Coral Reef Resilience And Resistance To Bleaching Pdf

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The concept of resilience is long established across a wide-range of disciplines, but its evaluation in many ecosystems has been challenging due to the complexities involved in quantifying a somewhat abstract dynamical phenomenon. We develop a framework of resilience-related concepts and describe their methodological approaches. Seven broad approaches were identified under the three principle concepts of 1 ecological resilience ecological resilience, precariousness and current attractor , 2 engineering resilience short-term recovery rate and long-term reef performance , and 3 vulnerability absolute and relative vulnerability respectively.

Coral reef resilience and resistance to bleaching

Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. Grimsditch and R. Grimsditch , R. Salm Published Environmental Science.

Caroline S. Ideally, global action to reduce emission of carbon dioxide and other greenhouse gases will be accompanied by local action. Effective management requires reduction of local stressors, identification of the characteristics of resilient reefs, and design of marine protected area networks that include potentially resilient reefs. Future research is needed on how stressors interact, on how climate change will affect corals, fish, and other reef organisms as well as overall biodiversity, and on basic ecological processes such as connectivity. Not all reef species and reefs will respond similarly to local and global stressors. Because reef-building corals and other organisms have some potential to adapt to environmental changes, coral reefs will likely persist in spite of the unprecedented combination of stressors currently affecting them.

Coral bleaching

Coral bleaching occurs when coral polyps expel algae that live inside their tissues. Normally, coral polyps live in an endosymbiotic relationship with these algae, which are crucial for the health of the coral and the reef. Bleached corals continue to live but begin to starve after bleaching. The leading cause of coral bleaching is rising water temperatures. In , bleaching of coral on the Great Barrier Reef killed between 29 and 50 percent of the reef's coral. The corals that form the great reef ecosystems of tropical seas depend upon a symbiotic relationship with algae-like single-celled flagellate protozoa called zooxanthellae that live within their tissues and give the coral its coloration. The zooxanthellae provide the coral with nutrients through photosynthesis , a crucial factor in the clear and nutrient-poor tropical waters.

Coral Bleaching pp Cite as. At the heart of these complex ecosystems is an obligate symbiosis between the coral animal and single-celled photosynthetic algae. This mutually beneficial relationship provides the coral host with sufficient cheap energy to form the massive reef structures that create diverse habitats for many other organisms. Aside from their natural beauty, many millions of people depend on healthy coral reefs for their livelihoods. Human activities, through increased greenhouse gases, are now imposing a compounding threat to maintenance of these charismatic ecosystems -- mass coral bleaching events where the coral--algal symbiosis breaks down due to thermal stress.

Coral Reef Resilience through Biodiversity

Ocean warming and acidification from increasing levels of atmospheric CO 2 represent major global threats to coral reefs, and are in many regions exacerbated by local-scale disturbances such as overfishing and nutrient enrichment. Our understanding of global threats and local-scale disturbances on reefs is growing, but their relative contribution to reef resilience and vulnerability in the future is unclear. Here, we analyse quantitatively how different combinations of CO 2 and fishing pressure on herbivores will affect the ecological resilience of a simplified benthic reef community, as defined by its capacity to maintain and recover to coral-dominated states.

Coral Health and Disease pp Cite as. Most of this destruction occurred in the Indian Ocean, where prolonged elevations of sea surface temperature were maintained by prevailing currents that pooled warm water in the western Indo-Pacific. In most cases, coral reef destruction equated to a dramatic reduction in live coral cover on these reefs e.

Resilience Concepts and Their Application to Coral Reefs

Coral reefs are a globally threatened ecosystem due to a range of anthropogenic impacts. Increasing sea surface temperatures associated with global warming are a particular threat, as corals grow close to their upper thermal limit. When this limit is exceeded for a sufficient length of time during thermal stress events, corals lose their algal symbionts, resulting in coral bleaching and possible mortality. Coral reefs have experienced the most severe and extended global bleaching event to date from to The most recent global climate models predict that similar global bleaching events are likely to become an annual occurrence by the middle of the present century. Current understanding of coral reef recovery following disturbance events is based around decadal to sub-decadal impacts, making the adaptive capacity of corals as bleaching events approach an annual frequency unknown. However, there is considerable spatial heterogeneity in bleaching impacts across a range of scales, from global reef provinces to local reef areas and between coral species.

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Globally increasing sea surface temperatures threaten coral reefs, both directly and through interactions with local stressors. More resilient reefs have a higher likelihood of returning to a coral-dominated state following a disturbance, such as a mass bleaching event. We calculated relative resilience scores for sites from an existing commonwealth-wide survey using eight resilience indicators—such as coral diversity, macroalgae percent cover, and herbivorous fish biomass—and assessed which indicators most drove resilience. We found that sites of very different relative resilience were generally highly spatially intermixed, underscoring the importance and necessity of decision making and management at fine scales. In combination with information on levels of two localized stressors fishing pressure and pollution exposure , we used the resilience indicators to assess which of seven potential management actions could be used at each site to maintain or improve resilience. Fishery management was the management action that applied to the most sites. Island-wide or community-level managers can use the actions and vulnerability information as a starting point for resilience-based management of their reefs.


PDF | On Jan 1, , Gabriel D. Grimsditch and others published Coral Reef Resilience and Resistance to Bleaching | Find, read and cite all the research you​.


1 Response
  1. Heninibal

    Foreword. Vast changes in the seas are destroying the world's precious coral reefs at an coral bleaching and what is meant by resistance 8th_ann_rept.​pdf.

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