Primary succession of lichen and bryophyte communities following glacial recession on Signy Island, South Orkney Islands, Maritime Antarctic

Abstract

Abstract:A directional primary succession with moderate species replacement was quantitatively characterized on Signy Island in zones of a glacial valley corresponding to their age since deglaciation. A continuous increase in diversity and abundance of lichens and bryophytes was observed between terrains deglaciated in the late 20th century, to areas where deglaciation followed the Little Ice Age, and others thought to be ice-free since soon after the Last Glacial Maximum. Classification (UPGMA) and ordination (principal co-ordinate analysis) of vegetation data identified three different stages of development: a) pioneer communities, which rapidly develop in a few decades, b) immature communities developing on three to four century old terrains, and c) a climax stage (Polytrichum strictum-Chorisodontium aciphyllum community) developing on the oldest terrains, but only where local-scale environmental features are more favourable. Multivariate analysis including environmental parameters (canonical correspondence analysis) indicated terrain age as being the dominant controlling factor, with other environmental factors also exhibiting significant conditional effects (duration of snow cover, surface stoniness). These findings not only quantitatively verify reports of the rapid colonization of Maritime Antarctic terrains following recent climate amelioration and associated decrease in glacial extent, but also show how local-scale environmental resistance may slow or even prevent vegetation succession from pioneer to more mature stages in future.

Spectral Discrimination of Vegetation Classes in Ice-Free Areas of Antarctica

“…Changes in vegetation can occur at very short-term scales, for instance due to trampling by humans [59] or indigenous animals (e.g., seals [60]), or at longer time scales, for instance due to climate change and glacial and permafrost retreat [6,29,61]. Reliable detailed mapping of different vegetation classes is important for monitoring changes in distribution at these time scales.…”

“…The Maritime Antarctica has experienced rapid warming over the past 50 years, and additional, more accelerated warming is predicted for the future [1,5]. Increasing temperatures result in the recession of glaciers and snow, exposing new bare ground for colonization by pioneer vegetation [6,7]. They also involve longer summer-growing seasons and higher water availability, thus ameliorating the harsh conditions prevailing in Antarctica.…”

“…Different communities characterize the successional stages of vegetation colonization after glacier and snow recession. These are indicative of the age of the terrain and of some environmental factors with important effects on vegetation development [6,17].…”

Cross-disciplinarity in the advance of Antarctic ecosystem research

“…Many of these processes have been occurring more extensively in recent decades (e.g. Favero-Longo et al, 2012) and open the opportunity to study them for the first time in the history of science.…”

Successional patterns along soil development gradients formed by glacier retreat in the Maritime Antarctic, King George Island

“…Unlike glacier retreat in montane areas on temperate continents, where invasions of higher developed plants occur rapidly from nearby vegetated areas, successional gradients in Antarctica largely follow a pattern of development from cyanobacteria and eukaryotic algae towards mosses, liverworts, and lichens and without interference from higher plants. Although studies on microbiological successions in short chronosequences in proglacial areas exist [15,16], there are few studies of vegetational succession along larger temporal gradients [17].…”