Coral bleaching is the detrimental expulsion of algal symbionts from their cnidarian hosts, and predominantly occurs when corals are exposed to thermal stress. The incidence and severity of bleaching is often spatially heterogeneous within reef-scales (<1 km), and is therefore not predictable using conventional remote sensing products. Here, we systematically assess the relationship between in situ measurements of 20 environmental variables, along with seven remotely sensed SST thermal stress metrics, and 81 observed bleaching events at coral reef locations spanning five major reef regions globally. We find that high-frequency temperature variability (i.e., daily temperature range) was the most influential factor in predicting bleaching prevalence and had a mitigating effect, such that a 1 °C increase in daily temperature range would reduce the odds of more severe bleaching by a factor of 33. Our findings suggest that reefs with greater high-frequency temperature variability may represent particularly important opportunities to conserve coral ecosystems against the major threat posed by warming ocean temperatures.

SignificanceMarine reserves that prohibit fishing are a critical tool for sustaining coral reef ecosystems, yet it remains unclear how human impacts in surrounding areas affect the capacity of marine reserves to deliver key conservation benefits. Our global study found that only marine reserves in areas of low human impact consistently sustained top predators. Fish biomass inside marine reserves declined along a gradient of human impacts in surrounding areas; however, reserves located where human impacts are moderate had the greatest difference in fish biomass compared with openly fished areas. Reserves in low human-impact areas are required for sustaining ecological functions like high-order predation, but reserves in high-impact areas can provide substantial conservation gains in fish biomass.

This study explores the social, economic, and ecological context within which communities in Papua New Guinea and Indonesia use adaptive coral reef management. We tested whether periodic closures had positive effects on reef resources, and found that both the biomass and the average size of fishes commonly caught in Indo-Pacific subsistence fisheries were greater inside areas subject to periodic closures compared to sites with year-round open access. Surprisingly, both long-lived and short-lived species benefited from periodic closures. Our study sites were remote communities that shared many socioeconomic characteristics; these may be crucial to the effectiveness of adaptive management of reef resources through periodic closures. Some of these factors include exclusive tenure over marine resources, a body of traditional ecological knowledge that allows for the rapid assessment of resource conditions, social customs that facilitate compliance with closures, relatively small human populations, negligible migration, and a relatively low dependence on fisheries. This dynamic adaptive management system, in which communities manage their resources among multiple social and ecological baselines, contrasts with western fisheries management practices, centered on maintaining exploited populations at stable levels in which net production is maximized.

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Threats from climate change and other human pressures have led to widespread 21 concern for the future of Australia's Great Barrier Reef (GBR) 1 , where increasingly 22 frequent and severe coral bleaching, fishing, and ongoing pollution are 23 undermining long-term persistence of coral-dominated reefs 2,3 . Future resilience 24 of coral-dominated reefs within the GBR will be determined by their ability to 25 resist disturbances and to recover from coral loss, generating intense interest in 26 management actions that can moderate these processes 4-7 . Here we quantify the 27 effect of environmental and human drivers on the resistance and recovery of hard 28 corals to multiple disturbances within the southern and central GBR. Using a 29 composite index for water quality, we find that reefs exposed to poor water quality 30 recover from disturbance more slowly and are more susceptible to outbreaks of 31 crown-of-thorns starfish and coral disease while also being more resistant to 32 coral bleaching. Protection from fishing and increased herbivory were not 33 associated with substantially faster recovery from disturbance. Water quality 34 mediation of a tradeoff between resistance and recovery illustrates that, while 35 reefs in waters of chronically-poor quality contain corals with greater bleaching 36 resistance, there is a net negative impact on recovery and long-term hard coral 37 cover. Given these conditions, we find that 11-23% improvements in water quality 38 will be necessary to bring recovery rates in line with projected increases in coral 39 bleaching among contemporary inshore and mid-shelf reefs. However such 40 reductions are unlikely to buffer projected bleaching effects among outer-shelf 41 GBR reefs dominated by fast growing, thermally sensitive corals, demonstrating 42 practical limits to local management of the GBR against the effects of global 43 warming. 44 45 46The Great Barrier Reef (GBR) has experienced unprecedented losses of hard coral cover 8 . Most 47 coral loss on the GBR has been due to acute disturbances including storms 9,10 , disease 11 , 48 outbreaks of crown-of-thorns starfish Acanthaster spp. (CoTS) 9 , and coral bleaching 8 . Many of 49 these impacts are predicted to become more frequent or intense due to climate change 2,10,12-14 . 50Key to long-term coral-dominance on reefs is whether coral communities can resist coral loss and 51 recover sufficiently quickly between successive disturbances to be resilient and sustain viable 52 populations 15 . However, there are currently few process-based models for quantifying intrinsic 53 rates of increase that accurately characterize recovery. Some of the key drivers thought to 54 influence coral cover recovery include rates of herbivory 16 , coral community composition 17,18 , 55 water quality 19-22 , and protection from fishing 23 . While research into individual drivers is well 56 developed, how cumulative stressors may interact under climate change is not; the potential for 57 non-linear responses to novel ecosystem states creates consid...

ABSTRACT. Although ecosystem services are increasingly recognized as benefits people obtain from nature, we still have a poor understanding of how they actually enhance multidimensional human well-being, and how well-being is affected by ecosystem change. We develop a concept of "ecosystem service elasticity" (ES elasticity) that describes the sensitivity of human well-being to changes in ecosystems. ES Elasticity is a result of complex social and ecological dynamics and is context dependent, individually variable, and likely to demonstrate nonlinear dynamics such as thresholds and hysteresis. We present a conceptual framework that unpacks the chain of causality from ecosystem stocks through flows, goods, value, and shares to contribute to the well-being of different people. This framework builds on previous conceptualizations, but places multidimensional well-being of different people as the final element. This ultimately disaggregated approach emphasizes how different people access benefits and how benefits match their needs or aspirations.Applying this framework to case studies of individual coastal ecosystem services in East Africa illustrates a wide range of social and ecological factors that can affect ES elasticity. For example, food web and habitat dynamics affect the sensitivity of different fisheries ecosystem services to ecological change. Meanwhile high cultural significance, or lack of alternatives enhance ES elasticity, while social mechanisms that prevent access can reduce elasticity.Mapping out how chains are interlinked illustrates how different types of value and the well-being of different people are linked to each other and to common ecological stocks. We suggest that examining chains for individual ecosystem services can suggest potential interventions aimed at poverty alleviation and sustainable ecosystems while mapping out of interlinkages between chains can help to identify possible ecosystem service trade-offs and winners and losers. We discuss conceptual and practical challenges of applying such a framework and conclude on its utility as a heuristic for structuring interdisciplinary analysis of ecosystem services and human wellbeing.

Complex histories of chronic and acute sea surface temperature (SST) stresses are expected to trigger taxon- and location-specific responses that will ultimately lead to novel coral communities. The 2016 El Niño-Southern Oscillation provided an opportunity to examine large-scale and recent environmental histories on emerging patterns in 226 coral communities distributed across 12 countries from East Africa to Fiji. Six main coral communities were identified that largely varied across a gradient of Acropora to massive Porites dominance. Bleaching intensity was taxon-specific and was associated with complex interactions among the 20 environmental variables that we examined. Coral community structure was better aligned with the historical temperature patterns between 1985 and 2015 than the 2016 extreme temperature event. Additionally, bleaching responses observed during 2016 differed from historical reports during past warm years. Consequently, coral communities present in 2016 are likely to have been reorganized by both long-term community change and acclimation mechanisms. For example, less disturbed sites with cooler baseline temperatures, higher mean historical SST background variability, and infrequent extreme warm temperature stresses were associated with Acropora-dominated communities, while more disturbed sites with lower historical SST background variability and frequent acute warm stress were dominated by stress-resistant massive Porites corals. Overall, the combination of taxon-specific responses, community-level reorganization over time, geographic variation, and multiple environmental stressors suggest complex responses and a diversity of future coral communities that can help contextualize management priorities and activities.

Aim: To describe, model and assess the relative importance of environmental and climatic factors likely influencing the regional distribution of coral cover and assemblages with contrasting life histories and susceptibilities to bleaching. Location:We compiled the first comprehensive empirical dataset for coral communities in the south-eastern Indian Ocean (SEIO), incorporating information from 392 sites along the western coast of Australia and offshore atolls/islands across ~19° of latitude. Methods:We assessed hard coral cover and community composition to genus using point-intercept transects or point-count analysis of digital images taken along transects. We explored spatial variation in environmental conditions and in composition of corals with contrasting life histories. After de-trending the temporal patterns, we assessed the relative importance of environmental metrics to coral cover, life histories 606 | ZINKE Et al.