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1. Knowledge of species distribution is critical to ecological management and conservation biology. Effective management requires the detection of populations, which can sometimes be at low densities and is usually based on visual detection and counting. 2. Recently, there has been considerable interest in the detection of short species-specific environmental DNA (eDNA) fragments to allow aquatic species monitoring within different environments due to the potential of greater sensitivity over traditional survey methods which can be time-consuming and costly. 3. Environmental DNA analysis is increasingly being used in the detection of rare or invasive species and has also been applied to eDNA persistence studies and estimations of species biomass and distribution. When combined with next-generation sequencing methods, it has been demonstrated that entire faunas can be identified. 4. Different environments require different sampling methodologies, but there remain areas where laboratory methodologies could be standardized to allow results to be compared across studies. 5. Synthesis and applications. We review recently published studies that use eDNA to monitor aquatic populations, discuss the methodologies used and the application of eDNA analysis as a survey tool in ecology. We include innovative ideas for how eDNA can be used for conservation and management citing test cases, for instance, the potential for on-site analyses, including the application of eDNA analysis to carbon nanotube platforms or laser transmission spectroscopy to facilitate rapid on-site detections. The use of eDNA monitoring is already being adopted in the UK for ecological surveys.

Chemical analysis of calcified structures continues to flourish, as analytical and technological advances enable researchers to tap into trace elements and isotopes taken up in otoliths and other archival tissues at ever greater resolution. Increasingly, these tracers are applied to refine age estimation and interpretation, and to chronicle responses to environmental stressors, linking these to ecological, physiological, and life-history processes. Here, we review emerging approaches and innovative research directions in otolith chemistry, as well as in the chemistry of other archival tissues, outlining their value for fisheries and ecosystem-based management, turning the spotlight on areas where such biomarkers can support decision making. We summarise recent milestones and the challenges that lie ahead to using otoliths and archival tissues as biomarkers, grouped into seven, rapidly expanding and application-oriented research areas that apply chemical analysis in a variety of contexts, namely: (1) supporting fish age estimation; (2) evaluating environmental stress, ecophysiology and individual performance; (3) confirming seafood provenance; (4) resolving connectivity and movement pathways; (5) characterising food webs and trophic interactions; (6) reconstructing reproductive life histories; and (7) tracing stock enhancement efforts. Emerging research directions that apply hard part chemistry to combat seafood fraud, quantify past food webs, as well as to reconcile growth, movement, thermal, metabolic, stress and reproductive life-histories provide opportunities to examine how harvesting and global change impact fish health and fisheries productivity. Ultimately, improved appreciation of the many practical benefits of archival tissue chemistry to fisheries and ecosystem-based management will support their increased implementation into routine monitoring.

1. Translocation is a popular conservation tool, but the outcomes are variable. Many tactics can be used to improve the probability of success, but a comprehensive summary of these does not exist. This increases the risk that valuable tactics will be overlooked, and inhibits effective communication. 2. We assess the diversity of 'translocation tactics' used in mammal and bird translocations, by reviewing the IUCN/SSC Guidelines for Reintroduction and other Conservation Translocations, 195 peer-reviewed articles and 73 case studies from the IUCN/SSC Global Réintroduction Perspectives Series. 3. We recorded descriptions of every technique used to influence the post-release performance of translocated wildlife. We developed the Translocation Tactics Classification System (TTCS) which defines a collection of 30 tactics and organize them into an ecologically relevant framework. We also assess the occurrence of tactics within the Guidelines, the primary literature and the case studies to evaluate how tactics are communicated within these mediums. 4. Our results indicate that the Guidelines are a valuable resource, but do not exhaustively cover tactics, and that detailed methodological accounts are rarely made publicly accessible. This highlights the need to develop context-specific resources to support the Guidelines, and to develop and exploit mediums that facilitate recording of methodological detail, the tactical rationale behind the design and evaluations of effectiveness. Although some forms of grey literature address this issue, the general lack of information limits the ability to investigate the relationship between tactics and translocation success. 5. Synthesis and applications. The Translocation Tactics Classification System (TTCS) provides a checklist which ensures that the full diversity of tactics is considered when developing translocation processes. Standardizing the communication of tactics, and encouraging detailed accounts of applied methodologies to be recorded, along with the tactical reasoning behind the design, will provide operational models and the data required to conduct broad-scale meta-analyses.

Protecting the world’s freshwater resources requires diagnosing threats over a broad range of scales, from global to local. Here we present the first worldwide synthesis to jointly consider human and biodiversity perspectives on water security using a spatial framework that quantifies multiple stressors and accounts for downstream impacts. We find that nearly 80% of the world’s population is exposed to high levels of threat to water security. Massive investment in water technology enables rich nations to offset high stressor levels without remedying their underlying causes, whereas less wealthy nations remain vulnerable. A similar lack of precautionary investment jeopardizes biodiversity, with habitats associated with 65% of continental discharge classified as moderately to highly threatened. The cumulative threat framework offers a tool for prioritizing policy and management responses to this crisis, and underscores the necessity of limiting threats at their source instead of through costly remediation of symptoms in order to assure global water security for both humans and freshwater biodiversity. Dual threat to river biodiversity and water security Access to fresh water is essential for all life forms, but water security for humans and biodiversity are often seen as competing priorities. A new analysis of the threats to the world's rivers breaks new ground by accounting for a broad array of stressors and their downstream effects, from both human and biodiversity perspectives. A subsequent analysis of investments in water resources offers insights into the sources of global disparities in human water security that separate rich from poor. The authors conclude that rivers are in a state of crisis, and that nearly 80% of humanity lives in areas where threat levels are relatively high. River-dwelling species face similarly great challenges around the world. Achieving a sustainable solution to these problems, the authors say, will require creative solutions that jointly address water security for humans and biodiversity, and that treat underlying causes rather than merely symptoms. Water security affects human wellbeing both directly and indirectly, through its effects on biodiversity. Here, a global map has been generated that shows threats to both direct and indirect water security from a full range of potential stressors. Technological investments have also been incorporated. The map shows that nearly 80% of the world's population is exposed to high levels of threat to water security. Investment enables rich nations to offset high stressor levels, but less wealthy nations remain vulnerable.

Global reef fish diversity is studied with metrics incorporating species abundances and functional traits; these identify diversity hotspots corresponding to the diversity of functional traits amongst individuals in the community, and greater evenness in the abundance of reef fishes at higher latitudes, findings that contrast with patterns reported previously using traditional richness-based methods. Cooler biodiversity hotspots revealed Traditional measures of biodiversity record species richness across different areas — in other words, they just count the number of species. This approach takes no account of the fact that different species will have different abundances, or that the range of functional traits present in a community is not dependent solely on the number of species. This paper presents a new measure of functional diversity, incorporating species abundances and functional traits into a global census of a vertebrate group —2,473 marine reef fish species — at 1,844 sites. The results reveal previously unknown diversity hotspots in temperate regions and in the Tropical Eastern Pacific, which are outside the species-rich tropical regions traditionally associated with high biodiversity. Species richness has dominated our view of global biodiversity patterns for centuries 1 , 2 . The dominance of this paradigm is reflected in the focus by ecologists and conservation managers on richness and associated occurrence-based measures for understanding drivers of broad-scale diversity patterns and as a biological basis for management 3 , 4 . However, this is changing rapidly, as it is now recognized that not only the number of species but the species present, their phenotypes and the number of individuals of each species are critical in determining the nature and strength of the relationships between species diversity and a range of ecological functions (such as biomass production and nutrient cycling) 5 . Integrating these measures should provide a more relevant representation of global biodiversity patterns in terms of ecological functions than that provided by simple species counts. Here we provide comparisons of a traditional global biodiversity distribution measure based on richness with metrics that incorporate species abundances and functional traits. We use data from standardized quantitative surveys of 2,473 marine reef fish species at 1,844 sites, spanning 133 degrees of latitude from all ocean basins, to identify new diversity hotspots in some temperate regions and the tropical eastern Pacific Ocean. These relate to high diversity of functional traits amongst individuals in the community (calculated using Rao’s Q 6 ), and differ from previously reported patterns in functional diversity and richness for terrestrial animals, which emphasize species-rich tropical regions only 7 , 8 . There is a global trend for greater evenness in the number of individuals of each species, across the reef fish species observed at sites (‘community evenness’), at higher latitudes. This contributes to the distribution of functional diversity hotspots and contrasts with well-known latitudinal gradients in richness 2 , 4 . Our findings suggest that the contribution of species diversity to a range of ecosystem functions varies over large scales, and imply that in tropical regions, which have higher numbers of species, each species contributes proportionally less to community-level ecological processes on average than species in temperate regions. Metrics of ecological function usefully complement metrics of species diversity in conservation management, including when identifying planning priorities and when tracking changes to biodiversity values.

A predictive understanding of the ecological impacts of nonnative species has been slow to develop, owing largely to an apparent dearth of clearly defined hypotheses and the lack of a broad theoretical framework. The context dependency of impact has fueled the perception that meaningful generalizations are nonexistent. Here, we identified and reviewed 19 testable hypotheses that explain temporal and spatial variation in impact. Despite poor validation of most hypotheses to date, evidence suggests that each can explain at least some impacts in some situations. Several hypotheses are broad in scope (applying to plants and animals in virtually all contexts) and some of them, intriguingly, link processes of colonization and impact. Collectively, these hypotheses highlight the importance of the functional ecology of the nonnative species and the structure, diversity, and evolutionary experience of the recipient community as general determinants of impact; thus, they could provide the foundation for a theoretical framework for understanding and predicting impact. Further substantive progress toward this goal requires explicit consideration of within-taxon and across-taxa variation in the per capita effect of invaders, and analyses of complex interactions between invaders and their biotic and abiotic environments.

Climate change is predicted to become a major threat to biodiversity in the 21st century, but accurate predictions and effective solutions have proved difficult to formulate. Alarming predictions have come from a rather narrow methodological base, but a new, integrated science of climate-change biodiversity assessment is emerging, based on multiple sources and approaches. Drawing on evidence from paleoecological observations, recent phenological and microevolutionary responses, experiments, and computational models, we review the insights that different approaches bring to anticipating and managing the biodiversity consequences of climate change, including the extent of species' natural resilience. We introduce a framework that uses information from different sources to identify vulnerability and to support the design of conservation responses. Although much of the information reviewed is on species, our framework and conclusions are also applicable to ecosystems, habitats, ecological communities, and genetic diversity, whether terrestrial, marine, or fresh water.

Coral reef recovery from major disturbance is hypothesized to depend on the arrival of propagules from nearby undisturbed reefs. Therefore, reefs isolated by distance or current patterns are thought to be highly vulnerable to catastrophic disturbance. We found that on an isolated reef system in north Western Australia, coral cover increased from 9% to 44% within 12 years of a coral bleaching event, despite a 94% reduction in larval supply for 6 years after the bleaching. The initial increase in coral cover was the result of high rates of growth and survival of remnant colonies, followed by a rapid increase in juvenile recruitment as colonies matured. We show that isolated reefs can recover from major disturbance, and that the benefits of their isolation from chronic anthropogenic pressures can outweigh the costs of limited connectivity.

Some people despair that most species will go extinct before they are discovered. However, such worries result from overestimates of how many species may exist, beliefs that the expertise to describe species is decreasing, and alarmist estimates of extinction rates. We argue that the number of species on Earth today is 5 ± 3 million, of which 1.5 million are named. New databases show that there are more taxonomists describing species than ever before, and their number is increasing faster than the rate of species description. Conservation efforts and species survival in secondary habitats are at least delaying extinctions. Extinction rates are, however, poorly quantified, ranging from 0.01 to 1% (at most 5%) per decade. We propose practical actions to improve taxonomic productivity and associated understanding and conservation of biodiversity.

World governments have committed to halting human-induced extinctions and safeguarding important sites for biodiversity by 2020, but the financial costs of meeting these targets are largely unknown. We estimate the cost of reducing the extinction risk of all globally threatened bird species (by > 1 International Union for Conservation of Nature Red List category) to be U.S. $0.875 to $1.23 billion annually over the next decade, of which 12% is currently funded. Incorporating threatened nonavian species increases this total to U.S. $3.41 to $4.76 billion annually. We estimate that protecting and effectively managing all terrestrial sites of global avian conservation significance (11,731 Important Bird Areas) would cost U.S. $ 65.1 billion annually. Adding sites for other taxa increases this to U.S. $76.1 billion annually. Meeting these targets will require conservation funding to increase by at least an order of magnitude.