Mapping Factors That Contribute to Coral Reef Resilience Using In situ and Satellite Data in East Africa

Abstract

Understanding factors that promote coral reef resilience to climatic and anthropogenic stressors is required in order to develop methods and decision support systems to establish resilient Marine Protected Areas (MPAs) and other marine managed areas. This study presents an analysis of coral reef resilience factors obtained from a rapid assessment of coral reefs in 5 locations along the East African coast. The sites span more than 600Km along the coastline of Kenya and Tanzania and are subjected to varying environmental conditions. The study also attempts to present an approach to mapping reef resilience factors and their integration into planning or decision support tools that inform management actions. The analysis revealed that coral reef resilience is highly influenced by biological and anthropogenic factors. Highly resilient reefs were found in areas with high scores for biological factors and low anthropogenic activities. It also revealed that areas with higher cumulative thermal stress and lower levels of pollution from terrestrial sources had higher overall resilience; whilst terrestrial pollution was a major limiting factor on coral reef resilience in the region. Interestingly, the results reveal that reefs with higher resilience are also found in more populated areas compared to reefs in marginal areas that were found to have relatively lower resilience scores. Although this correlation is the weakest compared to other correlations, it could imply that coral reefs found in these highly populated areas are at risk of degradation in the future. However, it is noteworthy that these reefs were those that are within already established MPAs. In order to anticipate and plan for future likelihood of degradation of these reefs, results from this study are proposed to assist in identifying and prioritizing alternative reefs for conservation and management away from such high population density areas. We conclude that incorporating coral reef resilience factors into decision support tools such as GIS can inform management actions aimed at conserving reef ecosystems.