A Decision Framework for Interventions to Increase the Persistence and Resilience of Coral Reefs (2019) / Chapter Skim
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1 Introduction
1 Introduction
Pages 19-32
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From page 19... ...
. Local stressors have historically been the main cause of coral reef loss and degradation, and control of local stressors is integral to continued coral persistence (Mcleod et al., 2019; see Bruno et al., 2019, for questions regarding the contribution of local management to coral reef resilience)
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From page 20... ...
, the committee described 23 interventions that have the potential to increase the persistence of coral reefs as environmental conditions deteriorate. While management of the entire reef community is essential for coral persistence and delivery of vital reef services, the interventions explored by the committee are those that improve the resilience of individuals, populations, or communities of corals directly.
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From page 21... ...
• Coral population and community interventions seek to directly alter the composition of an entire population or communities of corals through managed relocation at varying scales -- from movement within their range to across ocean basins. • Environmental interventions reduce exposure of coral reefs to increasing temperatures or acidifying waters at a local level (as opposed to methods of global climate engineering)
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From page 22... ...
TABLE 1.1 Overview of Interventions Examined in the Committee's First Report 22 Intervention What It Is Current Feasibility Potential Scale Limitations Risks Genetic and Reproductive Interventions Managed Selection Creating increased In laboratory and at Local reef scale; Needs large Decrease in genetic frequency of existing small local scales potentially populations variation tolerance genes transgenerational Managed Enhancing Success with some Local reef Depends on sufficient Decrease in genetic Breeding: population size by species at small scales population; population sampling variation Supportive captive rearing and potentially and recruitment Breeding release transgenerational success of released individuals Managed Introducing Demonstrated in Local reef Requires transport of Outbreeding Breeding: diversity from other laboratory for a few population; gametes or colonies depression; native Outcrossing populations through species potentially across distances and genotypes may be Between breeding transgenerational field testing across swamped Populations generations Managed Creation of novel Demonstrated in Local reef Limited ability to Outbreeding Breeding: genotypes through laboratory for a few population; create hybrids; requires depression; competition Hybridization breeding species potentially testing for fertility and with native species Between Species transgenerational fitness Gamete and Collection and Feasible at local scales Laboratory to Site-specific Limited genetic Larval Capture manipulation in the local reef scale; reproductive timing; diversity; selection for and Seeding field and laboratory potentially recruitment success can laboratory versus field and release into the transgenerational be poor success wild Coral Frozen storage of Feasibility is high for Materials can Requires excess Long-term survival Cryopreservation gametes and other sperm, and growing be transported gametes, larvae, or uncertain; genetic cells for later use and for other tissue types globally tissues variation reflects only transport current conditions
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From page 23... ...
Genetic Altering coral genes Technically feasible Would occur in Gene targets and Might alter wrong Manipulation: for new function for larvae laboratory; can be cellular raw material genes; unknown risks Coral self-perpetuating unidentified; long lead time to roll out to reefs Genetic Altering symbiont Not yet feasible Would occur in Technology not Might alter wrong Manipulation: genes for new laboratory; can be established; gene genes; kill target cells; Symbionts function self-perpetuating targets and cellular raw unknown risks material unidentified Physiological Interventions Pre-exposure Using stress exposure In laboratory and Local reef Difficult to scale up Could be detrimental if to make colonies small-scale field trials scale; may be beyond local applied incorrectly more tolerant temporary or transgenerational Algal Symbiont Changing algal Observed after Individual coral Difficult to scale; easier Ecological tradeoffs, Manipulation symbionts to more bleaching events; colony or large for some coral species e.g., slower growth tolerant types demonstrated in spawning events; than others laboratory unknown longevity Microbiome Maintaining/ Demonstrated in Locations on Reef-wide delivery Potential to increase Manipulation increasing abundance laboratory and reefs to reef scale; mechanisms are deleterious microbes, of the native or new nursery facilities for applied at times of lacking; lack of known decrease beneficial beneficial microbes limited coral species stress beneficial microbes; ones little understanding of direct or indirect effects Antibiotics Adding antibiotics to Used in aquaculture Laboratory, Lack of specificity to Promote antibiotic control pathogenic and demonstration in aquarium, and target pathogens limits resistance in microbes small-scale field trials colonies on reef; effectiveness deleterious microbes; requires repeated destabilization of application native beneficial microbiomes 23 continued
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From page 24... ...
TABLE 1.1 Continued 24 Intervention What It Is Current Feasibility Potential Scale Limitations Risks Phage Therapy Adding phage Demonstrated Local reef scale; Lack of identified Undesirable gene viruses to control in laboratory potential to self- target coral pathogens transfers across pathogenic microbes experiments propagate microbial populations; impact on beneficial microbes Antioxidants Reducing cellular Demonstrated in Laboratory only; Little understanding of May affect other reef oxidative damage some laboratory requires repeated direct or indirect effects species derived from stress experiments application using chemical treatments Nutritional Using nutrients Regular use in Laboratory Poor understanding of Shifts carbon, nitrogen, Supplementation to improve fitness coral research and and aquarium; balanced coral diets; and phosphate balance and increase stress aquaculture requires repeated reef-wide delivery and may benefit coral tolerance application mechanisms are lacking competitors Coral Population and Community Interventions Managed Increasing abundance Technically feasible Regional reef scale; Uncertain maintenance Moving nontarget Relocation: of stress-tolerant with information gaps can be permanent of stress tolerance over genes; ecological Assisted Gene genes or colonies regarding successful time tradeoffs Flow within population methods range Managed Moving stress- Technically feasible Regional reef scale; Uncertain maintenance Moving nontarget Relocation: tolerant or diverse with information gaps can be permanent of stress tolerance and genes, species, and Assisted Migration genes or colonies just regarding project persistence over time microbes; ecological outside of species' design between locations tradeoffs range
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From page 25... ...
regimes Abiotic Ocean Reducing CO2 levels Effective in small- Sites within reefs Costly to scale up Impact of chemicals on Acidification chemically scale laboratory depending on chemical quantities environment Interventions experiments environmental setting; requires consistent input Seagrass Meadows Reducing daytime Some efficacy shown Local reefs Limited environmental Detritus; altered and Macroalgal CO2 levels in field measurements depending on settings; need to nutrient loads; Beds biologically environmental remove macroalgae competition from setting; long-term macroalgae; increased benefit CO2 at night 25
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From page 26... ...
Whether action or inaction on specific interventions is more likely to produce coral reef gains is at the heart of the decision that will need to be made in local regions across the tropical oceans. In this report, the committee builds on its first report by outlining the necessary components of a structured decision process and providing an example framework within which to evaluate the information available BOX 1.1 Statement of Task An ad hoc study committee will be assembled to review the science and assess potential risks and benefits of ecological and genetic interventions that have potential to enhance the recovery and persistence of coral reefs threatened by rapidly deterio rating environmental conditions that are warmer, less favorable for calcification, have impaired water quality, and pose continuing disease threats.
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From page 27... ...
for Atlan tic/Caribbean coral reef systems based on the risk assessment framework and available information. Intervention strategies should be assessed relative to the objectives and performance measures, identified by the committee, for sustaining coral reefs and their ecological functions.
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From page 28... ...
Finally, Chapter 6 highlights the tropical western Atlantic/Caribbean region as a case study for how managers may consider their individual context and objectives in an evaluation of possible intervention strategies. REEF MANAGEMENT CONTEXT The process described in this report is meant to guide a particular component of the reef management decision process with which reef managers and other decision makers evaluate the risks and benefits of using innovative interventions within their restoration and conservation programs.
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From page 29... ...
A key influence on management options is the existing regulatory framework, through which management authorities, such as permitting and other approvals, are distributed across local, regional, state, and/or federal entities. For example, in the United States, there are eight jurisdictions that possess and regulate reef-building corals: the states of Florida, Hawaii, and Texas; the Territories of American Samoa, Guam, and the U.S.
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From page 30... ...
Although this is not within the scope of this report, the ability to evaluate risks and benefits, which is the focus of the report, will still be important for informing future regulatory and policy changes. Social Capital and Stakeholder Buy-in Coral reefs are social-ecological systems; humans are responsible for the greatest threats to reef persistence and resilience, yet are also among the primary beneficiaries of healthy and functional coral ecosystems that provide a variety of ecosystem services and benefit streams (Anthony et al., 2015; Aswani et al., 2015; Cinner et al., 2009; Folke, 2006; Hicks et al., 2015; Hughes et al., 2017b; Kittinger et al., 2012)
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From page 31... ...
It is important to note that costs of deploying an intervention would be evaluated against the expected benefit, as well as the cost of inaction. It is not in the committee's scope to do a cost–benefit analysis, but it is important to note that the ecosystem services provided by coral reefs provide high monetary value (e.g., Beck et al., 2018; Costanza et al.,
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From page 32... ...
. Global estimates of the economic value of coral reefs to fisheries, tourism, coastal protection, and biodiversity value (research, conservation, and nonuse)
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