Spatial Distribution Patterns of the Antarctic Hair Grass Deschampsia antarctica in Relation to Environmental Variables on Barton Peninsula, King George Island

摘要

Understanding the patterns in species distribution and abundance along environmental gradients is a keystone in field ecological study. Because the Antarctic terrestrial communities are simple, they provide a suitable opportunity for studying species distribution patterns in relation to environmental gradients. We applied diverse geostatistic methods and classical statistic descriptors to analyze the spatial patterns of several variables, such as Deschampsia antarctica abundance, moss cover, topography, and soil physical and chemical properties. Directional semivariograms and kriged maps showed that strong anisotropy in a topographic variable was reflected in the soil variables. Especially, soil texture and moss cover were correlated with elevation, and electric conductivity and Na~+ were influenced by the distance from the shoreline. Furthermore, the heavy snowfall in 2009 evidently affected the survival of the grass. A short growing period and waterlogging induced by heavy snowfall may limit survival of D. antarctica and the amount of snowfall can be a important factor limiting the grass expansion.