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Thomson DM, McEachern AK, Schultz EL, Niessen K, Wilken D, Chess K, Cole LF, Oliver RY, Phillips JD, Tucker A. Diverse native island flora shows rapid initial passive recovery after exotic herbivore removal on Santa Rosa Island, California. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02735-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bolas EC, Sollmann R, Crooks KR, Boydston EE, Shaskey L, Boser CL, Dillon A, Van Vuren DH. Role of microhabitat and temporal activity in facilitating coexistence of endemic carnivores on the California Channel Islands. J Mammal 2021. [DOI: 10.1093/jmammal/gyab125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Abstract
Most extinctions worldwide have occurred on islands, primarily due to interactions with exotic species, but rarely due to interactions among endemic species. This potential exists on two of the California Channel Islands, Santa Cruz and Santa Rosa, as endemic island spotted skunks (Spilogale gracilis amphiala) appear to have rapidly declined to rarity, possibly due to interference competition with endemic island foxes (Urocyon littoralis). Niche partitioning is expected in response to interference competition; hence, it is surprising that skunks and foxes show extensive overlap in macrohabitat use and circadian activity. However, the role of microhabitat associations and fine-scale temporal activity in facilitating coexistence of the two species has not been explored. We evaluated microhabitat associations of island spotted skunks and island foxes across both islands using data from live traps and wildlife cameras collected during 2015–2017, and we analyzed fine-scale temporal activity using camera data from 2016 and 2017. On both islands, skunks had a positive response to ground-level cover provided by rugged topography or woody vegetation such as shrubs or trees, whereas foxes had a weak or negative response, suggesting partitioning of these microhabitat characteristics. Additionally, on both islands the peak in timing of skunk activity offset the peak for foxes, which implies that skunks use fine-scale adjustments in activity to avoid foxes. Past grazing by exotic herbivores likely reduced habitat refuges for skunks; however, as vegetation on both islands recovers, regrowth of shrubs and trees may provide cover that will improve prospects for coexistence of island spotted skunks and island foxes.
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Affiliation(s)
- Ellen C Bolas
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA, USA
| | - Rahel Sollmann
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA, USA
| | - Kevin R Crooks
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, 115 Wagar, Fort Collins, CO, USA
| | | | - Laura Shaskey
- Channel Islands National Park, 1901 Spinnaker Drive, Ventura, CA, USA
| | | | - Adam Dillon
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, 115 Wagar, Fort Collins, CO, USA
| | - Dirk H Van Vuren
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA, USA
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Woolsey J, Hanna C, Mceachern K, Anderson S, Hartman BD. Regeneration and Expansion of Quercus tomentella (Island Oak) Groves on Santa Rosa Island. WEST N AM NATURALIST 2018. [DOI: 10.3398/064.078.0415] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Jay Woolsey
- Environmental Science and Resource Management Program, CSU Channel Islands, Camarillo, CA
| | - Cause Hanna
- Santa Rosa Island Research Station, CSU Channel Islands, Camarillo, CA
| | - Kathryn Mceachern
- U.S. Geological Survey, Western Ecological Research Center, Channel Islands Field Station, Ventura, CA
| | - Sean Anderson
- Environmental Science and Resource Management Program, CSU Channel Islands, Camarillo, CA
| | - Brett D. Hartman
- Environmental Science and Resource Management Program, CSU Channel Islands, Camarillo, CA
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