5 posts tagged with "Coral Reefs"

Coral reefs are important habitats that represent global marine biodiversity hotspots and provide important benefits to people in many tropical regions. However, coral reefs are becoming increasingly threatened by climate change, overfishing, habitat destruction, and pollution. Historical baselines of coral cover are important to understand how much coral cover has been lost, e.g., to avoid the ‘shifting baseline syndrome’. There are few quantitative observations of coral reef cover prior to the industrial revolution, and therefore baselines of coral reef cover are difficult to estimate. Here, we use expert and ocean-user opinion surveys to estimate baselines of global coral reef cover. The overall mean estimated baseline coral cover was 59% (±19% standard deviation), compared to an average of 58% (±18% standard deviation) estimated by professional scientists. We did not find evidence of the shifting baseline syndrome, whereby respondents who first observed coral reefs more recently report lower estimates of baseline coral cover. These estimates of historical coral reef baseline cover are important for scientists, policy makers, and managers to understand the extent to which coral reefs have become depleted and to set appropriate recovery targets.

Large marine protected areas (LMPAs) are increasingly being established and have a high profile in marine conservation. LMPAs are expected to achieve multiple objectives, and because of their size are postulated to avoid trade-offs that are common in smaller MPAs. However, evaluations across multiple outcomes are lacking. We used a systematic approach to code several social and ecological outcomes of 12 LMPAs. We found evidence of three types of trade-offs: trade-offs between different ecological resources (supply trade-offs); trade-offs between ecological resource conditions and the well-being of resource users (supply-demand trade-offs); and trade-offs between the well-being outcomes of different resource users (demand trade-offs). We also found several divergent outcomes that were attributed to influences beyond the scope of the LMPA. We suggest that despite their size, trade-offs can develop in LMPAs and should be considered in planning and design. LMPAs may improve their performance across multiple social and ecological objectives if integrated with larger-scale conservation efforts.

Ocean warming is expected to impact biodiversity and fisheries in the tropics through shifts in species’ distributions, leading to local extinctions and changes in species composition of catches. However, regional-scale patterns may differ from global trends due to the influence of important environmental factors such as ocean warming, fishing and habitat availability. Here, we used the mean temperature of the catch to test the hypothesis that, for the period of 1971 to 2010, regional variation in species-turnover of exploited reef fish assemblages among 9 Caribbean countries can be explained by differences in the rate of warming, species’ thermal preferences, changes in trophic structure due to fishing and potential reef habitat across the region. Sea surface temperature and the mean temperature of the catch displayed rates of increase of 0.14 and 0.19°C decade-1respectively, on par with the global average and higher when compared to the global average for all tropical fisheries. These rates also varied across the 9 Caribbean countries, ranging from 0.04 to 0.18°C decade-1 for sea surface temperature and 0.10 to 0.62°C decade-1 for the mean temperature of the catch. The negative interaction between potential reef habitats in each country and sea surface temperature in relation to the mean temperature of the catch suggests possible moderating effects of available habitats on the sensitivity of fish communities to warming. In addition, the negative relationship of trophic level with the mean temperature of the catch suggests that fishing increases their vulnerability. Findings from this study can help elucidate factors driving variations in the sensitivity of exploited fish communities to warming, and have implications for the management of living marine resources in the Caribbean region.

In this article, we examine the problem of coral reef destruction and discuss various stakeholders who suffer losses from the destruction. We then postulate a stakeholder versus threats matrix and outline an algorithm where public authorities can streamline policy based on expected losses. We also formulate, using local data, divergence between public good and individual benefits and examine the agent behaviour under monitoring. Our examples, using previous estimations on net benefits, give guidelines on how to form public policy and management strategies.

Corals and coral-associated species are highly vulnerable to the emerging effects of global climate change. The widespread degradation of coral reefs, which will be accelerated by climate change, jeopardizes the goods and services that tropical nations derive from reef ecosystems. However, climate change impacts to reef social–ecological systems can also be bi-directional. For example, some climate impacts, such as storms and sea level rise, can directly impact societies, with repercussions for how they interact with the environment. This study identifies the multiple impact pathways within coral reef social–ecological systems arising from four key climatic drivers: increased sea surface temperature, severe tropical storms, sea level rise and ocean acidification. We develop a novel framework for investigating climate change impacts in social–ecological systems, which helps to highlight the diverse impacts that must be considered in order to develop a more complete understanding of the impacts of climate change, as well as developing appropriate management actions to mitigate climate change impacts on coral reef and people.