Modeling the Determinants of Species Distributions in Antarctica

Abstract

Considered from a functional ecological perspective, Antarctica's present-day terrestrial biota is the product of two sets of limiting factors: the continent's isolation from sources of immigrant propagules and the severe environmental stresses to which successful immigrants are exposed. The result is a low-diversity community composed almost entirely of stress-tolerant cryptogams, microarthropods, meiofauna, and microbes. In this paper a conceptual model is proposed that reduces the action of geographical isolation and environmental factors into a series of selection filters. It is argued that the low number of parameterizations needed to represent organism-environment interactions in Antarctica renders the simulation of macroscale patterns of species distributions a tractable proposition. Significantly, biotic interactions of the type that determine community structure at lower latitudes may be discounted. However, stochastic factors represent a source of “noise” that potentially reduce the model's predictive capability.