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Biological soil crusts exhibit a dynamic response to seasonal rain and release from grazing with implications for soil stability

January 1, 2009

In Northern Mexico, long-term grazing has substantially degraded semiarid landscapes. In semiarid systems, ecological and hydrological processes are strongly coupled by patchy plant distribution and biological soil crust (BSC) cover in plant-free interspaces. In this study, we asked: 1) how responsive are BSC cover/composition to a drying/wetting cycle and two-year grazing removal, and 2) what are the implications for soil erosion? We characterized BSC morphotypes and their influence on soil stability under grazed/non-grazed conditions during a dry and wet season. Light- and dark-colored cyanobacteria were dominant at the plant tussock and community level. Cover changes in these two groups differed after a rainy season and in response to grazing removal. Lichens with continuous thalli were more vulnerable to grazing than those with semi-continuous/discontinuous thalli after the dry season. Microsites around tussocks facilitated BSC colonization compared to interspaces. Lichen and cyanobacteria morphotypes differentially enhanced resistance to soil erosion; consequently, surface soil stability depends on the spatial distribution of BSC morphotypes, suggesting soil stability may be as dynamic as changes in the type of BSC cover. Longer-term spatially detailed studies are necessary to elicit spatiotemporal dynamics of BSC communities and their functional role in biotically and abiotically variable environments. ?? 2009 Elsevier Ltd.

Citation Information

Publication Year 2009
Title Biological soil crusts exhibit a dynamic response to seasonal rain and release from grazing with implications for soil stability
DOI 10.1016/j.jaridenv.2009.05.009
Authors Aguilar A. Jimenez, E. Huber-Sannwald, J. Belnap, D.R. Smart, Moreno J.T. Arredondo
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Arid Environments
Series Number
Index ID 70037214
Record Source USGS Publications Warehouse
USGS Organization