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Walker AS, Kratochwill CA, van Woesik R. Past disturbances and local conditions influence the recovery rates of coral reefs. GLOBAL CHANGE BIOLOGY 2024; 30:e17112. [PMID: 38273580 DOI: 10.1111/gcb.17112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/28/2023] [Accepted: 11/28/2023] [Indexed: 01/27/2024]
Abstract
Corals are being increasingly subjected to marine heatwaves. Theory suggests that increasing the intensity of disturbances reduces recovery rates, which inspired us to examine the recovery rates of coral cover following marine heatwaves, cyclones, and other disturbances at 1921 study sites, in 58 countries and three oceans, from 1977 to 2020. In the Atlantic Ocean, coral cover has decreased fourfold since the 1970s, and recovery rates following disturbances have been relatively slow, except in the Antilles. By contrast, reefs in the Pacific and Indian Oceans have maintained coral cover and recovery rates over time. There were positive relationships between rates of coral recovery and prior cyclone and heatwave frequency, and negative relationships between rates of coral recovery and macroalgae cover and distance to shore. A recent increase in the variance in recovery rates in some ecoregions of the Pacific and Indian Oceans suggests that some reefs in those ecoregions may be approaching a phase shift. While marine heatwaves are increasing in intensity and frequency, our results suggest that regional and local conditions influence coral recovery rates, and therefore, effective local management efforts can help reefs recover from disturbances.
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Affiliation(s)
- Andrew S Walker
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, USA
| | - Chelsey A Kratochwill
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, USA
| | - Robert van Woesik
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, USA
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2
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Baumann JH, Zhao L, Stier AC, Bruno JF. Remoteness does not enhance coral reef resilience. GLOBAL CHANGE BIOLOGY 2022; 28:417-428. [PMID: 34668280 PMCID: PMC8671335 DOI: 10.1111/gcb.15904] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/07/2021] [Accepted: 09/07/2021] [Indexed: 05/02/2023]
Abstract
Remote coral reefs are thought to be more resilient to climate change due to their isolation from local stressors like fishing and pollution. We tested this hypothesis by measuring the relationship between local human influence and coral community resilience. Surprisingly, we found no relationship between human influence and resistance to disturbance and some evidence that areas with greater human development may recover from disturbance faster than their more isolated counterparts. Our results suggest remote coral reefs are imperiled by climate change, like so many other geographically isolated ecosystems, and are unlikely to serve as effective biodiversity arks. Only drastic and rapid cuts in greenhouse gas emissions will ensure coral survival. Our results also indicate that some reefs close to large human populations were relatively resilient. Focusing research and conservation resources on these more accessible locations has the potential to provide new insights and maximize conservation outcomes.
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Affiliation(s)
- Justin H. Baumann
- The Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-3280 USA
- Department of Marine Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-3300 USA
- Biology Department, Bowdoin College, Brunswick, Maine, 04011 USA
- Correspondence to: or
| | - Lily Zhao
- Department of Ecology, Evolution, and Marine Biology, The University of California Santa Barbara, Santa Barbara CA, 93106-9620, USA
| | - Adrian C. Stier
- Department of Ecology, Evolution, and Marine Biology, The University of California Santa Barbara, Santa Barbara CA, 93106-9620, USA
| | - John F. Bruno
- The Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-3280 USA
- Correspondence to: or
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3
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Abstract
Well-managed rangelands provide important economic, environmental, and cultural benefits. Yet, many rangelands worldwide are experiencing pressures of land-use change, overgrazing, fire, and drought, causing rapid degradation. These pressures are especially acute in the Hawaiian Islands, which we explore as a microcosm with some broadly relevant lessons. Absent stewardship, land in Hawaiʻi is typically subject to degradation through the spread and impacts of noxious invasive plant species; feral pigs, goats, deer, sheep, and cattle; and heightened fire risk. We first provide a framework, and then review the science demonstrating the benefits of well-managed rangelands, for production of food; livelihoods; watershed services; climate security; soil health; fire risk reduction; biodiversity; and a wide array of cultural values. Findings suggest that rangelands, as part of a landscape mosaic, contribute to social and ecological health and well-being in Hawaiʻi. We conclude by identifying important knowledge gaps around rangeland ecosystem services and highlight the need to recognize rangelands and their stewards as critical partners in achieving key sustainability goals, and in bridging the long-standing production-conservation divide.
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4
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van Woesik R, Cacciapaglia CW. Thermal stress jeopardizes carbonate production of coral reefs across the western and central Pacific Ocean. PLoS One 2021; 16:e0249008. [PMID: 33901212 PMCID: PMC8075252 DOI: 10.1371/journal.pone.0249008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/09/2021] [Indexed: 11/19/2022] Open
Abstract
Coral reefs protect islands, coastal areas, and their inhabitants from storm waves and provide essential goods and services to millions of people worldwide. Yet contemporary rates of ocean warming and local disturbances are jeopardizing the reef-building capacity of coral reefs to keep up with rapid rates of sea-level rise. This study compared the reef-building capacity of shallow-water habitats at 142 sites across a potential thermal-stress gradient in the tropical Pacific Ocean. We sought to determine the extent to which habitat differences and environmental variables potentially affect rates of net carbonate production. In general, outer-exposed reefs and lagoonal-patch reefs had higher rates of net carbonate production than nearshore reefs. The study found that thermal anomalies, particularly the intensity of thermal-stress events, play a significant role in reducing net carbonate production—evident as a diminishing trend of net carbonate production from the western to the central tropical Pacific Ocean. The results also showed a latent spatial effect along the same gradient, not explained by thermal stress, suggesting that reefs in the western tropical Pacific Ocean are potentially enhanced by the proximity of reefs in the Coral Triangle—an effect that diminishes with increasing distance and isolation.
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Affiliation(s)
- Robert van Woesik
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, United States of America
- * E-mail:
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5
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Abstract
Abstract
Modern-day Indo-Pacific coral reefs are characterized by rapid recovery driven by pulses of coral recruitment, but Caribbean reefs exhibit low rates of recruitment and poor recovery following a wide range of disturbance events. The contrasting evolutionary history of coral taxa offers key insight into biogeographic patterns of coral resilience. Following the closure of the Isthmus of Panama approximately 2.8 million years ago, widespread extinction of Caribbean corals led to an evolutionary bottleneck that favored large and long-lived species with a relatively high reliance on asexual versus sexual reproduction. In contrast, adaptive radiation led to the evolution of superrecruiting tabular, digitate, and corymbose corals that drive the rapid recovery of modern-day Indo-Pacific reefs following disturbance. The dominance of branching growth forms and evolutionary absence of superrecruiting growth forms throughout the entire evolutionary history of the Caribbean (approximately 38 million years ago to present) may explain the exceptionally high recruitment rates on modern-day Indo-Pacific reefs and low historical recruitment on Caribbean reefs. The evolutionary history of the Caribbean coral reef-building taxa implies that, even with a reversal of ecosystem state, widespread recovery of Caribbean reefs may be limited.
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Affiliation(s)
- George Roff
- School of Biological Sciences, University of Queensland, in St. Lucia, Australia
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6
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Wakwella A, Mumby PJ, Roff G. Sedimentation and overfishing drive changes in early succession and coral recruitment. Proc Biol Sci 2020; 287:20202575. [PMID: 33323081 DOI: 10.1098/rspb.2020.2575] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Sedimentation and overfishing are important local stressors on coral reefs that can independently result in declines in coral recruitment and shifts to algal-dominated states. However, the role of herbivory in driving recovery across environmental gradients is often unclear. Here we investigate early successional benthic communities and coral recruitment across a sediment gradient in Palau, Micronesia over a 12-month period. Total sedimentation rates measured by 'TurfPods' varied from 0.03 ± 0.1 SE mg cm-2 d-1 at offshore sites to 1.32 ± 0.2 mg cm-2 d-1 at inshore sites. To assess benthic succession, three-dimensional settlement tiles were deployed at sites with experimental cages used to exclude tile access to larger herbivorous fish. Benthic assemblages exhibited rapid transitions across the sediment gradient within three months of deployment. At low levels of sedimentation (less than 0.6 mg cm-2 d-1), herbivory resulted in communities dominated by coral recruitment inducers (short turf algae and crustose coralline algae), whereas exclusion of herbivores resulted in the overgrowth of coral inhibitors (encrusting and upright foliose macroalgae). An 'inducer threshold' was found under increasing levels of sedimentation (greater than 0.6 mg cm-2 d-1), with coral inducers having limited to no presence in communities, and herbivore access to tiles resulted in sediment-laden turf algal assemblages, while exclusion of herbivores resulted in invertebrates (sponges, ascidians) and terrestrial sediment accumulation. A 'coral recruitment threshold' was found at 0.8 mg cm-2 d-1, below which net coral recruitment was reduced by 50% in the absence of herbivores, while recruitment was minimal above the threshold. Our results highlight nonlinear trajectories of benthic succession across sediment gradients and identify strong interactions between sediment and herbivory that have cascading effects on coral recruitment. Local management strategies that aim to reduce sedimentation and turbidity and manage herbivore fisheries can have measurable effects on benthic community succession and coral recruitment, enhancing reef resilience and driving coral recovery.
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Affiliation(s)
- Ama Wakwella
- Marine Spatial Ecology Lab, School of Biological Sciences, University of Queensland, St Lucia, Queensland 4072, Australia
| | - Peter J Mumby
- Marine Spatial Ecology Lab, School of Biological Sciences, University of Queensland, St Lucia, Queensland 4072, Australia.,Palau International Coral Reef Center, Koror, Palau
| | - George Roff
- Marine Spatial Ecology Lab, School of Biological Sciences, University of Queensland, St Lucia, Queensland 4072, Australia
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7
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Pereira CM, Fonseca JS, Paiva ES, Costa PG, Mies M, Silva AG, Calderon EN, Bianchini A, Castro CB. Larvae of the South Atlantic coral Favia gravida are tolerant to salinity and nutrient concentrations associated with river discharges. MARINE ENVIRONMENTAL RESEARCH 2020; 161:105118. [PMID: 32890984 DOI: 10.1016/j.marenvres.2020.105118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/24/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
Rivers release freshwater, nutrients and pollutants into reefs. This type of environmental stress reduces coral larvae settlement and alter its energy metabolism. We investigated the tolerance of Favia gravida (Scleractinia) larvae to river discharges. We exposed larvae to (i) different salinities (25, 30, 35 and 40 PSU); and (ii) dilutions of river water containing nutrients and metals (0, 20, 40, 60, 80 and 100% river water) under control salinity of 35 PSU. We then examined settlement and larval enzymatic activity. No differences in settlement were detected among salinities. Settlement was also similar to control for larvae under 100% river water. Enzymatic activity for citrate synthase remained unaltered for all treatments. Lactate dehydrogenase activity was slightly altered under different salinities, suggesting a mild stress response. Findings suggest that F. gravida larvae are tolerant to a wide range of salinity and nutrient conditions and that this is a stress-tolerant species.
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Affiliation(s)
- Cristiano M Pereira
- Instituto Coral Vivo, R. dos Coqueiros 87, Parque Yaya, Santa Cruz Cabrália, BA, Brazil; Departamento de Invertebrados, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, São Cristóvão, Rio de Janeiro, RJ, Brazil.
| | - Juliana S Fonseca
- Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Av. Itália Km 8, Rio Grande, RS, Brazil
| | - Edney S Paiva
- Instituto Federal de Educação, Ciência e Tecnologia da Bahia, Rod. BR 367 Km 57,5, Porto Seguro, BA, Brazil
| | - Patrícia G Costa
- Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Av. Itália Km 8, Rio Grande, RS, Brazil
| | - Miguel Mies
- Instituto Coral Vivo, R. dos Coqueiros 87, Parque Yaya, Santa Cruz Cabrália, BA, Brazil; Instituto Oceanográfico, Universidade de São Paulo, Praça do Oceanográfico 191, São Paulo, SP, Brazil
| | - Allison G Silva
- Instituto Coral Vivo, R. dos Coqueiros 87, Parque Yaya, Santa Cruz Cabrália, BA, Brazil; Instituto Federal de Educação, Ciência e Tecnologia da Bahia, Rod. BR 367 Km 57,5, Porto Seguro, BA, Brazil
| | - Emiliano N Calderon
- Instituto Coral Vivo, R. dos Coqueiros 87, Parque Yaya, Santa Cruz Cabrália, BA, Brazil; Instituto de Biodiversidade e Sustentabilidade, Universidade Federal do Rio de Janeiro, Av. São José Barreto 764, Macaé, RJ, Brazil
| | - Adalto Bianchini
- Instituto Coral Vivo, R. dos Coqueiros 87, Parque Yaya, Santa Cruz Cabrália, BA, Brazil; Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, Av. Itália Km 8, Rio Grande, RS, Brazil
| | - Clovis B Castro
- Instituto Coral Vivo, R. dos Coqueiros 87, Parque Yaya, Santa Cruz Cabrália, BA, Brazil; Departamento de Invertebrados, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista, São Cristóvão, Rio de Janeiro, RJ, Brazil
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8
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Abstract
Over the last three decades corals have declined precipitously in the Florida Keys. Their population decline has prompted restoration effort. Yet, little effort has been invested in understanding the contemporary niche spaces of coral species, which could assist in prioritizing conservation habitats. We sought to predict the probability of occurrence of 23 coral species, including the critically endangered Acropora cervicornis, using observations at 985 sites from 2011–2015. We ran boosted regression trees to evaluate the relationship between the presence of these corals and eight potential environmental predictors: (i) bathymetry (m), (ii) mean of daily sea surface temperature (SST) (°C), (iii) variance of SST (°C), (iv) range of SST (°C), (v) chlorophyll-a concentration (mg m3), (vi) turbidity (m-1), (vii) wave energy (kJ m-2), and (viii) distance from coast (km). The Marquesas and the lower and upper Florida Keys were predicted to support the most suitable habitats for the 23 coral species examined. A. cervicornis had one of the smallest areas of suitable habitat, which was limited to the lower and upper Florida Keys, the Dry Tortugas, and nearshore Broward-Miami reefs. The best environmental predictors of site occupancy of A. cervicornis were SST range (4–5°C) and turbidity (K490 between 0.15–0.25 m-1). Historically A. cervicornis was reported in clear oligotrophic waters, although the present results find the coral species surviving in nearshore turbid conditions. Nearshore, turbid reefs may shade corals during high-temperature events, and therefore nearshore reefs in south Florida may become important refuges for corals as the ocean temperatures continue to increase.
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9
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Cross-shelf Heterogeneity of Coral Assemblages in Northwest Australia. DIVERSITY-BASEL 2019. [DOI: 10.3390/d11020015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Understanding the spatial and temporal distribution of coral assemblages and the processes structuring those patterns is fundamental to managing reef assemblages. Cross-shelf marine systems exhibit pronounced and persistent gradients in environmental conditions; however, these gradients are not always reliable predictors of coral distribution or the degree of stress that corals are experiencing. This study used information from government, industry and scientific datasets spanning 1980–2017, to explore temporal trends in coral cover in the geographically complex system of the Dampier Archipelago, northwest Australia. Coral composition at 15 sites surveyed in 2017 was also modelled against environmental and spatial variables (including turbidity, degree heat weeks, wave exposure, and distance to land/mainland/isobath) to assess their relative importance in structuring coral assemblages. High spatial and temporal heterogeneity was observed in coral cover and recovery trajectories, with reefs located an intermediate distance from the shore maintaining high cover over the past 20 years. The abundance of some prominent genera in 2017 (Acropora, Porites, and Turbinaria spp.) decreased with the distance from the mainland, suggesting that inshore processes play an important role in dictating the distribution of these genera. The atypical distributions of these key reef-building corals and spatial heterogeneity of historical recovery trajectories highlight the risks in making assumptions regarding cross-shelf patterns in geographically complex systems.
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10
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Marlow J, Davy SK, Haris A, Bell JJ. Photoacclimation to light-limitation in a clionaid sponge; implications for understanding sponge bioerosion on turbid reefs. MARINE POLLUTION BULLETIN 2018; 135:466-474. [PMID: 30301060 DOI: 10.1016/j.marpolbul.2018.07.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 06/08/2023]
Abstract
Watershed-based pollution is a common form of coral reef degradation. Affected reefs are often highly turbid, where light-limitation confines the distribution of photosynthetic benthic taxa and the capacity for photoacclimation is important for survival. We investigated low light photoacclimation in a Symbiodinium-hosting bioeroding sponge using in situ PAM fluorometry. Cliona aff. viridis was artificially shaded (70 & 95% ambient light reduction) on a low turbidity Indonesian reef for 25 days, with a subsequent 14-day recovery period. Significant changes in rETRmax, and qP, and a non-significant but observable decline in Ek, demonstrated that C. aff. viridis is able to photoacclimate to conditions of extreme light reduction and recover within a relatively short period of time. The sponge is therefore unlikely to be light limited on even the most turbid reefs. However, other aspects of watershed-pollution such as sedimentation may still limit their distribution in affected coastal waters.
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Affiliation(s)
- Joseph Marlow
- Victoria University of Wellington, School of Biological Sciences, Wellington, 6140, New Zealand.
| | - Simon K Davy
- Victoria University of Wellington, School of Biological Sciences, Wellington, 6140, New Zealand
| | - Abdul Haris
- Research and Development Centre on Marine, Coastal and Small Islands, Hasanuddin University, Makassar, Indonesia
| | - James J Bell
- Victoria University of Wellington, School of Biological Sciences, Wellington, 6140, New Zealand
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11
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Mumby PJ, Steneck RS. Paradigm Lost: Dynamic Nutrients and Missing Detritus on Coral Reefs. Bioscience 2018. [DOI: 10.1093/biosci/biy055] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Peter J Mumby
- Marine Spatial Ecology Lab at the School of Biological Sciences and the ARC Centre of Excellence for Coral Reef Science at the University of Queensland, in Australia
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12
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van Woesik R, Cacciapaglia CW. Keeping up with sea-level rise: Carbonate production rates in Palau and Yap, western Pacific Ocean. PLoS One 2018; 13:e0197077. [PMID: 29738545 PMCID: PMC5940225 DOI: 10.1371/journal.pone.0197077] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/25/2018] [Indexed: 11/18/2022] Open
Abstract
Coral reefs protect islands from tropical storm waves and provide goods and services for millions of islanders worldwide. Yet it is unknown how coral reefs in general, and carbonate production in particular, will respond to sea-level rise and thermal stress associated with climate change. This study compared the reef-building capacity of different shallow-water habitats at twenty-four sites on each of two islands, Palau and Yap, in the western Pacific Ocean. We were particularly interested in estimating the inverse problem of calculating the value of live coral cover at which net carbonate production becomes negative, and whether that value varied across habitats. Net carbonate production varied among habitats, averaging 10.2 kg CaCO3 m-2 y-1 for outer reefs, 12.7 kg CaCO3 m-2 y-1 for patch reefs, and 7.2 kg CaCO3 m-2 y-1 for inner reefs. The value of live coral cover at which net carbonate production became negative varied across habitats, with highest values on inner reefs. These results suggest that some inner reefs tend to produce less carbonate, and therefore need higher coral cover to produce enough carbonate to keep up with sea-level rise than outer and patch reefs. These results also suggest that inner reefs are more vulnerable to sea-level rise than other habitats, which stresses the need for effective land-use practices as the climate continues to change. Averaging across all reef habitats, the rate of carbonate production was 9.7 kg CaCO3 m-2 y-1, or approximately 7.9 mm y-1 of potential vertical accretion. Such rates of vertical accretion are higher than projected averages of sea-level rise for the representative concentration pathway (RCP) climate-change scenarios 2.6, 4.5, and 6, but lower than for the RCP scenario 8.5.
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Affiliation(s)
- Robert van Woesik
- Department of Biological Sciences, Florida Institute of Technology, West University Blvd., Melbourne, Florida, United States of America
- * E-mail:
| | - Christopher William Cacciapaglia
- Department of Biological Sciences, Florida Institute of Technology, West University Blvd., Melbourne, Florida, United States of America
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13
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Saunders MI, Bode M, Atkinson S, Klein CJ, Metaxas A, Beher J, Beger M, Mills M, Giakoumi S, Tulloch V, Possingham HP. Simple rules can guide whether land- or ocean-based conservation will best benefit marine ecosystems. PLoS Biol 2017; 15:e2001886. [PMID: 28877168 PMCID: PMC5587113 DOI: 10.1371/journal.pbio.2001886] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 07/20/2017] [Indexed: 01/11/2023] Open
Abstract
Coastal marine ecosystems can be managed by actions undertaken both on the land and in the ocean. Quantifying and comparing the costs and benefits of actions in both realms is therefore necessary for efficient management. Here, we quantify the link between terrestrial sediment runoff and a downstream coastal marine ecosystem and contrast the cost-effectiveness of marine- and land-based conservation actions. We use a dynamic land- and sea-scape model to determine whether limited funds should be directed to 1 of 4 alternative conservation actions—protection on land, protection in the ocean, restoration on land, or restoration in the ocean—to maximise the extent of light-dependent marine benthic habitats across decadal timescales. We apply the model to a case study for a seagrass meadow in Australia. We find that marine restoration is the most cost-effective action over decadal timescales in this system, based on a conservative estimate of the rate at which seagrass can expand into a new habitat. The optimal decision will vary in different social–ecological contexts, but some basic information can guide optimal investments to counteract land- and ocean-based stressors: (1) marine restoration should be prioritised if the rates of marine ecosystem decline and expansion are similar and low; (2) marine protection should take precedence if the rate of marine ecosystem decline is high or if the adjacent catchment is relatively intact and has a low rate of vegetation decline; (3) land-based actions are optimal when the ratio of marine ecosystem expansion to decline is greater than 1:1.4, with terrestrial restoration typically the most cost-effective action; and (4) land protection should be prioritised if the catchment is relatively intact but the rate of vegetation decline is high. These rules of thumb illustrate how cost-effective conservation outcomes for connected land–ocean systems can proceed without complex modelling. Many coastal marine ecosystems are threatened by anthropogenic activities, but often, the best way to restore and protect these important ecosystems is unclear. Conventional wisdom suggests that the 2 most effective conservation actions to benefit coastal marine ecosystems are implementation of marine protected areas or, alternatively, reduction of land-based threats. Active marine restoration is typically considered a low-priority option, in part due to high costs and low success rates. But does this conventional wisdom hold up to closer scrutiny? We developed a model to ask: should we restore or protect, on either the land or in the ocean, to maximise the extent of coastal marine ecosystems? We based the model on seagrass meadows and adjacent catchments in Queensland, Australia. Surprisingly, we found that direct, active marine restoration can be the most cost-effective approach to maximising extent of marine ecosystems over longer (decades-long) timescales. There is, however, substantial uncertainty in our understanding of the dynamics of complex linked land–sea ecosystems. Further, geomorphological and ecological conditions vary geographically. Therefore, we also used the model to investigate how uncertainty in key parameters affects decision-making outcomes. Our results can be used to guide investment into coastal marine conservation in the absence of complex, region-specific modelling.
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Affiliation(s)
- Megan I. Saunders
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
- School of Earth and Environmental Sciences, The University of Queensland, St. Lucia, Australia
- The Global Change Institute, The University of Queensland, St. Lucia, Australia
- School of Chemical Engineering, The University of Queensland, St. Lucia, Australia
- * E-mail:
| | - Michael Bode
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia
| | - Scott Atkinson
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
| | - Carissa J. Klein
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
- School of Earth and Environmental Sciences, The University of Queensland, St. Lucia, Australia
| | - Anna Metaxas
- Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jutta Beher
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
| | - Maria Beger
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
- School of Biology, University of Leeds, Leeds, United Kingdom
| | - Morena Mills
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, United Kingdom
| | - Sylvaine Giakoumi
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
- Université Côte d’Azur, CNRS, FRE 3729 ECOMERS, Parc Valrose, Nice, France
| | - Vivitskaia Tulloch
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
| | - Hugh P. Possingham
- Centre for Biodiversity and Conservation Science, The University of Queensland, St. Lucia, Australia
- Australian Research Council (ARC) Centre of Excellence in Environmental Decisions, University of Queensland, St. Lucia, Australia
- The Nature Conservancy, Arlington, Virginia, United States of America
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14
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Friedlander AM, Golbuu Y, Ballesteros E, Caselle JE, Gouezo M, Olsudong D, Sala E. Size, age, and habitat determine effectiveness of Palau's Marine Protected Areas. PLoS One 2017; 12:e0174787. [PMID: 28358910 PMCID: PMC5373616 DOI: 10.1371/journal.pone.0174787] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/15/2017] [Indexed: 11/18/2022] Open
Abstract
Palau has a rich heritage of conservation that has evolved from the traditional moratoria on fishing, or "bul", to more western Marine Protected Areas (MPAs), while still retaining elements of customary management and tenure. In 2003, the Palau Protected Areas Network (PAN) was created to conserve Palau's unique biodiversity and culture, and is the country's mechanism for achieving the goals of the Micronesia Challenge (MC), an initiative to conserve ≥30% of near-shore marine resources within the region by 2020. The PAN comprises a network of numerous MPAs within Palau that vary in age, size, level of management, and habitat, which provide an excellent opportunity to test hypotheses concerning MPA design and function using multiple discreet sampling units. Our sampling design provided a robust space for time comparison to evaluate the relative influence of potential drivers of MPA efficacy. Our results showed that no-take MPAs had, on average, nearly twice the biomass of resource fishes (i.e. those important commercially, culturally, or for subsistence) compared to nearby unprotected areas. Biomass of non-resource fishes showed no differences between no-take areas and areas open to fishing. The most striking difference between no-take MPAs and unprotected areas was the more than 5-fold greater biomass of piscivorous fishes in the MPAs compared to fished areas. The most important determinates of no-take MPA success in conserving resource fish biomass were MPA size and years of protection. Habitat and distance from shore had little effect on resource fish biomass. The extensive network of MPAs in Palau likely provides important conservation and tourism benefits to the Republic, and may also provide fisheries benefits by protecting spawning aggregation sites, and potentially through adult spillover.
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Affiliation(s)
- Alan M. Friedlander
- Pristine Seas, National Geographic Society, Washington, DC, United States of America
- Fisheries Ecology Research Laboratory, University of Hawaii, Honolulu, Hawaii, United States of America
- * E-mail:
| | | | | | - Jennifer E. Caselle
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, California, United States of America
| | | | | | - Enric Sala
- Pristine Seas, National Geographic Society, Washington, DC, United States of America
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15
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Bejarano S, Jouffray J, Chollett I, Allen R, Roff G, Marshell A, Steneck R, Ferse SCA, Mumby PJ. The shape of success in a turbulent world: wave exposure filtering of coral reef herbivory. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12828] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sonia Bejarano
- Department of Ecology Leibniz Centre for Tropical Marine Research (ZMT) Fahrenheitstraße 6 28359 Bremen Germany
| | - Jean‐Baptiste Jouffray
- Global Economic Dynamics and the Biosphere Academy Programme Royal Swedish Academy of Sciences PO Box 50005 Stockholm104 05 Sweden
- Stockholm Resilience Centre Stockholm University Stockholm106 91 Sweden
| | - Iliana Chollett
- Smithsonian Marine Station Smithsonian Institution Fort Pierce FL34949 USA
| | - Robert Allen
- Department of Life Sciences Silwood Park Imperial College London Ascot UK
| | - George Roff
- Marine Spatial Ecology Lab School of Biological Sciences & ARC Centre of Excellence for Coral Reef Studies The University of Queensland St. Lucia Qld4072 Australia
| | - Alyssa Marshell
- Marine Spatial Ecology Lab School of Biological Sciences & ARC Centre of Excellence for Coral Reef Studies The University of Queensland St. Lucia Qld4072 Australia
- Department of Marine Science and Fisheries College of Agricultural and Marine Sciences Sultan Qaboos University PO Box 34 Al Khoud 123 Muscat Oman
| | - Robert Steneck
- School of Marine Sciences University of Maine Darling Marine Center Walpole ME04573 USA
| | - Sebastian C. A. Ferse
- Department of Ecology Leibniz Centre for Tropical Marine Research (ZMT) Fahrenheitstraße 6 28359 Bremen Germany
- Department of Geography University of Hawaii Mānoa 2424 Maile Way Honolulu HI96822 USA
| | - Peter J. Mumby
- Marine Spatial Ecology Lab School of Biological Sciences & ARC Centre of Excellence for Coral Reef Studies The University of Queensland St. Lucia Qld4072 Australia
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16
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Neves LM, Teixeira-Neves TP, Pereira-Filho GH, Araújo FG. The Farther the Better: Effects of Multiple Environmental Variables on Reef Fish Assemblages along a Distance Gradient from River Influences. PLoS One 2016; 11:e0166679. [PMID: 27907017 PMCID: PMC5131968 DOI: 10.1371/journal.pone.0166679] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 11/02/2016] [Indexed: 11/25/2022] Open
Abstract
The conservation and management of site-attached assemblages of coastal reefs are particularly challenging because of the tremendous environmental variation that exists at small spatial scales. In this sense, understanding the primary sources of variation in spatial patterns of the biota is fundamental for designing effective conservation policies. We investigated spatial variation in fish assemblages around the windward and leeward sides of coastal islands situated across a gradient of riverine influence (13 km in length). Specifically, relationships between rocky reef fish assemblages and benthic, topographic and physical predictors were assessed. We hypothesized that river induced disturbances may overcome local habitat features in modeling spatial patterns of fish distribution. Fish assemblages varied primarily due to the strong directional gradient of riverine influence (22.6% of the estimated components of variation), followed by topographic complexity (15%), wave exposure (9.9%), and benthic cover (8%). The trophic structure of fish assemblages changed from having a high abundance of invertebrate feeders in macroalgae-dominated reefs close to river mouths to a high proportion of herbivores, planktivores and invertebrate feeder species in reefs with large boulders covered by epilithic algal matrices, as the distance from rivers increased. This gradient led to an increase of 4.5-fold in fish richness and fish trophic group diversity, 11-fold in fish biomass and 10-fold in fish abundance. Our results have implications for the conservation and monitoring of assemblages patchily distributed at small spatial scales. The major role of distance from river influences on fish assemblages rather than benthic cover and topographic complexity suggest that managing land-based activities should be a conservation priority toward reef restoration.
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Affiliation(s)
- Leonardo M. Neves
- Laboratório de Ecologia de Peixes, Departamento de Biologia Animal, Universidade Federal Rural do Rio de Janeiro, Campus Seropédica, RJ, Brazil
- Departamento de Ciências do Meio Ambiente, Universidade Federal Rural do Rio de Janeiro, Campus Três Rios, RJ, Brazil
| | - Tatiana P. Teixeira-Neves
- Laboratório de Ecologia de Peixes, Departamento de Biologia Animal, Universidade Federal Rural do Rio de Janeiro, Campus Seropédica, RJ, Brazil
| | - Guilherme H. Pereira-Filho
- Laboratório de Ecologia e Conservação Marinha, Instituto do Mar, Universidade Federal de São Paulo, Campus Baixada Santista, Santos, SP, Brazil
| | - Francisco G. Araújo
- Laboratório de Ecologia de Peixes, Departamento de Biologia Animal, Universidade Federal Rural do Rio de Janeiro, Campus Seropédica, RJ, Brazil
- * E-mail:
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17
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Duprey NN, Yasuhara M, Baker DM. Reefs of tomorrow: eutrophication reduces coral biodiversity in an urbanized seascape. GLOBAL CHANGE BIOLOGY 2016; 22:3550-3565. [PMID: 27414018 DOI: 10.1111/gcb.13432] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/18/2016] [Accepted: 06/23/2016] [Indexed: 06/06/2023]
Abstract
Although the impacts of nutrient pollution on coral reefs are well known, surprisingly, no statistical relationships have ever been established between water quality parameters, coral biodiversity and coral cover. Hong Kong provides a unique opportunity to assess this relationship. Here, coastal waters have been monitored monthly since 1986, at 76 stations, providing a highly spatially resolved water quality dataset including 68 903 data points. Moreover, a robust coral species richness (S) dataset is available from more than 100 surveyed locations, composed of 3453 individual colonies' observations, as well as a coral cover (CC) dataset including 85 sites. This wealth of data provides a unique opportunity to test the hypothesis that water quality, and in particular nutrients, drives coral biodiversity. The influence of water quality on S and CC was analyzed using GIS and multiple regression modeling. Eutrophication (as chlorophyll-a concentration; CHLA) was negatively correlated with S and CC, whereas physicochemical parameters (DO and salinity) had no significant effect. The modeling further illustrated that particulate suspended matter, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) had a negative effect on S and on CC; however, the effect of nutrients was 1.5-fold to twofold greater. The highest S and CC occurred where CHLA <2 μg L-1 , DIN < 2 μm and DIP < 0.1 μm. Where these values were exceeded, S and CC were significantly lower and no live corals were observed where CHLA > 15 μg L-1 , DIN > 9 μm and DIP > 0.33 μm. This study demonstrates the importance of nutrients over other water quality parameters in coral biodiversity loss and highlights the key role of eutrophication in shaping coastal coral reef ecosystems. This work also provides ecological thresholds that may be useful for water quality guidelines and nutrient mitigation policies.
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Affiliation(s)
- Nicolas N Duprey
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong SAR, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape D'Aguilar Road, Shek O, Hong Kong SAR, China
| | - Moriaki Yasuhara
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong SAR, China
- Swire Institute of Marine Science, The University of Hong Kong, Cape D'Aguilar Road, Shek O, Hong Kong SAR, China
- Department of Earth Sciences, The University of Hong Kong, James Lee Building, Pokfulam Road, Hong Kong SAR, China
| | - David M Baker
- School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong SAR, China.
- Swire Institute of Marine Science, The University of Hong Kong, Cape D'Aguilar Road, Shek O, Hong Kong SAR, China.
- Department of Earth Sciences, The University of Hong Kong, James Lee Building, Pokfulam Road, Hong Kong SAR, China.
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18
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Haywood MDE, Dennis D, Thomson DP, Pillans RD. Mine waste disposal leads to lower coral cover, reduced species richness and a predominance of simple coral growth forms on a fringing coral reef in Papua New Guinea. MARINE ENVIRONMENTAL RESEARCH 2016; 115:36-48. [PMID: 26874890 DOI: 10.1016/j.marenvres.2016.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/01/2016] [Accepted: 02/03/2016] [Indexed: 06/05/2023]
Abstract
A large gold mine has been operating at the Lihir Island Group, Papua New Guinea since 1997. The mine disposes of waste rock in nearshore waters, impacting nearby coral communities. During 2010, 2012 we conducted photographic surveys at 73 sites within 40 km of the mine to document impacts of mining operations on the hard coral communities. Coral communities close to the mine (∼2 km to the north and south of the mine) were depaurperate, but surprisingly, coral cover and community composition beyond this range appeared to be relatively similar, suggesting that the mine impacts were limited spatially. In particular, we found mining operations have resulted in a significant decrease in coral cover (4.4% 1.48 km from the disposal site c.f. 66.9% 10.36 km from the disposal site), decreased species richness and a predominance of less complex growth forms within ∼2 km to the north and south of the mine waste disposal site. In contrast to the two 'snapshot' surveys of corals performed in 2010 and 2012, long term data (1999-2012) based on visual estimates of coral cover suggested that impacts on coral communities may have been more extensive than this. With global pressures on the world's coral reefs increasing, it is vital that local, direct anthropogenic pressures are reduced, in order to help offset the impacts of climate change, disease and predation.
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Affiliation(s)
- M D E Haywood
- CSIRO Oceans and Atmosphere, Queensland Biosciences Precinct, 306 Carmody Rd., St. Lucia, Queensland 4067, Australia.
| | - D Dennis
- CSIRO Oceans and Atmosphere, Queensland Biosciences Precinct, 306 Carmody Rd., St. Lucia, Queensland 4067, Australia
| | - D P Thomson
- CSIRO Oceans and Atmosphere, 147 Underwood Ave, Floreat, Western Australia 6014, Australia
| | - R D Pillans
- CSIRO Oceans and Atmosphere, Queensland Biosciences Precinct, 306 Carmody Rd., St. Lucia, Queensland 4067, Australia
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19
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Shaaban AM, Tim RM, Brian EH, Isabelle MC, Lance L. Growth and corallite characteristics of Kenyan scleractinian corals under the influence of sediment discharge. ACTA ACUST UNITED AC 2015. [DOI: 10.5897/ijbc2015.0814] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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20
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Cabaitan PC, Yap HT, Gomez ED. Performance of single versus mixed coral species for transplantation to restore degraded reefs. Restor Ecol 2015. [DOI: 10.1111/rec.12205] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Patrick C. Cabaitan
- The Marine Science Institute; University of the Philippines; Diliman Quezon City 1101 Philippines
- Present address: Tropical Marine Science Institute; National University of Singapore; 18 Kent Ridge Road Singapore 119227 Singapore
| | - Helen T. Yap
- The Marine Science Institute; University of the Philippines; Diliman Quezon City 1101 Philippines
| | - Edgardo D. Gomez
- The Marine Science Institute; University of the Philippines; Diliman Quezon City 1101 Philippines
- Global Change Institute; The University of Queensland; St. Lucia Queensland 4072 Australia
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21
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Bartley R, Bainbridge ZT, Lewis SE, Kroon FJ, Wilkinson SN, Brodie JE, Silburn DM. Relating sediment impacts on coral reefs to watershed sources, processes and management: a review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 468-469:1138-1153. [PMID: 24121565 DOI: 10.1016/j.scitotenv.2013.09.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 08/06/2013] [Accepted: 09/09/2013] [Indexed: 06/02/2023]
Abstract
Modification of terrestrial sediment fluxes can result in increased sedimentation and turbidity in receiving waters, with detrimental impacts on coral reef ecosystems. Preventing anthropogenic sediment reaching coral reefs requires a better understanding of the specific characteristics, sources and processes generating the anthropogenic sediment, so that effective watershed management strategies can be implemented. Here, we review and synthesise research on measured runoff, sediment erosion and sediment delivery from watersheds to near-shore marine areas, with a strong focus on the Burdekin watershed in the Great Barrier Reef region, Australia. We first investigate the characteristics of sediment that pose the greatest risk to coral reef ecosystems. Next we track this sediment back from the marine system into the watershed to determine the storage zones, source areas and processes responsible for sediment generation and run-off. The review determined that only a small proportion of the sediment that has been eroded from the watershed makes it to the mid and outer reefs. The sediment transported >1 km offshore is generally the clay to fine silt (<4-16 μm) fraction, yet there is considerable potential for other terrestrially derived sediment fractions (<63 μm) to be stored in the near-shore zone and remobilised during wind and tide driven re-suspension. The specific source of the fine clay sediments is still under investigation; however, the Bowen, Upper Burdekin and Lower Burdekin sub-watersheds appear to be the dominant source of the clay and fine silt fractions. Sub-surface erosion is the dominant process responsible for the fine sediment exported from these watersheds in recent times, although further work on the particle size of this material is required. Maintaining average minimum ground cover >75% will likely be required to reduce runoff and prevent sub-soil erosion; however, it is not known whether ground cover management alone will reduce sediment supply to ecologically acceptable levels.
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22
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Scott A, Harrison PL, Brooks LO. Reduced salinity decreases the fertilization success and larval survival of two scleractinian coral species. MARINE ENVIRONMENTAL RESEARCH 2013; 92:10-14. [PMID: 24008005 DOI: 10.1016/j.marenvres.2013.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 07/30/2013] [Accepted: 08/02/2013] [Indexed: 06/02/2023]
Abstract
Successful reproduction by scleractinian corals is essential for the maintenance of populations that form the foundation of coral reef ecosystems. Laboratory experiments were done to determine the effects of reduced salinity on the fertilization success and larval survival of two coral species, Platygyra daedalea and Acropora millepora, from the Great Barrier Reef, Australia. Fertilization rates of P. daedalea and A. millepora were significantly reduced at 25.8 psu and 33.1 psu, respectively, and completed blocked at 18.4 psu for A. millepora. The estimated larval survival times were similar from 36.8 to 25.8 psu (P. daedalea 291-312 h, A. millepora 207-264 h), whereas the 18.4 psu treatment resulted in estimates of 153 h and 24 h for P. daedalea and A. millepora, respectively. These results demonstrate that reduced salinity is detrimental to the reproductive success of these corals, and if salinity is lowered by natural or anthropogenic sources during spawning, this would lead to decreased reproductive success and recruitment on reefs.
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Affiliation(s)
- Anna Scott
- National Marine Science Centre, School of Environment, Science and Engineering, Southern Cross University, PO Box 4321, Coffs Harbour, New South Wales 2450, Australia; Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, PO Box 157, Lismore, New South Wales 2480, Australia.
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23
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Houk P, Golbuu Y, Gorong B, Gorong T, Fillmed C. Watershed discharge patterns, secondary consumer abundances, and seagrass habitat condition in Yap, Micronesia. MARINE POLLUTION BULLETIN 2013; 71:209-215. [PMID: 23602259 DOI: 10.1016/j.marpolbul.2013.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 03/20/2013] [Accepted: 03/24/2013] [Indexed: 06/02/2023]
Abstract
Watershed discharge, water quality, and seagrass assemblages were examined along the western coast of Yap Proper, Micronesia. Submarine groundwater discharge (SGD) during low tides associated with new and full moons contributed disproportionally to freshwater delivery where compromised Thalassia habitats existed. Despite SGD influence, nutrient sampling indicated that one characteristic regime may be a net import of new nitrogen and phosphorous (NO3 and PO4) from offshore to inshore waters, agreeing with sparse watershed development. Biologically recycled nitrogen (NH4), however, was highest where SGD contribution was largest. Time-and-tide-limited sampling likely precluded generalized relationships between SGD and NH4 across the entire study area, however, spatial profiling of SGD during low-tide events (i.e., a proxy to nutrient input) was strongly associated with seagrass habitat condition (defined within). Concomitantly, sea cucumber densities were over a magnitude of order lower than in regionally comparable Thalassia habitats, and negatively correlated with seagrass condition. Both top-down and bottom-up considerations are discussed.
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Affiliation(s)
- Peter Houk
- University of Guam Marine Laboratory, Mangilao, GU.
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Golbuu Y, Wolanski E, Idechong JW, Victor S, Isechal AL, Oldiais NW, Idip D, Richmond RH, van Woesik R. Predicting coral recruitment in Palau's complex reef archipelago. PLoS One 2012; 7:e50998. [PMID: 23209842 PMCID: PMC3509094 DOI: 10.1371/journal.pone.0050998] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 10/30/2012] [Indexed: 11/24/2022] Open
Abstract
Reproduction and recruitment are key processes that replenish marine populations. Here we use the Palau archipelago, in the western Pacific Ocean, as a case study to examine scales of connectivity and to determine whether an oceanographic model, incorporating the complex reef architecture, is a useful predictor of coral recruitment. We tested the hypothesis that the reefs with the highest retention also had the highest densities of juvenile coral density from 80 field sites. Field comparisons showed a significant correlation between the densities of juvenile Acropora colonies and total larval recruitment derived from the model (i.e., calculated as the sum of the densities of larvae that self-seeded and recruited from the other reefs in the archipelago). Long-distance larval imports may be too infrequent to sustain coral populations, but are critical for recovery in times of extreme local stress.
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Woesik R, Houk P, Isechal AL, Idechong JW, Victor S, Golbuu Y. Climate-change refugia in the sheltered bays of Palau: analogs of future reefs. Ecol Evol 2012; 2:2474-84. [PMID: 23145333 PMCID: PMC3492774 DOI: 10.1002/ece3.363] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 07/23/2012] [Accepted: 07/26/2012] [Indexed: 11/11/2022] Open
Abstract
Coral bleaching and mortality are predicted to increase as climate change-induced thermal-stress events become more frequent. Although many studies document coral bleaching and mortality patterns, few studies have examined deviations from the expected positive relationships among thermal stress, coral bleaching, and coral mortality. This study examined the response of >30,000 coral colonies at 80 sites in Palau, during a regional thermal-stress event in 2010. We sought to determine the spatial and taxonomic nature of bleaching and examine whether any habitats were comparatively resistant to thermal stress. Bleaching was most severe in the northwestern lagoon, in accordance with satellite-derived maximum temperatures and anomalous temperatures above the long-term averages. Pocillopora populations suffered the most extensive bleaching and the highest mortality. However, in the bays where temperatures were higher than elsewhere, bleaching and mortality were low. The coral-community composition, constant exposure to high temperatures, and high vertical attenuation of light caused by naturally high suspended particulate matter buffered the corals in bays from the 2010 regional thermal-stress event. Yet, nearshore reefs are also most vulnerable to land-use change. Therefore, nearshore reefs should be given high conservation status because they provide refugia for coral populations as the oceans continue to warm.
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Affiliation(s)
- Robert Woesik
- Department of Biological Sciences, Florida Institute of Technology 150 West University Drive, Melbourne, Florida, 32901
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