Potential role of high-altitude wetlands in preservation of plant biodiversity under changing climatic conditions in the arid Eastern Pamir

Abstract

High-altitude wetlands in the Eastern Pamir are habitat islands located in an arid landscape. They play several important roles, including that of water sources and forage grounds for people and their livestock. Considering high variation in micro-relief and complexity of water supplies observed in these wetlands, we assessed their potential to play a role of refugia for species whose present ranges may be limited by climate changes projected for Central Asia. Such species currently occur typically in less moist habitats, often located at lower elevations (e.g. steppe and meadow species). To perform this assessment, we analyzed current spatial structure and species diversity of vegetation accompanying selected water bodies in the studied catchments, identified present changes in temperature and precipitation in these catchments and analyzed alterations in area of lakes and small water bodies located in the vegetation mosaic. Presently, the biodiversity of the studied wetlands comprises 110 species of vascular plants from 26 families, forming ten distinct vegetation types, over 40 recorded species are typical for steppes and various types of alpine meadows. Both meteorological data and satellite data on open water area indicated that with growing temperatures, areas of the studied lakes and small water bodies in the vegetation mosaic increase. This effect is probably caused by thawing of ground ice and permafrost, whose occurrence helps mitigate the effects of the ongoing warming and lessening precipitation. Thus, the wetlands may temporarily maintain their cold, wet and mesic characteristics under the changing climatic conditions and, as such, potentially become refugia for steppe and meadow species. However, after the period of intense thawing, lowering of groundwater level and huge surface water fluctuations may occur, potentially resulting in a decrease in the total vegetated area on lacustrine and riverine terraces in the Eastern Pamir.