Does the presence of exotic species decrease the initial development of native species in Brazilian seasonally dry tropical forests?

Abstract

We assessed the impacts of the biological invasion of Azadirachta indica on the quality of plant species native to a Seasonally Dry Tropical Forest. We planted Amburana cearensis, Libidibia ferrea, Mimosa caesalpiniifolia, and Cenostigma pyramidale individuals alone and interacting with the exotic species. We measured their diameters at ground level and heights for four months, calculating their monthly and general average. After this period, seedlings were destroyed to obtain their number of leaves, leaf area, specific leaf area, length and primary root area, wood density, wood dry matter, leaf dry matter, shoot dry matter, primary root dry matter, secondary root dry matter, root system dry matter, and total dry matter. The presence of the exotic species affected the functional characteristics of native species in different ways. We observed negative effects in M. caesalpiniifolia and A. cearensis, positive effects in C. pyramidale, and mixed effects in L. ferrea. In addition, we identified conflicting demands between pairs of characteristics of the interacting species A. cearensis and M. caesalpiniifolia. Based on the results, it is possible to conclude that A. indica decreases the quality of individuals of most native species studied, which may have consequences for their establishment and the local biodiversity.