Polar desert vegetation and plant recruitment in Murchisonfjord, Nordaustlandet, Svalbard

摘要

Vegetation descriptions of Nordaustlandet, Svalbard (80°N) are not well represented in published literature. Harsh climatic conditions in polar deserts may limit vascular plant growth and reproduction and inhibit germination and establishment. Rapid climatic changes in polar areas may precipitate vegetation change, so documentation of present vegetation as a baseline for the future is important. A vegetation survey in the vicinity of Kinnvika in Murchisonfjord, Nordaustlandet, was thus carried out at 23 sites ranging from sparsely vegetated to almost complete cover on the slopes under a birdcliff. In total, 36 vascular plant species were recorded in the area, 28 species under a birdcliff and 21 species at the other sites. Twenty-eight species were registered within quadrats as established plants, and at least 15 species as seedlings and small plants. Vascular plant cover was generally low and varied between sites of differing moisture and nutrient content. The Shannon-Wiener diversity index, H, was also low, ranging between 0 and 2.0, demonstrating uneven distribution of vascular species, with one dominating species at the dry and wet extremes, and several species contributing in the mesic and moist sites. Manured birdcliff sites with high vascular diversity and cover provide important reindeer and geese forage in otherwise sparsely vegetated areas. At moisture limited sites, recruiting plant density significantly correlated to cyanobacterial crust cover. This crust ameliorates the substrate surface providing moisture, warmth, nutrients and a more stable environment for establishing plants, and is thus of major importance for plant community development in High Arctic polar deserts.