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Response of the long-clawed ground squirrel (Spermophilopsis leptodactylus) to sheep grazing on a semi-arid rangeland in southern Uzbekistan

2012Response of the long-clawed ground squirrel (Spermophilopsis leptodactylus) to sheep grazing on a semi-arid rangeland in southern Uzbekistan.FORSSTROM Sofie (Canada)sofie@ualberta.ca
Organisation:University of East Anglia, Norwich (UK)Supervisor :Paul Dolman
Summary: Semi-arid to arid rangelands constitute nearly 30% of earthÂ’s land surface. Grazing is one of the most important uses of these areas. However, there is a lack of scientific consensus regarding the ecological effects of grazing. the scale and nature of impacts vary among ecosystems, in different environmental contexts, and according to site-specific variables and management. Much of the research on rangeland management focuses on consequences for livestock carrying capacity and productivity. Nevertheless, changes in vegetation due to grazing trigger bottom-up effects on ecosystem structure and composition, particularly for other primary consumers such as rodents, which can have knock-on effects on predator communities and secondary prey species. In the southern Kyzylkum Desert, Uzbekistan, the relative abundance of the long-clawed suslik Spermophilopsis leptodactylus was estimated using burrow counts in sites with different densities of sheep camps. Burrow densities were positively correlated with densities estimated from timed visual counts. Vegetation structure and composition were also measured at each site. Sheep browsing was found to reduce shrub heights and shift shrub community composition in favour of less-palatable species. Suslik densities were related to substrate and shrub densities, but not to sheep densities. Rodents with dissimilar foraging and predator-avoidance strategies may respond differently. future studies should explore the responses of the Kyzylkum rodent community to grazing-induced shifts in ecosystem dynamics, as well as interspecific relationships with predators.
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