Abstract
The ecological mechanisms that contribute to maintaining plant populations have been exhaustively examined worldwide, but the relative quantification of the effects of anthropogenic processes on these mechanisms in tropical dioecious tree species has not yet been performed. The aim of this study was to analyze the effects of debarking on the sex ratio, population structure, distribution and spatial correlation between the sexes and growth stages of Amphipterygium adstringens (Anaciardiaceae), a dioecious tree species that is highly exploited for its medicinal bark. We found differences in plant density between the harvested and nonharvested stands. The sex ratio was 1.33d':1 female in the harvested stands, while the opposite was true for the nonharvested stands (1.27 female:1d'), which suggested that selective debarking drives androic skewing and has an impact on reproductive performance. However, despite the dominance of a certain sex in terms of relative frequency under each condition, we did not observe spatial sex segregation since the analysis suggested that the spatial independence pattern did not differ between sites. In contrast, facilitation requirements (spatial attraction) between androic plants and plants and between seedlings and saplings were found in nonharvested areas, while spatial uniformity patterns at the population level suggest strategies to avoid competition over space and finite resources in stressful environments. These novel findings indicate that debarking not only modifies the spatial and population structure of a Mesoamerican tropical tree but also influences the sex ratio, consequently affecting the long-term conservation of A. adstringens stands.