Climate change has significantly impacted tropical ecosystems critical for sustaining local economies and community livelihoods at global scales. Coastal ecosystems have largely declined, threatening the principal source of protein, building materials, tourism-based revenue, and the first line of defense against storm swells and sea level rise (SLR) for small tropical islands. Climate change has also impacted public health (i.e., altered distribution and increased prevalence of allergies, water-borne, and vector-borne diseases). Rapid human population growth has exacerbated pressure over coupled social–ecological systems, with concomitant non-sustainable impacts on natural resources, water availability, food security and sovereignty, public health, and quality of life, which should increase vulnerability and erode adaptation and mitigation capacity. This paper examines cumulative and synergistic impacts of climate change in the challenging context of highly vulnerable small tropical islands. Multiple adaptive strategies of coupled social–ecological ecosystems are discussed. Multi-level, multi-sectorial responses are necessary for adaptation to be successful.
King scallop contamination (Pecten maximus) by domoic acid, a neurotoxin produced by some species of the diatom Pseudo-nitzschia, is highly problematic because of its lengthy retention in the bivalve tissue, leading to prolonged fishery closures. Data collected within the French Phytoplankton and Phycotoxin monitoring network (REPHY) over the 1995–2012 period were used to characterize the seasonal dynamics and the interannual variability of P.-nitzschia spp. blooms as well as the contamination of king scallop fishing grounds, in six contrasted bays distributed along the French Atlantic coast and English Channel. Monitoring revealed that these toxic events have become more frequent since the year 2000, but with varying magnitudes, frequencies and timing depending on the bay. Two bays, located in southern Brittany, exhibited both recurrent contaminations and high P.-nitzschia abundances. The Brest bay and the Seine bay were intermittently affected. The Pertuis Breton exhibited only one major toxic event related to an exceptionally intense bloom of P.-nitzschia in 2010, and the Saint Brieuc bay neither showed significant contamination nor high P.-nitzschia abundance. While high P.-nitzschia abundance appeared to be correlated to scallop toxicity, this study highlights the difficulty in linking P.-nitzschia spp. blooms to king scallop contamination through monitoring. Indeed, P.-nitzschia was determined at the genus level and data regarding species abundances and their toxicity levels are an absolute prerequisite to further assess the environmental control of ASP events. As results describe distinct P.-nitzschia bloom dynamics along the French coast, this may suggest distinct controlling factors. They also revealed that major climatic events, such as the winter storm Xynthia in 2010, can trigger toxicity in P.-nitzschia over a large spatial scale and impact king scallop fisheries all along the coast.
The future persistence of biodiversity is likely to be affected by global climate change. We propose a qualitative framework for assessing the resilience of coastal species to climate change, incorporating current and likely future breeding success, the availability of temporal and spatial climate refugia, the effect of future sea-level rise, behavioural plasticity and the level of other specific threats. We test this framework using one of the world's largest nesting rookeries of loggerhead sea turtles (Caretta caretta) in the island of Boa Vista (Republic of Cape Verde, West Africa). We measured air, sand and nest temperatures across more than 50 km of nesting habitat and four years to model the likely sex ratios produced and predicted what future sex ratios might be under one conservative future climate change scenario (RCP 2.6). We assessed the relative threat of sea-level rise, and other threats including beachfront construction, pollution and human harvest as well as to estimate the level of foraging behaviour plasticity observed for this population. Estimated sex ratio over the study period was 79.15% female and while an increase of 2 °C air temperature would lead to 99.86% female production, incubation temperature is unlikely to be lethal even in the hottest part of the year. Only half the total suitable length of coastline is currently used for nesting and there is a size-linked dichotomy in foraging strategies of loggerhead turtles of both sexes. Under our qualitative framework, we make the surprising observation that this population of conservation concern should have remarkable resilience to climate change due to some unique features of their habitat use and preferences. This may be compromised by high levels of human harvest and planned and on-going coastal development. The framework may be of utility in assessing the threat of climate change to other climate-sensitive, coastal and mobile species such as migratory seabirds, coastal fish and butterflies.
As pressures on coastal zones mount, there is a growing need for frameworks that can be used to conceptualize complex sustainability challenges and help organize research that increases understand about interacting ecological and societal processes, predicts change, and supports the management, persistence, and resilience of coastal systems. The Driver–Pressure–State–Impact–Response (DPSIR) framework is one such approach that has been adopted in some coastal zones around the world. Although the application of the DPSIR framework has considerable potential to bridge the gap between scientific disciplines and link science to coastal policy and management, current applications of DPSIR in coastal environments have been limited and new innovations in the application of the DPSIR model are needed. We conducted a structured review of literature on the DPSIR framework as applied to the function, process and components of complex coastal systems. Our specific focus was on how the DPSIR framework has been used as a tool to organize sophisticated empirical scientific research, support transdisciplinary knowledge at a level appropriate for building understanding about coastal systems, and how adopting a DPSIR approach can help stakeholders to articulate and structure challenges in coastal systems and use the framework to support policy and management outcomes. The review revealed that DPSIR models of coastal systems have been largely used to support and develop conceptual understanding of coastal social–ecological systems and to identify drivers and pressures in the coastal realm. A limited number of studies have used DPSIR as a starting point for semi-quantitative or quantitative analyses, although our review highlights the continued need for, and potential of, transformative quantitative analyses and transdisciplinary applications of the DPSIR framework. The DPSIR models we reviewed were predominantly single sector, encompassing ecological or biophysical factors or focusing primarily on socio-cultural dimensions rather than full integration of both types of information. Only in eight of 24 shortlisted articles did researchers actively engage decision-makers or citizens in their research: given the potential opportunity for using DPSIR as a tool to successfully engage policy-makers and stakeholders, it appears that the DPSIR framework has been under-utilized in this regard.
Compared to traditional hard engineering, nature-based flood protection can be more cost effective, use up less raw materials, increase system adaptability and present opportunities to improve ecosystem functioning. However, high flood safety standards cause the need to combine nature-based structures with traditional civil engineered structures. This increases complexity assessing when and how ecological and engineering objectives of such flood protection systems are achieved. This study classifies the degree to which coastal designs are nature based using criteria for ecosystem-based management (EBM). For the engineering criterion the distinction between main and supporting structures is introduced. To evaluate the ecological criterion five design concepts have been introduced, ranging from completely engineered to completely nature-based.
The method results in an EBM-ranking of the coast, showing where a particular flood protection design stands on the range between completely engineered (low EBM-rank) and nature-based (high EBM-rank). It thus facilitates comparison of different flood protection systems.
The method was the applied on the North-Sea coast of Belgium, the Netherlands, and Germany. The results show that combinations of civil-engineered and nature-based structures are widely applied. However, due to the overall low contribution to flood protection by the nature-based structures, about 85% of the coast is dominated by engineered structures. The majority of these stretches is located in relatively sheltered areas. Improving the flood protection capacity of the nature based structures in these areas is hard to achieve. Therefore, application of more nature-based design concepts on the main structures is the most promising way to improve the EBM-rank of many flood protection systems.
Ecosystem-based management of the North Sea demersal fish community uses the large fish indicator (LFI), defined as the proportion by weight of fish caught in the International Bottom Trawl Survey (IBTS) exceeding a length of 40 cm. Current values of the LFI are ∼0.15, but the European Union (EU) Marine Strategy Framework Directive (MSFD) requires a value of 0.3 be reached by 2020. An LFI calculated from an eight-species subset correlated closely with the full community LFI, thereby permitting an exploration of the effects of various fishing scenarios on projected values of the LFI using an extension of a previously published multi-species length-structured model that included these key species. The model replicated historical changes in biomass and size composition of individual species, and generated an LFI that was significantly correlated with observations. A community-wide reduction in fishing mortality of ∼60% from 2008 values was necessary to meet the LFI target, driven mainly by changes in cod and saithe. A 70% reduction in cod fishing mortality alone, or a 75% reduction in otter trawl effort, was also sufficient to achieve the target. Reductions in fishing mortality necessary to achieve maximum sustainable harvesting rates are projected to result in the LFI over-shooting its target.
Distinct spatial variation and fisheries exchange routes for dolphinfish (Coryphaena hippurus) were resolved relative to the northeastern Caribbean Sea and U.S. east coast using conventional (n = 742; mean ± SD cm FL: 70.5 ± 15.2 cm FL) and pop-up satellite archival tags (n = 7; 117.6 ± 11.7 cm FL) from 2008 to 2014. All dolphinfish released in the northeastern Caribbean Sea moved westward (274.42° ± 21.06°), but slower in the tropical Atlantic than Caribbean Sea, with a maximum straight-line distance recorded between San Juan, Puerto Rico, and Charleston, South Carolina (1917.49 km); an 180-day geolocation track was obtained connecting the South Atlantic Bight to the northern limits of the Mona Passage. Two recaptures occurred within the Mona Passage from San Juan, Puerto Rico, and St. John, United States Virgin Islands, providing the first evidence that dolphinfish may cross the Greater Antilles island chain between the Atlantic Ocean and Caribbean Sea in both directions during their migration. To investigate this further, fish movements were compared to surface drifter tracks (n = 196) in the region. Entry of drifters into the Caribbean Sea from the Atlantic Ocean occurred through the northern Lesser Antilles, the Anegada Passage, and the Mona Passage; both passages were observed to be an entry and exit. Results suggest domestic and international fisheries exchanges occur annually between the United States and Caribbean island nations (Antigua and Barbuda, Anguilla, St. Kitts, United States Virgin Islands, Puerto Rico, Hispaniola, The Bahamas, Cuba, Bermuda), with return migration directed towards the Yucatan Channel/Loop Current (south of the Greater Antilles) or Straits of Florida/Gulf Stream (north). Understanding dolphinfish movements and regional connectivity among exclusive economic zones of northern Caribbean islands and the United States is critical for accurate assessments of fishing mortality, spawning biomass and stock health, and given the regional connectivity, management must be consistent between jurisdictions.
This paper examines five representative sites on the California coast to illustrate a cost-effective methodology using tools and data that local decision makers can apply to analyse the economics of sea level rise (SLR) adaptation. We estimate the costs/benefits of selected responses (e.g. no action, nourishment, seawalls) to future flooding and erosion risks exacerbated by SLR. We estimate the economic value of changes to public/private property, recreational and habitat value, and beach related spending/tax revenues. Our findings indicate that the costs of SLR are significant but uneven across communities, and there is no single best strategy for adaptation. For example, Los Angeles's Venice Beach could lose $450 million in tourism revenue by 2100 with a 1.4 m SLR scenario while San Francisco's Ocean Beach would lose $80 million, but the impacts to structures could total nearly $560 million at Ocean Beach compared to $50 million at Venice Beach.
Ecosystem-based management efforts in coral reefs typically focus on reducing fishing pressure. However, independent of overfishing, tourism can degrade coral reefs through coastal development, as well as the physical presence of tourists within the ecosystem, the effects of which remain poorly understood. We combined a 3-year dataset on coral and algal cover with a more extensive survey of the benthic community to examine the effect of intensive tourism on a coral reef in Akumal Bay, Mexico. Results from our 3-year dataset indicated that near the peak snorkeling area in the bay, coral cover decreased by 79 % from summer 2011 through summer 2014, a period in which the number of monthly snorkelers increased by more than 400 %. Our summer 2013 survey of the benthic community between sites within a zone of dense snorkeler traffic versus site at a nearby control location revealed negative effects of intensive tourism on particular coral morphologies and on the abundance of herbivorous reef fishes. Our results suggest that uncontrolled tourism, including accelerating growth in the number of snorkelers, is likely contributing to the decline of the coral reef in Akumal Bay, where further expansions in tourism are planned. Indeed, the ecosystems threatened by overexploitation via tourism in the Mayan Riviera also form the basis for the regional tourism industry. Thus, long-term ecological monitoring coupled with the establishment and enforcement of regulations on tourism may be essential for the sustainability of coral reefs, as well as the socioeconomic benefits they provide in Mexico.
The purpose of this doctoral research is to characterize and assess how social networks enhance and inhibit the governance of marine protected areas (MPAs). Specifically, I examine the structure and function of multiple networks between social actors to better understand their role in the governance of MPAs, and to address a gap in our understanding of how formal and informal rules, rule-making systems, and actor networks contribute to different MPA outcomes. A focus on the social dimensions of MPAs is critical, as they have emerged as a significant marine conservation and climate change adaptation strategy with substantial implications for coastal communities. The research pursues three specific research objectives: (1) to conceptually develop and illustrate the utility of a social relational network perspective for policy-relevant MPA science; (2) to identify and describe how social networks support and constrain transitions to co-management of small-scale fisheries and MPAs; and (3) to examine how social connectivity among actors affiliated with a MPA network can enhance and inhibit governance fit.
Formal and informal social networks have been repeatedly cited as a key attribute of multi-actor governance arrangements (e.g., co-managed MPAs) in the broader natural resource management literature. Similarly, the role of social networks has been identified as one of the research frontiers for policy-relevant MPA science. However, not all networks are structurally equal with research suggesting that different patterns of social relations contribute to different management and governance outcomes. Accordingly, understanding how social networks influence outcomes of MPAs is a key research area that has been understudied.
A synthetic review was first conducted to outline the emergence and benefit of applying a structurally explicit, social relational network perspective to inform the establishment and governance of MPAs and MPA networks. This social relational network perspective was then used to gain key insights regarding the role of networks for the governance of MPAs and MPA networks based on two empirical cases in Jamaica. The first was a comparative study focused on three Special Fishery Conservation Areas (SFCAs) – i.e., marine no-take areas – and focused on ties between individual fishermen and wardens. The second case examined the actors associated with the national network of Special Fishery Conservation Areas – of which there are fourteen in total – and thus focused on ties between organizations from across the island that contribute to the governance of the SFCAs. Data were collected via a social relational survey (n = 380), semi-structured interviews (n = 63), an organizational network survey (n = 18), focus groups (n = 10), literature and document review, and participant observations. Social network analysis was coupled with qualitative content analysis to assess how patterns of relational ties and interactions between social actors enhance and inhibit the governance of MPAs.
This thesis conceptually develops and empirically illustrates the insights and contributions to be gained from taking a social relational network perspective to examine MPA governance, including how such an approach can be applied at different scales (e.g., community level interactions, organizational interactions) and to understand different aspects and issues (e.g., transitions to co-management, governance fit). The second contribution of this study is to illustrate the utility of a social relational network perspective to examine and understand key governance attributes previously identified in the literature – specifically community cohesion and leadership. The third contribution of this study concerns the re-orientation of thinking about MPA networks from a purely ecological and biophysical perspective towards a greater emphasis on social connectivity. A re-orientation towards the consideration of social connectivity among actors associated with a MPA network contributed to preliminary insights concerning how the structure and function of governance networks may enhance and inhibit mismatches (i.e., spatial, temporal, functional) that plague individual MPAs. While the findings presented here are based on research in Jamaica, they are germane to a wide range of contexts given the global expansion of MPAs and MPA networks where similar social relational challenges and opportunities are bound to occur.