Habitat selection and space use overlap between feral horses, pronghorn, and greater sage‐grouse in cold arid steppe

Hennig, Jacob D.; Scasta, John Derek; Pratt, Aaron C.; Wanner, Caitlyn P.; Beck, Jeffrey L.

doi:10.1002/jwmg.22329

Cited by 2 publications

(1 citation statement)

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“…The GPS technique reveals that our findings are consistent with other studies assessing water resource use in equids, demonstrating higher usage of this resource during hotter hours or seasons. Consequently, management plans could prioritize mitigation programs targeting these areas (Hennig et al 2023, Karish et al 2023).…”

Section: Discussionmentioning

confidence: 99%

Jaguar predation on domestic horses in the dry forest of northwestern Costa Rica

Morera,

Montalvo,

Moya

et al. 2024

J Wildl Manag

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Depredation of domestic horses (Equus caballus) by jaguars (Panthera onca) is an example of human–wildlife conflict that has not received much attention. We monitored spatio‐temporal activity and distribution of horses in a 2.64‐km2 fenced area in the dry forest of northwestern Costa Rica in response to 16 jaguar killings of horses during January‐November 2017. We monitored 4 horses (2 males, 2 females) equipped with global positioning system transmitters from February‐September 2018 to identify daily and seasonal patterns of use of cover types and a water source by horses. We then compared these results to the previous locations where jaguars killed horses to identify the circumstances under which horses seemed more vulnerable to jaguar predation. Based on 1,693 locations, horses spent most time in grassland (92%) rather than forest and edge vegetation (8%) and used a core area of 0.74 km2 (kernel density estimation) to 0.86 km2 (minimum convex polygon). Of 16 horse predation events by jaguars, 9 events (56%) occurred in grasslands, 4 in forested areas (25%), and 3 in the forest edge (19%), indicating predation events occurred disproportionately from expected counts based on horse use of vegetation. The predation sites were characterized by a higher proportion of edge and a lower proportion of forest compared to a random points. We suggest that when horses explored areas near the edge of forested areas, the chances of being preyed on by jaguars increased.

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Section: Discussionmentioning

confidence: 99%

Jaguar predation on domestic horses in the dry forest of northwestern Costa Rica

Morera,

Montalvo,

Moya

et al. 2024

J Wildl Manag

View full text Add to dashboard Cite

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Free‐roaming horses exceeding appropriate management levels affect multiple vital rates in greater sage‐grouse

Beck,

Milligan,

Smith

et al. 2024

J Wildl Manag

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Since the passage of the Wild Free‐Roaming Horses and Burros Act of 1971, federal agencies have been responsible for managing free‐roaming equids in the United States. Over the last 20 years, management has been hampered by direct opposition from advocacy groups, budget limitations, and a decline in the public's willingness to adopt free‐roaming horses (Equus caballus). As a result, free‐roaming equid numbers have increased to >3 times the targeted goal of 26,785 (horses and burros [E. asinus] combined), the cumulative sum of the appropriate management levels (AML) for all 177 designated herd management areas (HMA) managed by the Bureau of Land Management. This increase is one of the causes of greater sage‐grouse (Centrocercus urophasianus) population declines, owing to habitat alteration from free‐roaming equids exacerbated by ongoing drought. To evaluate potential demographic mechanisms influencing these declines, we compiled survival data from 4 studies in central Wyoming, USA, including 995 adult female (first‐year breeders or older) sage‐grouse during the breeding season, 1,075 nests, 372 broods, and 136 juveniles (i.e., overwinter survival for fledged young), from 2008–2022. During this period, we also obtained population information for free‐roaming horses from 9 HMAs used by individual grouse in our sample. Population estimates of free‐roaming horses for these HMAs ranged from 59% to 7 times of the maximum appropriate management level (AMLmax). Sage‐grouse monitored outside of HMAs represented control populations and, because we assumed they were not exposed to populations of free‐roaming horses, we set values of AMLmax to zero for all grouse located outside of HMAs. To evaluate whether free‐roaming horses were negatively affecting sage‐grouse, we modeled daily survival of breeding age females, nest, broods, and juveniles. There was strong or moderate evidence that overabundant free‐roaming horses negatively affected nest, brood, and juvenile survival. When horse abundance increased from AMLmax to 3 times AMLmax, survival was reduced 8.1%, 18.3%, 18.2%, and 18.2% for nests, early broods (≤20 days after hatch), late broods (>20 days to 35 days after hatch), and juveniles, respectively. These results indicate increasing free‐roaming horse numbers affected vital rates for important life stages of sage‐grouse, and that maintaining free‐roaming horse numbers below AMLmax would reduce negative effects to sage‐grouse populations.

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Habitat selection and space use overlap between feral horses, pronghorn, and greater sage‐grouse in cold arid steppe

Cited by 2 publications

References 64 publications

Jaguar predation on domestic horses in the dry forest of northwestern Costa Rica

Jaguar predation on domestic horses in the dry forest of northwestern Costa Rica

Free‐roaming horses exceeding appropriate management levels affect multiple vital rates in greater sage‐grouse

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