Zooplankton assemblages related to environmental characteristics in treeline ponds in Finnish Lapland

Zooplankton communities of 17 subarctic ponds with differing catchment area s and habitat types in northern Finland were surveyed during the open water season from June to August. Ponds were located along a gradient that chang es from a mountain birch woodland to a treeless tundra. In all sites, clado ceran abundance dominated that of copepods although there was a consistent pattern of increasing relative abundance of copepods toward the most barren ponds. Species richness declined with increasing altitude but diversity re mained constant. Zooplankton communities within the same habitat type were similar. Temporal variation in species abundance showed a coherent temperat ure driven pattern along the whole altitudinal transect.