Sentiment Analysis of Conservation Studies Captures Successes of Species Reintroductions

Learning from the rapidly growing body of scientific articles is constrained by human bandwidth. Existing methods in machine learning have been developed to extract knowledge from human language and may automate this process. Here, we apply sentiment analysis, a type of natural language processing, to facilitate a literature review in reintroduction biology. We analyzed 1,030,558 words from 4,313 scientific abstracts published over four decades using four previously trained lexicon-based models and one recursive neural tensor network model. We find frequently used terms share both a general and a domain-specific value, with either positive (success, protect, growth) or negative (threaten, loss, risk) sentiment. Sentiment trends suggest that reintroduction studies have become less variable and increasingly successful over time and seem to capture known successes and challenges for conservation biology. This approach offers promise for rapidly extracting explicit and latent information from a large corpus of scientific texts

The vertical distribution and biological transport of marine microplastics across the epipelagic and mesopelagic water column.

Plastic waste has been documented in nearly all types of marine environments and has been found in species spanning all levels of marine food webs. Within these marine environments, deep pelagic waters encompass the largest ecosystems on Earth. We lack a comprehensive understanding of the concentrations, cycling, and fate of plastic waste in sub-surface waters, constraining our ability to implement effective, large-scale policy and conservation strategies. We used remotely operated vehicles and engineered purpose-built samplers to collect and examine the distribution of microplastics in the Monterey Bay pelagic ecosystem at water column depths ranging from 5 to 1000 m. Laser Raman spectroscopy was used to identify microplastic particles collected from throughout the deep pelagic water column, with the highest concentrations present at depths between 200 and 600 m. Examination of two abundant particle feeders in this ecosystem, pelagic red crabs (Pleuroncodes planipes) and giant larvaceans (Bathochordaeus stygius), showed that microplastic particles readily flow from the environment into coupled water column and seafloor food webs. Our findings suggest that one of the largest and currently underappreciated reservoirs of marine microplastics may be contained within the water column and animal communities of the deep sea

The Economic Value of Sea Otters and Recreational Tourism in a California Estuary

The recovery of marine megafauna can lead to improved ecosystem function and services, but not all stakeholders may benefit equally. Quantifying the local economic value of a species’ presence may appeal to broader range of stakeholders when developing conservation strategies. This study aims to examine the economic effect recreational activities can have on a local region, and to determine what role the presence of southern sea otters (Enhydra lutris nereis) had on the value visitors placed on the visit and the area’s preservation. We surveyed visitors to Elkhorn Slough, a small estuary in California known for diverse wildlife, modeled direct and indirect economic contributions to local economics, and evaluated perceptions and value placed on the area and wildlife. Annually, visitors contributed approximately $3.2 million (USD) in direct spending, with an additional$1.85 million in indirect economic gains, which could support over 300 full-time, part-time, and seasonal jobs to the region. Whether sea otters were observed during a trip influenced how visitors ranked their importance, and the perceived value of the estuary and sea otters. Combined, this study quantified what recreational visitors could contribute to local economies and that sea otters play a role in what visitor’s value about their visit. These results provide additional support to the benefits of species presence at a local scale. We discuss how these types of studies can be used as part of larger species and ecosystem management plans, particularly considering species recovery and range expansion

Prevalence of microplastics and anthropogenic debris within a deep-sea food web

Microplastic particles (\u3c5 mm) are ubiquitous throughout global marine ecosystems, including the deep sea. Ingestion of microplastics and other anthropogenic microparticles is reported in diverse marine taxa across trophic levels. Trophic transfer, or the movement of microplastics across trophic levels, is reported in laboratory studies but not yet widely measured in marine food webs. The Monterey Bay submarine canyon ecosystem contains a well-studied, known deep-sea food web in which to examine the trophic fate of microplastics. We measured microplastic abundance across 17 genera spanning approximately 5 trophic levels and a diversity of feeding behaviors. Samples were collected using remotely operated vehicles and oblique midwater trawls, and gut contents of all individuals examined (n = 157) were analyzed for microplastic abundance and other anthropogenic particles greater than 100 μm using stereo microscopy. Microparticles were analyzed with Raman spectroscopy to confirm material type. Anthropogenic particles were found in all genera examined, across crustacean, fish, mollusk, and gelatinous organisms, in amounts ranging from 0 to 24 particles per individual. There was no significant relationship between microplastic amount and fish trophic level, suggesting that the trophic transfer of microparticles is not occurring. Body size was positively correlated with microplastic abundance across all taxa. The fish genus Scomber sp. drove this relationship, suggesting higher microparticle abundance in mobile individuals with broad horizontal distributions. Future work should examine physiological pathways for microplastic transport within organisms (e.g. excretion, accumulation on gills, internal translocation of particles) and between organisms within shared habitats to more fully understand the fate of microplastics within aquatic food webs

Seabird Trophic Position Across Three Ocean Regions Tracks Ecosystem Differences

We analyze recently collected feather tissues from two species of seabirds, the sooty tern (Onychoprion fuscatus) and brown noddy (Anous stolidus), in three ocean regions (North Atlantic, North Pacific, and South Pacific) with different human impacts. The species are similar morphologically and in the trophic levels from which they feed within each location. In contrast, we detect reliable differences in trophic position amongst the regions. Trophic position appears to decline as the intensity of commercial fishing increases, and is at its lowest in the Caribbean. The spatial gradient in trophic position we document in these regions exceeds those detected over specimens from the last 130 years in the Hawaiian Islands. Modeling suggests that climate velocity and human impacts on fish populations strongly align with these differences

Towards a global understanding of the drivers of marine and terrestrial biodiversity

Understanding the distribution of life’s variety has driven naturalists and scientists for centuries, yet this has been constrained both by the available data and the models needed for their analysis. Here we compiled data for over 67,000 marine and terrestrial species and used artificial neural networks to model species richness with the state and variability of climate, productivity, and multiple other environmental variables. We find terrestrial diversity is better predicted by the available environmental drivers than is marine diversity, and that marine diversity can be predicted with a smaller set of variables. Ecological mechanisms such as geographic isolation and structural complexity appear to explain model residuals and also identify regions and processes that deserve further attention at the global scale. Improving estimates of the relationships between the patterns of global biodiversity, and the environmental mechanisms that support them, should help in efforts to mitigate the impacts of climate change and provide guidance for adapting to life in the Anthropocene

Projecting marine mammal distribution in a changing climate

Climate-related shifts in marine mammal range and distribution have been observed in some populations; however, the nature and magnitude of future responses are uncertain in novel environments projected under climate change. This poses a challenge for agencies charged with management and conservation of these species. Specialized diets, restricted ranges, or reliance on specific substrates or sites (e.g., for pupping) make many marine mammal populations particularly vulnerable to climate change. High-latitude, predominantly ice-obligate, species have experienced some of the largest changes in habitat and distribution and these are expected to continue. Efforts to predict and project marine mammal distributions to date have emphasized data-driven statistical habitat models. These have proven successful for short time-scale (e.g., seasonal) management activities, but confidence that such relationships will hold for multi-decade projections and novel environments is limited. Recent advances in mechanistic modeling of marine mammals (i.e., models that rely on robust physiological and ecological principles expected to hold under climate change) may address this limitation. The success of such approaches rests on continued advances in marine mammal ecology, behavior, and physiology together with improved regional climate projections. The broad scope of this challenge suggests initial priorities be placed on vulnerable species or populations (those already experiencing declines or projected to undergo ecological shifts resulting from climate changes that are consistent across climate projections) and species or populations for which ample data already exist (with the hope that these may inform climate change sensitivities in less well observed species or populations elsewhere). The sustained monitoring networks, novel observations, and modeling advances required to more confidently project marine mammal distributions in a changing climate will ultimately benefit management decisions across time-scales, further promoting the resilience of marine mammal populations

Long-Term Climate Forcing in Loggerhead Sea Turtle Nesting

The long-term variability of marine turtle populations remains poorly understood, limiting science and management. Here we use basin-scale climate indices and regional surface temperatures to estimate loggerhead sea turtle (Caretta caretta) nesting at a variety of spatial and temporal scales. Borrowing from fisheries research, our models investigate how oceanographic processes influence juvenile recruitment and regulate population dynamics. This novel approach finds local populations in the North Pacific and Northwest Atlantic are regionally synchronized and strongly correlated to ocean conditions—such that climate models alone explain up to 88% of the observed changes over the past several decades. In addition to its performance, climate-based modeling also provides mechanistic forecasts of historical and future population changes. Hindcasts in both regions indicate climatic conditions may have been a factor in recent declines, but future forecasts are mixed. Available climatic data suggests the Pacific population will be significantly reduced by 2040, but indicates the Atlantic population may increase substantially. These results do not exonerate anthropogenic impacts, but highlight the significance of bottom-up oceanographic processes to marine organisms. Future studies should consider environmental baselines in assessments of marine turtle population variability and persistence

Author Correction: The vertical distribution and biological transport of marine microplastics across the epipelagic and mesopelagic water column.

An amendment to this paper has been published and can be accessed via a link at the top of the paper