Caught in the Middle: Combined Impacts of Shark Removal and Coral Loss on the Fish Communities of Coral Reefs

PLoS ONE, Год журнала: 2013, Номер 8(9), С. e74648 - e74648

Опубликована: Сен. 18, 2013

Due to human activities, marine and terrestrial ecosystems face a future where disturbances are predicted occur at frequency severity unprecedented in the recent past. Of particular concern is ability of systems recover multiple stressors act simultaneously. We examine this issue context coral reef ecosystem increases stressors, such as fisheries, benthic degradation, cyclones bleaching, occurring global scales. By utilizing long-term (decadal) monitoring programs, we examined combined effects chronic (removal sharks) pulse (cyclones, bleaching) on trophic structure fishes two isolated atoll off coast northwest Australia. provide evidence consistent with hypothesis that loss sharks can have an impact propagates down food chain, potentially contributing mesopredator release altering numbers primary consumers. Simultaneously, show how bottom-up processes bleaching appear propagate up chain through herbivores, planktivores corallivores, but do not affect carnivores. Because their presence may promote abundance removal by fishing has implications for both natural anthropogenic involving corals, herbivores critical progress outcome recovery.

Язык: Английский

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Herbivore cross‐scale redundancy supports response diversity and promotes coral reef resilience

Journal of Applied Ecology, Год журнала: 2015, Номер 53(3), С. 646 - 655

Опубликована: Апрель 23, 2015

Summary Functional redundancy contributes to resilience if different species in the same functional group respond disturbance ways (response diversity). If a perform their role at spatial scales (cross‐scale redundancy), they are expected differently scale‐specific disturbance. Consequently, variance over which may provide proxy for resilience. Coral reefs diverse systems that key ecosystem services and subject increasing anthropogenic disturbances. Algal grazing by herbivorous fish maintenance of coral‐dominated reefs. To date, there has been little evaluation traits driving response diversity among how this relates coral recovery following acute Using body size as scale function, we tested whether cross‐scale herbivores was an effective indicator on 21 monitored through climate‐induced caused bleaching widespread mortality. When assemblages operated broader range were present prior disturbance, more likely recover states after After temperature‐induced loss small compensated increases large herbivores. This indicative high drove overall increase herbivore biomass recovering sites. These compensatory mechanisms not found sites where narrower scales. Synthesis applications . Cross‐scale provides managers with reef resilience, although contribution will vary Maintaining given site requires no classes disproportionately depleted fishing. Balanced harvesting, all fished proportion potential production, would help achieve this.

Язык: Английский

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Temperature‐driven coral decline: the role of marine protected areas

Global Change Biology, Год журнала: 2012, Номер 18(5), С. 1561 - 1570

Опубликована: Янв. 31, 2012

Abstract Warming ocean temperatures are considered to be an important cause of the degradation world's coral reefs. Marine protected areas ( MPA s) have been proposed as one tool increase reef ecosystem resistance and resilience (i.e. recovery) negative effects climate change, yet few studies evaluated their efficacy in achieving these goals. We used a high resolution 4 km global temperature anomaly database from 1985–2005 8040 live cover surveys on unprotected reefs determine whether or not s effective mitigating temperature‐driven loss. Generally, protection did reduce effect warm anomalies declines. Shortcomings design, including size placement, may contributed lack effect. Empirical suggest that corals previously exposed moderate levels thermal stress greater adaptive capacity future events. Existing protect relatively fewer with frequencies, potentially reducing effectiveness. However, our results also benefits great enough offset magnitude losses acute Although conservation tools, limitations loss events they need complemented policies aimed at activities responsible for change.

Язык: Английский

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Recruitment Drives Spatial Variation in Recovery Rates of Resilient Coral Reefs

Scientific Reports, Год журнала: 2018, Номер 8(1)

Опубликована: Май 3, 2018

Tropical reefs often undergo acute disturbances that result in landscape-scale loss of coral. Due to increasing threats coral from climate change and anthropogenic perturbations, it is critical understand mechanisms drive recovery these ecosystems. We explored this issue on the fore reef Moorea, French Polynesia, following a crown-of-thorns seastar outbreak cyclone dramatically reduced cover During five-years disturbances, rate re-establishment differed systematically around triangular-shaped island; returned most rapidly at sites where least amount live remained after disturbances. Although greatly return coral, all showed some evidence re-assembly their pre-disturbance community structure terms relative abundance taxa other benthic space holders. The primary driver spatial variation was recruitment sexually-produced corals; subsequent growth survivorship were less important shaping pattern. Our findings suggest that, although has been resilient, areas are unlikely attain taxonomic they had prior recent before advent another perturbation.

Язык: Английский

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Recovery of coral assemblages despite acute and recurrent disturbances on a South Central Pacific reef

Scientific Reports, Год журнала: 2018, Номер 8(1)

Опубликована: Июнь 20, 2018

Coral reefs are increasingly threatened by various types of disturbances, and their recovery is challenged accelerating, human-induced environmental changes. Recurrent disturbances reduce the pool mature adult colonies reef-building corals undermine post-disturbance from newly settled recruits. Using a long-term interannual data set, we show that coral assemblages on reef slope Moorea, French Polynesia, have maintained high capacity to recover despite unique frequency large-scale which, since 1990s, caused catastrophic declines in cover abundance. In 2014, only four years after one most extreme cases decline documented, abundance juvenile had regained or exceeded pre-disturbance levels, no phase-shift macroalgal dominance was recorded. This rapid has been achieved constantly low recruitment rates, suggesting survivorship However, taxonomic differences susceptibility contrasting trajectories resulted changes relative composition species. present context global decline, our study establishes new benchmark for certain benthic communities sustain repeated, intense disturbances.

Язык: Английский

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Nutrient supply from fishes facilitates macroalgae and suppresses corals in a Caribbean coral reef ecosystem

Scientific Reports, Год журнала: 2013, Номер 3(1)

Опубликована: Март 20, 2013

On coral reefs, fishes can facilitate growth via nutrient excretion; however, as abundance declines, these nutrients may help increases in macroalgae. By combining surveys of reef communities with bioenergetics modeling, we showed that fish excretion supplied 25 times more nitrogen to forereefs the Florida Keys, USA, than all other biotic and abiotic sources combined. One apparent result was a positive relationship between macroalgal cover on reefs. Herbivore biomass also negative cover, suggesting strong interactions top-down bottom-up forcing. Nutrient supply by correlation juvenile density, likely mediated competition macroalgae corals, hinder recovery following large-scale loss. Thus, impact be context-dependent reinforce either coral-dominant or coral-depauperate depending initial community states.

Язык: Английский

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The Influence of Coral Reef Benthic Condition on Associated Fish Assemblages

PLoS ONE, Год журнала: 2012, Номер 7(8), С. e42167 - e42167

Опубликована: Авг. 1, 2012

Accumulative disturbances can erode a coral reef's resilience, often leading to replacement of scleractinian corals by macroalgae or other non-coral organisms. These degraded reef systems have been mostly described based on changes in the composition benthos, and there is little understanding how such are influenced by, turn influence, components ecosystem. This study investigated spatial variation benthic communities fringing reefs around inner Seychelles islands. Specifically, relationships between underlying substrata, as well associated fish assemblages were assessed. High variability was found among reefs, with gradient from high cover (up 58%) structural complexity 95%) low at extremes. declining species richness fishes, reduced diversity functional groups, lower abundance corallivorous fishes. There no reciprocal increases herbivorous abundances, groups total weak. Reefs grouping extremes complex habitats low-complexity macroalgal displayed markedly different communities, only two invertebrate feeding fishes greater habitat. results negative implications for continuation many ecosystem processes services if more shift extreme conditions dominated macroalgae.

Язык: Английский

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Contrasting rates of coral recovery and reassembly in coral communities on the Great Barrier Reef

Coral Reefs, Год журнала: 2014, Номер 33(3), С. 553 - 563

Опубликована: Апрель 9, 2014

Changes in the relative abundances of coral taxa during recovery from disturbance may cause shifts essential ecological processes on reefs. Coral cover can return to pre-disturbance levels (coral recovery) without assemblage returning its previous composition (i.e., reassembly). The underlying such changes are not well understood due a scarcity long-term studies with sufficient taxonomic resolution. We assessed trajectories and time frames for reassembly communities following disturbances, using modeled based data broad spatial temporal monitoring program. studied at six reefs that suffered substantial loss subsequently regained least 50 % their cover. Five rates were remarkably consistent, taking 7–10 years. Four reassembled 8–13 three both ten two suggested they unlikely reassemble remaining community did regain had high abundance tabulate Acropora spp. this appear likely persist regime pulse disturbances intervals years or more. Communities failed either near-shore locations Porites soft corals. Under current regimes, these re-establish composition.

Язык: Английский

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Marine Heatwave Hotspots in Coral Reef Environments: Physical Drivers, Ecophysiological Outcomes, and Impact Upon Structural Complexity

Frontiers in Marine Science, Год журнала: 2019, Номер 6

Опубликована: Авг. 16, 2019

A changing climate is driving increasingly common and prolonged marine heatwaves (MHWs) these extreme events have now been widely documented to severely impact ecosystems globally. However MHWs rarely recently considered when examining temperature-induced degradation of coral reef ecosystems. Here we consider extreme, localised thermal anomalies, nested within broader increases in sea surface temperature, which fulfil the definitive criteria for MHWs. These acute intense events, referred here as MHW hotspots, are not always well represented current framework used describe bleaching, but do distinct ecological outcomes, including widespread bleaching rapid mass mortality putatively thermally tolerant species. The physical drivers hotspots discussed here, doing so present a comprehensive theoretical that links biological responses photo-endosymbiotic organism stress changes on reefs associated after hotspots. We how onset high temperatures drives immediate heat-stress induced cellular damage, overwhelming mechanisms would otherwise mitigate gradually accumulated stress. warm environment, increased light penetration skeleton due loss tissues, coupled with tissue decay support microbial growth skeletal microenvironment, resulting unrecognised consequence degeneration skeletons. This accelerated skeletonson scale hinder recovery populations increase likelihood phase shifts towards algal dominance. suggest through heat-induced mortality, compromise reefs' structural frameworks detriment long term recovery. propose be class reefs, expanded include these. urge further research into affects bioerosion by endoliths.

Язык: Английский

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Consumer Fronts, Global Change, and Runaway Collapse in Ecosystems

Annual Review of Ecology Evolution and Systematics, Год журнала: 2013, Номер 44(1), С. 503 - 538

Опубликована: Ноя. 23, 2013

Consumer fronts occur when grazers or predators aggregate in bands along the edges of a resource. Our review reveals that consumer are common phenomenon nature, many different ecosystems, and triggered by universal mechanisms: External forces locally increase top-down control beyond prey carrying and/or renewal capacity, resource-dependent movement leads to aggregation edge remaining population. Once formed, move through systems as spatially propagating waves, self-reinforced via intense overexploitation amplified density-dependent feedbacks. When restricted, they generate patchiness. In contrast, expansive, can lead runaway responses cause large-scale ecosystem degradation regime shifts. We conceptualize synergistic stress hypothesis model highlight how coupled intensification physical enhanced pressure trigger increased occurrence decreased system stability resilience. With escalating climate change food-web modification, biological conditions favoring consumer-front formation will likely become feature ecosystems.

Язык: Английский

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