Mediterranean Institute of Ecology
and Palaeoecology
Eco-biogeographical features and
threats within the Mediterranean
biodiversity hotspot
Pr. Frédéric Médail
Biodiversity and biogeography
of the Mediterranean region
The 34 terrestrial biodiversity hotspots of the Earth
The Mediterranean region, a major hotspot of plant biodiversity
2.1 millions km2 under a Mediterranean bioclimate
10 regional hotspots of plant biodiversity
10% of vascular plants richness of the World on 1.6% of the Earth surface
Europe : 11 500 plant species on 9.9 millions km2
Médail F. & Quézel P., 1997. Annals of the
Missouri Botanical Garden, 84, completed by
Véla E. & Benhouhou S., 2007. Comptes-Rendus Biologies, 330.
Biodiversity of the Mediterranean region
Specific
richness
Endemic
species
Endemism level
≈ 25 000
≈ 12 500
50%
Butterflies
321
148
46%
Reptiles
228
77
34%
Amphibians
86
27
31%
Freshwater fishes
216
63
29%
Mammals
224
25
11%
Breeding birds
497
32
6%
Taxonomic
group
Flowering plants and ferns
Diversity and heterogeneity of Mediterranean bioclimates
The different bioclimates defined by annual rainfall
Quézel P. & Médail F., 2003. Ecologie et biogéographie
des forêts du bassin méditerranéen. Elsevier, Paris.
Diversity of Mediterranean vegetation and landscapes
Altitudinal organisation into vegetation belts
North
South
Maritim Alps
Corsica
Diadema K. & Noble V., CBNMP, ined.
Gamisans J.,1991. La végétation de la Corse.
Conservatoire et jardins botaniques, Genève.
An oustanding biogeographical crossroads
The Mediterranean region and the adjacent biogeographical regions
White F. & Léonard J., 2001. Flora et Vegetatio Mundi, 9.
A highly complex and « reticulate biogeography »
Helicodiceros muscivorus
(ca. 30 Myr)
Arum pictum
(ca. 15 Myr)
Imprint of Tertiary history for the genetic structure of plants
The distribution of modern molecular lineages of Cork
Oak (Quercus
(Quercus suber), a probable testimony of the
Tertiary palaeogeography of the W. Mediterranean.
Distribution of the 5 cpDNA haplotypes and phylogenetic reconstruction
(110 populations, 14 cpADN markers)
of the relationships among them
Magri D. et al., 2007. Molecular Ecology, 16.
Biogeographical and evolutive role of the Messinian Crisis
Messinian Salinity Crisis (5.6-5.33 Ma):
- Promote active speciation of the
seeders’ lineage (ex. Cistus)
- Facilitated migrations of xerophytic
and halophytic plants
First MS crisis
Lygeum spartum
Second MS crisis
Lygeum spartum
Suc J.-P., UMR PEPS, Lyon, ined.
Pattern of tree richness linked to Quaternary glaciations
Tree richness for Europe at 27.5 km2 grain
Total number of tree species = 187
Variation of tree richness:
- Main driver = contemporary climate
- Second driver = lenght of time since an
area became deglaciated
(cell age explained 6-16% of the variance)
The major refugia of plants according to phylogeography
Médail F. & Diadema K., 2009. Journal of Biogeography,
Complete congruence between refugia and endemism areas
Zones of high endemism
(Médail & Quézel, 1997)
Refugia areas
(Médail & Diadema, 2009)
Significant over-representation of refugia within hotspots
Half of the 52 refugia are included in the 10 Mediterranean regional hotspots
(chi--2 = 29.26; d.f. = 1; P < 0.001).
(chi
Médail F. & Diadema K., 2009. Journal of Biogeography,
36.
An important centre for the wild relatives of crops
B
A
Near Eastern sites < 9000 B.C. with archaeobotanical cereal assemblages
The 2 main waves for the initial advancement of the Neolithic culture into Europe
Light gray zones: area of the Cardial culture (7500-6800 cal. B.P.) - Dark gray zones: area of the Impressa culture (8000-7500 cal. B.P.)
A : Fernandez H. et al., 2006. PNAS, 103.
B : Willcox G., 2005. Vegetation History and Archaeobotany, 14..
An important centre for the wild relatives of crops
Distribution of the Robert’s
Cabbage (Brassica montana Pourr.)
Populations of
Nice-Menton
Populations of
Toulon-Hyères
Brassica oleracea L. group (2n = 18 chromosomes) progenitor of:
- Several «culti-groups» of vegetable Cabbages: Cauliflower,
Brussels sprout, Broccoli, Kohlrabi
- Diverse fodder Cabbages
- Colza (B. oleracea X B. rapa).
Snogerup S. et al., 1990. Willdenowia, 19.
Threats on
Mediterranean biodiversity
Mediterranean ecoregions: confronting a biome crisis
Source : Millennium Ecosystem Assessment
Hoekstra J.M. et al., 2005. Ecology Letters, 8.
Main threat induced by the increase of human impacts
A huge increase (≈ 50%) of human population on coastal areas
Population changes (1960-2000) and projections to 2030,
for the main cities of the Mediterranean countries.
Destruction and fragmentation of Mediterranean forests
Cedrus atlantica
Cedrus libani
Main phases of the fragmentation process
(Harris & Silva-Lopez, 1992)
Quézel P. & Médail F., 2003. Ecologie et biogéographie
des forêts du bassin méditerranéen. Elsevier, Paris.
Land-use changes in the northern Mediterranean
Collapse of the agro-sylvosylvo-pastoral system
Central Var (Provence), around 1900
Schematic representation of major human-induced changes
in mixed Mediterranean oak woodlands
Central Var (Provence), year 2008
, 2006. Human Ecology, 34.
Fire hatching and pastoralism practices in Corsica
Micro-regions severely
threatened by fire hatching
between 1973-2004
Main cattle-rearings
A significant
congruence between
the most firefire-affected
micro--regions and the
micro
main areas of cattlecattlerearings.
28 000 starting fires
between 19731973-2004:
≈ 1000 starting fires /year
(Sartène: 992 fires !)
1/3 of the total surface
of Corsica was burned in
30 years :
207 838 ha in HauteHaute-Corse
108 615 ha in CorseCorse-du
du--Sud
Corsica Magazine, sept. 2005 & Prométhée Database (www.promethee.com)
Invasion by alien plants due to land-use and climatic changes
France
Spain
Mediterranean
sclerophyllous forests
and matorrals
Current vegetation
Vegetation map of the Tyrrhenian islands
according to the LJP-Guess model
France
Spain
Forests with broadleaved
invasive trees
(Ailanthus, Robinia)
Current distribution of
Ailanthus altissima in Corsica
(UE project EPIDEMIE, IMEP)
Tree of Heaven
Simulated vegetation for 2050
Gritti, Smith & Sykes, 2006. Journal of Biogeography, 33.
Spatial congruence between refugia and human population
Mediterranean refugia
Density of human population
25% of the refugia located
in sectors where human
density is very important
(> 250 inhab.
inhab. / km2)
Médail F. & Diadema K., 2006. Annales de Géographie, 651.
The amazing persistance of unique biodiversity in urban area
Principauté de Monaco:
World’s highest density of human population, but…
- 350 native plant species (18 with «patrimonial value»)
- ca. 350 Coleoptera species (2 new unknown species)
Principauté de Monaco
Area = 1.95 km2
16 000 inhabitants / km2
Programme MONACOBIODIV
Global change and extinction
risks of Mediterranean plants
Putative impacts of global change on Mediterranean ecoregions
3 scenarios of expected change
in biodiversity for the year 2100,
in case of null (A), antagonistic (B)
or synergistic (C) interactions.
According to different drivers:
Biotic exchanges
Land-use changes
Nitrogen deposition
Atmospheric CO2 deposition
Climatic changes
Sala O.E. et al., 2000. Science, 287.
Plant migrations linked to climatic changes?
Expansion of thermophilous plants in the N. Mediterranean: the case of Chamaerops
World distribution of the Dwarf Palm
D’après Médail F. & Quézel P. 1996. Comptes-Rendus de l’Académie des Sciences, Sciences de la Vie, 320.
Sardinia, E. coast, Cala Gonone.
Distribution of current populations in Mediterranean France
Source: Database SILENE of the CBNMP, http://silene.cbnmed.fr/
Mass extinction of European plants, or biased estimations?
DEFICIT
of
species
loss
EXCESS
of
species
loss
Regional projections of
the residuals from the
multiple regression of
species loss against
growing-degree days and
moisture availability.
Highly variable species loss across
climatic scenarios (27-42%) and regions
(2.5-86%)
Excess of species loss (ca. 60%):
mountain
areas,
Ibero-Lusitanian
region, ecotone zones between the
Mediterranean
and
Euro-Siberian
regions
Deficit of species loss:
Southern Mediterranean and part of the
Pannonian region
N = 2294 plants ⇒ 1350 plants (> 20 pixels)
The paradox of low plant extinction in the Mediterranean
Blondel J. & Médail F. 2009. Biodiversity and conservation.
In : J.C. Woodward (ed.). The physical geography of the
Mediterranean. Oxford University Press, Oxford.
Current survey:
42 species and sub-species probably extinct
(+10 doubtful taxa) within the Mediterranean
bioclimatic region
i.e. an extinction rate of 0.15%
16 of these taxa were not cited by Greuter
(1994) and only half of them are common in
the two surveys
Few taxa seem to have become extinct in
the Mediterranean region, except perhaps
on some islands (9 taxa = 21.4%)
?
North Africa
Syria - Lebanon - Jordany
Turkey
Greece
Croatia - Macedonia
Italy
France
Spain - Portugal
Extinct plants
0
1
2
3
?
4
5
6
7
8
9
10
Plant extinctions and habitat types in France
100%
90%
80%
Rochers
Rocky habitats
70%
Fruticˇes
Matorrals
60%
Pelouses
Grasslandset prairies
50%
Zone
littorale
Coastal
habitats
40%
Zones
humides
Wetlands
30%
Zones
anthropisˇes
Anthropogenic
habitats
20%
10%
0%
Nord
n = 115
Var
n = 140
Corse
n = 66
Extinctions:
9%
6.2
%
3.5 %
Extinctions
recensˇes
France
(continental)
S.E France (165 inhab./km2)
Corsica (47 inhab./km2)
R. Verlaque, IMEP, ined.
Plant extinctions in the Hérault departement (S.E. France)
Determinants of change on the rare Mediterranean flora during 115-years
The regional assemblage of rare plant species (1-2
occurrences) significantly changed during 18861886-2001
Rare species in 1886, and Eurosiberian plants have
a significantly higher rate of extinction
Mediterranean plants and orophytes remain stable
Lavergne S., Molina J. & Debussche M., 2006, Global Change Biology, 12.
Importance of local persistance for Mediterranean plants
Ancient distribution of Zelkova in Europe
Zelkova sicula
Garfi G., 1997. PhD Thesis, Aix-Marseille III University
Representation of multiple demographic
strategies of persistence and regeneration of
a long-lived species, and the biological traits
promoting them
L = Longevity
VR = Vegetative Reproduction
S = Seeding
Garcia & Zamora, 2003. Journal of Vegetation Science, 14.
Zelkova sicula population, Mts Iblei (S.E. Sicily)
Some challenges to include
biogeography
in biodiversity conservation
Identification of areas of conservatism / diversification of PFTs
Two main hypotheses to explain the convergences of traits for Mediterranean plants
(i) Evolutionary adaptation, i.e. the production of new phenotypes by the action
of natural selection.
(ii) Niche conservatism, with a relative stasis in trait evolution, induced by the
ecological match between organisms and their environment.
In relation to key environmental drivers (climate, fire…)
In relation to biogeographical history
Between and within some crucial areas (refugia, hotspots, islands…)
Towards a delimitation of areas of evolutionary novelty
Genus richness and phylogenetic diversity in the Cape Floristic Region
Genus Richness
Phylogenetic Diversity (735 genera)
Residuals of the regression PD/GR
25 x 27 km (n = 201)
PD values < expected values
Needs to consider fine and local phylogeographical structures
Menorca
Mediterranean territories constitute
significant reservoirs of genetic
diversity, not only for widespread
Mediterranean plants, but also for
endemic ones, and even on a
small geographical scale.
Mallorca
Balearic Islands
Geographical distribution and parsimony network
relationships of 7 chloroplast haplotypes found in Senecio
rodriguezii
Assigning conservation priorities by Conservation biogeography
Conservation Biogeography
« Application of biogeographical principles, theories, and analyses, being those
concerned with the distributional dynamics of taxa individually and collectively, to
problems concerning the conservation of biodiversity »
Tipping points – an illustration of the concept
Photos:
Annie Aboucaya, Gianluigi Bacchetta, Katia Diadema, Frank Dhermain, Giuseppe Garfi,
Hervé Gomila, Frédéric Médail, Philippe Ponel, Philippe Orsini, Sébastien Sant.
http://www.imep-cnrs.com
Plant extinctions: South-East France versus Corsica
Rates of extinction and rarity at low altitude (< 1000 m), for each Raunkiaer’s growth-form
Extinction rate (%)
20
S.E France
18
Corsica
16
14
12
10
8
Therophytes
6
Hemicryptophytes
4
Geophytes
2 PhanerophytesChamaephytes
0
10
15
20
25
Low threatened
30
35
40
Vulnerables
Hydrophytes
Parasites
Rarity rate (%)
45
50
55
60
65
70
Threatened
Verlaque R., Médail F. & Aboucaya A., 2001. C.R. Acad. Sci., Sci. Vie,
324.