Structural and floristic patterns in tropical swamp forests: A case study from the Pterocarpus officinalis (Jacq.) forest in Guadeloupe, French West Indies

In the coastal floodplains of most Caribbean islands, the monodominant Pterocarpus officinalis Jacq. forest constitutes the typical vegetation of undisturbed freshwater to slightly brackish swamps. Key ecological determinants of floristic and structural variation were assessed in this forest where the dominant species contributes nearly 90% of the basal area. A field inventory was conducted in a 100-ha forest tract located near the bay of the Grand Cul-de-sac Marin, Guadeloupe (French West Indies). The flora and the main descriptors of both forest structure and edaphic environment were surveyed in forty-one 200 m × 200 m plots using a systematic grid sampling. Redundancy analysis pointed out ground elevation as the key descriptor of forest flora and structure whereas hierarchical cluster analysis revealed four main ecological units. We propose an organization model of the P. officinalis swamp forest ecosystem in the regional context of the Holocene sea-level rise. The ultimate successional stage is the most species-rich stand found seaward on deep peaty soils, which accelerating sea-level rise is expected to threaten.