Spatial distribution pattern and inter-specific association of eight medicinal species in the brazilian savanna

Abstract

This main purpose of this work was the application of spatial dispersion indexes and inter-specific association among eight species with medicinal interest from the Brazilian Savanna, which are: Alibertia edulis, Anadenanthera falcata, Bauhinia holophyla, Bromelia balansae, Cochlospermum regium, Dimorphandra mollis, Duguetia furfuracea, and Tabebuia aurea. Data were collected in an area of 32 ha, where 32 plots of 30 x 10 meters, 100 meters far away from each other, were systematically allocated. In each plot, the number of individuals belonging to each specie were registered. In the characterization of the dispersion and interspecific association the following indexes were utilized: Morisita, McGuinnes, Fracker and Brishle, Payandeh, and the Hurlbert coefficient. According to the dispersion indexes analyzed, the majority of the species showed a clustering trend or being aggregated, and only Dimorphandra mollis presented random distribution. The Hurlbert s inter-specific association coefficient indicated independent association among the species Duguetia furfuracea and Tabebuia aurea with the other analyzed species. It should be emphasized that there was a negative association among Anadenanthera falcata and two other species: Alibertia edulis and Dimorphandra mollis. Studies have demonstrated that the Anadenanthera genus presents alelopatic effects upon test-pants, which should help to explain this occurrence. In general, the other species studied showed independent or positive association.