Os impactos do coral invasor Tubastraea spp. na produção de carbonato e na complexidade estrutural de um recife brasileiro: uma análise do crescimento esquelético, do potencial bioconstrutor e da modulação de vias tróficas.

Abstract

The invasion of non-native species poses a significant challenge to marine ecosystems, affecting habitat structure, community dynamics, and overall ecosystem functions. Structural complexity is crucial in regulating diversity and trophic levels in coral reefs. However, the specific influence of invasive species on reef topography and associated trophic effects remains poorly understood. In this study, we examined the impact of the invasive coral Tubastraea on the top reef areas of Cascos Reef, Bahia, Brazil, addressing its effects on benthic community structure, structural complexity, reef carbonate production, and the trophic structure of reef fish between 2017 and 2019. We utilized video transects, skeletal growth measurement techniques (linear extension, density, and calcification), digital depth probes, and high-resolution three-dimensional models of the investigated coral species. Results revealed changes in benthic assemblage patterns, characterized by increased Tubastraea spp. cover and a decline in encrusting calcareous algae over the years. Additionally, invasive corals exhibited higher skeletal extension rates and lower skeletal density than native species (Montastraea cavernosa and Siderastrea sp.), with no significant changes in overall reef carbonate production during the study period. Moreover, Tubastraea spp. skeletons significantly increased reef rugosity, contributing to substrate complexity on a submetric scale. However, this increase did not promote reef fish diversity but indicated the potential for altering trophic structure patterns. Specifically, a negative relationship was observed between the complexity index of Tubastraea sp. colonies and the abundance of certain fish trophic groups, such as roving herbivores and omnivores. In contrast, a positive relationship was noted with planktivores. These findings suggest that habitat attribute modifications induced by invasive corals can significantly impact benthos-fish dynamics, favoring certain fish groups over others and potentially affecting various ecosystem functions. This study underscores the importance of further understanding the ecological impacts of invasive species on coral reefs. Given the current scenario of rapidly accelerating global changes, which intensify invasion events worldwide, implementing robust regulatory and management policies becomes imperative to protect the marine environment and ensure the preservation of essential ecosystem services for human well-being.