Cobertura e sanidade de corais e zoantídeos (Cnidaria, Anthozoa) em recifes costeiros expostos a diferentes intensidades de uso turístico

Abstract

The continued growth of tourism has affected coastal ecosystems, especially the reef environments, negatively impacting on their organisms. high intensity tourist areas tend to have a less equal distribution of species and biological diversity lower compared to less frequented areas. This study aimed to describe the relationship between the degree of tourist use and the sanity and abundance of scleractinians corals and zoanthids in coastal reefs. For that purpose, six beaches of the coast of Pernambuco (northeastern Brazil) with different tourist use intensities were selected. The average number of visitors per beach was obtained through observations on days with different intensities of people flow (Sunday and Monday) and the beaches were classified as low use or heavy use. To measure coral cover and zoanthids were established nine transects 25m, parallel to the coast, six in midlittoral and three in the subtidal. Along each transect, three square 1x1m, with 81 points of intersection were arranged. Coral coverage, zoanthids, algae and total live coverage was calculated. All colonies that were within 50m2 each transect were counted, measured and the presence of death and bleaching were recorded. Were listed four species of zoanthids and five species of corals. The zoanthids were more abundant in areas of intense tourist use, in contrast corals were most abundant in the low tourist use, which they had higher diversity of anthozoans. The coral that had the highest number of partially bleached and dead colonies was Siderastrea stellata, besides being the most abundant in all areas. The tourist flow showed the highest relationship with the coral cover and zoanthids than with health indicators adopted for this study. However, factors such as acidification, nutrient increase and temperature fluctuations appear to act synergistically on the health of anthozoans. Changes in benthic community structure can have negative consequences for reef ecosystems, among them the phase shift, causing loss of biodiversity due to favoring the most resistant species, as algae and zoanthids at the expense of corals. Thus, due to the numerous ecosystem services, the reefs demonstrate once again being priority areas for conservation.