BEULIG,, A.; GANGE, , J.*; New College of Florida; New College of Florida: Coral reef and mangrove interactions in Bocas del Toro, Panama

Results from studies in the Caribbean and Indo-Pacific have differed on the importance of mangrove-derived biomass in the economy of reefs. We studied reciprocal influences of coral reef and mangrove forest in Bocas del Toro, Panama. We focused on movement and degradation of mangrove leaf litter, distribution of holothurian detritivores, and character of the fouling community on mangrove root systems as well as water quality in three different sites. Site A: sandy beach (no mangroves) with nearshore coral reef; Site B: coastal mangrove forest with no adjacent coral reef; Site C: mangrove shoreline with adjacent coral reef. Transects 150 m long with 2x10m quadrats every 10 m were established and organisms/leaves counted. When a coral reef was adjacent, there was significantly less settled mangrove leaf litter within the first 30 m from shore. There was significantly greater population density of holothurians when a coral reef was adjacent to the mangroves (Site C) than a shoreline with coral reef alone (Site A) or mangroves alone (Site B). Species diversity of the fouling community on mangrove root systems was greater on mangroves with adjacent coral reef. There were no significant differences among sites in water quality except for significantly greater silica concentration in Site A. It is suggested that mangrove-derived detritus (as well as some from reef) supported a larger population of sea cucumbers at Site C than at the other sites. Further, mature holothurians may carry out reproductive activities in the reef areas and when pelagic larvae settle, they may select mangroves and sea grasses as substrate. Survival and recruitment would be enhanced because of shelter and nutrients obtainable in the mangroves. It is also suggested that the reef may be a source of pelagic larvae of sessile organisms that may settle on mangrove roots for greater diversity. Corals were found growing on some mangrove roots.