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Katholieke Universiteit Leuven (2013)

Assessing the impact of anthropogenic stress on Moroccan temporary ponds using a resting egg bank analysis

Mertens, Jan

Titre : Assessing the impact of anthropogenic stress on Moroccan temporary ponds using a resting egg bank analysis

De impact van antropogene stress op Marokkaanse tijdelijke wetlands bepalen door gebruik te maken van een rusteibank

Auteur : Mertens, Jan

Université de soutenance : Katholieke Universiteit Leuven

Grade : Master in de Biologie 2013

Résumé
Wetlands are among the most productive ecosystems on the planet. Human kind depends heavily upon the ecosystem functions provided by these aquatic systems. Our influence induces a slow, yet steady degrading of the systems. Communities in (semi-)arid regions suffer the most since (temporary) wetlands there are often the primary water source. Temporary ponds are excavated, filled, drained, transformed into arable land, etc. resulting in the degradation of a naturally vulnerable habitat. Its destruction is followed by the loss of ecosystem services and species adapted to the temporary environment. Such temporary ponds must therefore be protected and monitored where possible.This study aimed at discovering the local, regional and anthropogenic (explanatory) variables that have an important influence on the community structure and species richness of Mediterranean temporary pond in the region of Benslimane (NW-Morocco). We conducted a resting egg bank analysis on sediment samples taken on-site. We then identified the hatched zooplankton community (Branchiopoda, Copepoda and Ostracoda) from each pond. The explanatory variables were also estimated and measured in the field.An optimisation experiment based on three temperature (10, 15, 20 °C) and conductivity (50, 500, 1000 µS/cm) regimes isolated the temperature and conductivity at which most species hatch within a 30-day period (20 °C, 500 µS/cm). These conditions were used in the actual hatching experiment. We used univariate and multivariate statistics to isolate the important explanatory variables that explain most of the variance in community structure and species richness. Finally, we compared the large branchiopod species richness found during the hatching experiment with a snapshot sampling of the active community during the start of the wet season (November).We find that several anthropogenic (e.g. amount of cattle, waste and agriculture in the ponds) and local (e.g. turbidity, hydroperiod and the surface

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Page publiée le 26 septembre 2017