COMPETIÇÃO INTERESPECÍFICA NÃO É UM PROCESSO ESTRUTURADOR IMPORTANTE EM UMA COMUNIDADE ARBÓREA TROPICAL

A competição interespecífica é um dos processos ecológicos mais importantes para a coexistência de espécies. Em comunidades arbóreas, a morte de indivíduos da espécie competitivamente mais fraca leva à relação espacial de dissociação entre populações de espécies competidoras. Além disso, pode haver redução no crescimento das plantas nas proximidades de competidores mais fortes. Normalmente, os efeitos da competição são mais intensos entre espécies filogeneticamente mais próximas devido à sua similaridade funcional. Para testar se a competição entre espécies arbóreas é um importante processo em uma área de Floresta Ombrófila Densa Submontana no sudeste do Brasil, utilizamos análises espaciais para determinar a relação espacial entre populações, a influência da proximidade de heteroespecíficos sobre o tamanho dos indivíduos de uma determinada espécie, a diferença entre a distância filogenética de espécies com populações com diferentes relações espaciais, e a relação entre distância filogenética e tamanho de heteroespecíficos em função da distância espacial entre eles. Poucos pares de espécies apresentaram populações dissociadas. Não encontramos redução no tamanho dos indivíduos de uma espécie em função da distância de heteroespecíficos, diferença entre a distância filogenética de espécies com populações com diferentes relações espaciais, e relação entre distância filogenética e redução no tamanho dos indivíduos em função da distância de competidores. Assim, não há evidências de que a competição interespecífica seja importante na estruturação da comunidade estudada. Isso difere dos resultados encontrados em outras florestas tropicais e aponta que outros processos, como competição intraespecífica, competição difusa e processos neutros, sejam mais importantes na estruturação da comunidade. INTERSPECIFIC COMPETITION IS NOT AN IMPORTANT STRUCTURING PROCESS IN A TROPICAL TREE COMMUNITY. Interspecific competition is one of the most important ecological processes maintaining species coexistence. In tree communities, the death of individuals of competitively weaker species results in the spatial relationship of dissociation between populations of competing species. Additionally, there may be a decrease in growth of plants located near strong competitors. Usually, the effects of interspecific competition are more intense in phylogenetically close species due to their functional similarity. To test whether competition among tree species is an important ecological process in an area of Submontane Atlantic Rainforest in SE Brazil, we used spatial analysis to determine the spatial relationship between populations, the influence of the proximity of heterospecifics on the size of individuals of a given species, the difference among the phylogenetic distance of species with populations with different spatial relationships, and the relationship between phylogenetic distance and the size of heterospecifics as a function of the spatial distance between them. Few pairs of species showed dissociated populations. We did not find reduced size of individuals located near heterospecifics, difference among the phylogenetic distance of species with populations with different spatial relationships, and relationship between phylogenetic distance and the size of individuals as a function of the distance from competitors. Therefore, there is no evidence that interspecific competition is important in structuring the community studied. This differs from results found in other tropical forests and suggests that other processes, such as intraspecific competition, diffuse competition and neutral processes, are more important in structuring the community

Tropical forests in the Americas are changing too slowly to track climate change

Understanding the capacity of forests to adapt to climate change is of pivotal importance for conservation science, yet this is still widely unknown. This knowledge gap is particularly acute in high-biodiversity tropical forests. Here, we examined how tropical forests of the Americas have shifted community trait composition in recent decades as a response to changes in climate. Based on historical trait-climate relationships, we found that, overall, the studied functional traits show shifts of less than 8% of what would be expected given the observed changes in climate. However, the recruit assemblage shows shifts of 21% relative to climate change expectation. The most diverse forests on Earth are changing in functional trait composition but at a rate that is fundamentally insufficient to track climate change

Tropical forests in the Americas are changing too slowly to track climate change

Understanding the capacity of forests to adapt to climate change is of pivotal importance for conservation science, yet this is still widely unknown. This knowledge gap is particularly acute in high-biodiversity tropical forests. Here, we examined how tropical forests of the Americas have shifted community trait composition in recent decades as a response to changes in climate. Based on historical trait-climate relationships, we found that, overall, the studied functional traits show shifts of less than 8% of what would be expected given the observed changes in climate. However, the recruit assemblage shows shifts of 21% relative to climate change expectation. The most diverse forests on Earth are changing in functional trait composition but at a rate that is fundamentally insufficient to track climate change

Tropical forests in the Americas are changing too slowly to track climate change

Understanding the capacity of forests to adapt to climate change is of pivotal importance for conservation science, yet this is still widely unknown. This knowledge gap is particularly acute in high-biodiversity tropical forests. Here, we examined how tropical forests of the Americas have shifted community trait composition in recent decades as a response to changes in climate. Based on historical trait-climate relationships, we found that, overall, the studied functional traits show shifts of less than 8% of what would be expected given the observed changes in climate. However, the recruit assemblage shows shifts of 21% relative to climate change expectation. The most diverse forests on Earth are changing in functional trait composition but at a rate that is fundamentally insufficient to track climate change