Influência da facilitação e diversidade de plantas sobre o sequestro de carbono de uma planta pioneira durante a restauração da Caatinga

Abstract

Forest restoration has great potential for mitigating climate change. In seasonally dry tropical forests such as the Caatinga in Brazil, natural regeneration plays an important role in this process, but its dynamics are poorly understood. This study sought to understand how tree species diversity and the facilitation potential of these trees influence carbon input in a key species of natural regeneration, Jatropha mollissima (Pohl) Baill. (pinhão), in a Caatinga restoration experiment. A total of 3,519 individuals of J. mollissima were sampled in an experimental gradient of planted species diversity (0, 1, 2, 4, 8, and 16 species). Above-ground biomass was estimated using a specific allometric equation (exponential model, R² = 0.95). It was observed that carbon accumulation by the pine nut was mediated by a significant interaction between the richness of planted species and the potential for facilitation. At low levels of diversity, facilitation negatively influenced carbon stocks. In contrast, in plots with high species richness, facilitation positively affected carbon sequestration by pinhão. The results demonstrate that pinhão successfully colonizes degraded areas, exhibiting high abundance at all levels of diversity. Furthermore, we conclude that the high diversity of planted species, together with a high facilitation potential, increases the capacity of this regenerating species to contribute to carbon stocks. The results of the study emphasize that planning restoration projects with a high diversity of facilitating species is a strategy that can maximize restoration success and carbon sequestration in seasonally dry tropical forests.