Severe Impact and Subsequent Recovery of a Coral Assemblage following the 1997–8 El Niño Event: A 17-Year Study from Bahia, Brazil

The coral reefs of northern Bahia evolved in isolation from other Atlantic systems and under conditions of high environmental stress, particularly high turbidity. We have monitored the scleractinian assemblage of four shallow bank reefs (Praia do Forte, Itacimirim, Guarajuba and Abai) annually for 17 years since 1995, collecting quantitative data on diversity and density of coral colonies. As the sampling period included the 1997-8 El Niño event, the most severe on record, for the first time these results allow a quantitative assessment of the long-term impact of this major environmental stressor on such a coral assemblage. After El Niño, most species showed significantly reduced densities of colonies, this decline occurring for the subsequent two years without evidence of any new settlement until 2001. From 2000 to 2007 the species Porites astreoides went unrecorded. Recovery was slow, and multivariate analysis revealed that assemblages had not returned to the pre-El Niño state until 2011. It therefore took 13 years for full recovery of the coral assemblage to occur, which has consequences for reef systems if such El-Niño events become more frequent in the future

Araca: biodiversity, impacts and threats

Araca Bay (Sao Sebastiao, State of Sao Paulo), within one of Brazil's most beautiful coastlines, has small relict mangrove stands and a very diverse marine ecosystem. As such, the bay is a natural laboratory as well as important for local small scale fishing. In this study we summarize the large literature base to comprehensibly list the flora and fauna as a preliminary biodiversity inventory of Araca Bay. We place this in the historical context of human impact on the environment of the bay and we emphasize new, introduced and threatened species as bioindicators and natural resources. With this information, we provide a basis to inform conservation decisions as well as data for conservation management plans and call attention to the urgent need to protect this fragile environment and biota. We also emphasize that this small and uniquely biologically rich bay should be preserved, revitalized and integrated into the growing urban environment.10121926