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

Jimenez, Aguilar, A.; Huber-Sannwald, E.; Belnap, J.; Smart, D. R.; Arredondo, Moreno, J. T.

Abstract:

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.

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Article

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70037214

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Jimenez, Aguilar, A.; Huber-Sannwald, E.; Belnap, J.; Smart, D. R.; Arredondo, Moreno, J. T.

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1169

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English

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Journal of Arid Environments

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Biological soil crusts exhibit a dynamic response to seasonal rain and release from grazing with implications for soil stability; 2009; Article; Journal; Journal of Arid Environments; Jimenez, Aguilar, A.; Huber-Sannwald, E.; Belnap, J.; Smart, D. R.; Arredondo, Moreno, J. T.