Annual variation in the distribution of summer snowdrifts in the Kosciuszko alpine area, Australia, and its effect on the composition and structure of alpine vegetation

Australian alpine ecosystems are expected to diminish in extent as global warming intensifies. Alpine vegetation patterns are influenced by the duration of snow cover including the presence of snowdrifts in summer, but there is little quantitative information on landscape-scale relationships between vegetation patterns and the frequency of occurrence of persistent summer snowdrifts in the Australian alps. We mapped annual changes in summer snowdrifts in the Kosciuszko alpine region, Australia, from Landsat TM images and modelled the frequency of occurrence of persistent summer snowdrifts from long-term records (1954–2003) of winter snow depth. We then compared vegetation composition and structure among four classes that differed in the frequency of occurrence of persistent summer snowdrifts. We found a curvilinear relationship between annual winter snow depth and the area occupied by persistent snowdrifts in the following summer (r²=0.9756). Only 21 ha (0.42% of study area) was predicted to have supported summer snowdrifts in 80% of the past 50 years, while 440 ha supported persistent summer snow in 10% of years. Mean cover and species richness of vascular plants declined significantly, and species composition varied significantly, as the frequency of summer snow persistence increased. Cushion plants and rushes were most abundant where summer snowdrifts occurred most frequently, and shrubs, grasses and sedges were most abundant in areas that did not support snowdrifts in summer. The results demonstrate strong regional relationships between vegetation composition and structure and the frequency of occurrence of persistent summer snowdrifts. Reductions in winter snow depth due to global warming are expected to lead to substantial reductions in the extent of persistent summer snowdrifts. As a consequence, shrubs, grasses and sedges are predicted to expand at the expense of cushion plants and rushes, reducing landscape vegetation diversity. Fortunately, few vascular plant species (e.g. Ranunculus niphophilus) appear to be totally restricted to areas where summer snow occurs most frequently. The results from this study highlight potential indicator species that could be monitored to assess the effects of global warming on Australian alpine environments.

The Documentary Take

Documentary photography and contemporary art are existentially quite distinct practices. Occasionally, with the passing of time, great documentary lifts from the contact sheet, the magazine page or the short print run book and finds its way onto gallery walls as art.Presented within the context of Walker Evans: the magazine work, curated by David Campany, The documentary take invites the question, what aspects of documentary practice are seeping into contemporary art now? In his commentary and practice, Evans distinguished between documentary as a forensic practice and the 'documentary style', which he saw as art making.With the exception of work presented by Ponch Hawkes and David Wadelton, the artists here—Destiny Deacon and Virginia Fraser; Simryn Gill; Sonia Leber and David Chesworth; Louis Porter; Patrick Pound and Charlie Sofo—are far from documentarians, yet all benefit from proximity to the foundational practice of Walker Evans.While Walker Evans may or may not be influential on these artists, his work forms a language that is now background knowledge for the making of images about the world where, artifice aside, truth is at least relevant. Perhaps documentary practice enables contemporary art to "attend to the real" [i], without binding it to a utilitarian or forensic intention.In attending to the real, the quest for the documentarian is to reveal something of the world, while that of the contemporary artist is to make meaning in and of the world.