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Nelson's big horn sheep ( Ovis canadensis nelsoni ) trample Agassiz's desert tortoise ( Gopherus agassizii ) burrow at a California wind energy facility

Mickey Agha·David F. Delaney·Jeffrey E. Lovich·Jessica Briggs·Meaghan Austin·Steven J. Price
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Abstract

Research on interactions between Agassiz's desert tortoises ( Gopherus agassizii ) and ungulates has focused exclusively on the effects of livestock grazing on tortoises and their habitat (Oldemeyer, 1994). For example, during a 1980 study in San Bernardino County, California, 164 desert tortoise burrows were assessed for vulnerability to trampling by domestic sheep ( Ovis aries ). Herds of grazing sheep damaged 10% and destroyed 4% of the burrows (Nicholson and Humphreys 1981). In addition, a juvenile desert tortoise was trapped and an adult male was blocked from entering a burrow due to trampling by domestic sheep. Another study found that domestic cattle ( Bos taurus ) trampled active desert tortoise burrows and vegetation surrounding burrows (Avery and Neibergs 1997). Trampling also has negative impacts on diversity of vegetation and intershrub soil crusts in the desert southwest (Webb and Stielstra 1979). Trampling of important food plants and overgrazing has the potential to create competition between desert tortoises and domestic livestock (Berry 1978; Coombs 1979; Webb and Stielstra 1979).

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Mickey Agha, David F. Delaney, Jeffrey E. Lovich, Jessica Briggs, Meaghan Austin, Steven J. Price. 2015. Nelson's big horn sheep ( Ovis canadensis nelsoni ) trample Agassiz's desert tortoise ( Gopherus agassizii ) burrow at a California wind energy facility. https://doi.org/10.3160/0038-3872-114.1.58

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