scrubland of Juniperus
hemisphaerica. The other association,
Monotropo-Abietetum apenninae, is
found on very steep, north-facing slopes,
and contains dense canopies with a
floristic cortège richer in nemoral species
(living in woods). The fir woods of Molise
belong to the Pulmonario apenninaeAbietetum albae association, and those
in the Abruzzi (Monti della Laga) to the
Cirsio erisithalis-Abietetum albae.
In the Alps, beech forests that do not
belong to the typically eastern AremonioFagion alliance may be of northern origin,
typical of central Europe, and therefore
grow on the northern side. If they are of
Atlantic origin, they grow on the western
side. The former type is more frequent
and includes beech forests of the
neutrophilic alliance Asperulo-Fagion
and Fagion sylvaticae, in addition to the
acidophilic ones of the Lazulo-Fagion.
Atlantic formations are part of the suballiance Ilici-Fagenion of the LuzuloFagion. The Asperulo-Fagion and, in
particular, the Asperulo-Fagetum, are
composed of pure or mixed neutrophilic
beech woods, often containing European
silver fir and Norway spruce, living
between mesotemperate and upper
supratemperate bioclimates. Their
undergrowth has great floristic diversity
(Habitat 9130 “Asperulo-Fagetum beech
forests”). Thermophilic beech woods in
hilly and submontane areas of the
southern Alps are included in the suballiance Cephalanthero-Fagenion of the
Fagion sylvaticae. These cliff beech
woods grow in small areas and have rich
underbrush, with Ostrya carpinifolia,
Quercus pubescens, Fraxinus ornus,
Buxus sempervirens, several sedges and
nemoral orchids (Habitat 9150 “MedioEuropean limestone beech forests of the
Cephalanthero-Fagion”). Subalpine
beech forests, which are sometimes
shrubby, contain sycamore maple (Acer
pseudoplatanus) and locally, larch, grow
near the upper forest limit, and belong to
the sub-alliance Acerenion pseudo
platani of the Fagion sylvaticae (Habitat
9140 “Medio-European subalpine beech
woods with Acer and Rumex arifolius”).
Central-European acidophilic beech
woods in submontane and altimontane
areas are part of the alliance LuzuloFagion and particularly the LuzuloFagetum, which includes pure or mixed
beech woods, sometimes with conifers
(Abies alba, Picea abies, Pinus sylvestris)
on silicate or particularly carbonate-poor
substrates with Luzula luzuloides,
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Polytrichum formosum, Deschampsia
flexuosa and Vaccinium myrtillus (Habitat
9110 “Luzulo-Fagetum beech forests”).
Lastly, acidophilic Atlantic beech woods
of the sub-alliance Ilici-Fagenion of the
Fagion sylvaticae develop in very acid
soil in the supratemperate bioclimate of
the Western Alps. Here they sometimes
come into contact with mixed formations
containing Quercus robur, which may
even dominate in the mesotemperate
bioclimate, and belong to the alliance
Quercion roboris of the order Quercetalia
roboris [Habitat 9120 “Atlantic
acidophilous beech forests with Ilex
and sometimes Taxus in the shrublayer
(Quercion robori-petreae or Ilici
Fagenion)”].
The phytogeographical relationship of
Italian mesophilous forests with those
in the Balkans occurs even in edaphicmesophilous forests dominated by
pedunculate oak (Quercus robur),
hornbeam (Carpinus betulus) and
Turkey oak in the upper mesotemperate
or lower supratemperate bioclimates in
deep, humic, neutral or slightly acid soils
on flat, slightly undulating land. From the
phytosociological viewpoint, these
coenoses are attributed to the alliance
Erythronio dentis-canis-Carpinion betuli
[Habitat 91L0 “Illyrian oak-hornbeam
forests (Erythronio-Carpinion)”] two suballiances of which live in Italy: Asparago
tenuifolii-Carpinenion betuli in the Po
plain, and Pulmonario apenninaeCarpinenion betuli in the central-northern
Apennines. In the southern Apennines,
they are replaced by the alliance
Physospermo verticillati-Quercion
cerridis, which includes mesophilous
Turkey oak forests growing on slopes,
maple woods with Neapolitan maple
(Acer obtusatum ssp. neapolitanum) and
hornbeam woods. The same may be said
of ravine formations of the alliance TilioAcerion with broadleaf forests growing in
gorges and in valleys near coarse debris
deposits. They contain broad-leaved lime
(Tilia platyphyllos), sycamore maple,
wych elm (Ulmus glabra), and many other
species. In the undergrowth of ravines
there are several types of ferns (Phyllitis
scolopendrium, Polystichum aculeatum,
mountain slopes. In the Alps, the most
widespread and attractive conifer forests
are composed of Norway spruce (Picea
abies), that covers entire valley slopes,
Norway spruce (Picea abies)
Hartstongue (Phyllitis scolopendrium)
P. braunii, P. setiferum). In Italy, these
habitats are dense in the Alps, but in
other parts of the peninsula grow as
relicts (Habitat 9180* “Tilio-Acerion
forests of slopes, screes and ravines”).
The alliance Lauro nobilis-Tilion
plataphyllae has recently been proposed
for southern Italy. It replaces the TilioAcerion and contains, in addition to
lime and wych elm, bay laurel, stinking
iris (Iris foetidissima) and many
Mediterranean species.
In the driest areas of the Alps and the
Apennines, there are partly natural
conifer forests, which are sometimes
hard to identify correctly because man
has made these trees grow well over
their potential, due to their economic
importance and because they grow
rapidly to cover extremely degraded
on both carbonate and silicate
substrates, in pure or mixed formations
with other conifers or beeches [Habitat
9410 “Acidophilous Picea forests of the
montane to alpine levels (VaccinioPiceetea)”]. These forests prefer the
subalpine level (Piceetum subalpinum),
where Norway spruce may grow at
altitudes of up to 2000-2300 m, often
together with European larch (Larix
decidua). In areas where the woods are
more open, there is alpenrose
(Rhododendron ferrugineum) and
Alpenrose (Rhododendron ferrugineum)
raspberry (Rubus idaeus). Among the
curious plants living in this environment,
there is the twinflower (Linnaea borealis)
dedicated to Carl Linnaeus, the father
of taxonomy.
The underbrush of montane spruce
forests (Piceetum montanum) in external
valleys and as far down as 900 m (even
300 m, for some single spruce
specimens) comes into contact with
stands of European silver fir and beech.
The undergrowth of mountain spruce
woods often contains woody species of
the beech forest cortège, revealing that,
in ancient times, these species were
deliberately planted. Proceeding from
east to west along the Alps, the belt with
spruce tends to become thinner and
thinner, as Norway spruce prefers a
continental climate. In the Western Alps,
particularly in Piedmont, it is only found
in the Ossola valley. In other locations,
these trees grow in fir forests with
European silver fir. Spruce forests are the
most important and widespread habitat
in the Alps, where they are expanding
rapidly in areas that were once
secondary grasslands. An example of
natural spruce forest, albeit very small
and therefore of great phyto- and
palaeogeographical importance, is found
in the Abetone area of the Apennines in
the Valle del Sestaione (Tuscany).
Research conducted by Chiarugi shows
that, during the Würm glaciation, spruce
reached the Tuscan coast and, when the
glaciers retreated, it only survived in the
highest locations of the northern
Apennines. The residual forest in the
Abetone, known as Pigelletum Chiarugi,
in which Picea excelsa (weeping Norway
spruce) mixes with beech (generally
attributed to the association Piceetum
subalpinum in the sub-association
myrtilletosum), is an exceptional relict
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Conifer forest with larch (Larix decidua) in the Julian Alps (Sella Bieliga, Friuli Venezia Giulia)
forest that urgently requires total
protection. Another conifer forest
particularly associated with the Alpine
environment is made up of larch, the
most typical plant of this mountain range
because European larch practically lives
only here, except for a few other
disjointed sites in the Carpathian
mountains and Poland (Habitat 9420
“Alpine Larix decidua and/or Pinus
cembra forests”). The European larch,
a microthermal, heliophilous species,
grows in the highest areas reached by
Alpine forest vegetation, and colonises
cliffs with continental climate between
800 and 2600 m in the Western Alps and
900-1900 m in the eastern Alps. Larch
grows in an open structure, typical of the
subalpine level and, in its most evolved
forms, is often associated with the Swiss
pine (Pinus cembra), producing the
association Larici-Cembretum (VaccinioPiceetalia).
Pure, natural larch forests are quite rare
and only found in inhospitable sites, like
screes and the pebbly banks of streams.
Most larch forests are severely influenced
by livestock grazing, as man keeps them
sparse in order to favour this type of
activity. Degraded aspects of this
vegetation are the so-called “park
landscapes”, in which larch woods grow
together with Alpine trefoil (Trifolium
alpinum) or matgrass (Nardus stricta)
grassland. Swiss pine may also give rise
to this type of landscape, albeit to a far
smaller extent, when it associates with
larch, producing dense woodland with
underbrush containing alpenrose,
blueberry and forest woodrush on
siliceous soils. In the Western Alps, it
associates with mountain pine (Pinus
uncinata=P. montana).
In the central-eastern Alps, the subalpine
and montane larch-Swiss pine woods,
which sometimes contain spruce, also
grow on calcareous substrates, and their
undergrowth hosts Rhododendron
hirsutum, Erica herbacea, Polygala
chamaebuxus and Pinus mugo. Spruce,
Shrubby milkwort (Polygala chamaebuxus)
Swiss pine and particularly larch colonise
abandoned grasslands quickly increasing
the Alpine forest cover. This natural
dynamic process is not always positive,
because the phythocoenotic diversity of
montane areas tends to be reduced,
because secondary grassland
environments, closely connected with
man’s activities, as already noted, are
important sources of biodiversity.
Mountain pine is found in various aspects
which, over time, have been attributed to
different species according to their
morphological characteristics, which
correspond to ecological conditions.
In Italy, there are two types: mountain
pine with tree characteristics, up to 10 m
high, with cones and asymmetric scutella
(found in the Western Alps and northern
Apennines), and the shrubby-creeping
Swiss mountain pine (Pinus mugo)
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growing up to 5 m high, with shorter,
round cones and symmetric scutella,
found in the eastern and central Alps,
Maritime Alps and central-southern
Apennines. The Habitats Directive makes
special reference to mountain pine in
Habitat 9430 [“Subalpine and montane
Pinus uncinata forests (*if on gypsum or
limestone)”] and to the protection of the
two types of forests it originates: one
mesophilous with Rhododendron
ferrugineum in the outer Western Alps, on
siliceous, decalcified soil of the subalpine
level (Rhododendro-Vaccinion), and one
xerophilous, growing in the inner Alps
and on the sunny slopes of the outer
Western Alps, in which Rhododendron
ferrugineum is rare or totally absent
(Ononido-Pinion). The communities of the
north-western Apennines belong to the
alliance Seslerio caeruleae-Pinion
uncinatae (Piceetalia excelsae).
Swiss mountain pine forests are some of
the most typical communities of
calcareous subalpine debris
environments in the Dolomites (southeastern Alps), and are also found at lower
altitudes, often near streams. Swiss
mountain pines naturally occur in the
Abruzzi-Molise Apennines, where they
produce relict, pioneering communities
on the mountains of the National Park of
Abruzzi, in Latium and Molise, on sunny,
steep flanks of the orotemperate
bioclimate, between 1800 and 2000 m,
and in the cryo-orotemperate bioclimate
up to 2500 m and on the Maiella [Habitat
4070* “Bushes with Pinus mugo and
Rhododendron hirsutum (MugoRhododendretum hirsuti)”].
Forests of Austrian pine (Pinus nigra) are
very common in Italy, but they are
generally the products of reafforestation
on the montane slopes of the Alps and
Apennines. Conversely, natural forests
with these trees are quite rare, and only
found in small areas. In the Eastern Alps,
the thermophilic Austrian pine (Pinus nigra
subsp. nigra) grows on the calcareous
Dolomites and, in the mountains of the
Abruzzi Park, the Italian variety of the
same species is found on the same
substrates. On acid substrates in
southern Italy there is Corsican pine
(Pinus nigra subsp. calabrica), which also
grows in Calabria (Sila and Aspromonte)
and on Mt Etna (Sicily) [Habitat 9530
“(Sub-) Mediterranean pine forests with
endemic black pines”]. On Monte Pollino
and some other peaks of the same range,
there are forests of Bosnian pine (Pinus
leucodermis=P. heldreichii subsp.
Bosnian pine (Pinus leucodermis)
Swiss mountain pines (Pinus mugo) in the Carnian Alps (Friuli Venezia Giulia)
leucodermis) distributed along the
beechwood belt between 1000 and 1400
m, where relict forests form. These are
open woods with monospecific trees and
several species of shrubs, large numbers
of common juniper and the rarer
Juniperus hemisphaerica (Habitat 95A0
“High oro-Mediterranean pine forests”).
At the upper limit of the beech forests, up
to 2000 m, some spectacular centuriesold Bosnian pines can still be found,
although associated with Alpine junipers.
They are considered to be durable, i.e.,
incapable of evolving due to the particular
environmental conditions.
On the Sicilian Madonie, there are rare
and localised relict populations of Sicilian
fir, presently amounting to 30 adult
specimens, 24 of which are sexually
mature, and 80 young trees that represent
the younger generation. This population is
associated with beech and Juniperus
hemisphaerica shrubs, and produces
sparse vegetation growing between 1360
and 1690 m, in a supra-oroMediterranean bioclimate affected by
frequent fog. It belongs to the association
Junipero hemisphaericae-Abietetum
nebrodensis of the class Pino-Juniperetea
(Habitat 9220* “Apennine beech forests
with Abies alba and beech forests with
Abies nebrodensis”). The name of the
class Pino-Juniperetea indicates
vegetation composed of gymnosperms,
which in the past occupied extensive
areas of the highest Mediterranean and
more generally, southern European
mountains, and was later almost
completely destroyed to provide space
for grazing land. In the western area of
the Mediterranean basin (North Africa,
Iberian Peninsula, Corsica and the
Western Alps), this vegetation is
associated with Spanish juniper
(Juniperus thurifera) and, in Italy, is found
in two sites: Valdieri (Val Gesso) and
Moiola (Valle Stura). Presumably, these
are refuge sites going back to before
the Würmian glaciation, because there
are several cliff endemics such as
Phoenician juniper (Juniperus phoenicia
subsp. phoenicia) which is clearly
different - although many taxonomists
do not acknowledge this - from the
thousand-year-old Sabinas (Juniperus
turbinata) of the Mediterranean coasts
(Habitat 9560* “Endemic forests with
Juniperus spp.”).
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