This paper describes a probabilistic approach for mapping of coastal flood hazards associated with sea-level rise and storm intensification toward the end of the 21st century. Under the Representative Concentration Pathway (RCP) 8.5, the Coupled Model Intercomparison Project Phase 5 (CMIP5) predicts a 0.6-m ensemble mean of sea-level rise for the Central Pacific from the 1986–2005 to 2081–2100 epochs. Fifty downscaling simulations of the 2080–2099 period from the CMIP5 NCAR-CCSM4 model produce 2492 hurricanes around the Hawaiian Islands. In comparison with a control dataset for the 1980–1999 period, the simulated future hurricanes show a slight increase in number and a northward shift of the tracks toward the Hawaiian Islands. There are 627 hurricanes in the 2080–2099 dataset with potential impact on Oahu, and the top 24 storms selected by wind speed at the urban Honolulu coast define a scenario set for inundation mapping. A suite of spectral wave, circulation, and Boussinesq models in a nested grid system describes generation and propagation of surge and waves across the ocean as well as wave setup and runup at the coast. The interoperable package includes phase-averaged and phase-resolving processes to determine the coastal flood hazards over a range of spatial and temporal scales during a hurricane event. Since the simulated dataset corresponds to a quasi 1000-year period, barring the tail end of the distribution, the suite of inundation scenarios enables definition of flood hazard maps with return periods of up to 500 years or annual exceedance probabilities of 0.2% or greater for climate change adaptation.
Environmental justice sheds light on the distributive and procedural aspects of planning and decision-making. We examined the challenges arising from the perspective of environmental justice on multi-level and participatory environmental governance by exploring the governance of aquatic environments in the Helsinki Metropolitan Area. We found three main challenges and potential responses to them. First, even though most of Helsinki’s shoreline is free and/or accessible by road and accordingly used actively by people for recreational purposes, many parts of the shoreline are perceived as inaccessible, reflecting a need to combine factual and perceived accessibility of aquatic environments in detail during the planning processes and to discuss reasons for possible discrepancies between these two. Second, there was a remarkable seasonal variation in the use of aquatic environments, so more attention should be paid to social-demographic factors explaining the distribution of the use of urban nature. Third, it seems to be difficult to capture the variety of perceptions of people and to integrate them into planning and decision-making processes even on a local scale, and this challenge is likely even more pronounced on higher levels of planning and governance. Thus, better integration of regional and local-scale planning procedures should be encouraged. Building on these observations, we conclude that integration of procedural and distributive environmental justice into the practices of the governance of aquatic environments could remarkably decrease unwanted trade-offs and potential conflicts in their use and management.
The land-sparing versus land-sharing debate centers around how different intensities of habitat use can be coordinated to satisfy competing demands for biodiversity persistence and food production in agricultural landscapes. We apply the broad concepts from this debate to the sea and propose it as a framework to inform marine zoning based on three possible management strategies, establishing: no-take marine reserves, regulated fishing zones, and unregulated open-access areas. We develop a general model that maximizes standing fish biomass, given a fixed management budget while maintaining a minimum harvest level. We find that when management budgets are small, sea-sparing is the optimal management strategy because for all parameters tested, reserves are more cost-effective at increasing standing biomass than traditional fisheries management. For larger budgets, the optimal strategy switches to sea-sharing because, at a certain point, further investing to grow the no-take marine reserves reduces catch below the minimum harvest constraint. Our intention is to illustrate how general rules of thumb derived from plausible, single-purpose models can help guide marine protected area policy under our novel sparing and sharing framework. This work is the beginning of a basic theory for optimal zoning allocations and should be considered complementary to the more specific spatial planning literature for marine reserve as nations expand their marine protected area estates.
Commercial and recreational fishing have impacts on fish assemblages and populations, but does their combined fishing pressure result in different fish assemblages in estuaries with only one type of fishing activity? This pilot study tested the model that estuaries with only one type of fishing activity have fewer impacts on fish assemblages and populations than estuaries with more than one type because the fishing pressure in the latter will be greater and results in different fish assemblages and taxa. Fish assemblages and populations, including diversity, abundance and size, did not significantly differ despite exposure to different fishing activities. Detecting differences in fish assemblages in estuaries associated with different fishing activities is difficult as smaller scale spatial and temporal factors have a significant influence on the patterns observed. This highlights the importance of paying close attention to the design of sampling programmes. The nested design of this study enabled identification of where greater effort is required to increase the capacity to detect differences. Recommendations for future studies are provided.
Marine protected areas (MPAs) have proven to be a valuable tool for both promoting the sustainable use of marine resources and long-term biodiversity conservation outcomes. Targets for marine protection under the Convention on Biological Diversity have seen rapid growth in MPAs globally, with progress judged using targets for total area protected rather than evaluating growth based on the capacity to protect biodiversity. The value of a MPA network to biodiversity conservation depends on a range of attributes of both individual MPAs and portfolios of MPAs, which are not captured by simple area-based targets. Therefore, a clear and efficient set of metrics are needed to effectively evaluate progress towards building MPA networks, considering the representation and adequacy of protection for biodiversity. We developed a universally applicable set of metrics that can evaluate network structure in relation to its capacity to conserve marine biodiversity. These metrics combine properties of effective individual MPAs with metrics for their capacity to function collectively as a network. To demonstrate the value of these metrics, we apply them to the Australian MPA network, the largest in the world. Collectively, the indicators suggest that while Australia has made significant progress in building a representative and well-structured MPA network, the level of protection offered to marine biodiversity is generally low, with insufficient coverage of no-take MPAs across many bioregions. The metrics reveal how the current value of the MPA network could be greatly increased by reducing the prevalence of multi-use zones that allow extractive activities known to negatively impact biodiversity.
Coastal erosion is a worldwide problem, so accurate knowledge of the factors involved in the shoreline evolution is of great importance. This study analysed three gravel beaches that were nourished with sand from the same source. However, the evolution of their shoreline was different in each case. For its analysis, different factors were studied such as the shoreline and cross-shore profile evolution, the maritime climate, sedimentology and mineralogy. From the results, it should be noted that Centro beach is the most stable with a loss of surface after the first regeneration of 12.8%, while Carrer de mar is the most instable with a loss of 20.9%. The Posidonia oceanica meadow is one of the factors that make Centro beach the most stable despite being the one that receives the most wave energy. Another factor is its mineralogy and more specifically the composition of the particles that form the sample. Thus, it is observed how the cracking or the formation of particles by different minerals with a fragile union, are factors that make the beaches behave differently against erosion. For this reason, it is concluded that in order for the shoreline to be as stable as possible over time, a previous study of the sediment to be used for nourishment is necessary, as well as its possible effect on the ecosystem, since the future shoreline evolution will depend on it.
Coral reefs are of great ecological importance to marine ecosystems, yet their origins are still poorly understood. Using a robust phylogenetic framework, Huang et al. (2017) show that most diversity within the Indo-Pacific Coral Triangle region is driven by range expansions of lineages from outside the region, rather than rapid diversification within. This highlights the need for macroevolutionary studies to fully understand species assemblages in biodiversity hotspots, and the potential importance of adjacent areas for conservation.
Sea ice decline is anticipated to increase human access to the Arctic Ocean allowing for offshore oil and gas development in once inaccessible areas. Given the potential negative consequences of an oil spill on marine wildlife populations in the Arctic, it is important to understand the magnitude of impact a large spill could have on wildlife to inform response planning efforts. In this study we simulated oil spills that released 25,000 barrels of oil for 30 days in autumn originating from two sites in the Chukchi Sea (one in Russia and one in the U.S.) and tracked the distribution of oil for 76 days. We then determined the potential impact such a spill might have on polar bears (Ursus maritimus) and their habitat by overlapping spills with maps of polar bear habitat and movement trajectories. Only a small proportion (1–10%) of high-value polar bear sea ice habitat was directly affected by oil sufficient to impact bears. However, 27–38% of polar bears in the region were potentially exposed to oil. Oil consistently had the highest probability of reaching Wrangel and Herald islands, important areas of denning and summer terrestrial habitat. Oil did not reach polar bears until approximately 3 weeks after the spills. Our study found the potential for significant impacts to polar bears under a worst case discharge scenario, but suggests that there is a window of time where effective containment efforts could minimize exposure to bears. Our study provides a framework for wildlife managers and planners to assess the level of response that would be required to treat exposed wildlife and where spill response equipment might be best stationed. While the size of spill we simulated has a low probability of occurring, it provides an upper limit for planners to consider when crafting response plans.
An alternate management system is introduced which uses seasonal and spatially explicit multi-species quotas generated from small-scale cooperative fishery acoustic surveys to manage the Aleutian Islands walleye pollock (Gadus chalcogrammus) fishery while limiting impacts on the endangered Western stock of Steller sea lions (Eumetopias jubatus). This is a novel collaboration among scientists, industry, and Alaska Natives considering a cooperative management approach. The proposed system integrates the catch monitoring and accounting systems already in place in the federal groundfish fisheries off Alaska with cooperative acoustic survey biomass estimates to facilitate more refined spatial and temporal fishery management decisions. Conditions were examined under which such a system could operate successfully and results from field work conducted to assess technical requirements were discussed. During field trials biomass estimates from each survey were produced within 24-h of survey completion. This suggests spatial abundance estimates can be available in a timely manner for managing local fisheries. The proposed management system was found feasible and relatively easy to initiate because of highly motivated and cooperative industry partners, a well-established mechanism for setting allowable catch limits, and a robust catch accounting system already in place. In addition, high quality commercial echosounders required for this system are currently used by industry and, with proper controls on calibration and survey design, produce biomass estimates of sufficient quality. The application of this approach beyond this case study is also discussed for managing fisheries worldwide where fine temporal and spatial scale management could benefit the conservation of other protected species.
Coastal communities around the world face challenges in planning for coastal flooding and sea-level rise related to climate change. This paper develops an approach for identifying typologies of communities on the basis of their hazard vulnerability characteristics. The approach first characterizes communities with a suite of vulnerability indicators, selected to meet criteria of breadth, relevance, and data requirements. Cluster analysis is then applied to the indicator profiles to identify groups of similar communities. The statistical centrotype of each group represents the corresponding community type. A new community from outside the original set can then be matched to the typology using a Hazard Vulnerability Similarity Index (HVSI). The approach is demonstrated with a case study of 50 communities on Canada's Pacific coast. Results yielded 10 community types, of which four were predominant. The types range from highly urbanized, wealthier, diverse central cities to remote, resource-dependent towns with semi-developed, flat coastlines. Three selected communities from a distant region, in Atlantic Canada, were then successfully matched to the most similar of these 10 types. Identifying groups of communities that share vulnerability profiles can facilitate sharing knowledge, lessons, and resources that are most relevant to local efforts to reduce natural hazard risk. This support may be especially valuable for connecting communities that are unfamiliar with one another, yet similarly vulnerable.