Unreliable Knowledge about Economic Impacts of Large Carnivores on Bovine Calves
Sommers et al. (2010) reported that recolonizing predators increased bovine calf mortality rates in the Upper Green River Cattle Allotment in western Wyoming. However, Sommers et al. (2010) failed to consider multiple competing hypotheses explaining calf loss rates, increasing the likelihood that th...
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ftbioone:10.1002/jwmg.206 2024-06-02T08:05:02+00:00 Unreliable Knowledge about Economic Impacts of Large Carnivores on Bovine Calves Mark Hebblewhite Mark Hebblewhite world 2011-11-01 text/HTML https://doi.org/10.1002/jwmg.206 en eng The Wildlife Society doi:10.1002/jwmg.206 All rights reserved. https://doi.org/10.1002/jwmg.206 Text 2011 ftbioone https://doi.org/10.1002/jwmg.206 2024-05-07T00:47:03Z Sommers et al. (2010) reported that recolonizing predators increased bovine calf mortality rates in the Upper Green River Cattle Allotment in western Wyoming. However, Sommers et al. (2010) failed to consider multiple competing hypotheses explaining calf loss rates, increasing the likelihood that their results are actually spurious. I reanalyzed their data using a multiple competing hypotheses framework that considered effects of livestock density, summer precipitation, bias in reporting rates, and whether mortality by different predator species was compensatory. I found support for a confounded web of factors influencing calf losses. Calf losses increased with livestock density (which increased during the study), but also during drier summers and with increasing rancher reporting rates. Although both wolves (Canis lupus) and grizzly bears (Ursus arctos) did increase calf losses, the presence of just grizzly bears alone did not significantly increase calf losses. Unconditional estimates of the effects of wolves and grizzly bears on calf losses were only 2.0% (95% CI 0.53–3.81), compared to 3.6% reported by Sommers et al. (2010). Most importantly, however, I report bias in favor of livestock producers in the authors' assumptions that cast further doubt on the rigor of their results. In conclusion, I recommend managers not consider the spurious predator compensation factors reported by Sommers et al. (2010) to be reliable. Text Canis lupus Ursus arctos BioOne Online Journals Sommers ENVELOPE(-63.550,-63.550,-65.067,-65.067) The Journal of Wildlife Management 75 8 1724 1730 |
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description |
Sommers et al. (2010) reported that recolonizing predators increased bovine calf mortality rates in the Upper Green River Cattle Allotment in western Wyoming. However, Sommers et al. (2010) failed to consider multiple competing hypotheses explaining calf loss rates, increasing the likelihood that their results are actually spurious. I reanalyzed their data using a multiple competing hypotheses framework that considered effects of livestock density, summer precipitation, bias in reporting rates, and whether mortality by different predator species was compensatory. I found support for a confounded web of factors influencing calf losses. Calf losses increased with livestock density (which increased during the study), but also during drier summers and with increasing rancher reporting rates. Although both wolves (Canis lupus) and grizzly bears (Ursus arctos) did increase calf losses, the presence of just grizzly bears alone did not significantly increase calf losses. Unconditional estimates of the effects of wolves and grizzly bears on calf losses were only 2.0% (95% CI 0.53–3.81), compared to 3.6% reported by Sommers et al. (2010). Most importantly, however, I report bias in favor of livestock producers in the authors' assumptions that cast further doubt on the rigor of their results. In conclusion, I recommend managers not consider the spurious predator compensation factors reported by Sommers et al. (2010) to be reliable. |
author2 |
Mark Hebblewhite |
format |
Text |
author |
Mark Hebblewhite |
spellingShingle |
Mark Hebblewhite Unreliable Knowledge about Economic Impacts of Large Carnivores on Bovine Calves |
author_facet |
Mark Hebblewhite |
author_sort |
Mark Hebblewhite |
title |
Unreliable Knowledge about Economic Impacts of Large Carnivores on Bovine Calves |
title_short |
Unreliable Knowledge about Economic Impacts of Large Carnivores on Bovine Calves |
title_full |
Unreliable Knowledge about Economic Impacts of Large Carnivores on Bovine Calves |
title_fullStr |
Unreliable Knowledge about Economic Impacts of Large Carnivores on Bovine Calves |
title_full_unstemmed |
Unreliable Knowledge about Economic Impacts of Large Carnivores on Bovine Calves |
title_sort |
unreliable knowledge about economic impacts of large carnivores on bovine calves |
publisher |
The Wildlife Society |
publishDate |
2011 |
url |
https://doi.org/10.1002/jwmg.206 |
op_coverage |
world |
long_lat |
ENVELOPE(-63.550,-63.550,-65.067,-65.067) |
geographic |
Sommers |
geographic_facet |
Sommers |
genre |
Canis lupus Ursus arctos |
genre_facet |
Canis lupus Ursus arctos |
op_source |
https://doi.org/10.1002/jwmg.206 |
op_relation |
doi:10.1002/jwmg.206 |
op_rights |
All rights reserved. |
op_doi |
https://doi.org/10.1002/jwmg.206 |
container_title |
The Journal of Wildlife Management |
container_volume |
75 |
container_issue |
8 |
container_start_page |
1724 |
op_container_end_page |
1730 |
_version_ |
1800749780385660928 |