diversity of species in beaverponds - martinez · introduction as a result of a re-introduction...
TRANSCRIPT
IntroductionAs a result of a re-introduction project in 1981 the EurasianBeaver returned to the Hürtgenwald, a large woodland area
in the Eifel mountain rangein the extreme west of Ger-many.
In the course of a diplomathesis (S. Schloemer) westudied the effects of thelarge scale changes to dra-gonfly and damselfly com-munities in the narrow,originally wooded, moun-tain valleys of the northerneifel.
MethodsIn order to compare beaver ponds with woodland streamsrepresentative of large areas north of the Alps, but yet notinfluenced by the beaver, we studied the following habitattypes:
1. Natural springs (definite woodland springs)
2. Streams (natural - semi-natural in woodland, not influenced by the beaver)
3. Beaver ponds (some 10 -15 years old, up to 2000 m², sunny to half-shaded).
4. Beaver ponds abandoned for 1 to 3 years.
All areas were searched for dragonflies and damselflies,their larvae and exuvia throughout the season in 2011 and2012. In addition chemical and physical parameters such as pH-value, temperature, and water speed were measured at allsample sites, and makrozoobenthos collected, in order togather information on the water quality in both the pre-sence and absence of the beaver.
Institute of crop Science and ResourceConservation (INRES)Department: Ecology of cultural landscape –Animal Ecology
ResultsWith a total of 29 species, the number of species in beaverponds is markedly higher than in ponds without beavers (4 species). Even in abandoned beaver ponds the number ofspecies is higher than in the streams (7 species).
Conclusion:Despite the relatively short period of time since the return of the beaver, and the rather small number of beaver ponds, the pondsalready now make a remarkable contribution to the conservation and spread of rare dragonfly and damselfly species.Beavers contribute markedly to nature and species conservation in the densely settled countryside of Central Europe. The speciesshould therefore be more greatly integrated into plans to implement conservation measures and renaturisation of water bodiesthan it has been to date.
Mean number of species in the four habitats
Mean values of running water species
source course of beaver abandonedstream pond beaver pond
source course of beaver abandonedstream pond beaver pond
1816141210
86420
3,0
2,5
2,0
1,5
1,0
0,5
0
Habitat createdby the beaverpromotes species diversityand frequencyof dragonfliesand Damselfliesfauna.
Established species also profit from thenewly createdhabitat.
� The extraordinary combinations of species (boreal alongside sub-Mediterranean species) � The extremely different habitat requirements of the species � The increase in typical stream dragonflies and damselflies in spite of damming by the beaver � The increase in part of highly endangered species
�Stream Source
Example: Rote Wehe
�Central stretchof the stream
Example:Frenck
� Beaver pond
Example:Thön
�Abandonedbeaver pond
Example:Frenck
Leucorrhinia pectoralis; RL 1 Biberteich Rote Wehe Leucorrhinia rubicunda; RL 2
Calopteryx virgo Orthetrum coerulescens; RL1 Cordulegaster boltonii; RL3 Ceriagrion tenellum; was considered as missing in the eifel
Foto
: Lut
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albe
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Foto
Joch
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oden
kirc
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DDiivveerrssiittyy ooff ssppeecciieess iinn BBeeaavveerrppoonnddssTThhee eeffffeecctt ooff tthhee EEuurraassiiaann BBeeaavveerr CCaassttoorr ff iibbeerr LL .. oonn DDrraaggoonnff ll iieess aanndd DDaammsseell ff ll iieess ((OOddoonnaattaa)) iinn tthhee NNoorrddeeii ffeell// NN RRWW..Sara Schloemer1, Lutz Dalbeck2, Andreè Hamm1
Contactaddress:
1 University of BonnInstitute of crop Science and Resource Conservation (INRES)Department: Ecology of cultural landscape – Animal EcologyMelbweg 42, 53127 Bonn, Germany, tierö[email protected]
2 Biological Institute of Nature Conservation District of Düren e.V.Zerkaller Straße 552385 Nideggen, [email protected]
[email protected]@[email protected]
Particularly notable are:
Rote
Weh
e
Wei
ße W
ehe
Frenck
Thön
1000 0 1000 Meter�
The beaver-territory with its great variety of very different habitats offers living space for dragonflies anddamselflies in any develop-mental stage.
Wehebach Reservoir inflowsHürtgenwald
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