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Desert grasslands, which are very sensitive to external drivers like climate change, are areas affected by rapid land degradation processes. In many regions of the world the common form of land degradation involves the rapid encroachment of woody plants into desert grasslands. This process, thought to be irreversible and sustained by biophysical feedbacks of global desertification, results in the heterogeneous distribution of vegetation and soil resources. Most of these shrub-grass transition systems at the desert margins are prone to disturbances such as fires, which affect the interactions between ecological, hydrological, and land surface processes. Here we investigate the effect of prescribed fires on the landscape...
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Although drying of soil has increased fertility in laboratory-based experiments, a direct link between longer-scale weather conditions associated with drought and soil fertility has not been documented at the field scale. Soil from a semiarid grassland on the Sevilleta National Wildlife Refuge (NWR) that was collected over a 10-year period had the highest levels of potentially mineralizable nitrogen (PMN, a measure of potential soil fertility) during drought periods in 1989 and 1995. Whereas previous soil collections on the Sevilleta NWR were made for different reasons, soils were collected in June 2002 near the peak of a regional-scale drought to test the hypothesis that potential soil fertility increased with...
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