Biotic and abiotic factors influencing soil properties across a latitudinal gradient in Victoria Land, Antarctica. (Special Section: Antarctic and soil forming processes in a changing environment.)

摘要

Through the cooperative efforts of the Scientific Committee on Antarctic Research (SCAR) Evolution and Biodiversity in Antarctica (EBA) Project and the Latitudinal Gradient Project (LGP), a monitoring network was established in Victoria Land in 2002 to assess the impacts of climate change on vegetation, soils, active-layer dynamics, and permafrost across a latitudinal gradient. In this study, we report on the key factors influencing soil development across the gradient, including vegetation, parent material characteristics, and climate. Physical and chemical soil properties at depths of 2-8 and 10-20 cm were investigated at 7 sites and on 14 permanent plots from Apostrophe Island in Northern Victoria Land (73 degrees 30'S, 167 degrees 50'E) to Granite Harbour in Southern Victoria Land (77 degrees 00'S, 162 degrees 26'E) along the Ross Sea coast. The relationships among vegetation, parent material, and regional climate and soil properties were tested with Principal Component Analyses. There were no significant correlations or relationships in soil properties across the climate gradient. In fact, local microclimatic appears to be more effective than the regional gradient in influencing the properties. Microclimate was also important relative to active-layer depth and vegetation distribution. Lithology was strongly related to several chemical parameters, notably extractable Al, Fe, Ca, K, but was unrelated to grain-size distribution. Vegetation was related to the chemistry of the surface-soil layer, including nitrate, organic carbon, C/N ratio and water content, and also the active-layer depth. Penguins had the greatest influence on soil properties in initiating the development of ornithogenic soils. Further analyses on soil properties, including a greater number of sites, will be required to represent more extensively the lithological variability and to extend the latitudinal extremes of the gradient. The results presented here are an important reference for future monitoring activities in Victoria Land.