CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Breen, K.; and Lévesque, E.
Date : 2007.
Title : Proglacial succession of biological soil crusts and vascular plants on a High Arctic glacier foreland.
Publication : ArcticNet 2007 Annual Scientific Meeting. December 11-14, 2007. Collingwood, Ontario.
Issue : Programme.
Page(s) : 33.
Abstract
The retreat of glaciers over much of the High Arctic since the end of the Little Ice Age (LIA) ca. 1850 has resulted in the exposure of new land surfaces to biotic colonization. Pioneering microorganisms such as cyanobacteria, green algae, lichens, mosses, fungi and heterotrophic bacteria are typically the first organisms to colonize this new terrain. These organisms can coalesce over time to form a visible organic matrix on the soil surface known as a biological soil crust. In polar deserts or recently deglaciated areas devoid of higher plants, these early colonizers are crucial in initiating the formation of an organic and nutrient-enriched substrate in which more complex organisms may become established. This poster outlines the influence of biological soil crusts on the establishment and maintenance of vascular plants along the Teardrop Glacier foreland in Sverdrup Pass (79°N), Ellesmere Island, Nunavut. Vegetation community analysis and investigations of soil characteristics undertaken during the summer of 2004 demonstrate that this unique foreland supports a welldeveloped community of biological soil crusts and vascular plants with enhanced soil moisture and nutrient characteristics. Greater plant species richness, cover and density were observed compared with other glacier foreland communities previously investigated in the Canadian High Arctic. Biological crusts were associated with rapid colonisation by vascular plants within 36 m of the glacier (<20 years following glacier retreat). Plant densities in the crusts were more than 3 times those of the surrounding polar desert region, underscoring the successful recruitment and establishment ability on the Teardrop foreland. Crusts did not increase seed retention or germination compared to bare soil; however, they significantly improved the nutrient status of the substrate. Species dominant in later successional stages (e.g. the shrubs Salix arctica and Dryas integrifolia) had a higher density in crust, suggesting that their successful recruitment and/or maintenance is associated with the presence of crust. Predicted increases in vegetation cover across the Arctic therefore may depend on the distribution of biological soil crusts.
Bibliography of Canadian Geomorphology