The complex structure of the abiotic factors in the Lesser Antilles leads to singular vegetation ranging from the dry to the humid. Geomorphology by means of the wide variety of topographic facets is the determining parameter which leads to gradients of mesological factors. Among the latter, both on the windward and leeward facades, the precipitation is distinguished by bioclimatic staging associated with plant stagings which consist of a mosaic of phytocenoses of variable sizes, ages, floristic compositions and structures as well as of different architecture. Based on examples of old and recent floristic surveys by authors which indicate ecotones, types and inversions of vegetation, we have shown the great phytocenotic diversity of the plant cover in the Lesser Antilles which are all biosystemic responses to the effects of natural and anthropogenic hazards. Thanks to this significant ecosystemic plasticity, the Lesser Antilles represent veritable laboratories for autoecological and synecological studies as well as of floristic succession.

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The complexity of the Lesser Antilles vegetation must be linked to the variety of topographic features that influence the structure of some climatic parameters, particularly the rainfall. The above mentioned environmental factors influence a plurality of biotopes colonized by specific phytocenoses. Using survey transects of different minimal areas, we highlighted the specific, biocenotic, structural and architectural heterogeneity of the survey stations. This spatio-temporal differentiation of plant groupings is strongly guided by the activities of the successive human societies. These elements show that the anthropized vegetation of the Lesser Antilles represents a true laboratory for the study of plant succession using the synchronic approach.

BackgroundIn many geographic areas influenced by tropical and temperate climates, natural forest ecosystems have been destroyed in favour of plantations of allochthonous trees which are economically profitable for different aspects of the timber industry. Some of these mature plantations degrade the soils and inhibit the regenerations of local flora species; others, due to the physical constraints which they impose, can contribute to the installation and the morphogenetic development of autochthonous taxa. The plantations of Swietenia macrophylla and Swietenia aubrevilleana (Mahoganys) in the Lesser Antilles are part of these processes. MethodsTo study the regeneration methods of forest plant species native to Martinique under plantations of Mahoganys, we carried out surveys in thirteen transects (stations) influenced by humid and subhumid bioclimates. ResultsThe results showed that affine natural flora species from various stages of the plant succession colonise the plots of mature Mahoganys. ConclusionsThis study shows that mature plantations of not very competitive introduced forest species can greatly accelerate phytocenotic succession and increase specific richness. It is therefore possible to use these introduced species (Swietenia macrophylla and Swietenia aubrevilleana) in reforestation processes of Lesser Antilles biotopes of sylvan potentiality degraded by anthropisation.

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