70 research outputs found
Marine Protected Areas: Country Case Studies on Policy, Governance and Institutional Issues
This document presents case studies of the policy, governance and institutional issues of marine protected areas (MPAs) in South America (Northeastern)-Brazil; India, Palau and Senegal. It is the first of four in a global series of case studies on MPAs. An initial volume provides a synthesis and analysis of all the studies. The set of global MPA case studies was designed to close a deficit in information on the governance of MPAs and spatial management tools, within both fisheries management and biodiversity conservation contexts. The studies examine governance opportunities in and constraints on the use of spatial management measures at the national level. They were also designed to inform implementation of the FAO Technical Guidelines on marine protected areas (MPAs) and fisheries, which were developed to provide information and guidance on the use of MPAs in the context of fisheries
Coral macrobioerosion is accelerated by ocean acidification and nutrients
Author Posting. © The Author(s), 2014]. This is the author's version of the work. It is posted here by permission of Geological Society of America for personal use, not for
redistribution. The definitive version was published in Geology 43 (2015): 7-10, doi: 10.1130/G36147.1.Coral reefs exist in a delicate balance between calcium carbonate (CaCO3) production and CaCO3 loss. Ocean acidification (OA), the CO2-driven decline in seawater pH and CaCO3 saturation state (Ω), threatens to tip this balance by decreasing calcification, and increasing erosion and dissolution. While multiple CO2 manipulation experiments show coral calcification declines under OA, the sensitivity of bioerosion to OA is less well understood. Previous work suggests that coral and coral reef bioerosion increase with decreasing seawater Ω. However, in the surface ocean, Ω and nutrient concentrations often covary, making their relative influence difficult to resolve. Here, we exploit unique natural gradients in Ω and nutrients across the Pacific basin to quantify the impact of these factors, together and independently, on macrobioerosion rates of coral skeletons. Using an automated program to quantify macrobioerosion in 3-D computerized tomography (CT) scans of coral cores, we show that macrobioerosion rates of live Porites colonies in both low-nutrient (oligotrophic) and high-nutrient (>1 µM nitrate) waters increase significantly as Ω decreases. However, the sensitivity of macrobioerosion to Ω is ten times greater under high-nutrient conditions. Our results demonstrate that OA (decreased Ω) alone can increase coral macrobioerosion rates, but the interaction of OA with local stressors exacerbates its impact, accelerating a shift toward net CaCO3 removal from coral reefs.This work was supported by NSF OCE 1041106 to A.L.C. and K.E.S., NSF OCE 1220529 to A.L.C., TNC award PNA/WHOI061810 to A.L.C., NSF Graduate Research Fellowships to T.M.D. and H.C.B., and a WHOI-OLI post-doctoral fellowship to K.E.S.2015-11-1
Conservation policies informed by food system feedbacks can avoid unintended consequences
Understanding the feedbacks between food systems and conservation policies can help avoid unintended environmental consequences. Using a survey-based choice experiment and economic modelling, we quantify the potential impact of tourists’ responses to a shift in offshore fish supply after the designation of a large-scale marine protected area in Palau. We find that this conservation policy may increase offshore fish prices and tourists’ consumption of reef fish, thereby further endangering local reef ecosystems. However, if tourists are offered a sustainable offshore choice, their demand for fish could be kept at current levels, and environmental impacts from increased reef fish consumption would be avoided
The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States: 2002
Called for by the U.S. Coral Reef Task Force’s (USCRTF) National Action Plan to Conserve Coral Reefs, this is the first biennial report on the condition of coral reefs. It is the scientific baseline for subsequent reports on the health of U.S. coral reef ecosystems that are to be used by NOAA and others to evaluate the efficacy of coral reef conservation and management practices. The National Oceanic and Atmospheric Administration’s National Ocean Service led the development of this report. It was authored by 38 experts and supported by 79 contributors from government agencies and non-governmental organizations across the nation and internationally. Over 100 Task Force members and other notable scientists have reviewed this document
Addressing Criticisms of Large-Scale Marine Protected Areas
Designated large-scale marine protected areas (LSMPAs, 100,000 or more square kilometers) constitute over two-thirds of the approximately 6.6% of the ocean and approximately 14.5% of the exclusive economic zones within marine protected areas. Although LSMPAs have received support among scientists and conservation bodies for wilderness protection, regional ecological connectivity, and improving resilience to climate change, there are also concerns. We identified 10 common criticisms of LSMPAs along three themes: (1) placement, governance, and management; (2) political expediency; and (3) social–ecological value and cost. Through critical evaluation of scientific evidence, we discuss the value, achievements, challenges, and potential of LSMPAs in these arenas. We conclude that although some criticisms are valid and need addressing, none pertain exclusively to LSMPAs, and many involve challenges ubiquitous in management. We argue that LSMPAs are an important component of a diversified management portfolio that tempers potential losses, hedges against uncertainty, and enhances the probability of achieving sustainably managed oceans
Responses of Palau\u27s coral reefs to disturbances at multiple scales
The coral reefs of Palau are being increasingly exposed to local and global threats. Among these threats, two of the most serious impacts are ocean warming and sedimentation through local land-use change. This thesis examines how Palau’s coral reefs respond to, and recover from, thermal stress and land-use change. The 1998 thermal stress event caused extensive bleaching and coral mortality that reduced mean coral cover from 50-70% to 14-23% on most reefs around Palau. However, the extent of mortality depended on reef types, with nearshore fringing reefs experiencing less mortality from bleaching than patch and exposed barrier reefs. Coral cover increased rapidly after 1998 in the sheltered bays (6.6 % per year), despite a low recruitment rate, suggesting that recovery in bays was primarily a consequence of remnant regrowth. Recruitment densities were consistently high on the wave-exposed reefs, particularly the western slopes. Recovery was initially more rapid at 10 m than at 3 m on outer reefs, but in 2004 recovery rates were similar at both depths and recovery was attributed to both recruitment and regrowth of remnants. Rapid recovery was possible because Palau’s coral reefs were buffered by remnant survival plus recruitment from the less impacted habitats.
The most river-impacted coral reefs of Palau were characterized by high accumulation of mud, low-coral cover and low-coral diversity. River-sediment yield was the best indicator of land-use development. Although reef geomorphology and hydrodynamic regimes affected the flow of sediments onto the reef, the greatest contribution to reef sedimentation was from land development. Coral diversity increased with increasing distance from the heavily impacted watersheds. Yet, total coral cover was not a suitable indicator of river impact. More suitable and sensitive indicators of land-use change were the abundance of Fungiidae, Pavona spp., Acropora spp., Pachyseris spp. and Porites rus, all of which significantly increased in cover with distance from the river.
Coral cover was related to mean suspended solid concentration, while coral richness, and density and recruits richness were related to terrestrial sedimentation. Indeed, the reefs adjacent to land with little development had high coral cover and high coral richness, while reefs adjacent to developed watersheds had low-coral cover and low-coral richness. Reefs were less impacted by sedimentation at sites farther from land, but their condition was also dependent on the presence of consolidated substrate. A transplant study along the watershed gradient showed that Acropora digitifera pigmentation was clearly different among sites, yet survival rates and coral growth did not differ significantly. This is most likely due to their large initial size, which enabled the transplants to ‘escape’ severe sedimentation stress.
While nearshore reefs were less impacted by the 1998 bleaching event, they are the reefs most susceptible to sedimentation stress from land-use change. These results strongly suggest that reducing threats to coral reefs from local land-use change, increases the likelihood of recovery from thermal stress, under an increasingly warming ocean
Oceanographic chaos and its role in larval self-recruitment and connectivity among fish populations in Micronesia
A 30-year time series of the recruitment of rabbit fish, a herbivorous coral reef fish, on the island of Guam in the tropical western Pacific, showed variability that ENSO alone does not explain. To help explain this variability, a high-resolution biophysical model that includes directional swimming reveals how mesoscale turbulence and ENSO-driven changes in the ocean circulation control the self-recruitment of rabbit fish. ENSO drives island wakes that enhance the capacity to retain locally spawned larvae, and mesoscale turbulence generates much variability and promotes seaward dispersion at time scales larger than the Pelagic Larval Duration. The same processes are predicted to occur for the self-recruitment of grouper fish, a carnivorous coral reef fish, in Palau, Micronesia. The models suggests that 99% of these fish larvae are exported seaward from Guam and Palau. Those larvae are the ones that could provide connectivity between reefs and islands in Micronesia. This connectivity for the grouper fish was predicted using an altimetry-driven advection-diffusion oceanography model for 40 mass spawning events spread over 10 years. The mesoscale turbulence, and not the mean oceanographic currents, is the dominant process controlling the connectivity, which is thus chaotic. This finding applies also in the Galapagos archipelago and the Coral Sea fringing the Great Barrier Reef
Trapping of fine sediment in a semi-enclosed bay, Palau, Micronesia
Abstract Airai Bay, Palau, is a small (3 km 2 ), semi-enclosed, mangrove-fringed, meso-tidal, coral lagoon on the southeast coast of Palau. It drains a small catchment area (26 km 2 ) of highly erodible soils in an area with high annual rainfall (3.7 m). River floods are shortlived and the sediment load is very large, with suspended fine sediment concentration exceeding 1500 mg l ÿ1 . The resulting river plume is about 2 m thick. The brackish water residence time is about 7 days; during this period the plume remains a distinct surface feature even after river runoff has ceased. About 98% of the riverine fine sediment settles in Airai Bay, of which about 15-30% is deposited in the mangroves during river floods. This mud remains trapped in Airai Bay because the bay is protected from ocean swells and the tidal currents and locally generated wind waves are too small to resuspend the mud in quantity. The mud is smothering coral reefs, creating a phase shift from coral to fleshy algae dominance, and is even changing habitats by creating mud banks. The persistence of Airai Bay marine resources may not be possible without improved soil erosion control in the river catchment
Trapping of fine sediment in a semi-enclosed bay, Palau, Micronesia
Airai Bay, Palau, is a small (3 km2), semi-enclosed, mangrove-fringed, meso-tidal, coral lagoon on the southeast coast of Palau. It drains a small catchment area (26 km2) of highly erodible soils in an area with high annual rainfall (3.7 m). River floods are short-lived and the sediment load is very large, with suspended fine sediment concentration exceeding 1500 mg l−1. The resulting river plume is about 2 m thick. The brackish water residence time is about 7 days; during this period the plume remains a distinct surface feature even after river runoff has ceased. About 98% of the riverine fine sediment settles in Airai Bay, of which about 15–30% is deposited in the mangroves during river floods. This mud remains trapped in Airai Bay because the bay is protected from ocean swells and the tidal currents and locally generated wind waves are too small to resuspend the mud in quantity. The mud is smothering coral reefs, creating a phase shift from coral to fleshy algae dominance, and is even changing habitats by creating mud banks. The persistence of Airai Bay marine resources may not be possible without improved soil erosion control in the river catchment
- …