Assumptions about fence permeability influence density estimates for brown hyaenas across South Africa
Abstract Wildlife population density estimates provide information on the number of individuals in an area and influence conservation management decisions. Thus, accuracy is vital. A dominant feature in many landscapes globally is fencing, yet the implications of fence permeability on density estima...
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doaj-a474d1e621a34b0cbe45d44887eb53e52021-01-17T12:35:29ZengNature Publishing GroupScientific Reports2045-23222021-01-0111111110.1038/s41598-020-77188-7Assumptions about fence permeability influence density estimates for brown hyaenas across South AfricaKathryn S. Williams0Samual T. Williams1Rebecca J. Welch2Courtney J. Marneweck3Gareth K. H. Mann4Ross T. Pitman5Gareth Whittington-Jones6Guy A. Balme7Daniel M. Parker8Russell A. Hill9Department of Anthropology, Durham UniversityDepartment of Anthropology, Durham UniversitySchool of Biology and Environmental Sciences, University of MpumalangaSchool of Biology and Environmental Sciences, University of MpumalangaPantheraPantheraPantheraPantheraSchool of Biology and Environmental Sciences, University of MpumalangaDepartment of Anthropology, Durham UniversityAbstract Wildlife population density estimates provide information on the number of individuals in an area and influence conservation management decisions. Thus, accuracy is vital. A dominant feature in many landscapes globally is fencing, yet the implications of fence permeability on density estimation using spatial capture-recapture modelling are seldom considered. We used camera trap data from 15 fenced reserves across South Africa to examine the density of brown hyaenas (Parahyaena brunnea). We estimated density and modelled its relationship with a suite of covariates when fenced reserve boundaries were assumed to be permeable or impermeable to hyaena movements. The best performing models were those that included only the influence of study site on both hyaena density and detection probability, regardless of assumptions of fence permeability. When fences were considered impermeable, densities ranged from 2.55 to 15.06 animals per 100 km2, but when fences were considered permeable, density estimates were on average 9.52 times lower (from 0.17 to 1.59 animals per 100 km2). Fence permeability should therefore be an essential consideration when estimating density, especially since density results can considerably influence wildlife management decisions. In the absence of strong evidence to the contrary, future studies in fenced areas should assume some degree of permeability in order to avoid overestimating population density.https://doi.org/10.1038/s41598-020-77188-7 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Kathryn S. Williams Samual T. Williams Rebecca J. Welch Courtney J. Marneweck Gareth K. H. Mann Ross T. Pitman Gareth Whittington-Jones Guy A. Balme Daniel M. Parker Russell A. Hill |
spellingShingle |
Kathryn S. Williams Samual T. Williams Rebecca J. Welch Courtney J. Marneweck Gareth K. H. Mann Ross T. Pitman Gareth Whittington-Jones Guy A. Balme Daniel M. Parker Russell A. Hill Assumptions about fence permeability influence density estimates for brown hyaenas across South Africa Scientific Reports |
author_facet |
Kathryn S. Williams Samual T. Williams Rebecca J. Welch Courtney J. Marneweck Gareth K. H. Mann Ross T. Pitman Gareth Whittington-Jones Guy A. Balme Daniel M. Parker Russell A. Hill |
author_sort |
Kathryn S. Williams |
title |
Assumptions about fence permeability influence density estimates for brown hyaenas across South Africa |
title_short |
Assumptions about fence permeability influence density estimates for brown hyaenas across South Africa |
title_full |
Assumptions about fence permeability influence density estimates for brown hyaenas across South Africa |
title_fullStr |
Assumptions about fence permeability influence density estimates for brown hyaenas across South Africa |
title_full_unstemmed |
Assumptions about fence permeability influence density estimates for brown hyaenas across South Africa |
title_sort |
assumptions about fence permeability influence density estimates for brown hyaenas across south africa |
publisher |
Nature Publishing Group |
series |
Scientific Reports |
issn |
2045-2322 |
publishDate |
2021-01-01 |
description |
Abstract Wildlife population density estimates provide information on the number of individuals in an area and influence conservation management decisions. Thus, accuracy is vital. A dominant feature in many landscapes globally is fencing, yet the implications of fence permeability on density estimation using spatial capture-recapture modelling are seldom considered. We used camera trap data from 15 fenced reserves across South Africa to examine the density of brown hyaenas (Parahyaena brunnea). We estimated density and modelled its relationship with a suite of covariates when fenced reserve boundaries were assumed to be permeable or impermeable to hyaena movements. The best performing models were those that included only the influence of study site on both hyaena density and detection probability, regardless of assumptions of fence permeability. When fences were considered impermeable, densities ranged from 2.55 to 15.06 animals per 100 km2, but when fences were considered permeable, density estimates were on average 9.52 times lower (from 0.17 to 1.59 animals per 100 km2). Fence permeability should therefore be an essential consideration when estimating density, especially since density results can considerably influence wildlife management decisions. In the absence of strong evidence to the contrary, future studies in fenced areas should assume some degree of permeability in order to avoid overestimating population density. |
url |
https://doi.org/10.1038/s41598-020-77188-7 |
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