<p>THE IMPORTANCE OF AGE AND GRAZING FOR POND VEGETATION IN THE COASTAL DUNES OF BELGIUM</p><p>Denys L., Packet J., Provoost S.</p><p>Research Institute for Nature and Forest Kliniekstraat 25, B-1070 Brussel, Belgium [email protected]</p><p>Various ungulate grazers are used to facilitate nature management and restoration in the Belgian coastal dunes. Grazers can affect the rate and course of succession, e.g. by speeding up colonization through zoochory, preventing development of palatable species, or changing environmental conditions. As for terrestrial habitats, their impact on pond vegetation varies, although this remains poorly documented. Heavy animal activity obviously associates with poor pond quality and fencing may appear sensible to protect sensitive sites. Often, however, this is less appropriate for practical or aesthetic reasons. Moreover, some grazing regimes may well promote diversity and survival of early successional species valued for conservation, whilst negative consequences may be linked to particular soil conditions or hydrology. </p><p>Indirectly, the increasing application of grazing management also affects the number and (biological) age distribution of ponds: in the last 15 years, the number of ponds in the study area doubled due to widespread digging and many older ponds were dredged to provide sufficient drinking water. As such, activities of man and livestock have replaced natural processes as primary agents in the dynamics of surface water. </p><p>These recent developments in management allow us to explore extensively how age and large grazers affect the composition and development of dune pond vegetation, both independently and in combination. This results in a more balanced view on the effects of large herbivore activity and is a first step to better integrate the management of these ponds with that of their surroundings.</p><p>Ideetjes: Conceptueel schema voor effecten begrazing opstellen, met testbare indicatoren voor selectie van aantal hypothesen? Hoeveel op klei + en – begrazing (vermoed sterkere degradatie vanwege retentie, vertroebeling bij betreding)? Zijn die met horizontale stroming en vnml verticale GW fluctuatie te scheiden? Verhouding permanent geïnundeerd deel/droogvallend deel per poel te bepalen (ifv effect begrazing)? Grime? </p>