Density and genetic diversity of grizzly bears at the northern edge of their distribution
Abstract Species at the periphery of their range are typically limited in density by poor habitat quality. As a result, the central–marginal hypothesis (CMH) predicts a decline in genetic diversity of populations toward the periphery of a species' range. Grizzly bears ( Ursus arctos ) once rang...
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Online Access: | http://dx.doi.org/10.1002/ecs2.4523 https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.4523 |
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crwiley:10.1002/ecs2.4523 2024-06-02T08:15:25+00:00 Density and genetic diversity of grizzly bears at the northern edge of their distribution Barrueto, Mirjam Jessen, Tyler D. Diepstraten, Rianne Musiani, Marco 2023 http://dx.doi.org/10.1002/ecs2.4523 https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.4523 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Ecosphere volume 14, issue 6 ISSN 2150-8925 2150-8925 journal-article 2023 crwiley https://doi.org/10.1002/ecs2.4523 2024-05-03T11:17:19Z Abstract Species at the periphery of their range are typically limited in density by poor habitat quality. As a result, the central–marginal hypothesis (CMH) predicts a decline in genetic diversity of populations toward the periphery of a species' range. Grizzly bears ( Ursus arctos ) once ranged throughout most of North America but have been extirpated from nearly half of their former range, mainly in the south. They are considered a species at risk even in Canada's remote North, where they occupy the northernmost edge of the species' continental distribution in a low‐productivity tundra environment. With climate change, one of their main prey species in the tundra (caribou), which has always shown yearly fluctuations, is declining, but simultaneously, grizzlies appear to be expanding their range northward in the same tundra environment. Yet, a lack of population density estimates across the North is hindering effective conservation action. The CMH has implications for the viability of peripheral populations, and the links between population fluctuations, potential bottlenecks, and genetic diversity need to be determined to contribute to species' conservation. Using noninvasive genetic sampling from 2012 to 2014 and autosomal DNA genotyping (via microsatellites), we estimated bear density using a spatial capture–recapture framework and analyzed genetic diversity using observed heterozygosity (Ho), allelic richness (AR), and expected heterozygosity (He). We compared our findings to other studies that used comparable methodologies on grizzly bears and a related species (black bears; Ursus americanus ). We found densities of grizzly bears that were low for the species but characteristic for the region (5.9 ± 0.4 bears/1000 km 2 ), but with high Ho (0.81 ± 0.05), AR (7 ± 0.78), and He (0.71 ± 0.03), despite a signal of recent bottlenecks. In both species, peripherality was not correlated with Ho but was negatively correlated with density. We suggest that the apparent growth of this expanding population of grizzlies ... Article in Journal/Newspaper Tundra Ursus arctos Wiley Online Library Ecosphere 14 6 |
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Wiley Online Library |
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language |
English |
description |
Abstract Species at the periphery of their range are typically limited in density by poor habitat quality. As a result, the central–marginal hypothesis (CMH) predicts a decline in genetic diversity of populations toward the periphery of a species' range. Grizzly bears ( Ursus arctos ) once ranged throughout most of North America but have been extirpated from nearly half of their former range, mainly in the south. They are considered a species at risk even in Canada's remote North, where they occupy the northernmost edge of the species' continental distribution in a low‐productivity tundra environment. With climate change, one of their main prey species in the tundra (caribou), which has always shown yearly fluctuations, is declining, but simultaneously, grizzlies appear to be expanding their range northward in the same tundra environment. Yet, a lack of population density estimates across the North is hindering effective conservation action. The CMH has implications for the viability of peripheral populations, and the links between population fluctuations, potential bottlenecks, and genetic diversity need to be determined to contribute to species' conservation. Using noninvasive genetic sampling from 2012 to 2014 and autosomal DNA genotyping (via microsatellites), we estimated bear density using a spatial capture–recapture framework and analyzed genetic diversity using observed heterozygosity (Ho), allelic richness (AR), and expected heterozygosity (He). We compared our findings to other studies that used comparable methodologies on grizzly bears and a related species (black bears; Ursus americanus ). We found densities of grizzly bears that were low for the species but characteristic for the region (5.9 ± 0.4 bears/1000 km 2 ), but with high Ho (0.81 ± 0.05), AR (7 ± 0.78), and He (0.71 ± 0.03), despite a signal of recent bottlenecks. In both species, peripherality was not correlated with Ho but was negatively correlated with density. We suggest that the apparent growth of this expanding population of grizzlies ... |
format |
Article in Journal/Newspaper |
author |
Barrueto, Mirjam Jessen, Tyler D. Diepstraten, Rianne Musiani, Marco |
spellingShingle |
Barrueto, Mirjam Jessen, Tyler D. Diepstraten, Rianne Musiani, Marco Density and genetic diversity of grizzly bears at the northern edge of their distribution |
author_facet |
Barrueto, Mirjam Jessen, Tyler D. Diepstraten, Rianne Musiani, Marco |
author_sort |
Barrueto, Mirjam |
title |
Density and genetic diversity of grizzly bears at the northern edge of their distribution |
title_short |
Density and genetic diversity of grizzly bears at the northern edge of their distribution |
title_full |
Density and genetic diversity of grizzly bears at the northern edge of their distribution |
title_fullStr |
Density and genetic diversity of grizzly bears at the northern edge of their distribution |
title_full_unstemmed |
Density and genetic diversity of grizzly bears at the northern edge of their distribution |
title_sort |
density and genetic diversity of grizzly bears at the northern edge of their distribution |
publisher |
Wiley |
publishDate |
2023 |
url |
http://dx.doi.org/10.1002/ecs2.4523 https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.4523 |
genre |
Tundra Ursus arctos |
genre_facet |
Tundra Ursus arctos |
op_source |
Ecosphere volume 14, issue 6 ISSN 2150-8925 2150-8925 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1002/ecs2.4523 |
container_title |
Ecosphere |
container_volume |
14 |
container_issue |
6 |
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1800739580286074880 |