The introduction of plants is not a new phenomenon and is

No abstract

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.

Biological invasions are the second most significant cause of biodiversity loss. They lead to the introduction of exogenous plant species which today threaten autochthonous and/or endemic species. Indeed, many plant species have disappeared. Other highly endangered species are currently in danger of extinction. Human activities, the overexploitation of resources, climate change but also biological invasions have advanced these extinctions. These phenomena have led to the progressive deterioration of the environments and a decrease in the diversity of the landscapes (a considerable depletion of the plant ecosystem) thus contributing to a loss of biodiversity. Natural (cyclones, etc.) or anthropogenic (pollution, etc.) perturbations create openings in the ground cover allowing more competitive species to install themselves. Introduced plant species install themselves in the open areas caused by these perturbations. They overcome a succession of barriers (physical, geographic, environmental) before they can become invasive. When conditions are favourable to their installation, they develop there to the detriment of the native populations. Insular environments (islands) are more sensitive to the phenomena of biological invasions. In Martinique, forests have gradually degraded and are losing their ecosystem resilience. This favours the installation and development of invasive species. Dichrostachys cinerea is an introduced species which is native to Africa and which has become naturalised on the island of Martinique. It colonises extensively perturbed areas, fallow land, abandoned farm plots located in the south of the island. A floristic analysis of the forests of the communes of southern Martinique (Sainte Anne, Marin, Vauclin) was carried out in order to establish the ecological profile of this shrub.