MEPS 490:37-52 (2013)  -  DOI:

Hydrodynamic regulation of salt marsh contributions to aquatic food webs

Ronald Baker1,2,*, Brian Fry3,5, Lawrence P. Rozas4, Thomas J. Minello

1NOAA National Marine Fisheries Service, SEFSC, Galveston Laboratory, 4700 Avenue U, Galveston, Texas 77551, USA
2Centre for Tropical Water and Aquatic Ecosystem Research, School of Marine and Tropical Biology, James Cook University, and CSIRO Land and Water, ATSIP Building, James Cook University, Townsville, Queensland 4811, Australia
3Department of Oceanography and Coastal Sciences, LSU, Baton Rouge, Louisiana 70803, USA
4NOAA National Marine Fisheries Service, SEFSC, Estuarine Habitats and Coastal Fisheries Center,
646 Cajundome Boulevard, Lafayette, Louisiana 70506, USA
5Present address: Australian Rivers Institute, Griffith University, 170 Kessels Road, Brisbane, Queensland 4111, Australia

ABSTRACT: Vegetated salt marsh habitats are widely considered critical for supporting many species of nekton, yet direct evidence of the processes controlling marsh habitat use for most species remains elusive. We related salt marsh flooding patterns and nekton trophic dynamics among 14 sites spanning 2500 km across the northern Gulf of Mexico (GoM) and southern Atlantic coasts of the USA. Functional access for nekton to marsh vegetation (edge flooded to ≥5 cm depth) ranged from <40% of the time at some central GoM sites to >90% access in the western GoM and Pamlico Sound. Food web mixing models based on stable isotope analysis show that the importance of Spartina trophic support for common nekton may be regulated by the duration of marsh surface flooding. In particular, the potential contribution of Spartina production was positively related to indices of marsh surface flooding for brown shrimp Farfantepenaeus aztecus, white shrimp Litopenaeus setiferus, small (≤60 mm carapace width) blue crabs Callinectes sapidus, grass shrimp Palaemonetes pugio, and killifish Fundulus heteroclitus/grandis. The value of Spartina salt marsh production to several common species of nekton appears to depend, at least in part, on direct access to the vegetated marsh surface, which is regulated by hydrodynamics. Hence, the substantial geographic and temporal variability in marsh flooding regulates the functional roles and value of these tidal wetlands for aquatic organisms.

KEY WORDS: Stable isotope · Nursery function · Essential fish habitat · Trophic dynamics · Hydroecology · Tidal wetlands

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Cite this article as: Baker R, Fry B, Rozas LP, Minello TJ (2013) Hydrodynamic regulation of salt marsh contributions to aquatic food webs. Mar Ecol Prog Ser 490:37-52.

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