Willow on Yellowstoneʼs northern range: evidence for a trophic cascade?
Reintroduction of wolves (Canis lupus) to Yellowstone National Park in 1995–1996 has been argued to promote a trophic cascade by altering elk (Cervus elaphus) density, habitat-selection patterns, and behavior that, in turn, could lead to changes within the plant communities used by elk. We sampled t...
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fttriple:oai:gotriple.eu:10670/1.10402/era.30287 2023-05-15T15:50:47+02:00 Willow on Yellowstoneʼs northern range: evidence for a trophic cascade? Merrill, E. Varley, N. Boyce, M. S. Beyer, H. L. 2007-01-01 https://doi.org/10.7939/R3Q52FD13 https://era.library.ualberta.ca/items/e473b24f-a70b-4046-ba4e-2747d9722cb6 en eng doi:10.7939/R3Q52FD13 10670/1.10402/era.30287 https://era.library.ualberta.ca/items/e473b24f-a70b-4046-ba4e-2747d9722cb6 other ERA : Education and Research Archive envir geo Other https://vocabularies.coar-repositories.org/resource_types/c_1843/ 2007 fttriple https://doi.org/10.7939/R3Q52FD13 2023-01-22T18:32:05Z Reintroduction of wolves (Canis lupus) to Yellowstone National Park in 1995–1996 has been argued to promote a trophic cascade by altering elk (Cervus elaphus) density, habitat-selection patterns, and behavior that, in turn, could lead to changes within the plant communities used by elk. We sampled two species of willow (Salix boothii and S. geyeriana) on the northern winter range to determine whether (1) there was quantitative evidence of increased willow growth following wolf reintroduction, (2) browsing by elk affected willow growth, and (3) any increase in growth observed was greater than that expected by climatic and hydrological factors alone, thereby indicating a trophic cascade caused by wolves. Using stem sectioning techniques to quantify historical growth patterns we found an approximately twofold increase in stem growth-ring area following wolf reintroduction for both species of willow. This increase could not be explained by climate and hydrological factors alone; the presence of wolves on the landscape was a significant predictor of stem growth above and beyond these abiotic factors. Growth-ring area was positively correlated with the previous year’s ring area and negatively correlated with the percentage of twigs browsed from the stem during the winter preceding growth, indicating that elk browse impeded stem growth. Our results are consistent with the hypothesis of a behaviorally mediated trophic cascade on Yellowstone’s northern winter range following wolf reintroduction. We suggest that the community-altering effects of wolf restoration are an endorsement of ecological-process management in Yellowstone National Park. Other/Unknown Material Canis lupus Unknown |
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envir geo Merrill, E. Varley, N. Boyce, M. S. Beyer, H. L. Willow on Yellowstoneʼs northern range: evidence for a trophic cascade? |
topic_facet |
envir geo |
description |
Reintroduction of wolves (Canis lupus) to Yellowstone National Park in 1995–1996 has been argued to promote a trophic cascade by altering elk (Cervus elaphus) density, habitat-selection patterns, and behavior that, in turn, could lead to changes within the plant communities used by elk. We sampled two species of willow (Salix boothii and S. geyeriana) on the northern winter range to determine whether (1) there was quantitative evidence of increased willow growth following wolf reintroduction, (2) browsing by elk affected willow growth, and (3) any increase in growth observed was greater than that expected by climatic and hydrological factors alone, thereby indicating a trophic cascade caused by wolves. Using stem sectioning techniques to quantify historical growth patterns we found an approximately twofold increase in stem growth-ring area following wolf reintroduction for both species of willow. This increase could not be explained by climate and hydrological factors alone; the presence of wolves on the landscape was a significant predictor of stem growth above and beyond these abiotic factors. Growth-ring area was positively correlated with the previous year’s ring area and negatively correlated with the percentage of twigs browsed from the stem during the winter preceding growth, indicating that elk browse impeded stem growth. Our results are consistent with the hypothesis of a behaviorally mediated trophic cascade on Yellowstone’s northern winter range following wolf reintroduction. We suggest that the community-altering effects of wolf restoration are an endorsement of ecological-process management in Yellowstone National Park. |
format |
Other/Unknown Material |
author |
Merrill, E. Varley, N. Boyce, M. S. Beyer, H. L. |
author_facet |
Merrill, E. Varley, N. Boyce, M. S. Beyer, H. L. |
author_sort |
Merrill, E. |
title |
Willow on Yellowstoneʼs northern range: evidence for a trophic cascade? |
title_short |
Willow on Yellowstoneʼs northern range: evidence for a trophic cascade? |
title_full |
Willow on Yellowstoneʼs northern range: evidence for a trophic cascade? |
title_fullStr |
Willow on Yellowstoneʼs northern range: evidence for a trophic cascade? |
title_full_unstemmed |
Willow on Yellowstoneʼs northern range: evidence for a trophic cascade? |
title_sort |
willow on yellowstoneʼs northern range: evidence for a trophic cascade? |
publishDate |
2007 |
url |
https://doi.org/10.7939/R3Q52FD13 https://era.library.ualberta.ca/items/e473b24f-a70b-4046-ba4e-2747d9722cb6 |
genre |
Canis lupus |
genre_facet |
Canis lupus |
op_source |
ERA : Education and Research Archive |
op_relation |
doi:10.7939/R3Q52FD13 10670/1.10402/era.30287 https://era.library.ualberta.ca/items/e473b24f-a70b-4046-ba4e-2747d9722cb6 |
op_rights |
other |
op_doi |
https://doi.org/10.7939/R3Q52FD13 |
_version_ |
1766385793957363712 |