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Providing evidence to improve practice

Individual study: The restoration of desert bighorn sheep in the Southwest,1951–2007: factors influencing success

Published source details

Wakeling B., Lee R., Brown D., Thompson R., Tluczek M. & Weisenberger M. (2009) The restoration of desert bighorn sheep in the Southwest,1951–2007: factors influencing success. Desert Bighorn Council Transactions, 50, 1-17


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Provide supplementary water to increase reproduction/survival Terrestrial Mammal Conservation

A replicated study in 1951–2007 in 10 desert sites in Arizona and New Mexico, USA, and the Gulf of California, Mexico (Wakeling et al. 2009) found that providing supplementary water at some sites was associated with increases in desert bighorn sheep Ovis canadensis population size. At three out of 10 sites where supplementary water was provided, it was associated with an increase in bighorn sheep populations. However, at one site, provision of water was associated with declines in sheep populations. The remaining six sites showed no association (data not presented). Data were obtained from historical records for ten sites with long-term survey and hunting information. Data included counts of bighorn sheep from both surveys and hunter harvests, and the number of watering sites provided.

(Summarised by Andrew Bladon)

Remove or control predators Terrestrial Mammal Conservation

A replicated study in 1951–2007 in nine desert sites in Arizona and New Mexico, USA, and the Gulf of California, Mexico (Wakeling et al. 2009) found that controlling mountain lions Puma concolor did not increase the population size of desert bighorn sheep Ovis canadensis. No bighorn sheep populations at sites where mountain lions were controlled increased in size (data not presented). Data were obtained from historical records for 10 sites with long-term survey and hunting information. Data included counts of bighorn sheep from both surveys and hunter harvests, and annual mountain lion harvests. No information on the number of mountain lions controlled is provided.

(Summarised by Andrew Bladon)

Translocate to re-establish or boost populations in native range Terrestrial Mammal Conservation

A replicated study in 1951–2007 in 10 desert sites in Arizona and New Mexico, USA, and the Gulf of California, Mexico (Wakeling et al. 2009) found that translocating desert bighorn sheep Ovis canadensis did not increase the population size at the release site. No bighorn sheep populations which were supplemented with translocated individuals significantly increased in size (data not presented). Between 1951 and 1990, a total of 654 bighorn sheep were released, but details of individual releases are not provided. Data were obtained from historical records for ten sites with long-term survey and hunting information. Data included counts of bighorn sheep from both surveys and hunter harvests, and bighorn sheep translocations.

(Summarised by Andrew Bladon)