EDI Staging Environment
We experimentally manipulated black mangrove (Avicennia germinans) cover in ten large plots and over five years (2014-2019) quantified the effects of mangrove cover on subsidies of floating organic material (wrack) into coastal wetlands. We hypothesized that the change from salt marsh to mangrove vegetation would alter the permeability of the intertidal habitat, and thus alter the nature of subsidies from marine to intertidal habitats. Data from field surveys of wrack distribution showed that as mangrove cover increased from zero to 100%, wrack cover and thickness decreased by ~60%, the distance that wrack penetrated into the plots decreased by ~70%, and the percentage of the wrack trapped in the first six m of the plot tripled. Data from wrack samples indicated that wrack samples collected from the fringe were ~3 times heavier than those from the interior of plots. Animals were ~40% more abundant in samples from the interior than from the fringe of plots, but this trend was not statistically significant due to low replication of interior samples. Data from a wrack experiment revealed that animal abundance and species composition varied between the fringe and interior of the plots, and between microhabitats dominated by salt marsh versus mangrove vegetation. Increasing mangrove cover decreased the relative importance of marine subsidies into the intertidal at the plot level, but concentrated subsidies at the front edge of the mangrove stand. Storms, however, may temporarily override mangrove attenuation of wrack inputs.
EDI is a collaboration between the University of New Mexico and the University of Wisconsin – Madison, Center for Limnology:
