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Trophic Cascades Induced by Lobster Fishing Are Not Ubiquitous in Southern California Kelp Forests
Fishing can trigger trophic cascades that alter community structure and dynamics and thus modify ecosystem attributes. We combined ecological data of sea urchin and macroalgal abundance with fishery data of spiny lobster (Panulirus interruptus) landings to evaluate whether: (1) patterns in the abund...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2012
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510206/ https://www.ncbi.nlm.nih.gov/pubmed/23209573 http://dx.doi.org/10.1371/journal.pone.0049396 |
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author | Guenther, Carla M. Lenihan, Hunter S. Grant, Laura E. Lopez-Carr, David Reed, Daniel C. |
author_facet | Guenther, Carla M. Lenihan, Hunter S. Grant, Laura E. Lopez-Carr, David Reed, Daniel C. |
author_sort | Guenther, Carla M. |
collection | PubMed |
description | Fishing can trigger trophic cascades that alter community structure and dynamics and thus modify ecosystem attributes. We combined ecological data of sea urchin and macroalgal abundance with fishery data of spiny lobster (Panulirus interruptus) landings to evaluate whether: (1) patterns in the abundance and biomass among lobster (predator), sea urchins (grazer), and macroalgae (primary producer) in giant kelp forest communities indicated the presence of top-down control on urchins and macroalgae, and (2) lobster fishing triggers a trophic cascade leading to increased sea urchin densities and decreased macroalgal biomass. Eight years of data from eight rocky subtidal reefs known to support giant kelp forests near Santa Barbara, CA, USA, were analyzed in three-tiered least-squares regression models to evaluate the relationships between: (1) lobster abundance and sea urchin density, and (2) sea urchin density and macroalgal biomass. The models included reef physical structure and water depth. Results revealed a trend towards decreasing urchin density with increasing lobster abundance but little evidence that urchins control the biomass of macroalgae. Urchin density was highly correlated with habitat structure, although not water depth. To evaluate whether fishing triggered a trophic cascade we pooled data across all treatments to examine the extent to which sea urchin density and macroalgal biomass were related to the intensity of lobster fishing (as indicated by the density of traps pulled). We found that, with one exception, sea urchins remained more abundant at heavily fished sites, supporting the idea that fishing for lobsters releases top-down control on urchin grazers. Macroalgal biomass, however, was positively correlated with lobster fishing intensity, which contradicts the trophic cascade model. Collectively, our results suggest that factors other than urchin grazing play a major role in controlling macroalgal biomass in southern California kelp forests, and that lobster fishing does not always catalyze a top-down trophic cascade. |
format | Online Article Text |
id | pubmed-3510206 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-35102062012-12-03 Trophic Cascades Induced by Lobster Fishing Are Not Ubiquitous in Southern California Kelp Forests Guenther, Carla M. Lenihan, Hunter S. Grant, Laura E. Lopez-Carr, David Reed, Daniel C. PLoS One Research Article Fishing can trigger trophic cascades that alter community structure and dynamics and thus modify ecosystem attributes. We combined ecological data of sea urchin and macroalgal abundance with fishery data of spiny lobster (Panulirus interruptus) landings to evaluate whether: (1) patterns in the abundance and biomass among lobster (predator), sea urchins (grazer), and macroalgae (primary producer) in giant kelp forest communities indicated the presence of top-down control on urchins and macroalgae, and (2) lobster fishing triggers a trophic cascade leading to increased sea urchin densities and decreased macroalgal biomass. Eight years of data from eight rocky subtidal reefs known to support giant kelp forests near Santa Barbara, CA, USA, were analyzed in three-tiered least-squares regression models to evaluate the relationships between: (1) lobster abundance and sea urchin density, and (2) sea urchin density and macroalgal biomass. The models included reef physical structure and water depth. Results revealed a trend towards decreasing urchin density with increasing lobster abundance but little evidence that urchins control the biomass of macroalgae. Urchin density was highly correlated with habitat structure, although not water depth. To evaluate whether fishing triggered a trophic cascade we pooled data across all treatments to examine the extent to which sea urchin density and macroalgal biomass were related to the intensity of lobster fishing (as indicated by the density of traps pulled). We found that, with one exception, sea urchins remained more abundant at heavily fished sites, supporting the idea that fishing for lobsters releases top-down control on urchin grazers. Macroalgal biomass, however, was positively correlated with lobster fishing intensity, which contradicts the trophic cascade model. Collectively, our results suggest that factors other than urchin grazing play a major role in controlling macroalgal biomass in southern California kelp forests, and that lobster fishing does not always catalyze a top-down trophic cascade. Public Library of Science 2012-11-29 /pmc/articles/PMC3510206/ /pubmed/23209573 http://dx.doi.org/10.1371/journal.pone.0049396 Text en © 2012 Guenther et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Guenther, Carla M. Lenihan, Hunter S. Grant, Laura E. Lopez-Carr, David Reed, Daniel C. Trophic Cascades Induced by Lobster Fishing Are Not Ubiquitous in Southern California Kelp Forests |
title | Trophic Cascades Induced by Lobster Fishing Are Not Ubiquitous in Southern California Kelp Forests |
title_full | Trophic Cascades Induced by Lobster Fishing Are Not Ubiquitous in Southern California Kelp Forests |
title_fullStr | Trophic Cascades Induced by Lobster Fishing Are Not Ubiquitous in Southern California Kelp Forests |
title_full_unstemmed | Trophic Cascades Induced by Lobster Fishing Are Not Ubiquitous in Southern California Kelp Forests |
title_short | Trophic Cascades Induced by Lobster Fishing Are Not Ubiquitous in Southern California Kelp Forests |
title_sort | trophic cascades induced by lobster fishing are not ubiquitous in southern california kelp forests |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510206/ https://www.ncbi.nlm.nih.gov/pubmed/23209573 http://dx.doi.org/10.1371/journal.pone.0049396 |
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