CONICET | Buscador de Institutos y Recursos Humanos

Climate-change forecasts predict increases in the frequency and intensity of droughts, which will affect biosphere integrity, biogeochemical flows, and land-system change. The impact of droughts on ecosystems depends on drought magnitude and the sensitivity of ecosystems to drought. We still lack a full understanding of what drives ecosystem sensitivity to drought: Does sensitivity varies in parameter space? Does it vary along climatic and soil variables? The International Drought Experiment as part of the Drought-Net Research Coordination Network is a distributed rainfall-manipulation experiment aimed at assessing terrestrial ecosystem responses to extreme drought. Drought-Net is poised to test hypotheses about the bio-physical variables that control sensitivity to drought. The ability of the network to test these hypotheses depends on whether it covers the global range of climate and soil variables. The objectives of this study were (1) to describe the global distribution of climatic and soil variables that may control ecosystem sensitivity to drought, and (2) to assess Drought-Net coverage in this parameter space. To accomplish these objectives, we selected climate and soil variables from global datasets to assess the distribution of these variables. Then, we evaluated the distribution of Drought-Net sites against these global patterns. We found that the Drought-Net network indeed represents the global variability of major climatic - mean annual temperature, precipitation, seasonality, continentality and precipitation range- and soil variables ? texture, depth, slope and soil organic carbon. We also observed that the different continents harbor unique combinations of soil and climate variables. Therefore, experiments distributed in a single continent cannot fully address hypotheses about ecosystem sensitivity to drought because they would be missing important combinations of variables and major controls on ecosystem functioning. Our results highlight global patterns of climate and soil variables that could be used in the design of future distributed networks and in evaluating past conclusions.