Crab Burrowing Limits Surface Litter Accumulation in a Temperate Salt Marsh: Implications for Ecosystem Functioning and Connectivity

GUTIÉRREZ, JORGE L.; JONES, CLIVE G.; RIBEIRO, PABLO D.; FINDLAY, STUART E. G.; GROFFMAN, PETER M.

ECOSYSTEMS (NEW YORK. PRINT)

SPRINGER

Lugar: Berlin; Año: 2018

1432-9840

Burial of aboveground plant litter by animals reducesthe amount available for surface transport andplaces it into a different environment, affectingdecomposition rates and fluxes of organic matter toadjacent ecosystems. Here we show that in aSouthwestern Atlantic salt marsh the burrowingcrab Neohelice granulata buries aboveground plantlitter at rates (0.5?8 g m-2 day-1) comparable tothose of litter production (3 g m-2 day-1). Buriedlitter has a low probability (0.6%) of returning to themarsh surface. The formation of burrow excavationmounds on the marsh surface is responsible for mostlitter burial, whereas litter trapped in burrows wasan order of magnitude lower than rates of burialunder excavation mounds. Crab exclusion markedlyincreased surface litter accumulation (3.5-fold injust 21 days). Tides with the potential to transportsignificant amounts of surface litter are infrequent;hence, most litter is buried before it can be transportedelsewhere or decomposes on the surface.Crab litter burial can account for the observed lowlevels of surface litter accumulation in this ecosystemand likely drives organic matter transformationand export. The impacts of ecosystemengineering bythis crab species are therefore substantial and comparablein magnitude to the large effects found fortropical crabs and other litter-burying organisms,such as anecic earthworms.