Predator‐specific mortality of sage‐grouse nests based on predator DNA on eggshells
Abstract Greater sage‐grouse (hereafter sage‐grouse; Centrocercus urophasianus) populations have declined across their range. Increased nest predation as a result of anthropogenic land use is one mechanism proposed to explain these declines. However, sage‐grouse contend with a diverse suite of nest...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2024-10-01
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| Series: | Ecology and Evolution |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/ece3.70213 |
| _version_ | 1826926512381624320 |
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| author | Nolan A. Helmstetter Courtney J. Conway Shane Roberts Jennifer R. Adams Paul D. Makela Lisette P. Waits |
| author_facet | Nolan A. Helmstetter Courtney J. Conway Shane Roberts Jennifer R. Adams Paul D. Makela Lisette P. Waits |
| author_sort | Nolan A. Helmstetter |
| collection | DOAJ |
| description | Abstract Greater sage‐grouse (hereafter sage‐grouse; Centrocercus urophasianus) populations have declined across their range. Increased nest predation as a result of anthropogenic land use is one mechanism proposed to explain these declines. However, sage‐grouse contend with a diverse suite of nest predators that vary in functional traits (e.g., search tactics or hunting mode) and abundance. Consequently, generalizing about factors influencing nest fate is challenging. Identifying the explicit predator species responsible for nest predation events is, therefore, critical to understanding causal mechanisms linking land use to patterns of sage‐grouse nest success. Cattle grazing is often assumed to adversely affect sage‐grouse recruitment by reducing grass height (and hence cover), thereby facilitating nest detection by predators. However, recent evidence found little support for the hypothesized effect of grazing on nest fate at the pasture scale. Rather, nest success appears to be similar on pastures grazed at varying intensities. One possible explanation for the lack of observed effect involves a localized response by one or more nest predators. The presence of cattle may cause a temporary reduction in predator density and/or use within a pasture (the cattle avoidance hypothesis). The cattle avoidance hypothesis predicts a decreased probability of at least one sage‐grouse nest predator predating sage‐grouse nests in pastures with livestock relative to pastures without livestock present during the nesting season. To test the cattle avoidance hypothesis, we collected predator DNA from eggshells from predated nests and used genetic methods to identify the sage‐grouse nest predator(s) responsible for the predation event. We evaluated the influence of habitat and grazing on predator‐specific nest predation. We evaluated the efficacy of our genetic method by deploying artificial nests with trail cameras and compared the results of our genetic method to the species captured via trail camera. Our molecular methods identified at least one nest predator captured predating artificial nests via trail camera for 33 of 35 (94%) artificial nests. We detected nest predators via our molecular analysis at 76 of 114 (67%) predated sage‐grouse nests. The primary predators detected at sage‐grouse nests were coyotes (Canis latrans) and corvids (Corvidea). Grazing did not influence the probability of nest predation by either coyotes or corvids. Sagebrush canopy cover was negatively associated with the probability a coyote predated a nest, distance to water was positively associated with the probability a corvid predated a nest, and average minimum temperature was negatively associated with the probability that either a coyote or a corvid predated a nest. Our study provides a framework for implementing an effective, non‐invasive method for identifying sage‐grouse nest predators that can be used to better understand how management actions at local and regional scales may impact an important component of sage‐grouse recruitment. |
| first_indexed | 2025-02-17T15:12:44Z |
| format | Article |
| id | doaj.art-b69e43bb7f364e3e8474f6442dd4c050 |
| institution | Directory Open Access Journal |
| issn | 2045-7758 |
| language | English |
| last_indexed | 2025-02-17T15:12:44Z |
| publishDate | 2024-10-01 |
| publisher | Wiley |
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| series | Ecology and Evolution |
| spelling | doaj.art-b69e43bb7f364e3e8474f6442dd4c0502024-12-20T09:05:59ZengWileyEcology and Evolution2045-77582024-10-011410n/an/a10.1002/ece3.70213Predator‐specific mortality of sage‐grouse nests based on predator DNA on eggshellsNolan A. Helmstetter0Courtney J. Conway1Shane Roberts2Jennifer R. Adams3Paul D. Makela4Lisette P. Waits5Idaho Cooperative Fish and Wildlife Research Unit, Department of Fish and Wildlife Sciences University of Idaho Moscow Idaho USAU.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit University of Idaho Moscow Idaho USAIdaho Department of Fish and Game Boise Idaho USADepartment of Fish and Wildlife Sciences University of Idaho Moscow Idaho USAU.S. Bureau of Land Management Boise Idaho USADepartment of Fish and Wildlife Sciences University of Idaho Moscow Idaho USAAbstract Greater sage‐grouse (hereafter sage‐grouse; Centrocercus urophasianus) populations have declined across their range. Increased nest predation as a result of anthropogenic land use is one mechanism proposed to explain these declines. However, sage‐grouse contend with a diverse suite of nest predators that vary in functional traits (e.g., search tactics or hunting mode) and abundance. Consequently, generalizing about factors influencing nest fate is challenging. Identifying the explicit predator species responsible for nest predation events is, therefore, critical to understanding causal mechanisms linking land use to patterns of sage‐grouse nest success. Cattle grazing is often assumed to adversely affect sage‐grouse recruitment by reducing grass height (and hence cover), thereby facilitating nest detection by predators. However, recent evidence found little support for the hypothesized effect of grazing on nest fate at the pasture scale. Rather, nest success appears to be similar on pastures grazed at varying intensities. One possible explanation for the lack of observed effect involves a localized response by one or more nest predators. The presence of cattle may cause a temporary reduction in predator density and/or use within a pasture (the cattle avoidance hypothesis). The cattle avoidance hypothesis predicts a decreased probability of at least one sage‐grouse nest predator predating sage‐grouse nests in pastures with livestock relative to pastures without livestock present during the nesting season. To test the cattle avoidance hypothesis, we collected predator DNA from eggshells from predated nests and used genetic methods to identify the sage‐grouse nest predator(s) responsible for the predation event. We evaluated the influence of habitat and grazing on predator‐specific nest predation. We evaluated the efficacy of our genetic method by deploying artificial nests with trail cameras and compared the results of our genetic method to the species captured via trail camera. Our molecular methods identified at least one nest predator captured predating artificial nests via trail camera for 33 of 35 (94%) artificial nests. We detected nest predators via our molecular analysis at 76 of 114 (67%) predated sage‐grouse nests. The primary predators detected at sage‐grouse nests were coyotes (Canis latrans) and corvids (Corvidea). Grazing did not influence the probability of nest predation by either coyotes or corvids. Sagebrush canopy cover was negatively associated with the probability a coyote predated a nest, distance to water was positively associated with the probability a corvid predated a nest, and average minimum temperature was negatively associated with the probability that either a coyote or a corvid predated a nest. Our study provides a framework for implementing an effective, non‐invasive method for identifying sage‐grouse nest predators that can be used to better understand how management actions at local and regional scales may impact an important component of sage‐grouse recruitment.https://doi.org/10.1002/ece3.70213cattleCentrocercus urophasianuscorvidcoyotegrazingIdaho |
| spellingShingle | Nolan A. Helmstetter Courtney J. Conway Shane Roberts Jennifer R. Adams Paul D. Makela Lisette P. Waits Predator‐specific mortality of sage‐grouse nests based on predator DNA on eggshells Ecology and Evolution cattle Centrocercus urophasianus corvid coyote grazing Idaho |
| title | Predator‐specific mortality of sage‐grouse nests based on predator DNA on eggshells |
| title_full | Predator‐specific mortality of sage‐grouse nests based on predator DNA on eggshells |
| title_fullStr | Predator‐specific mortality of sage‐grouse nests based on predator DNA on eggshells |
| title_full_unstemmed | Predator‐specific mortality of sage‐grouse nests based on predator DNA on eggshells |
| title_short | Predator‐specific mortality of sage‐grouse nests based on predator DNA on eggshells |
| title_sort | predator specific mortality of sage grouse nests based on predator dna on eggshells |
| topic | cattle Centrocercus urophasianus corvid coyote grazing Idaho |
| url | https://doi.org/10.1002/ece3.70213 |
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