We studied the impacts caused by the invasion of algaroba - Prosopis juliflora (Sw.) DC. - on Caatinga biodiversity and structure. Areas in two minicipalities in the state of Rio Grande do Norte were selected (Area I and Area II). Ten plots were established in each environment, in which all shrubby-arboreal individuals were sampled. The diversity indices, measured by the Shannon-Wiener function, were: in Areas I and II of Environment 1, respectively 2.74 and 2.44 for adults, and 1.96 and 1.83 for regenerating individuals; in Areas I and II of Environment 2 these values were only 0.88 and 0.42 for adults; 0.16 and 0.79 for regenerating individuals, respectively. The results showed that P. juliflora drastically affects the diversity and, therefore, the structure of invaded communities, making evident the need to control such an invasive species which threatens the native biodiversity of the Caatinga and related ecosystems.
biological invasion; exotic species; loss of diversity; caatinga; xeric vegetation
