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Fidler RY, Mahajan SL, Ojwang L, Obiene S, Nicolas T, Ahmadia GN, Slade L, Obura DO, Beatty H, Mohamed J, Kawaka J, Harborne AR. Individual and community empowerment improve resource users' perceptions of community-based conservation effectiveness in Kenya and Tanzania. PLoS One 2024; 19:e0301345. [PMID: 38687761 PMCID: PMC11060543 DOI: 10.1371/journal.pone.0301345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 03/13/2024] [Indexed: 05/02/2024] Open
Abstract
Community-based conservation has been increasingly recognized as critical to achieve both conservation and socio-economic development goals worldwide. However, the long-term sustainability of community-based conservation programs is dependent on a broadly shared perception among community members that management actions are achieving their stated goals. Thus, understanding the underlying factors driving differences in perceptions of management effectiveness can help managers prioritize the processes and outcomes most valued by resource users and thereby promote sustained support for conservation efforts. Here, we utilize large-scale interview survey data and machine learning to identify the factors most strongly associated with differences in perceived management effectiveness between resource users engaged in marine community-based conservation programs in Kenya and Tanzania. Perceptions of management effectiveness were generally favorable in both countries, and the most important predictors of positive perceptions were associated with community and individual empowerment in resource management and use, but within disparate focal domains. Improved perceptions of management effectiveness in Kenya were closely related to increases in women's empowerment in community-based conservation programs, while inclusionary and transparent governance structures were the most important factors driving improved perceptions in Tanzania. Additionally, the strongest predictors of differences between individuals in both countries often interacted synergistically to produce even higher rates of perceived effectiveness. These findings can help future initiatives in the region tailor management to match community-level priorities and emphasize the need for community-based conservation programs to understand local context to ensure that metrics of "success" are aligned with the needs and desires of local resource users.
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Affiliation(s)
- Robert Y. Fidler
- Institute of Environment and Department of Biological Sciences, Florida International University, North Miami, Florida, United States of America
| | - Shauna L. Mahajan
- Global Science, World Wildlife Fund US, Washington, District of Columbia, United States of America
- Ocean Conservation, World Wildlife Fund US, Washington, District of Columbia, United States of America
| | - Lenice Ojwang
- Coastal Oceans Research and Development–Indian Ocean (CORDIO) East Africa, Mombasa, Kenya
| | - Samson Obiene
- Coastal Oceans Research and Development–Indian Ocean (CORDIO) East Africa, Mombasa, Kenya
| | | | - Gabby N. Ahmadia
- Ocean Conservation, World Wildlife Fund US, Washington, District of Columbia, United States of America
| | - Lorna Slade
- Mwambao Coastal Community Network Tanzania, Tanga, Tanzania
| | - David O. Obura
- Coastal Oceans Research and Development–Indian Ocean (CORDIO) East Africa, Mombasa, Kenya
| | - Hope Beatty
- Mwambao Coastal Community Network Tanzania, Tanga, Tanzania
| | - Juma Mohamed
- Mwambao Coastal Community Network Tanzania, Tanga, Tanzania
| | - Joan Kawaka
- Coastal Oceans Research and Development–Indian Ocean (CORDIO) East Africa, Mombasa, Kenya
| | - Alastair R. Harborne
- Institute of Environment and Department of Biological Sciences, Florida International University, North Miami, Florida, United States of America
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Herbert-Read JE, Thornton A, Amon DJ, Birchenough SNR, Côté IM, Dias MP, Godley BJ, Keith SA, McKinley E, Peck LS, Calado R, Defeo O, Degraer S, Johnston EL, Kaartokallio H, Macreadie PI, Metaxas A, Muthumbi AWN, Obura DO, Paterson DM, Piola AR, Richardson AJ, Schloss IR, Snelgrove PVR, Stewart BD, Thompson PM, Watson GJ, Worthington TA, Yasuhara M, Sutherland WJ. A global horizon scan of issues impacting marine and coastal biodiversity conservation. Nat Ecol Evol 2022; 6:1262-1270. [PMID: 35798839 DOI: 10.1038/s41559-022-01812-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 05/24/2022] [Indexed: 11/09/2022]
Abstract
The biodiversity of marine and coastal habitats is experiencing unprecedented change. While there are well-known drivers of these changes, such as overexploitation, climate change and pollution, there are also relatively unknown emerging issues that are poorly understood or recognized that have potentially positive or negative impacts on marine and coastal ecosystems. In this inaugural Marine and Coastal Horizon Scan, we brought together 30 scientists, policymakers and practitioners with transdisciplinary expertise in marine and coastal systems to identify new issues that are likely to have a significant impact on the functioning and conservation of marine and coastal biodiversity over the next 5-10 years. Based on a modified Delphi voting process, the final 15 issues presented were distilled from a list of 75 submitted by participants at the start of the process. These issues are grouped into three categories: ecosystem impacts, for example the impact of wildfires and the effect of poleward migration on equatorial biodiversity; resource exploitation, including an increase in the trade of fish swim bladders and increased exploitation of marine collagens; and new technologies, such as soft robotics and new biodegradable products. Our early identification of these issues and their potential impacts on marine and coastal biodiversity will support scientists, conservationists, resource managers and policymakers to address the challenges facing marine ecosystems.
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Affiliation(s)
| | - Ann Thornton
- Conservation Science Group, Department of Zoology, Cambridge University, Cambridge, UK.
| | - Diva J Amon
- SpeSeas, D'Abadie, Trinidad and Tobago.,Marine Science Institute, University of California, Santa Barbara, CA, USA
| | | | - Isabelle M Côté
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Maria P Dias
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Department of Animal Biology, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.,BirdLife International, The David Attenborough Building, Cambridge, UK
| | - Brendan J Godley
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Sally A Keith
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Emma McKinley
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
| | - Lloyd S Peck
- British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
| | - Ricardo Calado
- ECOMARE, CESAM-Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Santiago University Campus, Aveiro, Portugal
| | - Omar Defeo
- Laboratory of Marine Sciences (UNDECIMAR), Faculty of Sciences, University of the Republic, Montevideo, Uruguay
| | - Steven Degraer
- Royal Belgian Institute of Natural Sciences, Operational Directorate Natural Environment, Marine Ecology and Management, Brussels, Belgium
| | - Emma L Johnston
- School of Biological, Earth, and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | | | - Peter I Macreadie
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood Campus, Burwood, Victoria, Australia
| | - Anna Metaxas
- Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - David O Obura
- Coastal Oceans Research and Development in the Indian Ocean, Mombasa, Kenya.,School of Biological Sciences, University of Queensland, St Lucia, Brisbane, Queensland, Australia
| | - David M Paterson
- Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, UK
| | - Alberto R Piola
- Servício de Hidrografía Naval, Buenos Aires, Argentina.,Instituto Franco-Argentino sobre Estudios de Clima y sus Impactos, CONICET/CNRS, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Anthony J Richardson
- School of Mathematics and Physics, The University of Queensland, St Lucia, Brisbane, Queensland, Australia.,Commonwealth Scientific and Industrial Research Organisation (CSIRO) Oceans and Atmosphere, Queensland Biosciences Precinct, St Lucia, Brisbane, Queensland, Australia
| | - Irene R Schloss
- Instituto Antártico Argentino, Buenos Aires, Argentina.,Centro Austral de Investigaciones Científicas (CADIC-CONICET), Ushuaia, Argentina.,Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur, Ushuaia, Argentina
| | - Paul V R Snelgrove
- Department of Ocean Sciences and Biology Department, Memorial University, St John's, Newfoundland and Labrador, Canada
| | - Bryce D Stewart
- Department of Environment and Geography, University of York, York, UK
| | - Paul M Thompson
- Lighthouse Field Station, School of Biological Sciences, University of Aberdeen, Cromarty, UK
| | - Gordon J Watson
- Institute of Marine Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - Thomas A Worthington
- Conservation Science Group, Department of Zoology, Cambridge University, Cambridge, UK
| | - Moriaki Yasuhara
- School of Biological Sciences, Area of Ecology and Biodiversity, Swire Institute of Marine Science, Institute for Climate and Carbon Neutrality, Musketeers Foundation Institute of Data Science, and State Key Laboratory of Marine Pollution, The University of Hong Kong, Kadoorie Biological Sciences Building, Hong Kong, China
| | - William J Sutherland
- Conservation Science Group, Department of Zoology, Cambridge University, Cambridge, UK.,Biosecurity Research Initiative at St Catharine's (BioRISC), St Catharine's College, University of Cambridge, Cambridge, UK
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Muir PR, Obura DO, Hoeksema BW, Sheppard C, Pichon M, Richards ZT. Conclusions of low extinction risk for most species of reef-building corals are premature. Nat Ecol Evol 2022; 6:357-358. [DOI: 10.1038/s41559-022-01659-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 01/07/2022] [Indexed: 01/31/2023]
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4
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Obura DO, Katerere Y, Mayet M, Kaelo D, Msweli S, Mather K, Harris J, Louis M, Kramer R, Teferi T, Samoilys M, Lewis L, Bennie A, Kumah F, Isaacs M, Nantongo P. Integrate biodiversity targets from local to global levels. Science 2021; 373:746-748. [PMID: 34385386 DOI: 10.1126/science.abh2234] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- David O Obura
- CORDIO East Africa, Mombasa, Kenya. .,University of Queensland, Brisbane, Australia.,Pwani University, Kilifi, Kenya
| | - Yemi Katerere
- Independent: Environmental and Policy Expert, Harare, Zimbabwe
| | - Mariam Mayet
- Africa Centre for Biodiversity, Johannesberg, South Africa
| | - Dickson Kaelo
- Kenya Wildlife Conservancies Association, Nairobi, Kenya
| | | | - Khalid Mather
- Wildlands Conservation Trust, Pietermaritzburg, South Africa
| | - Jean Harris
- Wildlands Conservation Trust, Pietermaritzburg, South Africa.,Institute for Coastal and Marine Research (CMR), Nelson Mandela University, Port Elizabeth, South Africa
| | - Maxi Louis
- Community Leadership Network (CLN) of Southern Africa, Windhoek, Namibia.,Namibian Association of Community Based Natural Resources Associations (NACSO), Windhoek, Namibia
| | - Rachel Kramer
- Wildlands Conservation Trust, Pietermaritzburg, South Africa
| | - Taye Teferi
- Independent: Conservation Scientist, Nairobi, Kenya
| | - Melita Samoilys
- CORDIO East Africa, Mombasa, Kenya.,Pwani University, Kilifi, Kenya.,University of Oxford, Oxford, UK
| | - Linzi Lewis
- Africa Centre for Biodiversity, Johannesberg, South Africa
| | - Andrew Bennie
- Africa Centre for Biodiversity, Johannesberg, South Africa.,Department of Sociology, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Moenieba Isaacs
- Institute for Poverty, Land and Agrarian Studies (PLAAS), University of the Western Cape, Cape Town, South Africa
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Raj KD, Mathews G, Obura DO, Laju RL, Bharath MS, Kumar PD, Arasamuthu A, Kumar TKA, Edward JKP. Low oxygen levels caused by Noctiluca scintillans bloom kills corals in Gulf of Mannar, India. Sci Rep 2020; 10:22133. [PMID: 33335160 PMCID: PMC7746711 DOI: 10.1038/s41598-020-79152-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 12/04/2020] [Indexed: 12/21/2022] Open
Abstract
Coral reefs around the world are undergoing severe decline in the past few decades. Mass coral mortalities have predominantly been reported to be caused by coral bleaching or disease outbreaks. Temporary hypoxic conditions caused by algal blooms can trigger mass coral mortalities though are reported rarely. In this study in Gulf of Mannar (GoM), southeast India, we report a significant coral mortality caused by a bloom of the ciguatoxic dinoflagellate Noctiluca scintillans during September–October 2019. Dissolved oxygen levels declined below 2 mg l−1 during the bloom causing temporary hypoxia and mortality (up to 71.23%) in the fast growing coral genera Acropora, Montipora and Pocillopora. Due to global climate change, more frequent and larger algal blooms are likely in the future. Hence, it is likely that shallow water coral reefs will be affected more frequently by episodic hypoxic conditions driven by algal blooms. More studies are, however, required to understand the mechanism of coral mortality due to algal blooms, impacts on community composition and the potential for subsequent recovery.
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Affiliation(s)
- K Diraviya Raj
- Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin, 628001, Tamil Nadu, India.
| | - G Mathews
- Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin, 628001, Tamil Nadu, India
| | - David O Obura
- CORDIO East Africa, P.O. Box 10135, Mombasa, 80101, Kenya
| | - R L Laju
- Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin, 628001, Tamil Nadu, India
| | - M Selva Bharath
- Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin, 628001, Tamil Nadu, India
| | - P Dinesh Kumar
- Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin, 628001, Tamil Nadu, India
| | - A Arasamuthu
- Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin, 628001, Tamil Nadu, India
| | - T K Ashok Kumar
- Gulf of Mannar Marine National Park, Ramanathapuram, 623 503, India
| | - J K Patterson Edward
- Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin, 628001, Tamil Nadu, India
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Abstract
The Phoenix Islands Protected Area is in a naturally iron-poor region in the equatorial central Pacific. The introduction of iron to this environment from shipwrecks is linked to proliferation of turf algae and cyanobacterial mats, and the formation of degraded ‘black reefs’. No recovery has been documented at black reefs observed between 2003 and 2015.
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Abstract
Background High sea surface temperatures resulted in widespread coral bleaching and mortality in Mayotte Island (northern Mozambique channel, Indian Ocean: 12.1°S, 45.1°E) in April–June 2010. Methods Twenty three representative coral genera were sampled quantitatively for size class distributions during the peak of the bleaching event to measure its impact. Results Fifty two percent of coral area was impacted, comprising 19.3% pale, 10.7% bleached, 4.8% partially dead and 17.5% recently dead. Acropora, the dominant genus, was the second most susceptible to bleaching (22%, pale and bleached) and mortality (32%, partially dead and dead), only exceeded by Pocillopora (32% and 47%, respectively). The majority of genera showed intermediate responses, and the least response was shown by Acanthastrea and Leptastrea (6% pale and bleached). A linear increase in bleaching susceptibility was found from small colonies (<2.5 cm, 83% unaffected) to large ones (>80 cm, 33% unaffected), across all genera surveyed. Maximum mortality in 2010 was estimated at 32% of coral area or biomass, compared to half that (16%), by colony abundance. Discussion Mayotte reefs have displayed a high level of resilience to bleaching events in 1983, 1998 and the 2010 event reported here, and experienced a further bleaching event in 2016. However, prospects for continued resilience are uncertain as multiple threats are increasing: the rate of warming experienced (0.1 °C per decade) is some two to three times less than projected warming in coming decades, the interval between severe bleaching events has declined from 16 to 6 years, and evidence of chronic mortality from local human impacts is increasing. The study produced four recommendations for reducing bias when monitoring and assessing coral bleaching: coral colony size should be measured, unaffected colonies should be included in counts, quadrats or belt transects should be used and weighting coefficients in the calculation of indices should be used with caution.
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Affiliation(s)
| | - Lionel Bigot
- UMR Entropie, Laboratoire d'écologie marine, Université de la Reunion, Saint Denis, Reunion
| | - Francesca Benzoni
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
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8
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Beyer HL, Kennedy EV, Beger M, Chen CA, Cinner JE, Darling ES, Eakin CM, Gates RD, Heron SF, Knowlton N, Obura DO, Palumbi SR, Possingham HP, Puotinen M, Runting RK, Skirving WJ, Spalding M, Wilson KA, Wood S, Veron JE, Hoegh‐Guldberg O. Risk‐sensitive planning for conserving coral reefs under rapid climate change. Conserv Lett 2018. [DOI: 10.1111/conl.12587] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Hawthorne L. Beyer
- Global Change Institute University of Queensland St. Lucia Queensland Australia
- Australian Research Council Centre of Excellence for Environmental Decisions University of Queensland St. Lucia Queensland Australia
| | - Emma V. Kennedy
- Global Change Institute University of Queensland St. Lucia Queensland Australia
| | - Maria Beger
- Australian Research Council Centre of Excellence for Environmental Decisions University of Queensland St. Lucia Queensland Australia
- School of Biology, Faculty of Biological Sciences University of Leeds Leeds UK
| | - Chaolun Allen Chen
- Biodiversity Research Center Academia Sinica Taipei Taiwan
- Institute of Oceanography National Taiwan University Taipei Taiwan
| | - Joshua E. Cinner
- Australian Research Council Centre of Excellence for Coral Reef Studies James Cook University Townsville Australia
| | - Emily S. Darling
- Department of Ecology and Evolutionary Biology University of Toronto Toronto Ontario Canada
- Marine Program Wildlife Conservation Society Bronx New York
| | - C. Mark Eakin
- Coral Reef Watch National Oceanic and Atmospheric Administration College Park Maryland
| | - Ruth D. Gates
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology University of Hawai‘i at Mānoa Kāne‘ohe Hawaii
| | - Scott F. Heron
- Coral Reef Watch National Oceanic and Atmospheric Administration College Park Maryland
- Marine Geophysical Laboratory, Physics Department, College of Science and Engineering James Cook University Townsville Queensland Australia
| | - Nancy Knowlton
- Department of Invertebrate Zoology, National Museum of Natural History Smithsonian Institution Washington District of Columbia
| | | | - Stephen R. Palumbi
- Department of Biology, Hopkins Marine Station Stanford University Pacific Grove California
| | - Hugh P. Possingham
- Australian Research Council Centre of Excellence for Environmental Decisions University of Queensland St. Lucia Queensland Australia
- School of Biological Sciences University of Queensland St. Lucia Queensland Australia
- The Nature Conservancy South Brisbane Queensland Australia
| | - Marji Puotinen
- Australian Institute of Marine Science, Indian Ocean Marine Research Centre University of Western Australia Crawley Western Australia Australia
| | - Rebecca K. Runting
- School of Biological Sciences University of Queensland St. Lucia Queensland Australia
| | - William J. Skirving
- Coral Reef Watch National Oceanic and Atmospheric Administration College Park Maryland
| | - Mark Spalding
- Global Ocean Team, The Nature Conservancy and Department of Zoology, University of Cambridge. c/‐Department of Physical, Earth and Environmental Sciences University of Siena Siena Italy
| | - Kerrie A. Wilson
- Australian Research Council Centre of Excellence for Environmental Decisions University of Queensland St. Lucia Queensland Australia
- School of Biological Sciences University of Queensland St. Lucia Queensland Australia
| | - Sally Wood
- School of Geographical Sciences University of Bristol Bristol UK
| | | | - Ove Hoegh‐Guldberg
- Global Change Institute University of Queensland St. Lucia Queensland Australia
- School of Biological Sciences University of Queensland St. Lucia Queensland Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies University of Queensland St Lucia Queensland Australia
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Sale PF, Agardy T, Ainsworth CH, Feist BE, Bell JD, Christie P, Hoegh-Guldberg O, Mumby PJ, Feary DA, Saunders MI, Daw TM, Foale SJ, Levin PS, Lindeman KC, Lorenzen K, Pomeroy RS, Allison EH, Bradbury RH, Corrin J, Edwards AJ, Obura DO, Sadovy de Mitcheson YJ, Samoilys MA, Sheppard CRC. Transforming management of tropical coastal seas to cope with challenges of the 21st century. Mar Pollut Bull 2014; 85:8-23. [PMID: 24997002 DOI: 10.1016/j.marpolbul.2014.06.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/02/2014] [Accepted: 06/03/2014] [Indexed: 06/03/2023]
Abstract
Over 1.3 billion people live on tropical coasts, primarily in developing countries. Many depend on adjacent coastal seas for food, and livelihoods. We show how trends in demography and in several local and global anthropogenic stressors are progressively degrading capacity of coastal waters to sustain these people. Far more effective approaches to environmental management are needed if the loss in provision of ecosystem goods and services is to be stemmed. We propose expanded use of marine spatial planning as a framework for more effective, pragmatic management based on ocean zones to accommodate conflicting uses. This would force the holistic, regional-scale reconciliation of food security, livelihoods, and conservation that is needed. Transforming how countries manage coastal resources will require major change in policy and politics, implemented with sufficient flexibility to accommodate societal variations. Achieving this change is a major challenge - one that affects the lives of one fifth of humanity.
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Affiliation(s)
- Peter F Sale
- Institute for Water, Environment and Health, United Nations University, 175 Longwood Rd, Hamilton, ON L8P0A1, Canada.
| | | | - Cameron H Ainsworth
- College of Marine Science, University of South Florida, St. Petersburg, FL 33701, USA
| | - Blake E Feist
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd E, Seattle, WA 98112, USA
| | - Johann D Bell
- Fisheries, Aquaculture and Marine Ecosystems Division, Secretariat of the Pacific Community, B.P. D5, 98848 Noumea Cedex, New Caledonia
| | - Patrick Christie
- School of Marine and Environmental Affairs and Jackson School of International Studies, University of Washington, Seattle, WA 98105-6715, USA
| | - Ove Hoegh-Guldberg
- Global Change Institute, University of Queensland, St. Lucia, Qld 4072, Australia
| | - Peter J Mumby
- School of Biological Sciences, University of Queensland, St. Lucia, Qld 4072, Australia
| | - David A Feary
- School of the Environment, University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Megan I Saunders
- Global Change Institute, University of Queensland, St. Lucia, Qld 4072, Australia
| | - Tim M Daw
- Stockholm Resilience Centre, Stockholm University, SE-106 91 Stockholm, Sweden; School of International Development, University of East Anglia, Norwich NR4 7HU, UK
| | - Simon J Foale
- School of Arts and Social Sciences, James Cook University, Townsville, Qld 4811, Australia
| | - Phillip S Levin
- Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd E, Seattle, WA 98112, USA
| | - Kenyon C Lindeman
- Dept. of Education & Interdisciplinary Studies, Florida Institute of Technology, Melbourne, FL 32901, USA
| | - Kai Lorenzen
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32653, USA
| | - Robert S Pomeroy
- Agricultural and Resource Economics/CT Sea Grant, University of Connecticut-Avery Point, Groton, CT 06340, USA
| | - Edward H Allison
- School of International Development, University of East Anglia, Norwich NR4 7HU, UK
| | - R H Bradbury
- Crawford School of Public Policy, Australian National University, Canberra, ACT 0200, Australia
| | - Jennifer Corrin
- Centre for Public, International and Comparative Law, and TC Beirne School of Law, University of Queensland, St. Lucia, Qld 4072, Australia
| | - Alasdair J Edwards
- School of Biology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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10
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Veron JEN, Hoegh-Guldberg O, Lenton TM, Lough JM, Obura DO, Pearce-Kelly P, Sheppard CRC, Spalding M, Stafford-Smith MG, Rogers AD. The coral reef crisis: the critical importance of<350 ppm CO2. Mar Pollut Bull 2009; 58:1428-36. [PMID: 19782832 DOI: 10.1016/j.marpolbul.2009.09.009] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Temperature-induced mass coral bleaching causing mortality on a wide geographic scale started when atmospheric CO(2) levels exceeded approximately 320 ppm. When CO(2) levels reached approximately 340 ppm, sporadic but highly destructive mass bleaching occurred in most reefs world-wide, often associated with El Niño events. Recovery was dependent on the vulnerability of individual reef areas and on the reef's previous history and resilience. At today's level of approximately 387 ppm, allowing a lag-time of 10 years for sea temperatures to respond, most reefs world-wide are committed to an irreversible decline. Mass bleaching will in future become annual, departing from the 4 to 7 years return-time of El Niño events. Bleaching will be exacerbated by the effects of degraded water-quality and increased severe weather events. In addition, the progressive onset of ocean acidification will cause reduction of coral growth and retardation of the growth of high magnesium calcite-secreting coralline algae. If CO(2) levels are allowed to reach 450 ppm (due to occur by 2030-2040 at the current rates), reefs will be in rapid and terminal decline world-wide from multiple synergies arising from mass bleaching, ocean acidification, and other environmental impacts. Damage to shallow reef communities will become extensive with consequent reduction of biodiversity followed by extinctions. Reefs will cease to be large-scale nursery grounds for fish and will cease to have most of their current value to humanity. There will be knock-on effects to ecosystems associated with reefs, and to other pelagic and benthic ecosystems. Should CO(2) levels reach 600 ppm reefs will be eroding geological structures with populations of surviving biota restricted to refuges. Domino effects will follow, affecting many other marine ecosystems. This is likely to have been the path of great mass extinctions of the past, adding to the case that anthropogenic CO(2) emissions could trigger the Earth's sixth mass extinction.
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Affiliation(s)
- J E N Veron
- Coral Reef Research, 10 Benalla Road, Townsville 4811, Australia.
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11
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Abstract
A rationale is presented here for a primary role of bleaching in regulation of the coral-zooxanthellae symbiosis under conditions of stress. Corals and zooxanthellae have fundamentally different metabolic rates, requiring active homeostasis to limit zooxanthellae production and manage translocated products to maintain the symbiosis. The control processes for homeostasis are compromised by environmental stress, resulting in metabolic imbalance between the symbionts. For the coral-zooxanthella symbiosis the most direct way to minimize metabolic imbalance under stress is to reduce photosynthetic production by zooxanthellae. Two mechanisms have been demonstrated that do this: reduction of the chlorophyll concentration in individual zooxanthellae and reduction of the relative biomass of zooxanthellae. Both mechanisms result in visual whitening of the coral, termed bleaching. Arguments are presented here that bleaching provides the final control to minimize physiological damage from stress as an adversity response to metabolic imbalance. As such, bleaching meets the requirements of a stress response syndrome/general adaptive mechanism that is sensitive to internal states rather than external parameters. Variation in bleaching responses among holobionts reflects genotypic and phenotypic differentiation, allowing evolutionary change by natural selection. Thus, reef corals bleach to resist stress, and thereby have some capacity to adapt to and survive change. The extreme thermal anomalies causing mass coral bleaching worldwide lie outside the reaction norms for most coral-zooxanthellae holobionts, revealing the limitations of bleaching as a control mechanism.
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Carpenter KE, Abrar M, Aeby G, Aronson RB, Banks S, Bruckner A, Chiriboga A, Cortés J, Delbeek JC, Devantier L, Edgar GJ, Edwards AJ, Fenner D, Guzmán HM, Hoeksema BW, Hodgson G, Johan O, Licuanan WY, Livingstone SR, Lovell ER, Moore JA, Obura DO, Ochavillo D, Polidoro BA, Precht WF, Quibilan MC, Reboton C, Richards ZT, Rogers AD, Sanciangco J, Sheppard A, Sheppard C, Smith J, Stuart S, Turak E, Veron JEN, Wallace C, Weil E, Wood E. One-Third of Reef-Building Corals Face Elevated Extinction Risk from Climate Change and Local Impacts. Science 2008; 321:560-3. [PMID: 18653892 DOI: 10.1126/science.1159196] [Citation(s) in RCA: 522] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Kent E Carpenter
- IUCN (International Union for Conservation of Nature) Species Programme Species Survival Commission (SSC), Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA.
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Abstract
The Kenya coast is bathed by the northward-flowing warm waters of the East Africa Coastal Current, located between latitudes 1 and 5 degrees S. With a narrow continental shelf, the coastal marine environments are dominated by coral reefs, seagrass beds and mangroves, with large expanses of sandy substrates where river inputs from Kenya's two largest rivers, the Tana and Athi rivers, prevent the growth of coral reefs. The northern part of the coast is seasonally influenced by upwelling waters of the Somali Current, resulting in lower water temperatures for part of the year. The coast is made up of raised Pleistocene reefs on coastal plains and hills of sedimentary origin, which support native habitats dominated by scrub bush and remnant pockets of the forests that used to cover East Africa and the Congo basin. The marine environment is characterized by warm tropical conditions varying at the surface between 25 degrees C and 31 degrees C during the year, stable salinity regimes, and moderately high nutrient levels from terrestrial runoff and groundwater. The semi-diurnal tidal regime varies from 1.5 to 4 m amplitude from neap to spring tides, creating extensive intertidal platform and rocky-shore communities exposed twice-daily during low tides. Fringing reef crests dominate the whole southern coast and parts of the northern coast towards Somalia, forming a natural barrier to the wave energy from the ocean. Coral reefs form the dominant ecosystem along the majority of the Kenya coast, creating habitats for seagrasses and mangroves in the lagoons and creeks protected by the reef crests. Kenya's marine environment faces a number of threats from the growing coastal human population estimated at just under three million in 2000. Extraction of fish and other resources from the narrow continental shelf, coral reef and mangrove ecosystems increases each year with inadequate monitoring and management structures to protect the resource bases. Coastal development in urban and tourist centers proceeds with little regard for environmental and social impacts. With a faltering economy, industrial development in Mombasa proceeds with few checks on pollution and other impacts. In 1998 Kenya's coral reefs suffered 50-80% mortality from the El Niño-related coral bleaching event that affected the entire Indian Ocean. The institutional, human resource and legal infrastructure for managing the coastal environment has in the past been low, however these are rapidly improving with the revitalization of national institutions and the passing in 1999 of an Environment Act. Marine Protected Areas are the key tool currently used in management of marine ecosystems, and focus principally on coral reefs and biodiversity protection. New initiatives are underway to improve application of fisheries regulations, and to use Integrated Coastal Area Management (ICAM) as a framework for protecting marine and coastal environments.
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