Meeting Abstract
Avicennia germinans (Black Mangrove) coverage has doubled in the last three decades in Northeast Florida’s salt marshes due to climate change (fewer cold days). These marshes were originally dominated by Spartina alterniflora (Smooth cordgrass), but now they are being outcompeted. This research focuses on how the influx of A. germinans impacts the ecosystem biogeochemically in the carbon and nitrogen it contributes, as well as biologically in the organisms it supports. Animal and vegetation tissues were collected between Marineland and St. Augustine, Florida. Stable isotope analysis was used to determine from which vegetation organisms were obtaining nutrients. Macro-scale trials with fiddler crabs and periwinkle snails were conducted to investigate which vegetation they preferred. The majority of organisms studied obtained their nutrients from S. alterniflora, although the A. pisonii (mangrove tree crab), G. demise (ribbed mussel), and C. virginica (oyster) fed on detritus derived from both plants. Furthermore, fiddler crabs preferred A. germinans soil whereas periwinkle snails preferred S. alterniflora vegetation. In conclusion, A. Germinans expansion will alter the ecosystem’s food web and species distribution.
