MANGROVES AND CLIMATE-CHANGE IN THE FLORIDA AND CARIBBEAN REGION - SCENARIOS AND HYPOTHESES

The principal scenario concerning the potential effects of climate change on mangrove forest communities revolves around sealevel rise with emphases on coastal abandonment and inland retreat attributable to flooding and saline intrusion. However, at the decade to century scale, changes in precipitation and catchment runoff may be a more significant factor at the regional level. Specifically, for any given sealevel elevation it is hypothesized that reduced rainfall and runoff would necessarily result in higher salinity and greater seawater-sulfate exposure. This would likely be associated with decreased production and increased sediment organic matter decomposition leading to subsidence. In contrast, higher rainfall and runoff would result in reduced salinity and exposure to sulfate, and also increase the delivery of terrigenous nutrients. Consequently, mangrove production would increase and sediment elevations would be maintained. Support for this scenario derives from studies of the high production in saline mangrove impoundments which are depleted in seawater sulfate. This paper also examines other components of climate change, such as UVb, temperature, and storm frequency, and presents a suite of hypotheses and analytical protocols to encourage scientific discussion and testing.