Kenya q Coral Reef Resilience Studies (original) (raw)
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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.
Assessing relative resilience potential of coral reefs to inform management
Ecological resilience assessments are an important part of resilience-based management (RBM) and can help prioritize and target management actions. Use of such assessments has been limited due to a lack of clear guidance on the assessment process. This study builds on the latest scientific advances in RBM to provide that guidance from a resilience assessment undertaken in the Commonwealth of the Northern Mariana Islands (CNMI). We assessed spatial variation in ecological resilience potential at 78 forereef sites near the populated islands of the CNMI: Saipan, Tinian/Aguijan, and Rota. The assessments are based on measuring indicators of resilience processes and are combined with information on anthropogenic stress and larval connectivity. We find great spatial variation in relative resilience potential with many high resilience sites near Saipan (5 of 7) and low resilience sites near Rota (7 of 9). Criteria were developed to identify priority sites for six types of management actions (e.g., conservation, land-based sources of pollution reduction, and fishery management and enforcement) and 51 of the 78 sites met at least one of the sets of criteria. The connectivity simulations developed indicate that Tinian and Aguijan are each roughly 10 × the larvae source that Rota is and twice as frequent a destination. These results may explain the lower relative resilience potential of Rota reefs and indicates that actions in Saipan and Tinian/Aguijan will be important to maintaining supply of larvae. The process we describe for undertaking resilience assessments can be tailored for use in coral reef areas globally and applied to other ecosystems.
Coral reefs are experiencing an unprecedented global decline due to a range of anthropogenic stressors. To slow this trend, better understanding of underlying mechanisms behind reef degradation is required. Recent efforts in coral reef research emphasize the importance of targeting different levels of biological organization and using innovative applications by complementing traditional ecological approaches with techniques from other disciplines (physiology, biogeochemistry, or microbiology). These efforts will lead to better insights into the complex interactions that build the resilience of the reef ecosystem. Proceedings of the YOUMARES 6: A Journey into the Blue - Ocean Research and Innovation, University of Bremen, Bremen, Germany; 09/2015 http://www.youmares.net/images/stories/YM6/pdf/BoA\_Youmares6\_final\_hiRes.pdf
Evaluation of coral reef management effectiveness using conventional versus resilience-based metrics
With increasing stressors to coral reefs, defining tools that evaluate their dynamics and resilience is important to interpret system trajectories and direct conservation efforts. In this context, surveys must go beyond conventional monitoring approaches that focus on abundance and biomass of key groups and quantify metrics that better assess ecological processes and ecosystem trajectories. By measuring a variety of conventional (e.g. proportional cover of broad benthic groups, biomass of herbivorous fish) and complementary resilience-based metrics (e.g. algal turf height, coral recruitment rates, juvenile coral densities, herbivorous fish grazing rates), this study evaluated the ecosystem responses to community-based management in Fiji. The study was conducted across three paired tabu areas (periodically closed to fishing) and adjacent fished sites. Conventional metrics reflected no management effect on benthic or herbivorous fish assemblages. In contrast, the complementary metrics generally indicated positive effects of management, particularly within the benthos. Significant differences were observed for turf height (33% lower), coral recruitment rate (159% higher) and juvenile coral density (42% higher) within areas closed to fishing compared to adjacent open reefs. In addition, turf height was inversely related to coral recruitment and juvenile coral density, and longer turfs (≥5 mm) were more competitive in interaction with corals. These results emphasise that conventional metrics may overlook benefits of local management to inshore reefs, and that incorporating complementary resilience-based metrics such as turf height into reef survey protocols will strengthen their capacity to predict the plausible future condition of reefs and their responses to disturbances.
Assessing Ecological Resilience of Indonesian Coral Reefs
Ecological resilience is an important property of natural ecosystem to be understood in coral reef management. Resilience of Indonesian coral reefs was assessed using 2009 COREMAP data. The assessment used 698 data of line intercept transects collected from 15 districts and 4 marine physiographies. Resilience index used in the assessment was developed by the authors but will be published elsewhere. The results showed that coral reefs at western region had higher average resilience indices than eastern region, and Sunda Shelf reefs had higher resilience indices than coral reefs at Indian Ocean, Sulawesi-Flores, or Sahul Shelf. Four districts were found to have coral reefs with highest resilience indices, i.e. Bintan and Natuna (western region), and Wakatobi and Buton (eastern region). Raja Ampat had coral reefs with lower average resilience indices than that of Wakatobi. Uses of resilience index in coral reef management should be coupled with other information such as maximum depth o...