Marine Community Spatial Distributions: Drivers and Patterns
Hundreds of thousands of shorebirds forage for small crustaceans, polychaetes, snails, and bivalves on the tidal mudflats found throughout Virginia's coastal bays annually. Agarophyton forms significant mats along with native macroalgal species that blanket mudflats at low tide. I studied how these macroalgal mats affected invertebrate communities, shorebird foraging and density on individual mudflats and among mudflats at a landscape scale. Work has addressed how macroalgal mats interact with the effects of mudflat geomorphology to jointly impact invertebrates and birds.
Shorebird and Invertebrate Abundance Across a Seascape
Total shorebird abundance varied across mudflats in relation to mudflat topography, worm prey abundance, and macroalgal abundance. These factors interacted to control access to prey. Bird abundance increased with worm abundance on smooth flats, but not on hummocky flats. Meanwhile, on hummocky flats, macroalgae likely improved access to subsurface prey so that bird abundance increased with macroalgal abundance.
Besterman, A.F. and M.L. Pace. (In press). Mudflat geomorphology determines invasive macroalgal effect on invertebrate prey and shorebird predators. Ecology. |
Foraging Habitat Selection
Specialized foragers like plovers and whimbrel avoided macroalgal mats at population-scales, while individuals used macroalgal mats neutrally (bottom). Generalized foragers such as dunlin and dowitchers preferentially selected macroalgal mats as foraging substrate at both population (top) and individual (bottom) scales. Meanwhile, bare habitat selection differed such that specialized foragers preferentially selected bare substrate for foraging at both population and individual scales. Generalized foragers avoided bare substrate at both scales.
Besterman AF, Karpanty SM, Pace ML. 2020. Impact of exotic macroalga on shorebirds varies with foraging specialization and spatial scale. PLoS ONE 15(4): e0231337. https://doi.org/10.1371/journal.pone.0231337 |
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