Recolonizing Wolves Trigger a Trophic Cascade in Wisconsin

We tested the hypothesis that wolves are reducing local browse intensity by white-tailed deer, thus indirectly mitigating the biotic impoverishment of understorey plant communities in northern Wisconsin. To assess the potential for such a top-down trophic cascade response, we developed a spatially a...

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Main Authors: Callan, Ramana, Nibbelink, Nathan P., Rooney, Thomas P., Wiedenhoeft, Jane E., Wydeven, Adrian P.
Format: Text
Language:unknown
Published: SelectedWorks 2014
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Online Access:https://works.bepress.com/thomas_rooney/107
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spelling ftwrightuniv:oai:works.bepress.com:thomas_rooney-1107 2023-05-15T15:51:23+02:00 Recolonizing Wolves Trigger a Trophic Cascade in Wisconsin Callan, Ramana Nibbelink, Nathan P. Rooney, Thomas P. Wiedenhoeft, Jane E. Wydeven, Adrian P. 2014-10-28T19:21:11Z https://works.bepress.com/thomas_rooney/107 unknown SelectedWorks https://works.bepress.com/thomas_rooney/107 Thomas P. Rooney Biodiversity Determinants of Plant Community Diversity and Structure Grey Wolf (Canis lupus) Herbivory Northern White Cedar (Thuja occidentalis) Species–Area Relationship Trophic Cascades Vegetation Dynamics White-Tailed Deer (Odocoileus virginianus) Wisconsin Biological Sciences Biology Life Sciences Medical Sciences Medicine and Health Sciences Systems Biology text 2014 ftwrightuniv 2021-11-21T09:26:15Z We tested the hypothesis that wolves are reducing local browse intensity by white-tailed deer, thus indirectly mitigating the biotic impoverishment of understorey plant communities in northern Wisconsin. To assess the potential for such a top-down trophic cascade response, we developed a spatially and temporally explicit model of wolf territory occupancy based on three decades of wolf monitoring data. Using a nested multiscale vegetation survey protocol, we compared the understorey plant communities of northern white cedar wetlands found in high wolf areas with control sites found in low wolf areas. We fit species–area curves for plant species grouped by vegetation growth form (based on their predicted response to release from herbivory, i.e. tree, seedling, shrub, forb, grass, sedge or fern) and duration of wolf territory occupancy. As predicted for a trophic cascade response, forb species richness at local scales (10 m2) was significantly higher in high wolf areas (high wolf areas: 10.7 ± 0.9, N = 16, low wolf areas: 7.5 ± 0.9, N = 16, P < 0.001), as was shrub species richness (high wolf areas: 4.4 ± 0.4, N = 16, low wolf areas: 3.2 ± 0.5, N = 16, P < 0.001). Also as predicted, percentage cover of ferns was lower in high wolf areas (high wolf areas: 6.2 ± 2.1, N = 16, low wolf areas: 11.6 ± 5.3, N = 16, P < 0.05). Beta richness was similar between high and low wolf areas, supporting earlier assumptions that deer herbivory impacts plant species richness primarily at local scales. Sampling at multiple spatial scales revealed that changes in species richness were not consistent across scales nor among vegetation growth forms: forbs showed a stronger response at finer scales (1–100 m2), while shrubs showed a response across relatively broader scales (10–1000 m2). Synthesis. Our results are consistent with hypothesized trophic effects on understorey plant communities triggered by a keystone predator recovering from regional extinction. In addition, we identified the response variables and spatial scales appropriate for detecting such differences in plant species composition. This study represents the first published evidence of a trophic cascade triggered by wolf recovery in the Great Lakes region. Text Canis lupus Wright State University: CORE Scholar (Campus Online Repository)
institution Open Polar
collection Wright State University: CORE Scholar (Campus Online Repository)
op_collection_id ftwrightuniv
language unknown
topic Biodiversity
Determinants of Plant Community Diversity and Structure
Grey Wolf (Canis lupus)
Herbivory
Northern White Cedar (Thuja occidentalis)
Species–Area Relationship
Trophic Cascades
Vegetation Dynamics
White-Tailed Deer (Odocoileus virginianus)
Wisconsin
Biological Sciences
Biology
Life Sciences
Medical Sciences
Medicine and Health Sciences
Systems Biology
spellingShingle Biodiversity
Determinants of Plant Community Diversity and Structure
Grey Wolf (Canis lupus)
Herbivory
Northern White Cedar (Thuja occidentalis)
Species–Area Relationship
Trophic Cascades
Vegetation Dynamics
White-Tailed Deer (Odocoileus virginianus)
Wisconsin
Biological Sciences
Biology
Life Sciences
Medical Sciences
Medicine and Health Sciences
Systems Biology
Callan, Ramana
Nibbelink, Nathan P.
Rooney, Thomas P.
Wiedenhoeft, Jane E.
Wydeven, Adrian P.
Recolonizing Wolves Trigger a Trophic Cascade in Wisconsin
topic_facet Biodiversity
Determinants of Plant Community Diversity and Structure
Grey Wolf (Canis lupus)
Herbivory
Northern White Cedar (Thuja occidentalis)
Species–Area Relationship
Trophic Cascades
Vegetation Dynamics
White-Tailed Deer (Odocoileus virginianus)
Wisconsin
Biological Sciences
Biology
Life Sciences
Medical Sciences
Medicine and Health Sciences
Systems Biology
description We tested the hypothesis that wolves are reducing local browse intensity by white-tailed deer, thus indirectly mitigating the biotic impoverishment of understorey plant communities in northern Wisconsin. To assess the potential for such a top-down trophic cascade response, we developed a spatially and temporally explicit model of wolf territory occupancy based on three decades of wolf monitoring data. Using a nested multiscale vegetation survey protocol, we compared the understorey plant communities of northern white cedar wetlands found in high wolf areas with control sites found in low wolf areas. We fit species–area curves for plant species grouped by vegetation growth form (based on their predicted response to release from herbivory, i.e. tree, seedling, shrub, forb, grass, sedge or fern) and duration of wolf territory occupancy. As predicted for a trophic cascade response, forb species richness at local scales (10 m2) was significantly higher in high wolf areas (high wolf areas: 10.7 ± 0.9, N = 16, low wolf areas: 7.5 ± 0.9, N = 16, P < 0.001), as was shrub species richness (high wolf areas: 4.4 ± 0.4, N = 16, low wolf areas: 3.2 ± 0.5, N = 16, P < 0.001). Also as predicted, percentage cover of ferns was lower in high wolf areas (high wolf areas: 6.2 ± 2.1, N = 16, low wolf areas: 11.6 ± 5.3, N = 16, P < 0.05). Beta richness was similar between high and low wolf areas, supporting earlier assumptions that deer herbivory impacts plant species richness primarily at local scales. Sampling at multiple spatial scales revealed that changes in species richness were not consistent across scales nor among vegetation growth forms: forbs showed a stronger response at finer scales (1–100 m2), while shrubs showed a response across relatively broader scales (10–1000 m2). Synthesis. Our results are consistent with hypothesized trophic effects on understorey plant communities triggered by a keystone predator recovering from regional extinction. In addition, we identified the response variables and spatial scales appropriate for detecting such differences in plant species composition. This study represents the first published evidence of a trophic cascade triggered by wolf recovery in the Great Lakes region.
format Text
author Callan, Ramana
Nibbelink, Nathan P.
Rooney, Thomas P.
Wiedenhoeft, Jane E.
Wydeven, Adrian P.
author_facet Callan, Ramana
Nibbelink, Nathan P.
Rooney, Thomas P.
Wiedenhoeft, Jane E.
Wydeven, Adrian P.
author_sort Callan, Ramana
title Recolonizing Wolves Trigger a Trophic Cascade in Wisconsin
title_short Recolonizing Wolves Trigger a Trophic Cascade in Wisconsin
title_full Recolonizing Wolves Trigger a Trophic Cascade in Wisconsin
title_fullStr Recolonizing Wolves Trigger a Trophic Cascade in Wisconsin
title_full_unstemmed Recolonizing Wolves Trigger a Trophic Cascade in Wisconsin
title_sort recolonizing wolves trigger a trophic cascade in wisconsin
publisher SelectedWorks
publishDate 2014
url https://works.bepress.com/thomas_rooney/107
genre Canis lupus
genre_facet Canis lupus
op_source Thomas P. Rooney
op_relation https://works.bepress.com/thomas_rooney/107
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