Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook

Baker, Andrew C.; Glynn, Peter W.; Riegl, Bernhard

doi:10.1016/j.ecss.2008.09.003

Cited by 1,066 publications

(963 citation statements)

References 302 publications

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“…For non-vegetated habitats, such as oyster and coral reefs, recovery has also been difficult [60,61]. However, the potential for recovery of native oyster reefs is emerging from restoration efforts at several key localities within Chesapeake Bay, Pamlico Sound, Strangford Lough in Northern Ireland and the Limfjord, Denmark [7].…”

Section: Reviewmentioning

confidence: 99%

Recovery of marine animal populations and ecosystems

Lotze¹,

Coll²,

Magera³

et al. 2011

Trends in Ecology & Evolution

351

316

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Many marine populations and ecosystems have experienced strong historical depletions, yet reports of recoveries are increasing. Here, we review the growing research on marine recoveries to reveal how common recovery is, its magnitude, timescale and major drivers. Overall, 10-50% of depleted populations and ecosystems show some recovery, but rarely to former levels of abundance. In addition, recovery can take many decades for long-lived species and complex ecosystems. Major drivers of recovery include the reduction of human impacts, especially exploitation, habitat loss and pollution, combined with favorable life-history and environmental conditions. Awareness, legal protection and enforcement of management plans are also crucial. Learning from historical recovery successes and failures is essential for implementing realistic conservation goals and promising management strategies.A new focus on recovery An increasing number of studies have reported strong declines in marine animal populations and the degradation of ocean ecosystems over past decades and centuries around the world [1][2][3][4][5][6][7], leading to a widespread perception of empty oceans and polluted waters. Yet, throughout history, humans have responded to declining resource abundance and ecosystem degradation by implementing management and conservation measures. Some of these have been successful and resulted in recovery, whereas others have failed [3,8,9].Therefore, an important question to science and management is: how common is recovery among depleted populations and degraded ecosystems in the ocean? Today, many marine mammal, bird, reptile and fish populations are at low abundance, and several species are endangered or extinct on regional or global scales [5,[10][11][12]. However, despite long periods of intense human impacts, most marine species persist and some populations do show signs of recovery [3,8,9]. Similarly, many coastal habitats, including wetlands, seagrass beds, mangrove and kelp forests, and oyster and coral reefs, have been severely reduced or degraded [2][3][4]6], yet partial recovery has been achieved in some regions in response to protection and pollution controls [3,13]. Restoration attempts at an ecosystem level have often been followed by the return and recovery of former species assemblages and ecosystem functions [13][14][15][16][17], but some ecosystems have remained in an altered state [18]. Such successes could serve as important guides for efforts to prevent further biodiversity loss and enhance future recoveries.Despite a growing number of case studies on the recovery of specific populations or ecosystems, an overview of the general patterns and drivers of marine recoveries over historical timescales is lacking. A recent review on the recovery of damaged ecosystems found that many terrestrial and marine ecosystems can recover on timescales of a few years to a few decades after major perturbations [19]. However, most case studies in the review, especially among marine and brackish examples, included small, short-...

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Section: Reviewmentioning

confidence: 99%

Recovery of marine animal populations and ecosystems

Lotze¹,

Coll²,

Magera³

et al. 2011

Trends in Ecology & Evolution

351

316

View full text Add to dashboard Cite

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“…However, the direct and interactive effects of climate-induced coral bleaching (1,2), ocean acidification (2,3), coral disease (4), coastal overfishing, and eutrophication (5)(6)(7)(8) have led to coral decline over wide areas. On many reefs, dramatic declines in coral cover have co-occurred with significant increases in fleshy macroalgae (9)(10)(11).…”

mentioning

confidence: 99%

Macroalgal terpenes function as allelopathic agents against reef corals

Rasher

Stout²,

Engel³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

206

269

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During recent decades, many tropical reefs have transitioned from coral to macroalgal dominance. These community shifts increase the frequency of algal-coral interactions and may suppress coral recovery following both anthropogenic and natural disturbance. However, the extent to which macroalgae damage corals directly, the mechanisms involved, and the species specificity of algal-coral interactions remain uncertain. Here, we conducted field experiments demonstrating that numerous macroalgae directly damage corals by transfer of hydrophobic allelochemicals present on algal surfaces. These hydrophobic compounds caused bleaching, decreased photosynthesis, and occasionally death of corals in 79% of the 24 interactions assayed (three corals and eight algae). Coral damage generally was limited to sites of algal contact, but algae were unaffected by contact with corals. Artificial mimics for shading and abrasion produced no impact on corals, and effects of hydrophobic surface extracts from macroalgae paralleled effects of whole algae; both findings suggest that local effects are generated by allelochemical rather than physical mechanisms. Rankings of macroalgae from most to least allelopathic were similar across the three coral genera tested. However, corals varied markedly in susceptibility to allelopathic algae, with globally declining corals such as Acropora more strongly affected. Bioassay-guided fractionation of extracts from two allelopathic algae led to identification of two loliolide derivatives from the red alga Galaxaura filamentosa and two acetylated diterpenes from the green alga Chlorodesmis fastigiata as potent allelochemicals. Our results highlight a newly demonstrated but potentially widespread competitive mechanism to help explain the lack of coral recovery on many present-day reefs.allelopathy | chemical ecology | competition | phase shift C orals are structurally complex foundation species that generate and maintain tropical reef biodiversity. However, the direct and interactive effects of climate-induced coral bleaching (1, 2), ocean acidification (2, 3), coral disease (4), coastal overfishing, and eutrophication (5-8) have led to coral decline over wide areas. On many reefs, dramatic declines in coral cover have co-occurred with significant increases in fleshy macroalgae (9-11). Once established, macroalgae can inhibit coral recruitment and decrease herbivore grazing, producing negative feedbacks that reinforce phase shifts and further diminish reef function (12-14). Thus, local (e.g., overfishing) and global (e.g., climate) stresses may interact in complex ways to suppress coral cover, promote algal proliferation, and compromise reef resilience; such complexities provide both challenges and opportunities for managing these dynamic ecosystems (11, 13).As corals decline and macroalgae proliferate, the frequency of algal-coral interactions will increase, potentially affecting the survivorship, growth, and reproduction of remnant adult corals and new coral recruits (12, 13). However, the consequences ...

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“…It is known that thermal stress can trigger coral bleaching (Muscatine, 1986;Hoegh-Guldberg and Smith, 1989;Jones et al, 1998). Mass bleaching events that affect entire reefs or coastal regions can occur when local or regional temperatures exceed the typical summer maximum for a period of a few weeks (Hoegh-Guldberg, 1999;Baker et al, 2008;Strong et al, 2011). The effect of elevated temperature is exacerbated by strong solar irradiance (Hoegh-Guldberg, 1999).…”

Section: Box 18-2 | Attribution Of Mass Coral Bleaching Events To CLImentioning

confidence: 99%

“…These events have often been followed by mass mortality (HoeghGuldberg, 1999;Baker et al, 2008). In the very warm year of 1998, for example, mass bleaching occurred in almost every part of the tropics and subtropics and resulted in the loss of a substantial fraction of the world's corals (Wilkinson et al, 1999).…”

Section: Box 18-2 | Attribution Of Mass Coral Bleaching Events To CLImentioning

confidence: 99%

“…Table 18-10 summarizes new evidence concerning this RFC. Generally, the strongest evidence of detected impacts related to extremes concerns warm-water corals where bleaching has been linked directly to hightemperature spells (Box 18-2; Baker et al, 2008;Strong et al, 2011). Outside of these coral reef systems, however, evidence for extreme event impacts is limited and mostly local.…”

Section: Reasons For Concernmentioning

confidence: 99%

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