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Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA

Riparian ecosystem restoration has been accomplished through exclusion of livestock using corridor fencing along hundreds of kilometers of streams in the western United States, for the benefit of riparian-obligate wildlife and endangered fishes. Yet, there are limited scientific studies that have ev...

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Autores principales: Kauffman, J. Boone, Coleman, Greg, Otting, Nick, Lytjen, Danna, Nagy, Dana, Beschta, Robert L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8782521/
https://www.ncbi.nlm.nih.gov/pubmed/35061670
http://dx.doi.org/10.1371/journal.pone.0250136
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author Kauffman, J. Boone
Coleman, Greg
Otting, Nick
Lytjen, Danna
Nagy, Dana
Beschta, Robert L.
author_facet Kauffman, J. Boone
Coleman, Greg
Otting, Nick
Lytjen, Danna
Nagy, Dana
Beschta, Robert L.
author_sort Kauffman, J. Boone
collection PubMed
description Riparian ecosystem restoration has been accomplished through exclusion of livestock using corridor fencing along hundreds of kilometers of streams in the western United States, for the benefit of riparian-obligate wildlife and endangered fishes. Yet, there are limited scientific studies that have evaluated more than short-term shifts in vegetation composition and diversity at a single location or handful of locations following grazing. We sampled riparian vegetation composition along 11-paired grazed and ungrazed (exclosed) stream reaches in northeastern Oregon. Exclosure ages ranged from 2 to >30 years and grazing treatments varied from light grazing every one out of three years to heavy season-long grazing. Species richness and diversity was higher in the ungrazed reaches (p = 0.002). The abundance of native sedges (Carex spp.) and broad-leaved forbs were also significantly (p ≤ 0.05) greater in ungrazed areas. In contrast, exotic species adapted to grazing such as Poa pratensis and Trifolium repens were more abundant in grazed stream reaches. The prevalence of hydrophytic species significantly increased (p ≤ 0.01) in ungrazed reaches, (based on wetland species indicator scores), indicating that wetland-dominated communities within the ungrazed stream reaches were replacing ones adapted to drier environments. The increased abundance of facultative and wetland-obligate species in ungrazed reaches compared to grazed reaches suggests that livestock grazing exacerbates those climate change effects also leading to warmer and drier conditions. Further, riparian-obligate shrub cover along the streambank was higher in 7 of 8 exclosures that were older than 5 years (p = 0.05). As a restoration approach, the inherent resilience of riparian ecosystems exhibited in ungrazed riparian zones suggest positive feedbacks to other beneficial ecosystem processes such as increased species and habitat diversity, increased carbon sequestration, enhanced allochthonous inputs and greater sediment retention, that would affect the aquatic and terrestrial biota, water quality, and stream morphology.
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spelling pubmed-87825212022-01-22 Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA Kauffman, J. Boone Coleman, Greg Otting, Nick Lytjen, Danna Nagy, Dana Beschta, Robert L. PLoS One Research Article Riparian ecosystem restoration has been accomplished through exclusion of livestock using corridor fencing along hundreds of kilometers of streams in the western United States, for the benefit of riparian-obligate wildlife and endangered fishes. Yet, there are limited scientific studies that have evaluated more than short-term shifts in vegetation composition and diversity at a single location or handful of locations following grazing. We sampled riparian vegetation composition along 11-paired grazed and ungrazed (exclosed) stream reaches in northeastern Oregon. Exclosure ages ranged from 2 to >30 years and grazing treatments varied from light grazing every one out of three years to heavy season-long grazing. Species richness and diversity was higher in the ungrazed reaches (p = 0.002). The abundance of native sedges (Carex spp.) and broad-leaved forbs were also significantly (p ≤ 0.05) greater in ungrazed areas. In contrast, exotic species adapted to grazing such as Poa pratensis and Trifolium repens were more abundant in grazed stream reaches. The prevalence of hydrophytic species significantly increased (p ≤ 0.01) in ungrazed reaches, (based on wetland species indicator scores), indicating that wetland-dominated communities within the ungrazed stream reaches were replacing ones adapted to drier environments. The increased abundance of facultative and wetland-obligate species in ungrazed reaches compared to grazed reaches suggests that livestock grazing exacerbates those climate change effects also leading to warmer and drier conditions. Further, riparian-obligate shrub cover along the streambank was higher in 7 of 8 exclosures that were older than 5 years (p = 0.05). As a restoration approach, the inherent resilience of riparian ecosystems exhibited in ungrazed riparian zones suggest positive feedbacks to other beneficial ecosystem processes such as increased species and habitat diversity, increased carbon sequestration, enhanced allochthonous inputs and greater sediment retention, that would affect the aquatic and terrestrial biota, water quality, and stream morphology. Public Library of Science 2022-01-21 /pmc/articles/PMC8782521/ /pubmed/35061670 http://dx.doi.org/10.1371/journal.pone.0250136 Text en © 2022 Kauffman et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Kauffman, J. Boone
Coleman, Greg
Otting, Nick
Lytjen, Danna
Nagy, Dana
Beschta, Robert L.
Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA
title Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA
title_full Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA
title_fullStr Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA
title_full_unstemmed Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA
title_short Riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern Oregon, USA
title_sort riparian vegetation composition and diversity shows resilience following cessation of livestock grazing in northeastern oregon, usa
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8782521/
https://www.ncbi.nlm.nih.gov/pubmed/35061670
http://dx.doi.org/10.1371/journal.pone.0250136
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