Shallow soft waters
Hein van Kleef (The person on the left)
| Bargerveen Foundation Department of Animal Ecology and Ecophysiology & Department of Environmental Studies Faculty of Science, Mathematics and Computing Science University of Nijmegen (KUN) P.O.box 9010 6500 GL Nijmegen The Netherlands tel: 024-3653275 fax: 024-3653030 GSM: 06-42092383 E-mail: Hvkleef@sci.kun.nl |
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Research
| During the last century most Dutch softwaters have disappeared or deteriorated as a result of land reclamation, acidification and eutrofication. As result the existence of many characteristic plants and animals is threatened. In order to ensure the survival of these ecosystems restoration measures are taken. These measures, consisting of removal of accumulated organic matter and restoring waterchemistry, have been successful in restoring characteristic softwater vegetations. However, little attention has been paid to the faunistic aspects of softwater restoration. And many questions about the effects of restoration on fauna remain unanswered. |  |
Direct effects of restoration
Most biota are removed with the restoration measures. For plants this posses no problems, because most characteristic species have persistent seedbanks from which they can repopulate the water. However, animals have to recolonize the water from other populations or survive the restoration measures. Surviving restoration in the long term may prove difficult for many species. If a species is able to persist in the water in the first place, it still has to succesfully complete its life cycle e.g. survive the larval stage, pupate and reproduce. After restoration the animal finds itself in a desolate area without shelter, food, etc. It may prove to be very difficult for an animal to complete its life cycle.
The direct effects of restoration are studied by comparing fauna composition before and after restoration measures have been taken. Shifts in species abundances are related to species traits and life cycles.
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Evaluation of former restoration projects
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In many softwaters restoration measures have been taken in the past. Evaluation mostly took place based on water chemistry and vegetation devellopment. So far it is unknown if restoration measures are able to restore characteristic fauna communities. Animals require different environmental circumstances than plants. it is unclear if the current restoration measures meet the animals' demands. Also, many aquatic macroinvertebrates have a limited flight ability and/ or are very rare, thus limiting their dispersal capacity. We expect that not all species are able to reach the restored waters and that additional measures have to be taken to ensure the survival of all characteristic fauna species in the Netherlands. Restoration projects are evaluated in 50 restored softwaters for different taxa (Dragonflies Odonata, Midges Chironomidae and Caddisflies Trichoptera). |
Dispersal, life cycle and habitat demands of Laccophilus poecilus
| As mentoned above, it is possible that animals experience problems completing their life cycle after restoration measures have been taken. An other problem may be the limited dispersal capacity of species. As a case study, I plan to investigate the dispersal ability, life cycle and habitat demands of Laccophilus poecilus. In the Netherlands the aquatic waterbeetle L. poecilus lives exclusively in softwaters. Its distribution is limited to three small areas in the provinces of Limburg and Brabant. In these waters it inhabits crevices in the shoreline dominated by macrophytes common in deteriorated waters (Molinea caerulea and Juncus effusus). So based on habitat preferences L. poecilus ought to be more widely distributed and is expected to be vulnerable for removal of macrophytes, a common restoration measure. |  |
Unwanted guests in restored waters
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After restoration an increasing number of waters become colonized by the Northamerican Pumpkinseeds (Lepomis gibbosus). Reproducing rapidly it can reach overwhelming numbers within a few years. Since nearly all native fauna is eaten by this fish, very few other species can survive in colonized waters. The reason why the Pumpkinseed can become a plage is probably because competition and predation are absent. |
| It is also possible that restoration management facilitates the settlement of Pumpkinseeds. Male Pumpkinseeds make depressions in the sand in which they guard the eggs. Before restoration they had ample oppurtunity to make these breeding holes because very few patches with sand were available. By creating breeding holes Pumpkinseeds possibly impede vegetation devellopment, reducing shelter for macroinvertebrates. The effects of Pumpkinseeds on softwater communities and the facilitation of Pumpkinseed settlement by restoration management will be studied in the field and micro- and mesocosms. |
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Student projects
Evaluation of softwater restoration
In many softwaters restoration measures have been taken in the past. Evaluation mostly took place based on water chemistry and vegetation devellopment. So far it is unknown if restoration measures are able to restore characteristic fauna communities.
In the early eighties the macroinvertebate communities have been studied in a large number of softwaters. Nowadays a lot of these waters have been restorated. In this study macrofauna composition will be surveyed in restored waters. Present fauna communities will be compared with those from 20 years ago. This study will determine if restoration management is able to restore softwater fauna communities.
Dispersal of Laccophilus poecilus
In the Netherlands the aquatic waterbeetle L. poecilus lives exclusively in softwaters. Its distribution is limited to three small areas in the provinces of Limburg and Brabant. In these waters it inhabits crevices in the shoreline dominated by macrophytes common in deteriorated waters (Molinea caerulea and Juncus effusus). Based on its habitat preferences L. poecilus ought to be more widely distributed. Is it possible that L. poecilus has problems colonizing new areas?
By comparing genetic differences between populations the dispersal capacity of a species can be assesed. In this study the genetic makup of populations will be studied in two closely related species (L. poecilus and L. minutus) using AFLP-techniques. Observed differences in dispersal capacity will be verified by measurements om wing and wing muscle morphology.
Effects of Pumpkinseeds on softwater communities
After restoration an increasing number of waters become colonized by the Northamerican Pumpkinseeds (Lepomis gibbosus). Reproducing rapidly it can reach overwhelming numbers within a few years. Since they eat nearly all species, Pumpkinseeds appear to have a major impact on other fauna. However, effects of Pumpkinseeds on vegetation still remain unclear. In this study field surveys and mesocosm experiments will be used to determine the impact of the Pumpkinseed on softwater communities.
Factors affecting Pumpkinseed settlement in restorated softwaters
After restoration an increasing number of waters become colonized by the Northamerican Pumpkinseeds (Lepomis gibbosus). Reproducing rapidly it can reach overwhelming numbers within a few years. A possible reason why the Pumpkinseed can become a plage is because competition and predation are absent.It is also possible that restoration management facilitates the settlement of Pumpkinseeds. Male Pumpkinseeds make depressions in the sand in which they guard the eggs. Before restoration they had ample oppurtunity to make these breeding holes because very few patches with sand were available. In this study meso- and microcosm experiments will be used to assess why Pumpkinseeds are able to reach high densities in restored waters.
Lemmings and large grazers: more than meets the eye?
Lemmings are notorious for complete collapse of their populations. For many years scientists have speculated and searched for the mechanism controling this phenomenon. Recent studies have demonstrated that the production of toxic substances by food plants is the probable cause. If this is true than grazing by other organisms is likely to affect Lemming cycles. The extensive literature on Arctic ecosystems will be used to study fluctuations in lemming populations in relation to the distribution and movements of grazers (Reindeer and Musk Oxes).
Publications
Journals and proceedings
Kleef H.H. van & J. Bustamante 1999. First recorded polygynous mating in the Red Kite (Milvus milvus). Journal of Raptor research 33(3): 254-257.
Volkov A.E., S. Khomenko, H. van Kleef & F. Willems 1999. Breeding of Brent Geese at Medusa Bay, Taimyr, and relation with Lemming predators. Casarca 5: 63-75.
Kleef H.H. van , R.S.E.W. Leuven, H. Esselink, R.P.W.H. Felix & G. van der Velde 2001. Herstelbeheer in vennen: macrofauna in gevaar? De Levende Natuur 102: 171-172.
Duinen G.A. van , H.H. van Kleef, J.T. Kuper, S.A. Lomans, T.M.J. Peeters, D. Scarse, J.G.M. Roelofs and H. Esselink, 2000. Does restoration of peatlands imply restoration of peatland dragonfly fauna? Proceedings of Québec 2000: 11th International Peat Congress, 764-770.
Duinen G.A. van, L. de Bruijn, D. Hanzen, H.H. van Kleef, J.T. Kuper, D. Scarse and H. Esselink, 2000. Do restoration measures help to restore dragonfly communities in raised bog remnants? Proceedings experimental and applied entomology, N.E.V., Amsterdam, Volume 11, 151-158.
Reports
Zekhuis M.J. & Tempelman (eds) 1998. Breeding birds of the Albanian wetlands, spring 1996. WIWO-report nr. 64, Zeist.
Willems F., C. van Turnhout, H. van Kleef & R. Felix 2002. Breeding birds of Medusa Bay, Taimyr, Russia. Methods for biological monitoring in the Arctic with results of 1998 and 1999. WIWO-report nr. 77, Zeist.