Potencial invasor de Cryptogestia madagascariensis: efeito de fatores bióticos e abióticos durante a colonização.

Abstract

The success of the invasion process is related to the species' ability to overcome different biotic and abiotic filters. The objective of this study was to evaluate the influence of biotic and abiotic factors on the invasive potential of Cryptostegia madagascariensis and its potential distribution in Brazil. We present the results in four chapters in manuscript form. In the first chapter (Manuscript I), we evaluated the effects of abiotic factors on germination and initial growth of C. madagascariensis. The results showed that high temperatures and saline and water stress inhibit its germination, but it does not depend on light. The seedlings develop well intermediate levels of water deficit and even in severe stress survive. In the second chapter (Manuscript II), we studied the initial growth of C. madagascariensis over time in different shadings. We observed that the seedlings tolerate shady environments, growing like shrub in the sun and investing in height in the shade. Increased light may favor the invasiveness of this species. In the third chapter (Manuscript III), we investigated the establishment of C. madagascariensis in disturbed areas and intra and interspecific competition with the native species Poincianella bracteosa and Piptadenia stipulacea in two environments (sun and shade). C. madagascariensis seedlings did not settle under canopy. Only intraspecific competition affected C. madagascariensis, while native species had their development negatively affected by competition with this invasive species. In the fourth chapter (Manuscript IV), we analyzed the potential distribution of C. madagascariensis in Brazil in current and future climatic conditions and the overlap of areas favorable to invasion with the potential distribution of Copernicia prunifera. We observed that approximately half of the areas with high probability of occurrence of C. prunifera overlap with those of C. madagascariensis. Currently the Northeast presents the most favorable areas for the establishment of this invader, and climate change favors its expansion in Brazil. Therefore, the invasiveness of C. madagascariensis is associated with high germination rates, rapid growth, morphological changes in different resource offerings and high competitive capacity. C. madagascariensis can invade a large extent of the Northeast and climate change must increase its invading potential in Brazil.