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Topographic ruggedness and rainfall mediate geographic range contraction of a threatened marsupial predator

Version 2 2024-06-05, 10:58
Version 1 2019-09-06, 14:30
journal contribution
posted on 2024-06-05, 10:58 authored by Harry A Moore, Judy A Dunlop, Leonie E Valentine, John CZ Woinarski, Euan RitchieEuan Ritchie, David M Watson, Dale G Nimmo
Aim: Species range contractions are increasingly common globally. The niche reduction hypothesis posits that geographic range contractions are often patterned across space owing to heterogeneity in threat impacts and tolerance. We applied the niche reduction hypothesis to the decline of a threatened marsupial predator across northern Australia, the northern quoll (Dasyurus hallucatus). Location: Northern Australia. Methods: We assembled a database containing 3,178 historic and contemporary records for northern quolls across the extent of their distribution dating between 1778 and 2019. Based on these records, we estimated changes in the geographic range of the northern quoll using α‐hulls across four main populations. We then examined how range contractions related to factors likely to mediate the exposure, susceptibility, or tolerance of northern quolls to threats. Result: The extent of range contractions showed an east–west gradient, most likely reflecting the timing of spread of introduced cane toads (Rhinella marina). There were clear changes in environmental characteristics within the contemporary compared to the historic geographic range, with the most substantial occurring in populations that have suffered the greatest range contractions. The contemporary range is comprised of higher quality habitats (measured using environmental niche models), characterized by higher topographical ruggedness and annual rainfall, and reduced distance to water, compared to the historic range. Main conclusions: Changes to range and niche likely reflect the capacity of complex habitats to ameliorate threats (namely predation and altered fire regimes), and access to resources that increase threat tolerance. This study highlights the multivariate nature of ecological refuges and the importance of high‐quality habitats for the persistence of species exposed to multiple threats. Our methods provide a useful framework which can be applied across taxa in providing valuable insight to management.

History

Journal

Diversity and distributions

Volume

25

Pagination

1818-1831

Location

Chichester, Eng.

Open access

  • Yes

ISSN

1366-9516

eISSN

1472-4642

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2019, The Authors

Issue

12

Publisher

Wiley

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