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Peter J Mumby - One of the best experts on this subject based on the ideXlab platform.

  • the ecological role of sharks on Coral Reefs
    Trends in Ecology and Evolution, 2016
    Co-Authors: George Roff, Christopher Doropoulos, Alice Rogers, Yvesmarie Bozec, Nils C Krueck, Eleanor Aurellado, Mark A Priest, Chico L Birrell, Peter J Mumby
    Abstract:

    Sharks are considered the apex predator of Coral Reefs, but the consequences of their global depletion are uncertain. Here we explore the ecological roles of sharks on Coral Reefs and, conversely, the importance of Reefs for sharks. We find that most reef-associated shark species do not act as apex predators but instead function as mesopredators along with a diverse group of reef fish. While sharks perform important direct and indirect ecological roles, the evidence to support hypothesised shark-driven trophic cascades that benefit Corals is weak and equivocal. Coral Reefs provide some functional benefits to sharks, but sharks do not appear to favour healthier reef environments. Restoring populations of sharks is important and can yet deliver ecological surprise.

  • tradeoffs between fisheries harvest and the resilience of Coral Reefs
    Proceedings of the National Academy of Sciences of the United States of America, 2016
    Co-Authors: Yvesmarie Bozec, Shay Ofarrell, Henrich J Bruggemann, Brian E Luckhurst, Peter J Mumby
    Abstract:

    Many countries are legally obliged to embrace ecosystem-based approaches to fisheries management. Reductions in bycatch and physical habitat damage are now commonplace, but mitigating more sophisticated impacts associated with the ecological functions of target fisheries species are in their infancy. Here we model the impacts of a parrotfish fishery on the future state and resilience of Caribbean Coral Reefs, enabling us to view the tradeoff between harvest and ecosystem health. We find that the implementation of a simple and enforceable size restriction of >30 cm provides a win:win outcome in the short term, delivering both ecological and fisheries benefits and leading to increased yield and greater Coral recovery rate for a given harvest rate. However, maintaining resilient Coral Reefs even until 2030 requires the addition of harvest limitations (<10% of virgin fishable biomass) to cope with a changing climate and induced Coral disturbances, even in Reefs that are relatively healthy today. Managing parrotfish is not a panacea for protecting Coral Reefs but can play a role in sustaining the health of Reefs and high-quality habitat for reef fisheries.

  • Tradeoffs between fisheries harvest and the resilience of Coral Reefs
    2016
    Co-Authors: Yvesmarie Bozec, Brian E Luckhurst, Shay O'farrell, J. Henrich Bruggemann, Peter J Mumby
    Abstract:

    Many countries are legally obliged to embrace ecosystem-based approaches to fisheries management. Reductions in bycatch and physical habitat damage are now commonplace, but mitigating more sophisticated impacts associated with the ecological functions of target fisheries species are in their infancy. Here we model the impacts of a parrotfish fishery on the future state and resilience of Caribbean Coral Reefs, enabling us to view the tradeoff between harvest and ecosystem health. We find that the implementation of a simple and enforceable size restriction of >30 cm provides a win:win outcome in the short term, delivering both ecological and fisheries benefits and leading to increased yield and greater Coral recovery rate for a given harvest rate. However, maintaining resilient Coral Reefs even until 2030 requires the addition of harvest limitations (

  • Multi-scale, object-based image analysis for mapping geomorphic and ecological zones on Coral Reefs
    International Journal of Remote Sensing, 2012
    Co-Authors: Stuart R Phinn, Christiaan M. Roelfsema, Peter J Mumby
    Abstract:

    Providing accurate maps of Coral Reefs where the spatial scale and labels of the mapped features correspond to map units appropriate for examining biological and geomorphic structures and processes is a major challenge for remote sensing. The objective of this work is to assess the accuracy and relevance of the process used to derive geomorphic zone and benthic community zone maps for three western Pacific Coral Reefs produced from multi-scale, object-based image analysis (OBIA) of high-spatial-resolution multi-spectral images, guided by field survey data. Three Quickbird-2 multi-spectral data sets from Reefs in Australia, Palau and Fiji and georeferenced field photographs were used in a multi-scale segmentation and objec-t-based image classification to map geomorphic zones and benthic community zones. A per-pixel approach was also tested for mapping benthic community zones. Validation of the maps and comparison to past approaches indicated the multi-s-cale OBIA process enabled field data, operator field experience and a conceptual hierarchical model of the Coral reef environment to be linked to provide output maps at geomorphic zone and benthic community scales on Coral Reefs. The OBIA mapping accuracies were comparable with previously published work using other methods; however, the classes mapped were matched to a predetermined set of features on the reef.

  • Monitoring Coral Reefs from space
    Oceanography, 2010
    Co-Authors: C. Mark Eakin, William J Skirving, Peter J Mumby, Carl J. Nim, Russell E. Brainard, Christoph Aubrecht, Christopher D. Elvidge, Dwight K. Gledhill, Frank E. Muller-karger, Alan E Strong
    Abstract:

    Coral Reefs are one of the world’s most biologically diverse and productive ecosystems. However, these valuable resources are highly threatened by human activities. Satellite remotely sensed observations enhance our understanding of Coral Reefs and some of the threats facing them by providing global spatial and time-series data on reef habitats and the environmental conditions influencing them in near-real time. This review highlights many of the ways in which satellites are currently used to monitor Coral Reefs and their threats, and provides a look toward future needs and capabilities.

H.s.j. Cesar - One of the best experts on this subject based on the ideXlab platform.

  • The recreational value of Coral Reefs: a meta-analysis
    Ecological Economics, 2007
    Co-Authors: Luke Brander, P.j.h. Van Beukering, H.s.j. Cesar
    Abstract:

    Abstract Coral Reefs are highly productive ecosystems that provide a variety of valuable goods and services, including recreational opportunities. The open-access nature and public good characteristics of Coral Reefs often result in them being undervalued in decision making related to their use and conservation. In response to this, there now exists a substantial economic valuation literature on Coral Reefs. For the purposes of conducting a meta-analysis of this literature, we collected 166 Coral reef valuation studies, 52 of which provided sufficient information for a statistical meta-analysis, yielding 100 separate value observations in total. Focusing on recreational values, we use US$ per visit as the dependent variable in our meta-analysis. The meta-regression results reveal a number of important factors in explaining variation in Coral reef recreational values, notably the area of dive sites and the number of visitors. Different valuation methods are shown to produce widely different values, with the contingent valuation method producing significantly lower value estimates. Using a multi-level modelling approach we also control for authorship effects, which proves to be highly significant in explaining variation in value estimates. We assess the prospects for using this analysis for out-of-sample value transfer, and find average transfer errors of 186%. We conclude that there is a need for further high-quality valuation research on Coral Reefs.

  • the recreational value of Coral Reefs a meta analysis
    IVM Report, 2006
    Co-Authors: L M Brander, P.j.h. Van Beukering, H.s.j. Cesar
    Abstract:

    Coral Reefs are highly productive ecosystems that provide a variety of valuable goods and services, including recreational opportunities. The open-access nature and public good characteristics of Coral Reefs often result in them being undervalued in decision making related to their use and conservation. In response to this, there now exists a substantial economic valuation literature on Coral Reefs. For the purposes of conducting a meta-analysis of this literature, we collected 166 Coral reef valuation studies, 52 of which provided sufficient information for a statistical meta-analysis, yielding 100 separate value observations in total. Focusing on recreational values, we use US$ per visit as the dependent variable in our meta-analysis. The meta-regression results reveal a number of important factors in explaining variation in Coral reef recreational values, notably the area of dive sites and the number of visitors. Different valuation methods are shown to produce widely different values, with the contingent valuation method producing significantly lower value estimates. Using a multi-level modelling approach we also control for authorship effects, which proves to be highly significant in explaining variation in value estimates. We assess the prospects for using this analysis for out-of-sample value transfer, and find average transfer errors of 186%. We conclude that there is a need for further high-quality valuation research on Coral Reefs. IVM Working Paper: IVM 06/07

Magnus Nyström - One of the best experts on this subject based on the ideXlab platform.

  • Ecological limitations to the resilience of Coral Reefs
    Coral Reefs, 2016
    Co-Authors: Camilo Mora, Nicholas A. J. Graham, Magnus Nyström
    Abstract:

    The decline of Coral Reefs has been broadly attributed to human stressors being too strong and pervasive, whereas biological processes that may render Coral Reefs fragile have been sparsely considered. Here we review several ecological factors that can limit the ability of Coral Reefs to withstand disturbance. These include: (1) Many species lack the adaptive capacity to cope with the unprecedented disturbances they currently face; (2) human disturbances impact vulnerable life history stages, reducing reproductive output and the supply of recruits essential for recovery; (3) Reefs can be vulnerable to the loss of few species, as niche specialization or temporal and spatial segregation makes each species unique (i.e., narrow ecological redundancy); in addition, many foundation species have similar sensitivity to disturbances, suggesting that entire functions can be lost to single disturbances; and (4) feedback loops and extinction vortices may stabilize degraded states or accelerate collapses even if stressors are removed. This review suggests that the degradation of Coral Reefs is due to not only the severity of human stressors but also the “fragility” of Coral Reefs. As such, appropriate governance is essential to manage stressors while being inclusive of ecological process and human uses across transnational scales. This is a considerable but necessary upgrade in current management if the integrity, and delivery of goods and services, of Coral Reefs is to be preserved

  • Coral Reefs as novel ecosystems embracing new futures
    Current Opinion in Environmental Sustainability, 2014
    Co-Authors: Nicholas A. J. Graham, Joshua E. Cinner, Albert V Norstrom, Magnus Nyström
    Abstract:

    The composition and functions of many ecosystems are changing, giving rise to the concept of novel ecosystems. Although some Coral Reefs are becoming non-Coral systems, others are becoming novel Coral-dominated ecosystems driven principally by differential species responses to climate change and other drivers, but also due to species range shifts at higher latitudes, and in some cases introduced species. Returning many Coral Reefs to pristine baselines is unrealistic, whereas embracing novel futures enables more pragmatic approaches to maintaining or re-building the dominance of Corals. Coral Reefs are changing in unprecedented ways, providing the impetus to improve our understanding of reef compositions that may dominate in the future, explore new management approaches, assess changes in ecosystem services, and investigate how human societies can adapt and respond to novel futures.

  • alternative states on Coral Reefs beyond Coral macroalgal phase shifts
    Marine Ecology Progress Series, 2009
    Co-Authors: Albert V Norstrom, Magnus Nyström, Jerker Lokrantz, Carl Folke
    Abstract:

    Degradation of Coral Reefs is often associated with changes in community structure where macroalgae become the dominant benthic life form. These phase shifts can be difficult to reverse. The debate ...

  • Spatial resilience of Coral Reefs
    Ecosystems, 2001
    Co-Authors: Magnus Nyström, Carl Folke
    Abstract:

    There have been several earlier studies that ad- dressed the influence of natural disturbance re- gimes on Coral Reefs. Humans alter natural distur- bance regimes, introduce new stressors, and modify background conditions of Reefs. We focus on how Coral reef ecosystems relate to disturbance in an increasingly human-dominated environment. The concept of ecosystem resilience-that is, the capac- ity of complex systems with multiple stable states to absorb disturbance, reorganize, and adapt to change-is central in this context. Instead of focus- ing on the recovery of certain species and popula- tions within disturbed sites of individual Reefs, we address spatial resilience-that is, the dynamic ca- pacity of a reef matrix to reorganize and maintain ecosystem function following disturbance. The in- terplay between disturbance and ecosystem resil- ience is highlighted. We begin the identification of spatial sources of resilience in dynamic seascapes and exemplify and discuss the relation between "ecological memory" (biological legacies, mobile link species, and support areas) and functional di- versity for seascape resilience. Managing for resil- ience in dynamic seascapes not only enhances the likelihood of conserving Coral Reefs, it also provides insurance to society by sustaining essential ecosys- tem services.

Nancy Knowlton - One of the best experts on this subject based on the ideXlab platform.

  • How rats wreak havoc on Coral Reefs
    Nature, 2018
    Co-Authors: Nancy Knowlton
    Abstract:

    The introduction of non-native rats can devastate island ecosystems. It now emerges that these rats also harm a complex web of interactions linking seabirds with the algae and fishes of nearby Coral Reefs. The introduction of non-native rats can devastate island ecosystems. It now emerges that these rats also harm a complex web of interactions linking seabirds with the algae and fishes of nearby Coral Reefs.

  • tropical dead zones and mass mortalities on Coral Reefs
    Proceedings of the National Academy of Sciences of the United States of America, 2017
    Co-Authors: Andrew H. Altieri, Seamus B Harrison, Janina Seemann, Rachel Collin, Robert J Diaz, Nancy Knowlton
    Abstract:

    Degradation of coastal water quality in the form of low dissolved oxygen levels (hypoxia) can harm biodiversity, ecosystem function, and human wellbeing. Extreme hypoxic conditions along the coast, leading to what are often referred to as "dead zones," are known primarily from temperate regions. However, little is known about the potential threat of hypoxia in the tropics, even though the known risk factors, including eutrophication and elevated temperatures, are common. Here we document an unprecedented hypoxic event on the Caribbean coast of Panama and assess the risk of dead zones to Coral Reefs worldwide. The event caused Coral bleaching and massive mortality of Corals and other reef-associated organisms, but observed shifts in community structure combined with laboratory experiments revealed that not all Coral species are equally sensitive to hypoxia. Analyses of global databases showed that Coral Reefs are associated with more than half of the known tropical dead zones worldwide, with >10% of all Coral Reefs at elevated risk for hypoxia based on local and global risk factors. Hypoxic events in the tropics and associated mortality events have likely been underreported, perhaps by an order of magnitude, because of the lack of local scientific capacity for their detection. Monitoring and management plans for Coral reef resilience should incorporate the growing threat of coastal hypoxia and include support for increased detection and research capacity.

  • Coral Reefs
    Ecology, 2012
    Co-Authors: Nancy Knowlton
    Abstract:

    Coral Reefs are the most diverse of marine ecosystems, with hundreds of thousands if not millions of species associated with Reefs. For this reason they are often called the rain forests of the sea, and as such they have been of interest not only to marine scientists but also to ecologists and evolutionary biologists broadly. The center of reef diversity is the Indo-West Pacific, especially the “Coral triangle,” comprised of the island-rich waters of Southeast Asia (e.g., Indonesia and the Philippines). The next most extensive area of reef building and reef diversity is in the tropical western Atlantic. In the early 21st century most Reefs are built primarily by stony Corals in the order Scleractinia (phylum Cnidaria, class Anthozoa), but large stony structures have in the past been built by microbes, clams, and other organisms. Coral Reefs are dynamic structures that are constantly being both built by the skeletons of Corals and other organisms, on the one hand, and broken down into rubble and sand, on the other. The ability of Corals to outpace the destructive forces of storms and bioeroders is due to their symbiosis with single-celled algal symbionts in their tissues. These zooxanthellae (a diverse group of dinoflagellates once thought to be a single species) transfer some of the products of their photosynthesis to their Coral hosts, which in return provide the zooxanthellae with nutrients. Also like rain forests, Coral reef ecosystems are highly threatened around the world, and many have been substantially affected by humans for centuries. Local impacts, such as habitat destruction, overfishing, pollution, and invasive species, have been joined by the global impacts of ocean warming and acidification. The result has been that many Coral Reefs have been taken over by macroalgae or other space occupiers that grow faster than Corals and are less sensitive to stressors associated with human activities. Coral disease, which is increasing due to warming and pollution, and Coral bleaching, caused primarily by ocean warming, are now important causes of Coral mortality. Overall, about one-half of all living Coral may already have been lost, and one-third of all Coral species are now deemed to be at risk of extinction; this places them on par with the most endangered terrestrial organisms. Because carbon dioxide emissions are continuing to rise, the best hopes in the short term for conserving and restoring Coral Reefs involve reducing local stressors. Measures to improve water quality and reduce overfishing (particularly of herbivores) are critical components of Coral reef management strategies. However, reducing carbon dioxide emissions will be essential for the long-term survival of Coral Reefs.

Maggie Johnson - One of the best experts on this subject based on the ideXlab platform.

  • Integrating the Effects of Ocean Acidification across Functional Scales on Tropical Coral Reefs
    Bioscience, 2016
    Co-Authors: Peter J. Edmunds, Steeve Comeau, Coulson Lantz, Andreas Andersson, Cherie Briggs, Anne Cohen, Jean-pierre Gattuso, John M. Grady, Kevin Gross, Maggie Johnson
    Abstract:

    There are concerns about the future of Coral Reefs in the face of ocean acidification and warming, and although studies of these phenomena have advanced quickly, efforts have focused on pieces of the puzzle rather than integrating them to evaluate ecosystem-level effects. The field is now poised to begin this task, but there are information gaps that first must be overcome before progress can be made. Many of these gaps focus on calcification at the levels of cells, organisms, populations, communities, and ecosystem, and their closure will be made difficult by the complexity of the interdependent processes by which Coral Reefs respond to ocean acidification, with effects scaling from cells to ecosystems and from microns to kilometers. Existing ecological theories provide an important and largely untapped resource for overcoming these difficulties, and they offer great potential for integrating the effects of ocean acidification across scales on Coral Reefs.