Résumé
Identifying the respective role of environmental, landscape and management factors in explaining the patternsin community composition is an important goal in ecology. Using a set of 32 temporary ponds in northern Morocco westudied the respective importance of local (within the pond) and regional (density of ponds in landscape) factors and theimpacts of different land uses on the plant species assemblages, separating pond and terrestrial species. The mainhypotheses tested were that (1) species assemblages respond to both local and regional environmental factors, (2)anthropogenic pressure has a negative influence on the number of pond species, and that (3) human activities differ in theirimpact on pond biodiversity. The results showed that (1) local factors explain most of the variation in plant communitycomposition, and (2) land use impacts the communities through changing local environmental conditions, leading to a lossof typical pond species. Aside from recreation, all other activities (grazing, drainage, agriculture and partial urbanisation)significantly reduced the number of pond species. The conservation strategy for rare pond species should focus onmaintaining networks of oligotrophic ponds, while allowing only low-impact activities.