Vegetation Succession and Environmental Relations at the Illisarvik Drained Lake Experiment, Western Arctic Coast, Canada

Illisarvik is a lake basin on Richards Island, NWT, that was experimentally drained in 1978. Surveys were conducted in 2016 at 110 sites within and surrounding the basin to study vegetation succession. These surveys extended previous records provided by L. Ovenden for 1985, 1993, and 2001. The vegetation at Illisarvik indicated a gradual shift towards undisturbed tundra species but was still compositionally distinct in 2016. Early colonizing species were rarely observed in 2016. Grasses and sedges have steadily increased in cover since drainage. Erect willows have become well-established since 1993, and the increased vegetation height has resulted in deeper snow packs. Surveys of other environmental characteristics in the basin indicated that volumetric water content and vegetation height were the primary factors controlling active-layer thickness and ground temperatures at Illisarvik. The vegetation height likely acts as a proxy for the insulating influence of the snow.