Benthic Assemblage Variability in the Upper San Francisco Estuary: A 27-Year Retrospective
<p>We used multivariate methods to explore changes in benthic assemblage structure over 27 years (1977–2003) at four monitoring stations located along a salinity gradient in the upper San Francisco Estuary. Changes in benthic assemblage composition were assessed relative to hydrologic variabil...
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| Format: | Article |
| Language: | English |
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eScholarship Publishing, University of California
2010-05-01
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| Series: | San Francisco Estuary and Watershed Science |
| Subjects: | |
| Online Access: | http://escholarship.org/uc/item/4d0616c6 |
| _version_ | 1818281892415275008 |
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| author | Heather A Peterson Marc Vayssieres |
| author_facet | Heather A Peterson Marc Vayssieres |
| author_sort | Heather A Peterson |
| collection | DOAJ |
| description | <p>We used multivariate methods to explore changes in benthic assemblage structure over 27 years (1977–2003) at four monitoring stations located along a salinity gradient in the upper San Francisco Estuary. Changes in benthic assemblage composition were assessed relative to hydrologic variability and to the presence of the high-impact invader <em>Corbula amurensis </em>in the estuary. We also explored the composition of benthic assemblages during a recent collapse of several pelagic populations in the upper estuary. Our results show that the <em>Corbula</em> invasion had both direct and indirect effects on the benthos in the estuary, causing significant changes in assemblage structure. We found no unprecedented patterns of benthic assemblage composition during the period of the Pelagic Organism Decline (2000–2003) in the upper estuary. Hydrologic variability was associated with significant changes in benthic assemblage composition at all locations. Benthic assemblage composition was more sensitive to mean annual salinity than other local physical conditions. That is, benthic assemblages were not geographically static, but shifted with salinity, moving down-estuary in years with high delta outflow, and up-estuary during years with low delta outflow, without strong fidelity to physical habitat attributes such as substrate composition or location in embayment vs. channel habitat. Organism abundance and species richness showed a bi-modal distribution along the salinity gradient, with lowest abundance and richness in the 5 to 8 psu range. We conclude that the continuity of benthic assemblages and community metrics along the salinity gradient is a powerful and necessary context for understanding historical variability in assemblage composition at geographically static monitoring stations.</p> |
| first_indexed | 2024-12-13T00:12:20Z |
| format | Article |
| id | doaj.art-a98520dbe3194224b299717d4c3ad71c |
| institution | Directory Open Access Journal |
| issn | 1546-2366 |
| language | English |
| last_indexed | 2024-12-13T00:12:20Z |
| publishDate | 2010-05-01 |
| publisher | eScholarship Publishing, University of California |
| record_format | Article |
| series | San Francisco Estuary and Watershed Science |
| spelling | doaj.art-a98520dbe3194224b299717d4c3ad71c2022-12-22T00:05:55ZengeScholarship Publishing, University of CaliforniaSan Francisco Estuary and Watershed Science1546-23662010-05-0181ark:13030/qt4d0616c6Benthic Assemblage Variability in the Upper San Francisco Estuary: A 27-Year RetrospectiveHeather A Peterson0Marc Vayssieres1U.S. Geological Survey and California Dept. of Water ResourcesCalifornia Dept. of Water Resources, Sacramento<p>We used multivariate methods to explore changes in benthic assemblage structure over 27 years (1977–2003) at four monitoring stations located along a salinity gradient in the upper San Francisco Estuary. Changes in benthic assemblage composition were assessed relative to hydrologic variability and to the presence of the high-impact invader <em>Corbula amurensis </em>in the estuary. We also explored the composition of benthic assemblages during a recent collapse of several pelagic populations in the upper estuary. Our results show that the <em>Corbula</em> invasion had both direct and indirect effects on the benthos in the estuary, causing significant changes in assemblage structure. We found no unprecedented patterns of benthic assemblage composition during the period of the Pelagic Organism Decline (2000–2003) in the upper estuary. Hydrologic variability was associated with significant changes in benthic assemblage composition at all locations. Benthic assemblage composition was more sensitive to mean annual salinity than other local physical conditions. That is, benthic assemblages were not geographically static, but shifted with salinity, moving down-estuary in years with high delta outflow, and up-estuary during years with low delta outflow, without strong fidelity to physical habitat attributes such as substrate composition or location in embayment vs. channel habitat. Organism abundance and species richness showed a bi-modal distribution along the salinity gradient, with lowest abundance and richness in the 5 to 8 psu range. We conclude that the continuity of benthic assemblages and community metrics along the salinity gradient is a powerful and necessary context for understanding historical variability in assemblage composition at geographically static monitoring stations.</p>http://escholarship.org/uc/item/4d0616c6Benthic invertebrateslong-term monitoringinvasionestuaryEcology, Evolution, Systematics, and Population Biology |
| spellingShingle | Heather A Peterson Marc Vayssieres Benthic Assemblage Variability in the Upper San Francisco Estuary: A 27-Year Retrospective San Francisco Estuary and Watershed Science Benthic invertebrates long-term monitoring invasion estuary Ecology, Evolution, Systematics, and Population Biology |
| title | Benthic Assemblage Variability in the Upper San Francisco Estuary: A 27-Year Retrospective |
| title_full | Benthic Assemblage Variability in the Upper San Francisco Estuary: A 27-Year Retrospective |
| title_fullStr | Benthic Assemblage Variability in the Upper San Francisco Estuary: A 27-Year Retrospective |
| title_full_unstemmed | Benthic Assemblage Variability in the Upper San Francisco Estuary: A 27-Year Retrospective |
| title_short | Benthic Assemblage Variability in the Upper San Francisco Estuary: A 27-Year Retrospective |
| title_sort | benthic assemblage variability in the upper san francisco estuary a 27 year retrospective |
| topic | Benthic invertebrates long-term monitoring invasion estuary Ecology, Evolution, Systematics, and Population Biology |
| url | http://escholarship.org/uc/item/4d0616c6 |
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