Ecohydrology
One of the first big learning
projects
Geert van Wirdum
Deltares (TNO - National Geological Survey)
Overview of the area
LIFE-news
Engbertsdijksvenen
to make best use of the changed conditions. The water level in
the moat has now risen considerably.
The research used as a point of departure the measurements
made by the same researcher 30 years previously, even before the first embankment had been built around the bog.
Some of the features of a well functioning raised
bog system are a high and stable water level (little
fluctuation), a low concentration of dissolved sub-
Calculations based on the temperature readings indicate that
substantial amounts of water are still penetrating deep into the
bog. However, this will definitely decline if the water level in the
moat remains high enough in the summers ahead. Although
stances and few temperature changes. In the deeper
all these improvements have only just been introduced, the
reaches of a well functioning raised bog the water
growth of sphagnum moss has already demonstrated a strong
is virtually still. Consequently, the rainwater, and
recovery. All in all, positive developments!
therefore the summer heat and winter cold as well,
penetrate less deeply than in a damaged bog. In a
well functioning raised bog the sphagnum mosses
Research
are able to get new bog growth going and
to maintain it. Although it is known that the
The European Union has very varied and
water is a key factor in bog restoration, the
rich natural resources, which are of great
water flow cannot be measured directly.
biological, aesthetic and economic value. To
The alternative is to get an impression of
conserve these natural resources the EuroIncreased sphagnum moss growth in the heart of the raised bog.
the water flow by measuring the temperature of the bog. At present, not enough is
known about the natural variances in these
factors and of the influence on them of climate fluctuations. This research will make
the Engbertsdijksvenen one of the first big
learning projects that will give us an insight
If this brochure has made you curious about the area, come along
pean Union has set up Natura 2000. This is
and see it for yourself. From the ‘De Pluus’ bird-watching hide you
a cohesive network of protected nature re-
will have a fine view of the heart of the raised bog.
serves. The Engbertsdijksvenen is one of
Colophon
and is part of the Natura 2000 network of
the last raised bog areas in the Netherlands
protected nature reserves.
Impressions: Dutch 2,000 copies
The Engbertsdijksvenen LIFE project has been
into how the interior of the bog reacts to the restora-
made possible by the following organisations:
tion measures, in a period with a changing climate.
Text: Staatsbosbeheer en Grontmij
Englishs 500 copies
Hans-Bert Schikora, Geert van Wirdum, Grontmij
Design: Staatsbosbeheer
been built at some distance from the old bog embankments.
Printing: Multicopy Assen 2008
This has created a sort of ‘moat’ between the embankment
and the heart of the bog, which will first rise to the desired
water level with the help of rain water before the water level in
More infor mation needed?
the heart of the bog rises. The moat was carefully filled thanks
Needless to say, you are always welcome at the offices of Staatsbosbeheer in Kloosterhaar,
to excellent teamwork between researchers and wardens: it
corporated overflows work well. Alongside this, full attention
continues to be paid to giving the flora and fauna sufficient time
Visibly better
Photo’s en illustrations: Bertus Webbink, Alex Huizinge
The new embankments around the heart of the raised bog have
was essential to ensure that the new embankment and the in-
1978
Geert van Wirdum studied the heart of the raised bog in 2007. There
was a lot more Purple moor-grass in 2007 than in 1978, as can be
seen from the photo at the top of the front page. An increase in Purple
moor-grass indicates dehydration.
Dorpsstraat 1a, contact person Roy Dear, raised bog warden district Salland-Twente
tel: 0523-241453 / 06-55765197 of [email protected]
2008
Invertebrates
Visibly better
Visibly better
Roy Dear, Raised bog warden
Salland-Twente District
Staatsbosbeheer Eastern Region
Northern harrier
To strengthen the relationship of the
heart of the raised bog with its direct surroundings, additional measures
have been taken on the north side. These include raising several footpaths, cutting of the dried-out top layer of the peat and removing scrub.
Despite the experience gained through various restoration projects, one
One of the last uncut areas of raised bog
in the Netherlands, with a surface area of
Keeping abr east of r aised
bog wildlife
of these species have been able to sustain themselves in the
Effect on nesting birds
core area despite peat extraction, burning peat to grow crops,
Gert-Jan van Duinen,
Bargerveen Foundation/department of Animal
Ecology, Radboud University of Nijmegen.
tury. If the water level were to rise sharply and a flood were
Herman Hazelhorst,
Engbertsdijksvenen bird count group
can never be certain how nature will react. So it was a surprise to see the
Little ringed plover and the Redshank starting to nest on the newly created
bare marsh area, but it was also comforting to know that winter guests
Nesting birds
The new embankments and weirs enable the water
dehydration and other changes that took place in the last cento occur in the core area of the raised bog, there is a chance
that these species would disappear, because in that case there
As a bird count group we made a study of nesting
could temporarily be insufficient nesting places and foraging
birds in the period prior to, during and after the
areas and the lack of prey could make it hard for ants, spi-
embankments were built (2003 to 2007). From the
ders and ground beetles to stay alive. The chance of these
beginning of April to mid-June we carried out five
nine hectares, has been saved for the fu-
like the Northern harrier, Great grey shrike and Pink-footed goose had
level to be controllably raised, at the same time
ture to form the heart of the regenerating
remained faithful to the area.
taking the vulnerable and characteristic local wild-
bertsdijksvenen again is very small, because potential source
nesting bird surveys, focusing on species on the
life species into consideration. After all, raising the
populations in other bog or wet heath areas are many kilome-
Red List and other scarce and rare species, such as
tres away. This is why the water level is being raised gradually
the Bluethroat. This research showed that, although
raised bog reserve. Solid embankments
have been built up around this vital part,
This large-scale raised bog restoration project is possible only if many
people are willing to associate themselves with the project. In this context
water level rapidly and substantially could lead to
less mobile wildlife species being able to colonise the Eng-
and changes in the core area of the raised bog are being moni-
building the embankment has an impact on the area,
Bleutroath
All in all there has been no negative effect, or at least no major
I would like to compliment, on behalf of Staatsbosbeheer (Dutch For-
the regrettable disappearance of rare and charac-
the conditions are now ideal for active
estry Service), the local residents, the Kloosterhaar local interest group,
teristic insect species. Therefore, at the start of the
the effect on the incidence of these nesting birds is
restoration process a precise study was carried out
relatively slight. This is why the embankments were
and a relatively small section of the original area has been af-
of the species present in the core area of
built outside the breeding season (i.e. after 15 June).
fected (where the embankment now stands). The
the raised bog. By assessing what species
It was also an important condition for the bird count
numbers must be considered relative to the total
are present now and repeating the study in
group to be able to agree to the work protocol that
a few years time, we can evaluate precisely
contractors have to abide by.
lovers, consultancies and contractors. I would also like to mention local
and establishment of sphagnum
authorities at various levels, such as the municipality of Twenterand, the
mosses in and directly around
municipality of Hardenberg, the Regge & Dinkel district water board, the
the heart already demonstrate
this. The excess rainwater on
Province of Overijssel, the Ministry of Agriculture, Nature and Food Quality
and last but not least the European Commission on behalf of LIFE-Nature
and Natura 2000.
the raised bog flows via overflow
facilities to the adjoining lower
parts of the site, thereby helping
The new De Pluus bird-watching hide on the north side of the raised bog,
the changed footpaths and the two new information panels enable the
general public to enjoy the Engbertsdijksvenen – a living raised bog in
the raised bog to form there as
development. The general public can now also see these developments
well.
better.
It is not yet known whether the restoration is on schedule, but several
Nor is this expected: the heart of the raised bog is still there
and birdlife have the opportunity of moving slightly
within the reserve. The numbers of most species
in the reserve are stable. Pioneer species like the
Little ringed plover have benefited, as is customary
fauna study particular attention has been
in this type of intervention.
paid to ground beetles, spiders, ants and
aquatic insects such as water beetles and
dragonfly larvae.
The Bluetroath, in spite of construction activities, remains true to
the embankments and it’s surroundings
During the study more than 100 spider species,
50 beetle species, 13 ant species, 10 grasshopper
ment, the plant growth and the animal world. The restoration work, such
species and dozens of other insect species were found in the
as gradually raising the water level, is being carried out on the basis of
Engbertsdijksvenen. Several of these species, such as the
the results of that research. Moreover, the results are being exchanged
be found throughout this brochure.
negative effect on the numbers of nesting birds up to now.
numbers in the Engbertsdijksvenen. It is a big area
the effects of the restoration project. In the
researchers are following closely the developments in the water manage-
internationally with managers of other raised bog areas. The findings can
tored closely.
The Pirate wolf spider is a characteristic spider species that inhabits
wet and open marshes such as sphagnum moss carpets. This spider
carries its eggs in a white egg sac under its rump (above). As soon as
the young spiders hatch, they climb onto the mother’s rump (below).
Number of birds
Number of pairs
70
8
Black bog ant and the characteristic Peatland beetle Agonum
65
7
ericeti (see photo), were found only in the core area of the
60
6
55
5
50
4
45
3
40
2
35
1
raised bog. This ground beetle cannot fly and Black bog ants
get around mainly on the ground too. Fortunately, populations
A population of the
rare and threatened
Peatland beetle Agonum
ericeti has managed to
sustain itself in the Engbertsdijksvenen despite
dehydration and grassencroachment in recent
decades.
Research
Foreword
raised bog. The spontaneous increase
the Sibculo local interest group, contract farmers, users’ groups, nature
Research
creating an area of 20 hectares in which
Explanation
Total number of birds in the
whole of Engbertsdijksvenen
Total number of pairs in the area
surrounding the embankments
Construction period of the
2003
2004
2005
Visibly better
2006
2007
embankments