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

The principal scenario concerning the potential effects of climate cha nge on mangrove forest communities revolves around sealevel rise with emphases on coastal abandonment and inland retreat attributable to flo oding and saline intrusion. However, at the decade to century scale, c hanges in precipitation and catchment runoff may be a more significant factor at the regional level. Specifically, for any given sealevel el evation it is hypothesized that reduced rainfall and runoff would nece ssarily result in higher salinity and greater seawater-sulfate exposur e. This would likely be associated with decreased production and incre ased sediment organic matter decomposition leading to subsidence. In c ontrast, higher rainfall and runoff would result in reduced salinity a nd exposure to sulfate, and also increase the delivery of terrigenous nutrients. Consequently, mangrove production would increase and sedime nt elevations would be maintained. Support for this scenario derives f rom studies of the high production in saline mangrove impoundments whi ch are depleted in seawater sulfate. This paper also examines other co mponents of climate change, such as UVb, temperature, and storm freque ncy, and presents a suite of hypotheses and analytical protocols to en courage scientific discussion and testing.