While ecological links between ecosystems have been long recognised, management rarely crosses ecosystem boundaries. Coral reefs are susceptible to damage through terrestrial run-off, and failing to account for this within management threatens reef protection. In order to quantify the extent to that coral reef users are willing to support management actions to improve ecosystem quality, we conducted a choice experiment with SCUBA divers on the island of Bonaire, Caribbean Netherlands. Specifically, we estimated their willingness to pay to reduce terrestrial overgrazing as a means to improve reef health. Willingness to pay was estimated using the multinomial, random parameter and latent class logit models. Willingness to pay for improvements to reef quality was positive for the majority of respondents. Estimates from the latent class model determined willingness to pay for reef improvements of between $31.17 - $413.18/year, dependent on class membership. This represents a significant source of funding for terrestrial conservation, and illustrates the potential for user fees to be applied across ecosystem boundaries. We argue that such across-ecosystem-boundary funding mechanisms are an important avenue for future investigation in many connected systems.
Conservation Targets & Planning
The global overexploitation of fish stocks is endangering many marine food webs. Scientists and managers now call for an ecosystem-based fisheries management, able to take into account the complexity of marine ecosystems and the multiple ecosystem services they provide. By contrast, many fishery management plans only focus on maximizing the productivity of harvested stocks. Such practices are suggested to affect other ecosystem services, altering the integrity and resilience of natural communities. Here we show that while yield-maximizing policies can allow for coexistence and resilience in predator-prey communities, they are not optimal in a multi-objective context. We find that although total prey and predator maximum yields are higher with a prey-oriented harvest, focusing on the predator improves species coexistence. Also, moderate harvesting of the predator can enhance resilience. Furthermore, increasing maximum yields by changing catchabilities improves resilience in predator-oriented systems, but reduces it in prey-oriented systems. In a multi-objective context, optimal harvesting strategies involve a general trade-off between yield and resilience. Resilience-maximizing strategies are however compatible with quite high yields, and should often be favored. Our results further suggest that balancing harvest between trophic levels is often best at maintaining simultaneously species coexistence, resilience and yield.
Text mining and analytics may offer possibilities to assess scientists' professional writing and identify patterns of co-occurrence between words and phrases associated with different environmental challenges and their potential solutions. This approach has the potential to help to track emerging issues, semi-automate horizon scanning processes, and identify how different institutions or policy instruments are associated with different types of ocean and coastal sustainability challenges. Here I examine ecologically-oriented ocean and coastal science journal article abstracts published between 2006 and 2015. Informed by the Institutional Analysis and Development (IAD) framework, I constructed a dictionary containing phrases associated with 40 ocean challenges and 15 solution-oriented instrument or investments. From 50,817 potentially relevant abstracts, different patterns of co-occurring text associated with challenges and potential solutions were discernable. Topics receiving significantly increased attention in the literature in 2014–15 relative to the 2006–13 period included: marine plastics and debris; environmental conservation; social impacts; ocean acidification; general terrestrial influences; co-management strategies; ocean warming; licensing and access rights; oil spills; and economic impacts. Articles relating to global environmental change were consistently among the most cited; marine plastics and ecosystem trophic structure were also focal topics among the highly cited articles. This exploratory research suggests that scientists' written outputs provide fertile ground for identifying and tracking important and emerging ocean sustainability issues and their possible solutions, as well as the organizations and scientists who work on them.
Decision-makers focus on representing biodiversity pattern, maintaining connectivity, and strengthening resilience to global warming when designing marine protected area (MPA) systems, especially in coral reef ecosystems. The achievement of these broad conservation objectives will likely require large areas, and stretch limited funds for MPA implementation. We undertook a spatial prioritisation of Brazilian coral reefs that considered two types of conservation zones (i.e. no-take and multiple use areas) and integrated multiple conservation objectives into MPA planning, while assessing the potential impact of different sets of objectives on implementation costs. We devised objectives for biodiversity, connectivity, and resilience to global warming, determined the extent to which existing MPAs achieved them, and designed complementary zoning to achieve all objectives combined in expanded MPA systems. In doing so, we explored interactions between different sets of objectives, determined whether refinements to the existing spatial arrangement of MPAs were necessary, and tested the utility of existing MPAs by comparing their cost effectiveness with an MPA system designed from scratch. We found that MPAs in Brazil protect some aspects of coral reef biodiversity pattern (e.g. threatened fauna and ecosystem types) more effectively than connectivity or resilience to global warming. Expanding the existing MPA system was as cost-effective as designing one from scratch only when multiple objectives were considered and management costs were accounted for. Our approach provides a comprehensive assessment of the benefits of integrating multiple objectives in the initial stages of conservation planning, and yields insights for planners of MPAs tackling multiple objectives in other regions.
Identifying the multifaceted biodiversity hotspots for marine mammals and their spatial overlap with human threats at the global scale.
We compiled a functional trait database for 121 species of marine mammals characterized by 14 functional traits grouped into five categories. We estimated marine mammal species richness (SR) as well as functional (FD) and phylogenetic diversity (PD) per grid cell (1° × 1°) using the FRic index (a measure of trait diversity as the volume of functional space occupied by the species present in an assemblage) and the PD index (the amount of evolutionary history represented by a set of species), respectively. Finally, we assessed the spatial congruence of these three facets of biodiversity hotspots (defined as 2.5% and 5% of the highest values of SR, FD and PD) with human threats at the global scale.
We showed that the FRic index was weakly correlated with both SR and the PD index. Specifically, SR and FRic displayed a triangular relationship, that is, increasing variability in FRic along the species richness gradient. We also observed a striking lack of spatial congruence (<0.1%) between current human threats and the distribution of the multiple facets of biodiversity hotspots.
We highlighted that functional diversity calculated using the FRic index is weakly associated with the species richness of marine mammals world-wide. This is one of the most endangered vertebrate groups playing a key ecological role in marine ecosystems. This finding calls for caution when using only species richness as a benchmark for defining marine mammal biodiversity hotspots. The very low level of spatial congruence between hotspots of current threats and those of the multiple facets of marine mammal biodiversity suggests that current biodiversity patterns for this group have already been greatly affected by their history of exploitation.
Marine reserve placement must account for the importance of places for resource use to minimize negative socioeconomic impacts and improve compliance. It is often assumed that placing marine reserves in locations that minimize lost fishing opportunities will reduce impacts on coastal communities, but the influence of the fishing data used on this outcome remains poorly understood. In the Madang Lagoon (Papua New Guinea), we compared three types of proxies for conservation costs to local fishing communities. We developed two types of proxies of opportunity costs commonly used in marine conservation planning: current fishing activity with fisher surveys (n = 68) and proximity from shore. We also developed proxies based on areas of importance for fishing as perceived by surveyed households (n = 52). Although all proxies led to different configurations of potential marine reserves, the three types of cost data reflect different aspects of importance for fishing and should be used as complementary measures.
Despite being a small part of the world's oceans, the Mediterranean Sea hosts a diverse marine mammal fauna, with a total of 28 different species known to occur, or to have occurred, in the region. Species currently recognised as regular in the Mediterranean—the Mediterranean monk seal (Monachus monachus) and 11 cetaceans (fin whale, Balaenoptera physalus; sperm whale, Physeter macrocephalus; Cuvier's beaked whale, Ziphius cavirostris; short-beaked common dolphin, Delphinus delphis; long-finned pilot whale, Globicephala melas; Risso's dolphin, Grampus griseus; killer whale, Orcinus orca; striped dolphin, Stenella coeruleoalba; rough-toothed dolphin, Steno bredanensis; common bottlenose dolphin, Tursiops truncatus; harbour porpoise, Phocoena phocoena relicta) have adapted well to the region's environmental conditions, but their coexistence with humans is problematic. All the regular species are represented in the Mediterranean by populations genetically distinct from their North Atlantic relatives. Seventeen other species (three pinnipeds and 14 cetaceans) occur or have occurred in the Mediterranean as vagrants from adjacent regions. Impacts on the conservation status of marine mammals in the region deriving from a variety of threats include: (a) mortality caused by deliberate killing (to a large extent resulting from fisheries interactions), naval sonar, ship strikes, epizootics, fisheries bycatch, chemical pollution and ingestion of solid debris; (b) short-term redistribution caused by naval sonar, seismic surveys, vessel disturbance and vessel noise; and (c) long-term redistribution caused by fishery-induced food depletion, coastal development and possibly climate change. Accordingly, seven of the 12 marine mammals regular in the Mediterranean region are listed as Threatened on IUCN's Red List; regrettably, three are Data Deficient and two remain unassessed.
Over the past decades, much research has focused on understanding the critical factors for marine extinctions with the aim of preventing further species losses in the oceans. Although conservation and management strategies are enabling several species and populations to recover, others remain at low abundance levels or experience further declines. To understand these discrepancies, we asked which intrinsic and extrinsic factors are critical for the recovery of marine mammals. Building on a published database on abundance trends of 137 marine mammal populations worldwide, we compiled data on 28 potential critical factors and used random forests and additive mixed models in our analytical approach. Our results highlight that a mix of life-history characteristics, ecological traits, phylogenetic relatedness, population size, geographic range, human impacts and management efforts were important in explaining why populations recover or not. Generally, species with lower age at maturity and intermediate habitat area were more likely to recover, which is consistent with life-history and ecological theory. Body size and ocean basin were also important, as well as trophic level, social interactions, the dominant habitat and habitat disturbance. Overall, our results highlight that not one or two, but a range of intrinsic and extrinsic factors are important for recovery, pointing to cumulative effects. This new line of research provides important information for improving conservation and management strategies particularly for those populations that have been unable to recover to date.
- Causes of non-intentional mortality may pose conservation challenges for long-lived, migratory species. Recovery attempts for Atlantic sturgeon Acipenser oxyrinchus oxyrinchus populations in the USA have mainly involved closures of targeted fishing, but bycatch mortality from fisheries targeting other species remains a significant obstacle. Natural and fishing mortality levels are highly uncertain and difficult to separate, but quantifying spatial and temporal patterns of movements and total mortality can directly inform management policies regarding fishing activity that affects sturgeon.
- Subadult sturgeon were tagged with acoustic transmitters to track their movements with receivers deployed in active fishing areas within the New York Bight. Multi-state mark–recapture models were used to quantify seasonal patterns in survival and migration while accounting for detection probabilities of tagged fish.
- Movement patterns of sturgeon were highly variable among seasons along the Long Island Coast, with frequent south-westward movements during the increase in sea surface temperature in spring. North-eastward movements were most pronounced during winter, when temperatures were lowest. Sturgeon were less common along coastal Long Island during summer.
- Larger fish transitioned among strata more frequently, but also had slightly lower survival than smaller fish, which may result from selectivity for larger individuals caught incidentally in bottom trawl or gillnet fisheries. Weekly total mortality rates, including both natural and fishing mortality, averaged 0·24%. Highest weekly survival rates were observed during periods of decreasing sea surface temperature in autumn and winter, while lowest survival was observed during periods of increasing temperature in spring and summer while sturgeon migrated through areas of known bycatch.
- Policy implications. Movement and survival patterns of Atlantic sturgeon suggest that late spring, coinciding with periods of ocean bycatch in fisheries along the coast of Long Island, is a particularly sensitive period for Atlantic sturgeon. Conservation efforts could target these few weeks using real-time observations from acoustic telemetry and remote sensing technologies to implement in-season fishery closures, thereby reducing incidental mortality of Atlantic sturgeon. Such bycatch management measures would aid in recovery attempts of a long-lived, migratory population with endangered status.
Fishing and habitat degradation have increased the extinction risk of sharks, and conservation strategies recognize that survival of juveniles is critical for the effective management of shark populations. Despite the rapid expansion of marine protected areas (MPAs) globally, the paucity of shark-monitoring data on large scales (100s–1000s km) means that the effectiveness of MPAs in halting shark declines remains unclear. Using data collected by baited remote underwater video systems (BRUVS) in northwestern Australia, we developed generalized linear models to elucidate the ecological drivers of habitat suitability for juvenile sharks. We assessed occurrence patterns at the order and species levels. We included all juvenile sharks sampled and the 3 most abundant species sampled separately (grey reef [Carcharhinus amblyrhynchos], sandbar [Carcharhinus plumbeus], and whitetip reef sharks [Triaenodon obesus]). We predicted the occurrence of juvenile sharks across 490,515 km2 of coastal waters and quantified the representation of highly suitable habitats within MPAs. Our species-level models had higher accuracy (ĸ ≥ 0.69) and deviance explained (≥48%) than our order-level model (ĸ = 0.36 and deviance explained of 10%). Maps of predicted occurrence revealed different species-specific patterns of highly suitable habitat. These differences likely reflect different physiological or resource requirements between individual species and validate concerns over the utility of conservation targets based on aggregate species groups as opposed to a species-focused approach. Highly suitable habitats were poorly represented in MPAs with the most restrictions on extractive activities. This spatial mismatch possibly indicates a lack of explicit conservation targets and information on species distribution during the planning process. Non-extractive BRUVS provided a useful platform for building the suitability models across large scales to assist conservation planning across multiple maritime jurisdictions, and our approach provides a simple for method for testing the effectiveness of MPAs.