Facilitating translocation: an endangered rodent engineer improves outcomes for re-introduced San Joaquin antelope squirrels

Despite the popularity of translocation for conservation, many wildlife translocations fail. Research on translocation failure has most often focused on negative species interactions like competition or predation, but positive interactions such as facilitation may be just as important. Ecosystem eng...

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Main Authors: Patrick Anderson, Craig Fiehler, William Timothy Bean
Format: Article
Language:English
Published: California Department of Fish and Wildlife 2024-12-01
Series:California Fish and Wildlife Journal
Subjects:
Online Access:https://journal.wildlife.ca.gov/2024/12/27/facilitating-translocation-an-endangered-rodent-engineer-improves-outcomes-for-re-introduced-san-joaquin-antelope-squirrels/
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author Patrick Anderson
Craig Fiehler
William Timothy Bean
author_facet Patrick Anderson
Craig Fiehler
William Timothy Bean
author_sort Patrick Anderson
collection DOAJ
description Despite the popularity of translocation for conservation, many wildlife translocations fail. Research on translocation failure has most often focused on negative species interactions like competition or predation, but positive interactions such as facilitation may be just as important. Ecosystem engineers, including burrowing rodents, play a key role in maintaining high levels of biodiversity and could be used to improve translocation outcomes. However, ecosystem engineers might simultaneously facilitate and compete with translocated species. We used a natural experiment to assess translocation outcomes with a soft release for the threatened San Joaquin antelope squirrel (Ammospermophilus nelsoni) at a site with and without giant kangaroo rats (Dipodomys ingens)—an endangered species and ecosystem engineer. We further compared these outcomes to a control, non-translocated population of antelope squirrels. Survival was highest at the control site, lower at the site with giant kangaroo rats present, and lowest at the site with no giant kangaroo rats. In the year following translocation, we found evidence of reproduction at all three sites. After four years, the antelope squirrel population re-introduced to the kangaroo rat present site persisted, but the population at the kangaroo rat absent site appears to have failed. Home range sizes were much larger at the translocation sites compared to the control. Antelope squirrels dispersed farther from initial release at the site with giant kangaroo rats than the site without, but these results may have suffered from survivorship bias—that is, squirrels at the kangaroo rat absent site either stayed directly within the release footprint or dispersed so far that we could not find them. Our results suggest that the positive impacts of a burrowing ecosystem engineer outweigh the potential negative impacts from competition.
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spelling doaj-art-75d2a04eba0a4eb8b39b2382300feeea2025-01-07T20:30:47ZengCalifornia Department of Fish and WildlifeCalifornia Fish and Wildlife Journal2689-419X2689-42032024-12-01110410.51492/cfwj.110.17Facilitating translocation: an endangered rodent engineer improves outcomes for re-introduced San Joaquin antelope squirrelsPatrick Anderson0Craig Fiehler1William Timothy Bean2https://orcid.org/0000-0001-6595-5885California Polytechnic State University, San Luis ObispoCalifornia Department of Fish and WildlifeCalifornia Polytechnic State University, San Luis ObispoDespite the popularity of translocation for conservation, many wildlife translocations fail. Research on translocation failure has most often focused on negative species interactions like competition or predation, but positive interactions such as facilitation may be just as important. Ecosystem engineers, including burrowing rodents, play a key role in maintaining high levels of biodiversity and could be used to improve translocation outcomes. However, ecosystem engineers might simultaneously facilitate and compete with translocated species. We used a natural experiment to assess translocation outcomes with a soft release for the threatened San Joaquin antelope squirrel (Ammospermophilus nelsoni) at a site with and without giant kangaroo rats (Dipodomys ingens)—an endangered species and ecosystem engineer. We further compared these outcomes to a control, non-translocated population of antelope squirrels. Survival was highest at the control site, lower at the site with giant kangaroo rats present, and lowest at the site with no giant kangaroo rats. In the year following translocation, we found evidence of reproduction at all three sites. After four years, the antelope squirrel population re-introduced to the kangaroo rat present site persisted, but the population at the kangaroo rat absent site appears to have failed. Home range sizes were much larger at the translocation sites compared to the control. Antelope squirrels dispersed farther from initial release at the site with giant kangaroo rats than the site without, but these results may have suffered from survivorship bias—that is, squirrels at the kangaroo rat absent site either stayed directly within the release footprint or dispersed so far that we could not find them. Our results suggest that the positive impacts of a burrowing ecosystem engineer outweigh the potential negative impacts from competition.https://journal.wildlife.ca.gov/2024/12/27/facilitating-translocation-an-endangered-rodent-engineer-improves-outcomes-for-re-introduced-san-joaquin-antelope-squirrels/ammospermophilus nelsoncommensalismdipodomys ingensecosystem engineerfacilitationhome rangekangaroo ratreintroduction
spellingShingle Patrick Anderson
Craig Fiehler
William Timothy Bean
Facilitating translocation: an endangered rodent engineer improves outcomes for re-introduced San Joaquin antelope squirrels
California Fish and Wildlife Journal
ammospermophilus nelson
commensalism
dipodomys ingens
ecosystem engineer
facilitation
home range
kangaroo rat
reintroduction
title Facilitating translocation: an endangered rodent engineer improves outcomes for re-introduced San Joaquin antelope squirrels
title_full Facilitating translocation: an endangered rodent engineer improves outcomes for re-introduced San Joaquin antelope squirrels
title_fullStr Facilitating translocation: an endangered rodent engineer improves outcomes for re-introduced San Joaquin antelope squirrels
title_full_unstemmed Facilitating translocation: an endangered rodent engineer improves outcomes for re-introduced San Joaquin antelope squirrels
title_short Facilitating translocation: an endangered rodent engineer improves outcomes for re-introduced San Joaquin antelope squirrels
title_sort facilitating translocation an endangered rodent engineer improves outcomes for re introduced san joaquin antelope squirrels
topic ammospermophilus nelson
commensalism
dipodomys ingens
ecosystem engineer
facilitation
home range
kangaroo rat
reintroduction
url https://journal.wildlife.ca.gov/2024/12/27/facilitating-translocation-an-endangered-rodent-engineer-improves-outcomes-for-re-introduced-san-joaquin-antelope-squirrels/
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AT craigfiehler facilitatingtranslocationanendangeredrodentengineerimprovesoutcomesforreintroducedsanjoaquinantelopesquirrels
AT williamtimothybean facilitatingtranslocationanendangeredrodentengineerimprovesoutcomesforreintroducedsanjoaquinantelopesquirrels