Effects of Physical Disturbance on Arctic Vegetation in the Queen Elizabeth Islands

Abstract

As basic ecological information is sparse, a regional approach to the assessment of disturbance was used. A combination of manipulation experiments in the Truelove Lowland on Devon Island and investigations of past disturbance at a number of industrial sites elsewhere in the Canadian Arctic Archipelago was undertaken to gain comprehensive information on the effects of vehicle travel and other types of potential use in a broad range of habitats. Objectives were to determine the effects of physical disturbance and to assess the capacities of natural plant communities for recovery. GEOGRAPHY AND VEGETATION OF THE STUDY REGION The area covered included the northernmost islands of the Canadian Arctic Archipelago (primarily the Queen Elizabeth group, 75-80? N, 70-120? W) and excluded the large islands adjacent to the North American mainland (Banks, Victoria, Prince of Wales and Baffin). The climate of this region is ameliorated by the sea except in the interiors of larger islands where a more continental climate prevails. The summer cooling effect of largely frozen ocean plus the extreme latitude result in low growing season temperatures. Precipitation is low (5-20 cm/year) with some exceptions in mountainous areas. Parent materials vary from Precambrian Shield granitics on eastern Devon and Ellesmere Islands to late Tertiary and Quaternary alluvium and drift of the Arctic Coastal Plain along the north-western margin of the archipelago. Arctic platform sediments of Cambrian and Devonian age are exposed immediately west of Shield granitics on Devon and Ellesmere, but most of the archipelago is composed of uplifted Silurian through Tertiary sediments (Geological Survey of Canada 1969). High arctic soil characteristics are the result of low temperatures, frost action, and the presence of permafrost, which inhibits drainage and affects vertical movement of soil water. Wind erosion, salinization and, in particular, the sparseness of higher plants as a source of organic matter are also important factors (Tedrow 1966, 1968). A high frequency of limestone or other largely carbonaceous sediments is responsible for the predominance of alkaline soils. As most of the soils in the region are little more than sediments or colluvium weakly