Environmental variables associated with littoral macroinvertebrate community composition in Arctic lakes

Abstract

The relationship between littoral macroinvertebrate communities and environmental gradients in Arctic lakes is poorly understood, making it difficult to predict whether these important components of lake ecosystems will be affected by emerging stressors such as permafrost thaw and road development. To better understand how littoral macroinvertebrates are related to environmental gradients, we characterized macroinvertebrate communities and environmental variables for 32 Arctic lakes across the boreal–tundra transition in the Northwest Territories. Our analysis showed that a small selection of variables had strong relationships with community structure: calcium, conductivity, latitude, surface area, catchment area, percent fine sediment, chlorophyll a, and whitefish (Coregonus clupeaformis or Coregonus nasus) presence. Many of these variables, including calcium, conductivity, and chlorophyll a levels, are affected by permafrost thaw and road dust contamination. Based on the direction and magnitude of these relationships, we hypothesize that macroinvertebrate abundance might decline in response to permafrost thaw and road dust contamination, while taxon diversity may rise. While correlative in nature, our results and hypotheses may be valuable as future studies evaluate ongoing changes in Canada’s Arctic lakes.