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Topographic complexity potentially mediates cat predation risk for a critically endangered rodent


McDonald, PJ and Stewart, A and Jensen, MA and McGregor, HW, Topographic complexity potentially mediates cat predation risk for a critically endangered rodent, Wildlife Research, 47, (8) pp. 643-648. ISSN 1035-3712 (2020) [Refereed Article]

DOI: doi:10.1071/WR19172


Context: The niche reduction hypothesis (NRH) predicts that the realised niche of declining species is reduced by threats that are mediated by environmental, biotic and evolutionary processes, explaining why species decline in some locations but not others. The critically endangered central rock-rat (CRR) survives only in rugged mountain range habitat in central Australia and is highly vulnerable to cat predation. We predicted that cat density and ranging behaviour, and, hence, predation risk, is mediated by habitat complexity, thus explaining the mechanism maintaining the CRR refuge.

Aims: We sought to determine whether cat densities were lower in the rugged CRR refuge than in an adjacent valley dominated by less complex rocky habitats and no longer occupied by CRRs.

Methods: We installed arrays of camera traps along two parallel mountain ranges in the refuge and in the intervening valley habitats. We identified uniquely patterned individual cats and compared spatially explicit capture–recapture (SECR) models to evaluate our hypothesis that cat density varies with topographic complexity.

Key results: The dominant effect in all models was the significant negative relationship between cat detection probability and fine-scale topographic ruggedness. Two of the best three SECR models indicated lower cat densities and relative home-range sizes in the refuge than in the valley. In total, 17% of cats were detected in both habitat types.

Conclusions: We found some evidence that cat density and home-range size were mediated by habitat complexity. Further, the negative relationship between cat detection probability and topographic complexity suggests that cats spend less time foraging in CRR refuge habitat.

Implications: Cat management programs, aimed at reducing predation pressure on the CRR, must include the refuge and surrounding habitats to control cats that pose a threat to CRR subpopulations.

Item Details

Item Type:Refereed Article
Keywords:arid, Felis catus, mammal decline, niche reduction hypothesis, SECR, feral cats, central rock rat, density
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Terrestrial ecology
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Control of pests, diseases and exotic species in terrestrial environments
UTAS Author:McGregor, HW (Dr Hugh McGregor)
ID Code:145843
Year Published:2020
Web of Science® Times Cited:6
Deposited By:Plant Science
Deposited On:2021-08-08
Last Modified:2021-08-13

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