Avaliação do nicho isotópico de herbívoros nos recifes de corais da Área de proteção Ambiental Costa dos Corais

Abstract

Coral reefs are one of the most biodiverse ecosystems on the planet, playing a fundamental role in the health of the oceans, in addition to their great economic potential. Understanding processes such as herbivory by distinct taxonomic species can be a useful way to investigate dynamic of biotic interactions contributing to management tools. This study aimed to evaluate the effect of management zoning on trophic niche of the three herbivory species in Marine Protect Area Costa dos Corais (APACC) investigating stable isotopes δ 15N and δ 13C signatures of the sea urchin Echinometra lucunter and reef fish, the blennid Ophioblennius trinitatis and damselfish Stegastes fuscus. The methodology steps included specimens’ collection on the Maragogi e Japaratinga reefs using snorkelling, and processing and analysis of isotopes samples in the laboratory (Laboratório de Biologia Marinha e Conservação, LAMARC) of the Federal University of Alagoas. Using niche parameter Corrected Standard Ellipse Area (SEAc), the results showed that isotopic niche amplitude of the S. fuscus, E. lucunter and O. trinitatis were distinct. S. fuscus occupied superior trophic position with the highest δ 15N signatures (10.12 ± 0.35 mean amplitude ± standard deviation δN‰), but, in contrast, E. lucunter had the highest SEAc value (1,91). The species isotopic niche had a greater amplitude in the non-take areas (ZPVM) and smaller in tourism areas (ZV). The results also showed that trophic niche varied between localities, being SEAc values highest in Japaratinga (14,14) than Maragogi (12,53) reefs. The results showed that management zoning and natural attributes in APACC reefs influenced species isotopic niche. Thus, it was possible to discuss how different management regimes can influence trophic niche of herbivores and their influence on coral reef functioning. We conclude that management zoning can be determinant to maintain trophic niche interactions, especially between herbivores and algae, implicating on coral reefs ecological processes.