Patterns of natural and anthropogenic disturbance of the mangroves on the Pacific Island of Kosrae

Abstract

Mangroves in many parts of the world are subjected to frequent, large-scaledisturbances. A possible exception is Kosrae, Federated States of Micronesia(FSM), a small volcanic island in the west-central Pacific Ocean. Relativesea level has been stable for most of the last 1000 years and the last tropical cyclone to affect the island was in 1905. Many trees on Kosrae,especially individuals of the species Sonneratia alba, thereforeappear to die only after reaching advanced ages and exceptional sizes. Themost widespread anthropogenic disturbance is harvesting of trees for fuelwoodand poles, which is done selectively and generally creates small, dispersedgaps. Other forms of anthropogenic disturbance, such as modifications ofcoastal landforms, alterations of freshwater inflows road construction andconversion to residential or agricultural uses, are still relatively minorbut have led to some irreversible losses. The economy of Kosrae is basedto a large degree on income derived from a Compact of Free Association betweenthe FSM and the United States, an agreement that has an uncertain future.Many of the funding provisions of the Compact expire in 2001 and, if notrenewed, may have dramatic impacts on resource use. This in turn may leadto a much greater level of anthropogenic disturbance of what are now someof the world's most intact mangrove swamps.