INFLUENCE OF ANTHROPOGENIC PRESSURES ON THE DEGRADATION OF CARIBBEAN CORAL REEFS IN BOCAS DEL TORO, PANAMA

Human impact on Caribbean coral reefs has increased rapidly within the past century, leading to degradation of the reefs and a potential loss of biodiversity. Anthropogenic activity is often implicated in reef degradation, but the extent and cause of degradation that pre-dates direct observation is difficult to determine due to a lack of ecological data. We examined the subfossil assemblages sediment cores collected from two coral reef sites in Bocas del Toro, Panama, to better understand the relationship between historical human activity and the several components of the ecological community as a measure of reef health. Our hope is that by identifying when reef communities began to change in Panama, we will be able to pinpoint what human activities contribute to reef degradation. Previous work on the historical ecology of fossil reefs has used bivalves to infer reef health, as they are found in diverse environments, are abundant in Caribbean reefs and have easily identifiable functional groups that can be used to infer their habitat. We identified and counted 226 individual bivalves in the core from the Punta Donato site, which ranges from 1100 to 1980 AD and 388 individuals in the core from the Airport Point site, which ranges from 1000 BC to 1300 AD. Within both cores, a decrease in the abundance of epifaunal genera (e.g. Barbatia, Chama and Arcopsis) is followed by an increase in the abundance of infaunal genera (e.g. Gouldia and Parvilucina), as well as a shift in the major diet of bivalves – from suspension feeders to an increase of chemosymbiotic lucinids. The shift in bivalve functional groups suggests reef degradation, because there is significant decrease in the relative abundance of functional groups associated with coral reefs (e.g. epifaunal and suspension feeding bivalves) through time. In the Punta Donato core, these trends closely correspond with periods of increased human impact in the Bocas del Toro region, suggesting that reef degradation can be attributed to fertilizer run-off from nearby banana plantations.