DOI: https://doi.org/10.3354/meps12982
copiedDiverse resource-use strategies in a large-bodied marine predator guild: evidence from differential use of resource subsidies and intraspecific isotopic variation
ABSTRACT: Observations of resource-use dynamics are sparse for higher trophic level species in marine systems, but important given their role in driving the distribution and functional roles of species. For a guild comprised of 7 large-bodied shark species captured in Florida Bay, we used multi-tissue stable isotope analysis to evaluate the extent of resource-use diversity within and between 2 time periods. We examined: (1) variation in community-wide isotopic niche structure across time (i.e. Layman’s community metrics); (2) variation in species’ trophic position; (3) reliance upon dominant resource pools (inland mangroves vs. coastal neritic [i.e. seagrass and/or reef-associated prey]; and (4) patterns of intraspecific isotopic variation across species (i.e. standard ellipse area, ellipse eccentricity E, ellipse inclination θ, and total isotopic overlap). Community-wide isotopic niche characteristics varied with tissue type, suggesting temporal plasticity in community resource use. Our novel approach integrating multiple isotopic baselines resulted in consistently high trophic position estimates (>5.0), but the utilization of available resource subsidies varied with species and tissue type. Whole blood suggested recent use of inland mangrove-derived prey resources, while fin tissue suggested differential use of both inland mangroves and coastal neritic-derived subsidies. Our results suggest that sharks display dynamic resource use in space and time, with limited functional complementarity across species. The adoption of diverse resource-use strategies, both within and among species, could facilitate the co-occurrence of large-bodied predator species and underscores the role of sharks as vectors of ecosystem connectivity.
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Oliver N. Shipley (Corresponding Author)
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA
Austin J. Gallagher (Co-author)
- Beneath the Waves, PO Box 126, Herndon, VA 20172, USA
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33146, USA
David S. Shiffman (Co-author)
- Earth to Oceans Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
Leslie Kaufman (Co-author)
- Boston University Marine Program, Department of Biology, 1 Silber Way, Boston, MA 02215, USA
Neil Hammerschlag (Co-author)
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33146, USA
- Leonard and Jayne Abess Center for Ecosystem Science and Policy, University of Miami, Coral Gables, FL 33146, USA
