Soil–landform–plant-community relationships of a periglacial landscape on Potter Peninsula, maritime Antarctica

E L Poelking,A A Spielmann,C E R Schaefer,E I Fernandes Filho,A M De Andrade

doi:10.5194/se-6-583-2015

Abstract

Abstract. Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on the monitoring of climate change in maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated on Potter Peninsula, King George Island, maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil–landform–vegetation relationships. The vegetation map was obtained by classification of a QuickBird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities on Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils that have greater moisture or are poorly drained, and with acid to neutral pH, are favourable for moss sub-formations. Saline, organic-matter-rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felsenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens at the highest surface. Lichens sub-formations cover the largest vegetated area, showing varying associations with mosses.

Highlights

Ice-free areas in maritime Antarctica have a peculiar flora dominated by a “fellfield” physiognomy, cryptogams with dominance of bryophytes, two species of talus algae (Prasiola crispa and Prasiola cladophylla) and approximately 360 known species of lichens
The most rich and diverse flora is found in the oldest exposed areas that developed after the Holocene deglaciation, as well as in ornithogenic landscapes
Organic-matter-rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with associations of mosses and grasses, while stable felsenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and H. lugubris lichens, at the highest level

Summary

Introduction

Ice-free areas in maritime Antarctica have a peculiar flora dominated by a “fellfield” physiognomy, cryptogams with dominance of bryophytes (including mosses and liverworts), two species of talus algae (Prasiola crispa and Prasiola cladophylla) and approximately 360 known species of lichens. Two native phanerogams occur (Antarctic hair grass, Deschampsia antarctica Desv., and Antarctic pearlwort, Colonbanthus quitensis (Kunth) Bartl.; Øvstedal and Smith, 2001). The poorly diverse maritime Antarctic tundra ecosystems are best developed on ice-free areas under strong faunal influence during the summer period. Most biotic communities occur as small isolated patches, adapted to cold climate, relatively low light, high UV radiation and winter snow coverage (Bargagli et al, 1995)

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