| Richards Island, Northwest Territories, Canada, is characterized by thermokarst lakes which record Holocene limnological change. This study reports for the first time thecamoebian assemblages and continuous annual lake water temperature profiles from these lakes. Ecological environments on Richards Island are influenced by a climatic gradient resulting from the contrasting influences of the cold Beaufort Sea to the north and the warm waters of the Mackenzie Delta to the east and west.;Population abundance and species diversity of thecamoebian assemblages on Richards Island are not significantly different from those reported from temperate and semi-tropical latitudes. However, certain assemblage characteristics such as large and coarse tests, dominance of assemblages by one or two species and low morphological variation are interpreted to be diagnostic of Arctic conditions. The camoebian assemblages in core material from the area indicate that the local climate may have changed within about the last 3 ka, which is unrecorded by pollen data.;Paleoenvironmental interpretations in a permafrost landscape have to take into account morphological instability of thermokarst lakes, which can be the cause of the paleolimnological and consequently faunal change. In this area geomorphology is clearly related to ecosystem development. |
