Coral reefs are among the most biodiverse ecosystems on Earth in large part owing to their unique three-dimensional (3D) structure, which provides niches for a variety of species. Metrics of structural complexity have been shown to correlate with the abundance and diversity of fish and other marine organisms, but they are imperfect representations of a surface that can oversimplify key structural elements and bias discoveries. Moreover, they require researchers to make relatively uninformed guesses about the features and spatial scales relevant to species of interest. This paper introduces a machine-learning method for automating inferences about fish abundance from reef 3D models. It demonstrates the capacity of a convolutional neural network (ConvNet) to learn ecological patterns that are extremely subtle, if not invisible, to the human eye. It is the first time in the literature that no a priori assumptions are made about the bathymetry–fish relationship.
Mass coral bleaching events during the last 20 years have caused major concern over the future of coral reefs worldwide. Despite damage to key ecosystem engineers, little is known about bleaching frequency prior to 1979 when regular modern systematic scientific observations began on the Great Barrier Reef (GBR). To understand the longer-term relevance of current bleaching trajectories, the likelihood of future coral acclimatization and adaptation, and thus persistence of corals, records, and drivers of natural pre-industrial bleaching frequency and prevalence are needed. Here, we use linear extensions from 44 overlapping GBR coral cores to extend the observational bleaching record by reconstructing temperature-induced bleaching patterns over 381 years spanning 1620–2001. Porites spp. corals exhibited variable bleaching patterns with bleaching frequency (number of bleaching years per decade) increasing (1620–1753), decreasing (1754–1820), and increasing (1821–2001) again. Bleaching prevalence (the proportion of cores exhibiting bleaching) fell (1670–1774) before increasing by 10% since the late 1790s concurrent with positive temperature anomalies, placing recently observed increases in GBR coral bleaching into a wider context. Spatial inconsistency along with historically diverging patterns of bleaching frequency and prevalence provide queries over the capacity for holobiont (the coral host, the symbiotic microalgae and associated microorganisms) acclimatization and adaptation via bleaching, but reconstructed increases in bleaching frequency and prevalence, may suggest coral populations are reaching an upper bleaching threshold, a “tipping point” beyond which coral survival is uncertain.
The Marine Protected Area Governance (MPAG) framework can be used to analyse MPA governance by moving away from conceptual discussions to focus on particular governance approaches leading to effectiveness. The framework was applied to the Lyme Bay MPA, southwest England, the site of a controversial fisheries closure, which has subsequently been proposed as a Special Area of Conservation (SAC), as well the location for an NGO-led project focusing on stakeholder engagement. This paper examines a broad range of perspectives on the governance of this MPA, via semi-structured interviews with representatives of different interest groups and document analyses. The MPAG framework found a governance structure with a diversity of incentives, providing for bottom-up stakeholder engagement and awareness-raising coupled with strong top-down legislative structures. Although the fisheries closure and subsequent SAC restrictions have provided the main mechanisms for protecting biodiversity, an NGO-led project has provided a complement to the legislative framework and helped to facilitate a mechanism for adaptive co-management. However, the site is predicted to be subject to external pressures from changes in legislation, state resource restrictions and reduced NGO involvement, which will test the resilience of the structure and whether such a diversity of incentives provides sufficient resilience to maintain MPA effectiveness in the face of these pressures.
Species morpho-functional traits provide general and predictable rules to understand the dynamics of ecological communities; therefore, considering species identity is crucial in understanding ecosystem functioning. Here, we propose a framework to estimate the species-specific functional contribution of Caribbean corals according to their capacity to create complex three-dimensional structures by means of calcium carbonate precipitation and their morphological complexity. We use a combination of field data and bibliographic information to integrate a Reef Functional Index (RFI) that considers the calcification rate, structural complexity and abundance (cover) of each coral species. As an example application of this tool, we evaluated various sites along the Mesoamerican Reef showing that the RFI can be used to compare reef sites or communities. The construction capacities of Caribbean coral species are highly variable, thus, different species configurations of a coral community result in a high level of functional variation. Most coral assemblages on the Mesoamerican Reef show non-framework species dominance (e.g. Undaria spp. and Poritesastreoides), compromising reef functioning. However, sites with key reef-building species present showed considerably greater functioning despite those species not being dominant. The functional approximation for coral species proposed can be used by future studies considering changes in coral community composition, keystone species loss or to estimate reef function loss due to climate change or other stressors.
Seals are killed in a number of European countries and regions for commercial, management and recreational reasons. This is the first review to make a comparison across different nations, and it reveals that a variety of methods are employed, including the use of firearms, clubs, netting and harpoons. There is disparity in terms of which firearms and ammunition may be used and what, if any, training is required in killing methods. Seal killing presents serious animal welfare challenges and this may be exacerbated in some cases by the absence of close seasons, the practice of shooting from moving platforms or when conditions are suboptimal, and the use of nets. The introduction of internationally agreed standards could help ensure that welfare is paramount in seal management, legislation and practice. If lethal control measures are to continue, then good practice should include the annual training and assessment of hunters, the implementation and enforcement of relevant legislation, increased effort to improve the efficiency of killing (including the assessment of this through the expert and independent examination of carcasses), and minimising conflict by locating fish farms away from core seal habitat.
The marine, intertidal zone is the optimal environment for eelgrass (Zostera spp.) and bivalve aquaculture. Eelgrass is a valuable and protected nearshore habitat. It is important to understand how bivalve aquaculture interacts with eelgrass to support the sustainable development of this globally expanding industry. This study provides a comprehensive understanding of the positive and negative effects of bivalve aquaculture on eelgrass by conducting the first quantitative, global meta-analysis of aquaculture-eelgrass studies. A literature review resulted in 125 studies that met established criteria for inclusion in this analysis. The meta-analysis determined: (1) how eelgrass responds to on-bottom and off-bottom bivalve aquaculture, (2) how these responses vary between regions and specific grow-out methods, and (3) the resilience of eelgrass after harvesting disturbances. On-bottom culture (laying directly on the sediment potentially including predator exclusion devices) corresponded to significant increases in eelgrass growth and reproduction, and a decrease in density and biomass. Off-bottom culture (e.g., longline and suspended bag) resulted in significant decreases in eelgrass density, percent cover, and reproduction. Results support a space-competition hypothesis for on-bottom culture and provide limited support for light limitation in off-bottom culture, although other mechanisms of interaction are potentially occurring as well. A US west coast case study revealed regional differences in eelgrass responses, including a more negative trend in eelgrass density from off-bottom culture, and a neutral effect on reproduction from on-bottom culture (relative to neutral and positive trend, respectively, in the average of all other studies). Eelgrass densities recovered after all harvest methods, however mechanical harvest methods created greater initial impact and longer recovery times than manual harvest methods. The time-period over which observations were reported was an important variable that was not included in the analysis but could influence these results. These analyses suggest the response of eelgrass to bivalve aquaculture varies depending on eelgrass characteristics, grow-out approaches, and harvesting methods, with potential regionally specific relationships. Questions remain, regarding how this dynamic relationship between eelgrass and aquaculture habitat relate to ecological functions and services in the nearshore environment.
Vessel-generated underwater noise can affect humpback whales, harbor seals, and other marine mammals by decreasing the distance over which they can communicate and detect predators and prey. Emerging analytical methods allow marine protected area managers to use biologically relevant metrics to assess vessel noise in the dominant frequency bands used by each species. Glacier Bay National Park (GBNP) in Alaska controls summer visitation with daily quotas for vessels ranging from cruise ships to yachts and skiffs. Using empirical data (weather, AIS vessel tracks, marine mammal survey data, and published behavioral parameters) we simulated the movements and acoustic environment of whales and seals on 3 days with differing amounts of vessel traffic and natural ambient noise. We modeled communication space (CS) to compare the area over which a vocalizing humpback whale or harbor seal could communicate with conspecifics in the current ambient noise environment (at 10-min intervals) relative to how far it could communicate under naturally quiet conditions, known as the reference ambient noise condition (RA). RA was approximated from the quietest 5th percentile noise statistics based on a year (2011) of continuous audio data from a hydrophone in GBNP, in the frequency bands of whale and seal sounds of interest: humpback “whup” calls (50–700 Hz, 143 dB re 1 μPa source level, SL); humpback song (224–708 Hz, 175 dB SL), and harbor seal roars (4–500 Hz, 144 dB SL). Results indicate that typical summer vessel traffic in GBNP causes substantial CS losses to singing whales (reduced by 13–28%), calling whales (18–51%), and roaring seals (32–61%), especially during daylight hours and even in the absence of cruise ships. Synchronizing the arrival and departure timing of cruise ships did not affect CS for singing whales, but restored 5–12% of lost CS for roaring seals and calling whales, respectively. Metrics and visualizations like these create a common currency to describe and explore methods to assess and mitigate anthropogenic noise. Important next steps toward facilitating effective conservation of the underwater sound environments will involve putting modeling tools in the hands of marine protected area managers for ongoing use.
Effectively translating scientific knowledge into policy and practice is essential for helping humanity navigate contemporary environmental challenges. The likelihood of achieving this can be increased through the study of bright spots—instances where science has successfully influenced policy and practice—and the sense of optimism that this can inspire.
Economic information is critical for explaining why recreational fishing and marine stewardship is important to all citizens of a nation. Successfully raising public awareness of the importance of healthy and abundant marine fisheries is dependent on having reliable economic insights. These types of data can be used to inform discussions about how to institute better conservation policies, secure new partners and resources for conservation initiatives, and ultimately boost the long-term health and productivity of marine fisheries. Until now, the economic contribution of recreational marine fishing in New Zealand has not been measured, placing recreational fishing interests at a disadvantage compared to the commercial sector that has such information in various forms. This project filled that vacuum. Beginning with the $946 million spent annually by more than 600,000 resident and visiting New Zealand fishers, these dollars circulate through the national economy, supporting 8000 jobs, stimulating $1.7 billion in total economic activity, contributing $638 million in Gross Domestic Product and $342 million in salaries, wages and small business profits while adding nearly $187 million in tax revenues. This study was built using data collection and analytical approaches available for use by other nations to increase public awareness of the critical economic importance of their marine fisheries.
Coastal nations have embarked on a rapid program of marine protected area (MPA) establishment, incentivised by the approaching 2020 deadline of United Nations global marine protection targets. Alongside, efforts are underway to extend protection into areas beyond national jurisdiction through a new international legally binding instrument. These developments are welcome but there are risks that in meeting them, nations will still fail to supply adequate protection to marine life. An increasing number of MPAs protect the seabed while the water column remains open to fishing. This is because vulnerable habitats in need of protection are disproportionately perceived to be those on the seabed, while the water column is viewed as much less at risk. The seabed and water column are, however, inextricably linked. Transitions between human-defined vertical ocean zones are blurred, with animals and oceanographic features moving across depths. Here, we explore a rapidly growing literature on ecological and environmental connections through the water column, and between the water column and the seabed, to consider whether vertically stratified management is justified from an ecological standpoint. We find that emerging research increasingly links upper-ocean communities and processes to seabed ecology and biogeochemistry suggesting that exploitation of the water column is likely to have a significant and widely distributed footprint in the deep-sea. We conclude that there is a strong a priori case for surface to seabed protection within MPAs, and that this should be the default, precautionary approach to safeguard intact ecosystems with as near to natural function as possible.
Acoustic deterrent devices (ADDs) are used in attempts to mitigate pinniped depredation on aquaculture sites through the emission of loud and pervasive noise. This study quantified spatio-temporal changes in underwater ADD noise detections along western Scotland over 11 years. Acoustic point data (‘listening events’) collected during cetacean line-transect surveys were used to map ADD presence between 2006 and 2016. A total of 19,601 listening events occurred along the Scottish west coast, and ADD presence was recorded during 1371 listening events. Results indicated a steady increase in ADD detections from 2006 (0.05%) to 2016 (6.8%), with the highest number of detections in 2013 (12.6%), as well as substantial geographic expansion. This study demonstrates that ADDs are a significant and chronic source of underwater noise on the Scottish west coast with potential adverse impacts on target (pinniped) and non-target (e.g. cetaceans) species, which requires further study and improved monitoring and regulatory strategies.
Reef ecosystems are amply distributed and ecologically relevant in Mexico, however, there is not an integrated inventory of these ecosystems, and information about uses and pressures is disperse. With the aim of generating updated information that allows to know the presence and distribution of the different types of reefs (coral, rocky-coral, rocky, and rocky with Macrocystis pyrifera), as well as to know the uses and pressures to which they are subjected. In this article we present an inventory of the 755 reef ecosystems known in Mexico based in a literature review of 194 documents and validated by informal interviews to key Mexican experts. Mexican reefs are distributed in seven regions identified for reef management purposes, according to the combination of eight maritime regionalization proposals of the Mexican seas. The main uses of reef ecosystems are fishing, tourism, nautical, and mining, which produce eight main pressures: pollution, habitat fragmentation, coral bleaching, overfishing, exotic species introduction, sedimentation, coral mortality, and coral diseases. These uses and pressures are distributed heterogeneously in the seven reef regions. The main conservation tool used by Mexican Federal Government to protect these reefs are the Marine Protected Areas (MPAs). Almost 45% of the listed reefs are within one of the 30 Mexican MPAs, being the coral reefs the ones that predominate in this protection scheme. In this research we present relevant information for the management of the reef ecosystems of Mexico, which support the debate on the analysis of public policies for their conservation.
The release of classified documents in the past years have offered a rare glimpse into the opaque world of tax havens and their role in the global economy. Although the political, economic and social implications related to these financial secrecy jurisdictions are known, their role in supporting economic activities with potentially detrimental environmental consequences have until now been largely ignored. Here, we combine quantitative analysis with case descriptions to elaborate and quantify the connections between tax havens and the environment, both in global fisheries and the Brazilian Amazon. We show that while only 4% of all registered fishing vessels are currently flagged in a tax haven, 70% of the known vessels implicated in illegal, unreported and unregulated fishing are, or have been, flagged under a tax haven jurisdiction. We also find that between October 2000 and August 2011, 68% of all investigated foreign capital to nine focal companies in the soy and beef sectors in the Brazilian Amazon was transferred through one, or several, known tax havens. This represents as much as 90–100% of foreign capital for some companies investigated. We highlight key research challenges for the academic community that emerge from our findings and present a set of proposed actions for policy that would put tax havens on the global sustainability agenda.
The courts have played a central role in climate policy, including the landmark Supreme Court case that led to the mandatory regulation of greenhouse gases by the United States. A wide variety of litigants have used the courts to affect policy outcomes at all scales. Therefore, to understand how the court addresses climate change is critical. Here we constructed and analysed a database of all the United State domestic climate lawsuits 1990–2016 (873), and collected qualitative data in the form of 78 in-depth interviews with litigants, involved scientists and advocates. We find proregulation litigants tend to win renewable energy and energy efficiency cases, and more frequently lose coal-fired power plant cases. Strategies such as the use of climate science and other science as well as collaboration in specific types of coalitions affect the outcomes of cases. Efforts to affect climate policy should consider these trends and outcomes.
Because mangroves store greater amounts of carbon (C) per area than any other terrestrial ecosystem, conservation of mangrove forests on a global scale represents a potentially meaningful strategy for mitigating atmospheric greenhouse‐gas (GHG) emissions. However, analyses of how coastal ecosystems influence the global C cycle also require the mapping of ecosystem area across the Earth's surface to estimate C storage and flux (movement) in order to compare how different ecosystem types may mitigate GHG enrichment in the atmosphere. In this paper, we propose a new framework based on diverse coastal morphology (that is, different coastal environmental settings resulting from how rivers, tides, waves, and climate have shaped coastal landforms) to explain global variations in mangrove C storage, using soil organic carbon (SOC) as a model to more accurately determine mangrove contributions to global C dynamics. We present, to the best of our knowledge, the first global mangrove area estimate occupying distinct coastal environmental settings, comparing the role of terrigenous and carbonate settings as global “blue carbon” hotspots. C storage in deltaic settings has been overestimated, while SOC stocks in carbonate settings have been underestimated by up to 50%. We encourage the scientific community, which has largely focused on blue carbon estimates, to incorporate coastal environmental settings into their evaluations of C stocks, to obtain more robust estimates of global C stocks.
Blue carbon policy supports carbon sequestration whilst also conserving our remaining seagrass meadows. The complex biogeochemical processes within the sediment of seagrass meadows are responsible for the longevity of the stored carbon. Carbon stock and accumulation rates are controlled by the interaction of hydrodynamic, geochemical and biotic processes unique to each meadow. Carbon content (stock and flux) of a meadow must be quantified for inclusion in carbon accounting, whether for market trading or national greenhouse gas accounting. Management of seagrass blue carbon also requires estimates of additionality, leakage, permanence, conversion and emission factors.
Highly productive coastal wetlands play an essential role in storing blue carbon as one of their ecosystem services, but they are increasingly jeopardized by intensive reclamation activities to facilitate rapid population growth and urbanization. Coastal reclamation causes the destruction and severe degradation of wetland ecosystems, which may affect their abilities to store blue carbon. To assist with international accords on blue carbon, we evaluated the dynamics of blue carbon storage in coastal wetlands under coastal reclamation in China. By integrating carbon density data collected from field measurement experiments and from the literature, an InVEST model, Carbon Storage and Sequestration was used to estimate carbon storage across the reclamation area between 1990 and 2015. The result is the first map capable of informing about blue carbon storage in coastal reclamation areas on a national scale. We found that more than 380,000 hectares of coastal wetlands were affected by reclamation, which resulted in the release of ca. 20.7 Tg of blue carbon. The carbon loss from natural wetlands to artificial wetlands accounted for 72.5% of total carbon loss, which highlights the major task in managing coastal sustainability. In addition, the top 20% of coastal wetlands in carbon storage loss covered 4.2% of the total reclamation area, which can be applied as critical information for coastal redline planning. We conclude that the release of blue carbon due to the conversion of natural wetlands exceeded the total carbon emission from energy consumption within the reclamation area. Implementing the Redline policy could guide the management of coastal areas resulting in greater resiliency regarding carbon emission and sustained ecosystem services.
The human-mediated introduction of marine non-indigenous species is a centuries- if not millennia-old phenomenon, but was only recently acknowledged as a potent driver of change in the sea. We provide a synopsis of key historical milestones for marine bioinvasions, including timelines of (a) discovery and understanding of the invasion process, focusing on transfer mechanisms and outcomes, (b) methodologies used for detection and monitoring, (c) approaches to ecological impacts research, and (d) management and policy responses. Early (until the mid-1900s) marine bioinvasions were given little attention, and in a number of cases actively and routinely facilitated. Beginning in the second half of the 20th century, several conspicuous non-indigenous species outbreaks with strong environmental, economic, and public health impacts raised widespread concerns and initiated shifts in public and scientific perceptions. These high-profile invasions led to policy documents and strategies to reduce the introduction and spread of non-indigenous species, although with significant time lags and limited success and focused on only a subset of transfer mechanisms. Integrated, multi-vector management within an ecosystem-based marine management context is urgently needed to address the complex interactions of natural and human pressures that drive invasions in marine ecosystems.
Seagrasses form one of the most ecologically important and productive three-dimensional habitats in coastal seas. Knowing the global distribution of seagrass meadows is essential for conservation and blue carbon estimates. Here, we modelled the global distribution of seagrass using 43,037 occurrence records and 13 environmental variables within the modelling software MaxEnt at 30 arc sec resolution (c. 1 km at the equator). We found that sea surface temperature and distance from land contributed most in predicting seagrass distribution globally. Comparison of summing models for individual species, genera, and families found that a model combining all species occurrence records best fitted the known geographic distribution. In addition, this model fills geographic gaps in previous maps. We predicted the seagrass biome may occupy 1,646,788 km2, more than double previous global estimates. Applications for this dataset include blue carbon estimates, spatial planning such as for designing Marine Protected Areas, environmental sensitivity mapping, and monitoring of change in biome cover.
There are growing calls for the articulation and consideration of different value systems and emotions in shaping conservation and natural resource management decisions and participatory resource governance. This requires recognition of the socio-cultural relations attached to landscape and seascape in marine conservation policy. Taking into account the relationship between the socio-natural environment and socio-political institutions and processes complicates conservation. Making human values and assumptions explicit within the conservation discourse reveals the inadequacy of conservation that is focused on a biodiversity that is framed only as other-than-human nature. This paper considers how the perceived separation between nature and culture underpinning conservation policy and practice exacerbated a conflict between members of a small Scottish island community and the Scottish Government around the creation of a marine protected area (MPA) off the coast of the island. A rich maritime heritage and a distinctive way of knowing the sea suggested the presence of embedded values that appeared to be colliding with values driving the MPA designation process. Social, historical and cultural forces have shaped the perceptions of landscape and seascape of many of the islanders and can help to explain the local resistance to the MPA. Visual participatory methods were used to explore local understandings of the meaning of conservation. The case-study offers insights into different ways in which marine spaces are conceptualised and how this relates to marine resource governance. It contributes to a more complete understanding of human relations with the marine environment in the context of a marine conservation conflict.