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Sewage Pollution: Mitigation Is Key For Coral Reef Stewardship

In this new paper, the authors highlight the importance of addressing sewage, a global stressor affecting coral reefs. The authors note that of 112 coral reef geographies, 104 have documented sewage contamination problems, with the majority documenting direct ocean discharge. Despite this threat, the authors find that scientists and conservationists have paid less attention to understanding and abating sewage impacts on coral reefs, as compared to other stressors like overfishing. They suggest that reasons for this include the challenges of dealing with a large-scale diffuse threat, the diversity of pollutants involved, the high cost of water-treatment facilities, and bureaucracy. The authors explore how sewage discharge is often mischaracterized as a single stressor in coral reef management and suggest that it is important to recognize that sewage is a conglomerate of many potentially toxic and distinct stressors, including freshwater, inorganic nutrients, pathogens, endocrine disrupters, suspended solids, sediments, heavy metals, and other toxins. The authors state that mitigating the threat of sewage pollution will require: 1) understanding tolerance thresholds that corals have to sewage exposure, evaluating individual contaminants, additive, and synergistic combinations of contaminants; 2) quantifying the spatial extent and magnitude of the sewage discharge problems; and, most importantly, (3) testing both proactive and reactive strategies that can be employed to reduce the adverse impacts of human sewage in tropical coastal waters.

Author: Wear, S.L. and R. Vega-Thurber
Year: 2015
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Annuals of the New York Academy of Sciences: 1–16. doi: 10.1111/nyas.12785

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Recovery Potential Of The World’s Coral Reef Fishes

Fishing is the primary source of reduced reef function globally. Marine reserves are a critical tool to help fish populations recover, however, there are no benchmarks to determine if the protection is effective, or whether a reserve has recovered enough to be fished again. By studying remote and marine protected areas, they estimate how many fish would be on a coral reef without fishing, and how long it should take newly protected areas to recover. This helps to assess the impact of reef fisheries, and make informed management decisions that include timeframes for recovery.

Specifically, this paper presents the first empirical estimate of coral reef fisheries recovery potential, compiling data from 832 coral reefs across 64 localities (countries and territories. The authors estimate the expected density of reef fish on unfished reefs; quantify the rate of reef fish biomass recovery in well-enforced marine reserves; characterize the state of reef fish communities within fished and managed areas; predict the time required to recover biomass and ecosystem functions; and explore the potential returns in biomass and function using off-reserve management throughout the broader reefscape. The research team studied the fish biomass on coral reefs around the world and discovered that near-pristine reefs contain 1,000 kg of fish per hectare. Using this figure as a benchmark, they found that 83% of fished reefs have lost more than half of their fish biomass (volume of fish).

The authors discuss how reef fish populations were better off when fishing activities were restricted (e.g., including limitations on the species that could be caught, the gears that could be used, and controlled access rights). The authors determined that once protected, fished reefs take about 35 years to recover, while heavily depleted reefs take almost 60 years. Although the influence of marine reserves can be detected within several years, this global analysis demonstrated that full recovery of reef fish biomass takes decades to achieve. Importantly, this suggests that most marine reserves implemented in the past 10–20 years, will require many more years to achieve their recovery potential. This has important implications for managing expectations of MPAs and also reinforces the need for continued, effective protection and consideration of other viable management options. The authors also found that in reef areas where MPAs cannot be implemented, a range of fisheries can have substantial effects on fish functional groups that support important reef processes.

Author: MacNeil, M.A., N.A.J. Graham, J.E. Cinner, S.K. Wilson, I.D. Williams, J. Maina, S. Newman, A.M. Friedlander, S. Jupiter, N.V.C. Polunin, and T.R. McClanahan
Year: 2015
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Email for the full article: resilience@tnc.org

Nature 520: 341-344. doi:10.1038/nature14358

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Persistence and Change in Community Composition of Reef Corals through Present, Past and Future Climates

This study looked at long-term data from fossil and modern coral reefs to test for variation among coral genera over time, both in rates and directions of change in abundance. Data was synthesized from seven extant reefs, creating 78 trajectories of changing coral cover by genus in the Caribbean and 153 trajectories in the Indo-Pacific. Fossil records from 70 localities from late Miocene to late Pleistocene were used to understand the temporal nature of changes affecting current coral reef communities. A model was developed to evaluate potential coral reef composition of the future under increased thermal stress predicted by climate change. The model suggested that coral mortality and adult coral growth were the most important ecological indicators of coral persistence; thermal tolerance became increasingly important when looking at severe climate change. Overall, corals most likely to persist in future climate scenarios are characterized by rapid growth and moderate mortality but changes in the genera of coral composition in the future are likely to occur.

Author: Edmunds, P.J., M. Adjeroud, M.L. Baskett, I.B. Baums, A.F. Budd, et al.
Year: 2014
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PLoS ONE 9(10): e107525. doi: 10.1371/journal.pone.0107525

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New and improved Network Forum

The Reef Resilience Network has launched a new and improved online discussion forum!

Now part of the Reef Resilience website, this interactive online community is a place where coral reef managers and practitioners from around the world can connect and share with others to better manage marine resources.

If you work to protect, manage, or promote coral reefs please join the conversation: www.reefresilience.org/network

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Meta-Analysis Indicates Habitat-Specific Alterations to Primary Producer and Herbivore Communities in Marine Protected Areas

A recent global quantitative review and meta-analysis was conducted on the effects of MPAs on coral reef herbivores and primary producers to support management decisions. Based on criteria for the meta-analysis, which included only well-enforced no-take MPAs, 41 individual publications representing 57 MPAs worldwide were included in the study. The authors found that within MPAs, macroalgal cover and sea urchin density were significantly lower as compared to fished areas. The relationship between macroalgae cover and herbivores was also explored. MPAs with higher populations of herbivorous fishes had significantly lower macroalgal cover. The authors conclude that the community response to MPAs is highly variable. Management implications include protecting key echinoid predators which appear crucial to the recovery of reefs. Also, actively managing grazers and predators should be an integral component of MPA design.

Author: Gilby, B.L. and T. Stevens
Year: 2014
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Global Ecology and Conservation 2: 289-299. doi: 0.1016/j.gecco.2014.10.005

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How Are Our MPAs Doing? Challenges in Assessing Global Patterns in Marine Protected Area Performance

Marine protected areas (MPAs) are established for a variety of reasons including: protecting marine biodiversity and habitats from degradation, replenishing depleted fish populations, regulating tourism and recreation, accommodating conflicting resource uses, and enhancing the welfare of local communities. In some cases effectively managed MPAs can lead to poverty alleviation, while in others, they may adversely affect local communities. This study utilized biophysical, social, and governance indicators from a commonly applied guidebook, How is your MPA doing?, to explore trends across 24 MPAs worldwide. The objective was to examine protected area goals and objectives and explore the possibility of using site-level data to understand how MPAs might be more effectively established and managed.

The authors found that monitoring is skewed toward biophysical goals and objectives. All five top MPA goals and all 20 of the top MPA objectives most commonly assessed by managers were biophysical. The authors suggest that this may be because biophysical goals and objectives can be assessed using few indicators, compared to governance or socioeconomic goals and objectives which require more indicators to assess. In addition, the authors found that smaller MPAs were correlated with better performance. The authors call for increased efforts to build awareness and capacity to conduct social science research to ensure that managers have the necessary skills to effectively assess the social consequences of MPA establishment. The authors also emphasize the importance of site-specific factors in driving MPA performance. They suggest that future MPA performance guidance include indicators to assess the effects of MPA networks, based on the idea that MPAs are likely to function better as part of a network than on their own. They also reinforce the need for greater emphasis on measuring the social impacts of MPAs to more accurately assess MPA performance. With improved global MPA datasets, policymakers and practitioners in the conservation and development community will be better able to understand what governance structures and resource use patterns are linked to stronger MPA performance.

Author: Fox, H.E., J.L. Holtzman, K.M. Haisfield, C.G. McNally, G.A. Cid, M.B. Mascia, J.E. Parks, and R.S. Pomeroy
Year: 2014
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Email for the full article: resilience@tnc.org

Coastal Management 42: 207–226. doi: 10.1080/08920753.2014.904178

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Coral reefs work as nature’s sea walls – It pays to look after them

A group of researchers found that intact coral reefs reduce wave energy by 97% and wave height by 84%. The study, published recently in the journal Nature Communications found that the risk reduction provided by reefs is relevant to some 200 million people worldwide.

At a time when towns, cities and countries are making major investments in climate and weather-related hazard protection, the authors found that coral reef protection makes economic, ecological and practical, risk-reduction sense when compared with artificial solutions such as seawalls.

To dive deeper:

Read a summary of the article and download the full paper. Also, read co-author Mike Beck’s summary of the study and explanation of how implementing better coral reef management and restoration as part of storm risk reduction has become a new field of science and practical application.

Read why Coral Reefs Soften Ocean’s Fury for Millions of Coastal Dwellers and how economics, location, restoration and threat of coral bleaching may all effect healthy reefs and the 200 million people worldwide that rely on them.

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Designing Marine Reserves for Fisheries Management, Biodiversity Conservation, and Climate Change Adaptation

Coral reef ecosystem goods and services, such as fisheries, are threatened by local and global stressors. Effectively designed and managed marine reserve networks (areas closed to all extractive uses) can reduce local threats and build resilience of coral reefs. This paper reviews recent scientific advances in criteria for designing marine reserve networks to achieve multiple objectives such as fisheries management, conservation, and climate change adaptation. The authors provide integrated guidelines regarding habitat representation, risk spreading, protecting critical habitat, incorporating connectivity, allowing time for recovery, adapting to changes in climate, and minimizing local threats. Integration of marine reserve networks into broader management frameworks is also stressed. Although the guidelines were written for the Coral Triangle region, they can be applied to coral reefs worldwide.

Ecological considerations and guidelines for marine reserve design outlined in the paper include:
Habitat representation: protect 20-40% of each major habitat
Risk spreading: protect at least 3 examples of each major habitat and spread them out
Critical areas: protect critical areas such as fish spawning aggregations, nursery, nesting, breeding, and feeding areas
Incorporating connectivity: apply minimum and variable sizes, 0.5-1 km and 5-20 km across, space reserves 1-15 km apart with smaller reserves closer together
Allowing time for recovery: put reserves in place for 20-40 years or permanently, use periodic closures in addition to long-term protection
Adapting to changes in climate: protect refugia of more resilient habitats
Minimizing local threats: place reserves in areas less likely to be impacted by local threats such as land-based pollution

Author: Green, A.L., L. Fernandes, G. Almany, R. Abesamis, E. McLeod, P.M. Aliño, A.T. White, R. Salm, J. Tanzer, and R.L. Pressey 
Year: 2014
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Email for the full article: resilience@tnc.org

Coastal Management 42(2): 143-159. doi:10.1080/08920753.2014.877763

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The Effectiveness of Coral Reefs for Coastal Hazard Risk Reduction and Adaptation

A global meta-analysis revealed that coral reefs reduce wave energy on coastlines by 97% on average, with the reef crest responsible for attenuating 86% of the energy. Coral reef restoration projects were found to cost significantly less, $1290 USD per meter (median cost), compared to $19,791 USD per meter for building artificial breakwaters, making it significantly cheaper to restore reefs rather than build breakwaters in tropical environments. This study supports the role of coral reefs in risk reduction, including shoreline erosion and flooding, and can be used by managers and policy makers to motivate greater reef protection and restoration.

Author: Ferrario, F., M.W. Beck, C.D. Storlazzi, F. Micheli, C.C. Shepard, and L. Airoldi
Year: 2014
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Nature Communications 5(3794). doi:10.1038/ncomms4794

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