Field data are still recorded on paper in many worldwide beach surveys of nesting marine turtles. The data must be subsequently transferred into an electronic database, and this can introduce errors in the dataset. To minimize such errors, the “Turtles” software was developed and piloted to record field data by one software user accompanying one Tortuguero in Akumal beaches, Quintana Roo, Mexico, from June 1st to July 31st during the night patrols. Comparisons were made between exported data from the software with the paper forms entered into a database (henceforth traditional). Preliminary assessment indicated that the software user tended to record a greater amount of metrics (i.e., an average of 18.3 fields ± 5.4 sd vs. 8.6 fields ± 2.1 sd recorded by the traditional method). The traditional method introduce three types of “errors” into a dataset: missing values in relevant fields (40.1%), different answers for the same value (9.8%), and inconsistent data (0.9%). Only 5.8% of these (missing values) were found with the software methodology. Although only tested by a single user, the software may suggest increased efficacy and warrants further examination to accurately assess the merit of replacing traditional methods of data recording for beach monitoring programmes.
The coastal zone is a region where land, ocean and atmosphere interact and hence it is dynamic in nature. India has a long coastline which was not adequately monitored until the advent of the satellite remote sensing era in the 70s. India has a very robust remote sensing program that the Indian Remote Sensing Satellite (IRS) series of satellites were effectively used to monitor coastal habitats, landforms, shoreline, water quality, etc., and changes were identified during the last 40 years. The classification system for coastal habitats and the classification and geometric accuracies of products were standardized. Detailed information for mangroves communities and characteristics of coral reefs were generated. The high and low tide lines were delineated seamlessly for the entire coastline using satellite data. All these data were organized in a GIS and the coastal database for the entire country was created. Impacts of various hazards on such as cyclones, tsunami and sea level changes on coastal habitats were documented. Based on topography, shoreline changes and tides, coastal multi-hazard vulnerability maps were characterized by employing the elevation data derived from satellite data and were prepared for the coastline of India. The information on ocean color and sea surface temperature was used to generate potential fishery advisories, which are provided daily to fishermen. The coastal database was utilized effectively to identify coastal regulation zones, marine protected areas, vulnerable zones, etc. Various services for tsunami, fishery and coral reef bleaching were generated for societal benefits. It is planned to develop models for the coastal zone, so that impeding dangers and likely changes in the coastal zone can be predicted and suitable actions can be undertaken. It is necessary to integrate socio-economic data with the knowledge database of coastal zone to understand the impact of anthropogenic activities and the changing climate on the coastal zone.
The mitigation hierarchy is increasingly used in environmental policy as a way of reconciling economic development and biodiversity conservation. The principle of the mitigation hierarchy is to avoid, reduce and offset the environmental impacts arising from development projects by providing ecological gains through conservation or restoration measures. Most of the research on its implementation to date has focused on terrestrial ecosystems. In this study, we investigated the relevance of marine ecosystem restorationin meeting offset requirements. Stemming from a brief literature review on existing restoration techniques for marine ecosystems (e.g. coral reefs, seagrass meadows, macroalgae beds, ‘green’ marine construction, and marine sediment remediation) and our experience on Environmental Impact Assessments undertaken in mainland France and in its oversea territories, we discuss the main criteria ensuring a suitable use of ‘restoration’ practice regarding offset requirements. We then clarify the different levels of equivalence that should be met when designing offsets relying on ‘restoration’ techniques. This study aims to clarify to what extent the environmental impacts of economic activity on marine biodiversity can be offset through marine ecosystem restoration.
Population growth rate, which depends on several biological parameters, is valuable information for the conservation and management of pelagic sharks, such as blue and shortfin mako sharks. However, reported biological parameters for estimating the population growth rates of these sharks differ by sex and display large variability. To estimate the appropriate population growth rate and clarify relationships between growth rate and relevant biological parameters, we developed a two-sex age-structured matrix population model and estimated the population growth rate using combinations of biological parameters. We addressed elasticity analysis and clarified the population growth rate sensitivity. For the blue shark, the estimated median population growth rate was 0.384 with a range of minimum and maximum values of 0.195–0.533, whereas those values of the shortfin mako shark were 0.102 and 0.007–0.318, respectively. The maturity age of male sharks had the largest impact for blue sharks, whereas that of female sharks had the largest impact for shortfin mako sharks. Hypotheses for the survival process of sharks also had a large impact on the population growth rate estimation. Both shark maturity age and survival rate were based on ageing validation data, indicating the importance of validating the quality of these data for the conservation and management of large pelagic sharks.
Coastal wetlands are sites of rapid carbon (C) sequestration and contain large soil C stocks. Thus, there is increasing interest in those ecosystems as sites for anthropogenic greenhouse gas emission offset projects (sometimes referred to as “Blue Carbon”), through preservation of existing C stocks or creation of new wetlands to increase future sequestration. Here we show that in the globally-widespread occurrence of diked, impounded, drained and tidally-restricted salt marshes, substantial methane (CH4) and CO2 emission reductions can be achieved through restoration of disconnected saline tidal flows. Modeled climatic forcing indicates that tidal restoration to reduce emissions has a much greater impact per unit area than wetland creation or conservation to enhance sequestration. Given that GHG emissions in tidally-restricted, degraded wetlands are caused by human activity, they are anthropogenic emissions, and reducing them will have an effect on climate that is equivalent to reduced emission of an equal quantity of fossil fuel GHG. Thus, as a landuse-based climate change intervention, reducing CH4 emissions is an entirely distinct concept from biological C sequestration projects to enhance C storage in forest or wetland biomass or soil, and will not suffer from the non-permanence risk that stored C will be returned to the atmosphere.
Understanding how and when cooperative human behaviour forms in common-pool resource systems is critical to illuminating social–ecological systems and designing governance institutions that promote sustainable resource use. Before assessing the full complexity of social dynamics, it is essential to understand, concretely and mechanistically, how resource dynamics and human actions interact to create incentives and pay-offs for social behaviours. Here, we investigated how such incentives for information sharing are affected by spatial dynamics and management in a common-pool resource system. Using interviews with fishermen to inform an agent-based model, we reveal generic mechanisms through which, for a given ecological setting characterized by the spatial dynamics of the resource, the two ‘human factors’ of information sharing and management may heterogeneously impact various members of a group for whom theory would otherwise predict the same strategy. When users can deplete the resource, these interactions are further affected by the management approach. Finally, we discuss the implications of alternative motivations, such as equity among fishermen and consistency of the fleet's output. Our results indicate that resource spatial dynamics, form of management and level of depletion can interact to alter the sociality of people in common-pool resource systems, providing necessary insight for future study of strategic decision processes.
Asymmetries in responses to climate change have the potential to alter important predator–prey interactions, in part by altering the location and size of spatial refugia for prey. We evaluated the effect of ocean warming on interactions between four important piscivores and four of their prey in the U.S. Northeast Shelf by examining species overlap under historical conditions (1968–2014) and with a doubling in CO2. Because both predator and prey shift their distributions in response to changing ocean conditions, the net impact of warming or cooling on predator–prey interactions was not determined a priori from the range extent of either predator or prey alone. For Atlantic cod, an historically dominant piscivore in the region, we found that both historical and future warming led to a decline in the proportion of prey species’ range it occupied and caused a potential reduction in its ability to exert top-down control on these prey. In contrast, the potential for overlap of spiny dogfish with prey species was enhanced by warming, expanding their importance as predators in this system. In sum, the decline in the ecological role for cod that began with overfishing in this ecosystem will likely be exacerbated by warming, but this loss may be counteracted by the rise in dominance of other piscivores with contrasting thermal preferences. Functional diversity in thermal affinity within the piscivore guild may therefore buffer against the impact of warming on marine ecosystems, suggesting a novel mechanism by which diversity confers resilience.
Crustose coralline algae (CCA) concretions, or reefs, are mainly found below 10 m in temperate waters (Ballesteros 2006) and rarely in subtropical and tropical oceans. However, a massive CCA reef occurs on tidal flats extending continuously along the coastline of Taoyuan City, Northwest Taiwan (25°07′00.11″N, 121°14′22.23″E to 24°59′19.34″N, 121°00′47.00″E) (Fig. 1a). It is approximately 27 km long and a maximum of 450 m wide with a large tidal range of 4 m (Fig. 1b; Electronic supplementary video). Carbon-14 dating indicates that the reef dates from around 7500 BP; it consists of some sediment-tolerant corals, such as Cyphastrea and Dipsastraea (Dai et al. 2009). From 4400 BP to the present, CCA genera, such as Mesophyllum, Phymatolithon, and Harveylithon, have contributed to the present algal reef through constant growth as stacked layers over the surface of the reef (Fig. 1c), which is porous (Fig. 1d). The Taoyuan CCA reef performs similar ecosystem functions to those of coral reefs. However, long-term industrial pollution and continuous habitat destruction by land reclamation for an industrial park (Liou 2017) and windmill constructions (Fig. 1b) threaten the future of this reef system. The discovery of a newly described endemic coral species, Polycanthus chaishanensis, two undescribed species of CCA (Fig. 1e), and changes in the composition of layers over time highlight the merit of prioritizing conservation of this unique ecosystem in Taiwan.
Marine ecosystems play a central role in economic and social life in the Republic of Palau, a Small Island Developing State in the Western Pacific. Marine resources underpin subsistence and commercial fisheries, as well as tourism activities, contributing substantially to Palau's GDP and employment. Since 1992, Palau has been actively developing conservation initiatives to protect marine resources, promote ecotourism, and ensure revenue generation. Marine reserves represent a particularly important tool in the country's sustainable development strategy. In 2015, Palau designated 80% of its marine EEZ as a National Marine Sanctuary, with the remaining 20% slated for domestic fisheries. That same year, Palau received 160 thousand tourists, over 9 times the country's population. In early 2017, the President proposed a bill effectively limiting budget travel and actively promoting high-end tourism. This study uses a quantitative social-ecological model to explore policy scenarios involving tourism, marine conservation and local food security. While climate change had the largest expected impact on local ecosystems, reef fish consumption contributes considerably to future projected declines in marine resources. Therefore, for Palau to achieve its goals of boosting revenues while sustainably stewarding marine resources, it will be necessary to transfer some level of consumption from reef fish on to tuna and other pelagics. Such changes, which align with the current proposal of developing an offshore national fishery as part of the Sanctuary's management plan, may allow Palau to meet future seafood demand, while protecting reef systems and the industries that rely on them.
Many conservationists undertake environmentally harmful activities in their private lives such as flying and eating meat, while calling for people as a whole to reduce such behaviors. To quantify the extent of our hypocrisy and put our actions into context, we conducted a questionnaire-based survey of 300 conservationists and compared their personal (rather than professional) behavior, across 10 domains, with that of 207 economists and 227 medics. We also explored two related issues: the role of environmental knowledge in promoting pro-environmental behavior, and the extent to which different elements of people's footprint co-vary across behavioral domains. The conservationists we sampled have a slightly lower overall environmental footprint than economists or medics, but this varies across behaviors. Conservationists take fewer personal flights, do more to lower domestic energy use, recycle more, and eat less meat - but don't differ in how they travel to work, and own more pets than do economists or medics. Interestingly, conservationists also score no better than economists on environmental knowledge and knowledge of pro-environmental actions. Overall footprint scores are higher for males, US nationals, economists, and people with higher degrees and larger incomes, but (as has been reported in other studies) are unrelated to environmental knowledge. Last, we found different elements of individuals' footprints are generally not intercorrelated, and show divergent demographic patterns. These findings suggest three conclusions. First, lowering people's footprints may be most effectively achieved via tailored interventions targeting higher-impact behaviors (such as meat consumption, flying and family size). Second, as in health matters, education about environmental issues or pro-environmental actions may have little impact on behavior. Last, while conservationists perform better on certain measures than other groups, we could (and we would argue, must) do far more to reduce our footprint.
Numerous studies have now demonstrated that the most common method of ageing sharks and rays, counting growth zones on calcified structures, can underestimate true age. I reviewed bomb carbon dating (n = 15) and fluorochrome chemical marking (n = 44) age validation studies to investigate the frequency and magnitude of this phenomenon. Age was likely to have been underestimated in nine of 29 genera and 30% of the 53 populations studied, including 50% of those validated using bomb carbon dating. Length and age were strongly significant predictors of occurrence, with age typically underestimated in larger and older individuals. These characteristics suggest age underestimation is likely a systemic issue associated with the current methods and structures used for ageing. Where detected using bomb carbon dating, growth zones were reliable up to 88% of asymptotic length (L∞) and 41% of maximum age (AMax). The maximum magnitude of age underestimation, ΔMax, ranged from five to 34 years, averaging 18 years across species. Current perceptions of shark and ray life histories are informed to a large extent by growth studies that assume calcified ageing structures are valid throughout life. The widespread age underestimation documented here shows this assumption is frequently violated, with potentially important consequences for conservation and management. In addition to leading to an underestimation of longevity, the apparent loss of population age-structure associated with it may unexpectedly bias growth and mortality parameters. Awareness of these biases is essential given shark and ray population assessments often rely exclusively on life history parameters derived from ageing studies.
The history of the Earth system is a story of change. Some changes are gradual and benign, but others, especially those associated with catastrophic mass extinction, are relatively abrupt and destructive. What sets one group apart from the other? Here, I hypothesize that perturbations of Earth’s carbon cycle lead to mass extinction if they exceed either a critical rate at long time scales or a critical size at short time scales. By analyzing 31 carbon isotopic events during the past 542 million years, I identify the critical rate with a limit imposed by mass conservation. Identification of the crossover time scale separating fast from slow events then yields the critical size. The modern critical size for the marine carbon cycle is roughly similar to the mass of carbon that human activities will likely have added to the oceans by the year 2100.
We document a tendency for published estimates of population size in sea turtles to be increasing rather than decreasing across the globe. To examine the population status of the seven species of sea turtle globally, we obtained 299 time series of annual nesting abundance with a total of 4417 annual estimates. The time series ranged in length from 6 to 47 years (mean, 16.2 years). When levels of abundance were summed within regional management units (RMUs) for each species, there were upward trends in 12 RMUs versus downward trends in 5 RMUs. This prevalence of more upward than downward trends was also evident in the individual time series, where we found 95 significant increases in abundance and 35 significant decreases. Adding to this encouraging news for sea turtle conservation, we show that even small sea turtle populations have the capacity to recover, that is, Allee effects appear unimportant. Positive trends in abundance are likely linked to the effective protection of eggs and nesting females, as well as reduced bycatch. However, conservation concerns remain, such as the decline in leatherback turtles in the Eastern and Western Pacific. Furthermore, we also show that, often, time series are too short to identify trends in abundance. Our findings highlight the importance of continued conservation and monitoring efforts that underpin this global conservation success story.
Coastal wetland responses to sea-level rise are greatly influenced by biogeomorphic processes that affect wetland surface elevation. Small changes in elevation relative to sea level can lead to comparatively large changes in ecosystem structure, function, and stability. The surface elevation table-marker horizon (SET-MH) approach is being used globally to quantify the relative contributions of processes affecting wetland elevation change. Historically, SET-MH measurements have been obtained at local scales to address site-specific research questions. However, in the face of accelerated sea-level rise, there is an increasing need for elevation change network data that can be incorporated into regional ecological models and vulnerability assessments. In particular, there is a need for long-term, high-temporal resolution data that are strategically distributed across ecologically-relevant abiotic gradients. Here, we quantify the distribution of SET-MH stations along the northern Gulf of Mexico coast (USA) across political boundaries (states), wetland habitats, and ecologically-relevant abiotic gradients (i.e., gradients in temperature, precipitation, elevation, and relative sea-level rise). Our analyses identify areas with high SET-MH station densities as well as areas with notable gaps. Salt marshes, intermediate elevations, and colder areas with high rainfall have a high number of stations, while salt flat ecosystems, certain elevation zones, the mangrove-marsh ecotone, and hypersaline coastal areas with low rainfall have fewer stations. Due to rapid rates of wetland loss and relative sea-level rise, the state of Louisiana has the most extensive SET-MH station network in the region, and we provide several recent examples where data from Louisiana’s network have been used to assess and compare wetland vulnerability to sea-level rise. Our findings represent the first attempt to examine spatial gaps in SET-MH coverage across abiotic gradients. Our analyses can be used to transform a broadly disseminated and unplanned collection of SET-MH stations into a coordinated and strategic regional network. This regional network would provide data for predicting and preparing for the responses of coastal wetlands to accelerated sea-level rise and other aspects of global change.
Sea level rise exhibits significant regional differences. Based on Coupled Model Intercomparison Project Phase 5 (CMIP5) models, sea level projections have been produced for the Australian region by taking account of regional dynamic changes, ocean thermal expansion, mass loss of glaciers, changes in Greenland and Antarctic ice sheets and land water storage, and glacial isostatic adjustment. However, these regional projections have a coarse resolution (~100 km), while coastal adaptation planners demand finer scale information at the coast. To address this need, a 1/10° near-global ocean model driven by ensemble average forcings from 17 CMIP5 models is used to downscale future climate. We produce high-resolution sea level projections by combining downscaled dynamic sea level with other contributions. Off the southeast coast, dynamic downscaling provides better representation of high sea level projections associated with gyre circulation and boundary current changes. The high-resolution sea level projection should be a valuable product for detailed coastal adaptation planning.
Alien species, one of the biggest threats to natural ecosystems worldwide, are of particular concern for oceanic archipelagos such as Galápagos. To enable more effective management of alien species, we reviewed, collated and analysed all available records of alien species for Galápagos. We also assembled a comprehensive dataset on pathways to and among the Galápagos Islands, including tourist and resident numbers, tourist vessels, their itineraries and visitation sites, aircraft capacity and occupancy, air and sea cargo and biosecurity interceptions. So far, 1,579 alien terrestrial and marine species have been introduced to Galápagos by humans. Of these, 1,476 have become established. Almost half of these were intentional introductions, mostly of plants. Most unintentional introductions arrived on plants and plant associated material, followed by transport vehicles, and commodities (in particular fruit and vegetables). The number, frequency and geographic origin of pathways for the arrival and dispersal of alien species to and within Galápagos have increased over time, tracking closely the increase in human population (residents and tourists) on the islands. Intentional introductions of alien species should decline as biosecurity is strengthened but there is a danger that unintentional introductions will increase further as tourism on Galápagos expands. This unique world heritage site will only retain its biodiversity values if the pathways for invasion are managed effectively.
We have developed a global biogeographic classification of the mesopelagic zone to reflect the regional scales over which the ocean interior varies in terms of biodiversity and function. An integrated approach was necessary, as global gaps in information and variable sampling methods preclude strictly statistical approaches. A panel combining expertise in oceanography, geospatial mapping, and deep-sea biology convened to collate expert opinion on the distributional patterns of pelagic fauna relative to environmental proxies (temperature, salinity, and dissolved oxygen at mesopelagic depths). An iterative Delphi Method integrating additional biological and physical data was used to classify biogeographic ecoregions and to identify the location of ecoregion boundaries or inter-regions gradients. We define 33 global mesopelagic ecoregions. Of these, 20 are oceanic while 13 are ‘distant neritic.’ While each is driven by a complex of controlling factors, the putative primary driver of each ecoregion was identified. While work remains to be done to produce a comprehensive and robust mesopelagic biogeography (i.e., reflecting temporal variation), we believe that the classification set forth in this study will prove to be a useful and timely input to policy planning and management for conservation of deep-pelagic marine resources. In particular, it gives an indication of the spatial scale at which faunal communities are expected to be broadly similar in composition, and hence can inform application of ecosystem-based management approaches, marine spatial planning and the distribution and spacing of networks of representative protected areas.
As the Arctic warms and sea ice decreases, increased shipping will lead to higher ambient noise levels in the Arctic Ocean. Arctic marine mammals are vulnerable to increased noise because they use sound to survive and likely evolved in a relatively quiet soundscape. We model vessel noise propagation in the proposed western Canadian Arctic shipping corridor in order to examine impacts on marine mammals and marine protected areas (MPAs). Our model predicts that loud vessels are audible underwater when > 100 km away, could affect marine mammal behaviour when within 2 km for icebreakers vessels, and as far as 52 km for tankers. This vessel noise could have substantial impacts on marine mammals during migration and in MPAs. We suggest that locating the corridor farther north, use of marine mammal observers on vessels, and the reduction of vessel speed would help to reduce this impact.
There is increasing evidence that science & engineering PhD students lose interest in an academic career over the course of graduate training. It is not clear, however, whether this decline reflects students being discouraged from pursuing an academic career by the challenges of obtaining a faculty job or whether it reflects more fundamental changes in students’ career goals for reasons other than the academic labor market. We examine this question using a longitudinal survey that follows a cohort of PhD students from 39 U.S. research universities over the course of graduate training to document changes in career preferences and to explore potential drivers of such changes. We report two main results. First, although the vast majority of students start the PhD interested in an academic research career, over time 55% of all students remain interested while 25% lose interest entirely. In addition, 15% of all students were never interested in an academic career during their PhD program, while 5% become more interested. Thus, the declining interest in an academic career is not a general phenomenon across all PhD students, but rather reflects a divergence between those students who remain highly interested in an academic career and other students who are no longer interested in one. Second, we show that the decline we observe is not driven by expectations of academic job availability, nor by related factors such as postdoctoral requirements or the availability of research funding. Instead, the decline appears partly due to the misalignment between students’ changing preferences for specific job attributes on the one hand, and the nature of the academic research career itself on the other. Changes in students’ perceptions of their own research ability also play a role, while publications do not. We discuss implications for scientific labor markets, PhD career development programs, and science policy.
Climate change is a mounting threat to biological diversity1, compromising ecosystem structure and function, and undermining the delivery of essential services worldwide2. As the magnitude and speed of climate change accelerates3, greater understanding of the taxonomy and geography of climatic vulnerability is critical to guide effective conservation action. However, many uncertainties remain regarding the degree and variability of climatic risk within entire clades and across vast ecosystem boundaries4. Here we integrate physiological estimates of thermal sensitivity for 2,960 ray-finned fishes with future climatic exposure, and demonstrate that global patterns of vulnerability differ substantially between freshwater and marine realms. Our results suggest that climatic vulnerability for freshwater faunas will be predominantly determined by elevated levels of climatic exposure predicted for the Northern Hemisphere, whereas marine faunas in the tropics will be the most at risk, reflecting their higher intrinsic sensitivity. Spatial overlap between areas of high physiological risk and high human impacts, together with evidence of low past rates of evolution in upper thermal tolerance, highlights the urgency of global conservation actions and policy initiatives if harmful climate effects on the world’s fishes are to be mitigated in the future.