A spatial risk assessment of bighorn sheep extirpation by grazing domestic sheep on public lands

Carpenter, Tim E.; Coggins, Victor L.; McCarthy, Clinton; O’Brien, Chans S.; O’Brien, Joshua; Schommer, Timothy J.

doi:10.1016/j.prevetmed.2014.01.008

Cited by 23 publications

(22 citation statements)

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“…State and federal natural resource agencies have widely instituted policies to prevent pathogen spillover by encouraging or requiring spatial separation between wild sheep and domestic sheep and goats (Western Association of Fish and Wildife Agencies Wild Sheep Working Group , Bureau of Land Management 2016). Federal and state policies are informed by models, such as the USDA Forest Service's Bighorn Sheep Risk of Contact Tool (Woolever et al ), which incorporate bighorn sheep space use, habitat preferences, foray probabilities, and demographics (Clifford et al , Cahn et al , Carpenter et al , O'Brien et al ) to identify geographic locations with high risk of domestic‐wild sheep contact. These models allow comparison of proposed management alternatives and assessment of population‐level consequences for bighorn sheep.…”

Section: Management Of Pneumonia In Bighorn Sheepmentioning

confidence: 99%

Pneumonia in bighorn sheep: Risk and resilience

Manlove²,

et al. 2017

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Infectious disease contributed to historical declines and extirpations of bighorn sheep (Ovis canadensis) in North America and continues to impede population restoration and management. Reports of pneumonia outbreaks in freeranging bighorn sheep following contact with domestic sheep have been validated by the results of 13 captive commingling experiments. However, ecological and etiological complexities still hinder our understanding and control of respiratory disease in wild sheep. In this paper, we review the literature and summarize recent data to present an overview of the biology and management of pneumonia in bighorn sheep. Many factors contribute to this population-limiting disease, but a bacterium (Mycoplasma ovipneumoniae) host-specific to Caprinae and commonly carried by healthy domestic sheep and goats, appears to be a primary agent necessary for initiating epizootics. All-age epizootics are usually associated with significant population declines, but mortality rates vary widely and factors influencing disease severity are not well understood. Once introduced, M. ovipneumoniae can persist in bighorn sheep populations for decades. Carrier females may transmit the pathogen to their susceptible lambs, triggering fatal pneumonia outbreaks in nursery groups, which limit recruitment and slow or prevent population recovery. The demographic costs of disease persistence can be equal to or greater than the impacts of the initial epizootic. Strain typing suggests that spillover of M. ovipneumoniae into bighorn sheep populations from domestic small ruminants is ongoing and that consequences of spillover are amplified by movements of infected bighorn sheep across populations. Therefore, current disease management strategies focus on reducing risk of spillover from reservoir populations of domestic sheep and goats and on limiting transmission among bighorn sheep.

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Section: Management Of Pneumonia In Bighorn Sheepmentioning

confidence: 99%

Pneumonia in bighorn sheep: Risk and resilience

Manlove²,

et al. 2017

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“…Schommer and Woolever (2008),Wehausen et al (2011), mathematical models inClifford et al (2009), Cahn et al (2011), and Carpenter et al (2014, and additional data inShannon et al (2014) andSells et al (2015).…”

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Evidence based review: positive versus negative effects of livestock grazing on wildlife. What do we really know?

Schieltz

Rubenstein

2016

Environ. Res. Lett.

154

137

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More than a quarter of earth's land surface is used for grazing domestic livestock. Livestock grazing is generally assumed to negatively affect wildlife, however, a number of studies have found positive impacts as well. We conducted an evidence-based review of the existing literature using a series of livestock-and wildlife-related search words to systematically query Google Scholar and Web of Science. A total of 807 sources were included in the final list, including 646 primary sources which reported original data. The majority of studies were conducted in North America (338) or Europe (123), with many fewer from Africa (57), Australia (54), Central/South America (43), or Asia (31). Most studies examined birds (330) and mammals (262), with fewer including reptiles (91) or amphibians (58). We extracted further information from studies that included mammals on positive, negative, and neutral effects of livestock grazing on mammals. We found that livestock change vegetation structure and cover in ways important to small mammals, while ungulates may be affected more by interference competition and changes in forage quantity and quality. Community-level total abundance of small mammals typically declines with grazing. Species richness of small mammals either declines or stays the same, as many studies found a change in species composition from ungrazed to grazed sites while the number of species remained similar. Individual species responses of small mammals vary. Voles, harvest mice, cotton rats, and shrews show consistently negative responses to grazing while deer mice, kangaroo rats, ground squirrels, and lagomorphs show positive or variable responses. In general, species adapted to open habitats are often positively affected by grazing, while species needing denser cover are negatively affected. Studies of wild ungulates are more variable in methodology and quality than those for small mammals. We found more negative (n=86) than positive (n=34) ungulate responses overall, however, most studies have been on browsers and mixed feeders, namely deer and elk, and there is little available data for other groups. Although data is limited, several of the grazing species in Africa may show a trend toward positive responses, suggesting possible facilitation. For a number of species, responses varied by season. We find a strong need for additional research on ungulates of varying diets and body sizes, especially in the developing world, and across longer time scales to examine possible tradeoffs between competition and facilitation from livestock.

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“…Managing to minimize disease transmission from domesticated animals to wild sheep impinges on the fundamental right of private landowners in North America to determine how they manage livestock on their own land. Avoiding grazing management conflicts on public lands might be easier to accomplish but still requires careful coordination between agricultural and wildlife interests (Carpenter et al ).…”

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confidence: 99%