Food web fuel differs across habitats and seasons of a tidal freshwater estuary

Estuaries and Coasts
By: , and 

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Abstract

Estuarine food webs are fueled by multiple different primary producers. However, identifying the relative importance of each producer to consumers is difficult, particularly for fishes that utilize multiple food sources due to both their mobility and their generally high trophic levels. Previous studies have documented broad spatial differences in the importance of primary producers to fishes within the Upper San Francisco Estuary, California, including separation between pelagic and littoral food webs. In this study, we evaluated the importance of primary producers to adult fishes in three closely spaced subregions that represented disparate habitat types (a tidal wetland channel, a turbid backwater channel, and a deep open-water channel), each a potential outcome of local restoration projects. Using stable isotope analysis coupled with a Bayesian mixing model, we identified significant differences in primary-producer contribution to fishes and invertebrates across habitats and seasons, especially in the relative contribution of submersed aquatic vegetation and phytoplankton. Most fishes utilized multiple primary producers and showed little segregation between pelagic and littoral food webs among habitats. Availability of primary producers differs seasonally and across multiple spatial scales, helping to buffer environmental variability and thus enhancing food web resilience. Ecosystem restoration may improve with emphasis on restoring a wide variety of primary producers to support consumers.

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Publication type Article
Publication Subtype Journal Article
Title Food web fuel differs across habitats and seasons of a tidal freshwater estuary
Series title Estuaries and Coasts
DOI 10.1007/s12237-020-00762-9
Volume 44
Year Published 2021
Language English
Publisher Springer
Contributing office(s) California Water Science Center
Description 16 p.
First page 286
Last page 301
Country United States
State California
Other Geospatial Sacramento-San Joaquin Delta, Upper San Francisco Estuary
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