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Significance The consumption of an important food source, seafood, has increased over the past half century. It is now the most globally traded food commodity and its supply chains are often complex and opaque. Contemporaneous with the growth of overall production, evidence of seafood product mislabeling has become ubiquitous. We show that enabling conditions exist for mislabeling to generate negative impacts on marine populations and to support consumption of products from poorly managed fisheries. More holistic approaches that include consumer and industry engagement, well-designed and targeted testing, and regulatory traceability programs could reduce seafood mislabeling and improve transparency related to impacts of seafood product consumption., Over the past decade, seafood mislabeling has been increasingly documented, raising public concern over the identity, safety, and sustainability of seafood. Negative outcomes from seafood mislabeling are suspected to be substantial and pervasive as seafood is the world’s most highly traded food commodity. Here we provide empirical systems-level evidence that enabling conditions exist for seafood mislabeling in the United States (US) to lead to negative impacts on marine populations and support consumption of products from poorly managed fisheries. Using trade, production, and mislabeling data, we determine that substituted products are more likely to be imported than the product listed on the label. We also estimate that about 60% of US mislabeled apparent consumption associated with the established pairs involves products that are exclusively wild caught. We use these wild-caught pairs to explore population and management consequences of mislabeling. We find that, compared to the product on the label, substituted products come from fisheries with less healthy stocks and greater impacts of fishing on other species. Additionally, substituted products are from fisheries with less effective management and with management policies less likely to mitigate impacts of fishing on habitats and ecosystems compared with the label product. While we provide systematic evidence of environmental impacts from food fraud, our results also highlight the current challenges with production, trade, and mislabeling data, which increase the uncertainty surrounding seafood mislabeling consequences. More integrated, holistic, and collaborative approaches are needed to understand mislabeling impacts and design interventions to minimize mislabeling.

The majority of species at risk of being listed under the United States (U.S.) Endangered Species Act (ESA) relies on habitat located on privately owned land (Turner & Rylander, 1998). There are nu...

The success of conservation efforts for imperiled and endangered wildlife species relies on private landowners, yet a definitive model of landowner cooperation remains elusive. We use a case study to explore the multiple pathways by which demographics, rootedness, resource dependence, environmental attitudes, social influence, and program structure intersect to jointly explain participation in a federally funded cost-share program to help prevent the Lesser Prairie-Chicken from being listed under the U.S. Endangered Species Act. We conducted structured interviews across three ecoregions with 64 participants and 22 nonparticipants. We analyzed the data using fuzzy-set qualitative comparative analysis, an approach that identifies the multiple combinations of conditions related to engagement in the program. We found that two concepts, landowner characteristics and social influence, were most commonly associated with participation while profiles representing typical landowner tropes performed poorly. Finally, the positive effect of encouragement by agency representatives suggests that agency staff play a central role in determining participation. It also suggests landowners' decision processes may not be as deliberative as the literature on private lands conservation suggests. The results of our case study suggest new avenues for research that explicitly consider the role of heuristics in decisions to participate. Pheasants Forever, Grant/Award Number: 68-3A-14-120; USDA National Institute of Food and Agriculture McIntire-Stennis Program, Grant/Award Number: 1007271 Published version

Seafood mislabeling is receiving increased attention by civil society, and programs and policies to address it are being implemented widely. Yet, evidence for the causes of mislabeling are largely limited to anecdotes and untested hypotheses. Mislabeling is commonly assumed to be motivated by the desire to label a lesser value product as a higher value one. Using price data from mislabeling studies, Δmislabel is estimated (i.e., the difference between the price of a labeled seafood product and its substitute when it was not mislabeled) and a meta-analysis is conducted to evaluate the evidence for an overall mislabeling for profit driver for seafood fraud. Evidence is lacking; rather, Δmislabel is highly variable. Country nor location in the supply chain do not account for the observed heterogeneity. The Δmislabel of substitute species, however, provides insights. Some species, such a sturgeon caviar, Atlantic Salmon, and Yellowfin Tuna have a positive Δmislabel, and may have the sufficient characteristics to motivate mislabeling for profit. Atlantic Bluefin Tuna and Patagonian Toothfish have a negative Δmislabel, which could represent an incentive to mislabel in order to facilitate market access for illegally-landed seafood. Most species have price differentials close to zero—suggesting other incentives may be influencing seafood mislabeling. Less than 10% of studies report price information; doing so more often could provide insights into the motivations for fraud. The causes of mislabeling appear to be diverse and context dependent, as opposed to being driven primarily by one incentive.

As a critical stage in the life cycle of ant colonies, nest establishment depends on external and internal factors. This study investigates the effect of the number of queens on queen and worker behavior during nest establishment in invasive Argentine ants (Linepitema humile) and native Mediterranean Tapinoma nigerrimum. We set up experimental colonies with the same number of workers but with one or six queens. At different time points, we recorded the positions of queens and workers inside and outside the nest. Our results highlight the influence of the number of queens on the position of queens and workers with between-species differences. Queens of both species entered the nests more quickly when there were six queens. During nest establishment, more workers were inside nests with six queens for both species, with this effect being greater for T. nigerrimum. Once nests were established, fewer workers of both species were engaged in nest maintenance and feeding in nests with six queens, T. nigerrimum had fewer workers engaged in patrolling. These results suggest that the number of queens is a key factor driving queen and worker behavior during and after nest establishment with different species responses.

While illegal, unreported, and unregulated (IUU) fishing is a premier issue facing ocean sustainability, characterizing it is challenging due to its clandestine nature. Current approaches can be resource intensive and sometimes controversial. Using Chile as an example, we present a structured process leveraging existing capacity, fisheries officers, that provides a monitoring tool to produce transparent and stand-alone estimates on the level, structure, and characteristics of illegal fishing. We provide a national illegal fishing baseline for Chile, estimating illegal activity for 20 fisheries, representing ~ 70% of annual national landings. For four fisheries, we also estimate the relative importance of illegal activities across sectors, stakeholders, and infrastructure. While providing new information, our results also confirm previous evidence on the general patterns of illegality. Our approach provides an opportunity for government agencies to formalize their institutional knowledge, while accounting for potential biases and reducing fragmentation of knowledge that can prevent effective enforcement. Estimating illegal activity directly from fisheries enforcement officers is complementary to existing approaches, providing a cost-effective, rapid, and rigorous method to measure, monitor, and inform solutions to reduce IUU fishing.

While invasive species eradications are at the forefront of biodiversity conservation, ant eradication failures are common. We reviewed ant eradications worldwide to assess the practice and identify knowledge gaps and challenges. We documented 316 eradication campaigns targeting 11 species, with most occurring in Australia covering small areas (

Stawitz and colleagues (2016) present an analysis of seafood mislabeling and make inferences about its financial and ecological implications. We applaud the authors for tackling this important topic. As presented, however, we have reservations about the research which call into question the main conclusions. First, based on the data and results that are presented, there appear to be errors and some of the conclusions are not supported. Second, there may be a bias in the analyses that favors the conclusions. Third, details are lacking regarding the analyses, challenging their verification. We briefly describe some of the issues. This article is protected by copyright. All rights reserved

Allee effects have important implications for many aspects of basic and applied ecology. The benefits of aggregation of conspecific individuals are central to Allee effects, which have led to the widely held assumption that social species are more prone to Allee effects. Robust evidence for this assumption, however, remains rare. Furthermore, previous research on Allee effects has failed to adequately address the consequences of the different levels of organisation within social species' populations. Here, we review available evidence of Allee effects and model the role of demographic and behavioural factors that may combine to dampen or strengthen Allee effects in social species. We use examples across various species with contrasting social structure, including carnivores, bats, primates and eusocial insects. Building on this, we provide a conceptual framework that allows for the integration of different Allee effects in social species. Social species are characterised by nested levels of organisation. The benefits of cooperation, measured by mean individual fitness, can be observed at both the population and group levels, giving rise to "population level" and "group level" Allee effects respectively. We also speculate on the possibility of a third level, reporting per capita benefits for different individuals within a group (e.g. castes in social insects). We show that group size heterogeneity and intergroup interactions affect the strength of population-level demographic Allee effects. Populations with higher group size heterogeneity and in which individual social groups cooperate demonstrate the weakest Allee effects and may thus provide an explanation for why extinctions due to Allee effects are rare in social species. More adequately accounting for Allee effects in social species will improve our understanding of the ecological and evolutionary implications of cooperation in social species.

Many ants are among the most globally significant invasive species. They have caused the local decline and extinction of a variety of taxa ranging from plants to mammals. They disturb ecosystem processes, decrease agricultural production, damage infrastructure and can be a health hazard for humans. Overall, economic costs caused by invasive ants amount to several billion US $ annually. There is general consensus that the future distributions of invasive species are likely to expand with climate change, however this dogma remains poorly tested. Here we model suitable area globally for 15 of the worst invasive ant species, both currently and with predicted climate change (in 2080), globally, regionally and within the world’s 34 biodiversity hotspots. Surprisingly, the potential distribution of only five species was predicted to increase (up to 35.8 %) with climate change, with most declining by up to 63.3 %. The ant invasion hotspots are predominantly in tropical and subtropical regions of South America, Africa, Asia and Oceanic islands, and particularly correspond with biodiversity hotspots. Contrary to general expectations, climate change and invasive ant species will not systematically act synergistically. However, ant invasions will likely remain as a major global problem, especially where invasion hotspots coincide with biodiversity hotspots.

Conservation practitioners are increasingly embracing evidence-based and return on investment (ROI) approaches. Much evidence now exists that documents island biodiversity impacts by invasive mammals. The technical ability to eradicate invasive mammals from islands has increased exponentially; consequently, strategic planning focused on maximizing the ROI is now a limiting factor for island restoration. We use a regional ROI approach to prioritize eradications on islands for seabird conservation in British Columbia, Canada. We do so by integrating economic costs of interventions and applying a resource allocation approach. We estimate the optimal set of islands for eradication under two conservation objectives each with a series of increasing thresholds of population sizes and breeding locations. Our approach (1) identified the most cost-effective interventions, (2) determined whether or not those interventions were nested with increasing thresholds, and (3) helped justify larger investments when appropriate. More often than not, conservation decisions are made at a regional scale, and decision-makers often must make choices on how to allocate funds across a number of potential conservation actions. A regional, ROI framework can serve as a decision-support tool for organizations engaging in discrete interventions in order to maximize benefits for the minimum cost.

Species distribution models (SDMs) have become an important tool to predict the impact of climate change on the distribution of a given species. Generally, projections for a chosen time horizon in the future are compared with the size of the species’ current distribution. In this study, we show that selection of the target time horizon can qualitatively alter the prediction of a species’ future distribution. We illustrate this by assessing the potential distribution of 15 invasive ant species in 2020, 2050 and 2080 at a global scale. Our results indicate that for 6 out of the 15 species modelled, the trend of potential habitat size (i.e., decrease or increase) changed over time following climate change. In four species, the sign of the trend changed, from an initial expansion to a subsequent reduction or vice versa, depending on the date projected to. In some cases, these changes were great (e.g., from an initial increase of 36.5% in 2050 to a decrease of −64.3% in 2080). Our findings stress the importance of using several projection horizons to avoid misled species management decisions.

International audience; Biological invasions are among the greatest threats to global biodiversity, but in contrast to most other global threats, they suffer from specific communication issues. Our paper presents the first new addition to the widely cited IUCN list of ''100 of the world's worst invasive species'', a list created a decade ago in response to these communication issues. We briefly present this list, the recent removal of one species from that list, and the rationale to include a novel, 100th species to replace it. The new species of this list, giant salvinia (Salvinia molesta), was chosen by the community of invasion biologists (over 650 experts from over 60 countries). This new addition to the list will draw public attention to the damage caused by invasive alien species and it will help stimulate the necessary discussion of this critical issue in science and policy circles.

Asclimaticallysuitablerangeprojectionsbecomeincreasinglyusedtoassessdistributionsofspecies, we recommend systematic assessments of the quality of habitat in addition to the classical binary classification of habitat. We devised a method to assess occurrence probability, captured by a climatic suitability index, through which we could determine variations in the quality of potential habitat. This relative risk assessment circumvents the use of an arbitrary suitability threshold. We illustrated our method with 2 case studies on invasive ant species. We estimated invasion potential of the destroyer ant (Monomorium destructor) and the European fire ant (Myrmica rubra) on a global scale currently and by 2080 with climate change. We found that 21.1% of the world's landmass currently has a suitable climate for the destroyer ant and 16% has a suitable climate for European fire ant. Our climatic suitability index showed that both ant species would benefit from climate change, but in different ways. The size of the potential distribution increased by 35.8% for the destroyer ant. Meanwhile, the total area of potential distribution remained the same for the European fire ant (>0.05%), but the level of climatic suitability within this range increased greatly and led to an improvement in habitat quality (i.e., of invasive species' establishment likelihood). Either through quantity or quality of suitable areas, both invasive ant species are likely to increase the extent of their invasion in the future, following global climate change. Our results show that species may increase their range if either more areas become suitable or if the available areas present improved suitability. Studies in which an arbitrary suitability threshold was used may overlook changes in area quality within climatically suitable areas and as a result reach incorrect predictions.

Agence Nationale de la Recherche (Sextinction project) ANR-2010-BLAN-1717 (RARE project) ANR-2009-PEXT-01001 Fondation de Recherche sur la Biodiversite (VORTEX project) APP-IN-2009-052; The Allee effect is a theoretical model predicting low growth rates and the possible extinction of small populations. Historically, studies of the Allee effect have focused on demography. As a result, underlying processes other than the direct effect of population density on fitness components are not generally taken into account. There has been heated debate about the potential of genetic processes to drive small populations to extinction, but recent studies have shown that such processes clearly impact small populations over short time scales, and some may generate Allee effects. However, as opposed to the ecological Allee effect, which is underpinned by cooperative interactions between individuals, genetically driven Allee effects require a change in genetic structure to link the decline in population size with a decrease in fitness components. We therefore define the genetic Allee effect as a two-step process whereby a decrease in population size leads to a change in population genetic structure and, in turn, to a decrease in individual fitness. We describe potential underlying mechanisms and review the evidence for this original type of component Allee effect, using published examples from both plants and animals. The possibility of considering demogenetic feedback in light of genetic Allee effects clarifies the analysis and interpretation of demographic and genetic processes, and the interplay between them, in small populations.

Small-scale habitat complexity has been shown to influence interspecific competition and resource use in ant communities. Nevertheless, in Mediterranean communities, where temperature variations have a stronger effect on the foraging of subordinate species than competition by dominants, the effect of small-scale habitat complexity on resource use by ants is unknown. We investigated the influence of an experimental spatial mosaic of microhabitats (interior, edge and open) on the dynamics of resource use in a guild of ants of a Mediterranean grassland. We used baits containing one of three food resource types (honey, tuna and seeds) placed in the different microhabitats. Variation in resource use among microhabitats appears to result from differential responses among ant species to small-scale spatial heterogeneity. Analysis of frequency of occurrence, number of foragers and monopoly at baits of ant species indicated that the resource use and recruitment intensity was modified by microhabitat, once the effect of temperature was removed from the analysis. Thus, foraging activity and competitive interactions of ant species were influenced by the different microhabitats apart from temperature, which suggests an effect of small-scale structural complexity. Small-scale spatial variations in structural complexity have an effect in resource use by most ants in this system that is not wholly explained by differences in temperature. Finally, this suggests that microhabitat may be one factor influencing the outcome of the dominance hierarchies.

Summary 1. Allee effects occur when the aggregation of individuals result in mutually beneficial intraspecific interactions whereby individual fitness, or per capita growth rate, increases with the number of individuals. Allee effects are common in social species due to their cooperative behaviours, such as breeding, feeding or defence. Allee effects have important implications for many aspects of basic and applied ecology. Over the past decades, the study of Allee effects has influenced population dynamics, community ecology, endangered species management and invasion biology. 2. Despite the fact that cooperation is the basis of their social structure, Allee effects have received little attention among eusocial insects. Extreme cooperation is common, and reproductive specialization of individuals occurs due to division of labour. These life-history traits suggest that the potential contribution of each caste to reproduction and survival may be differential and nonadditive. 3. We studied Allee effects in the invasive Argentine ant (Linepithema humile). In this species, many queens and workers are present in colonies, which allowed us to explore the differential effects of castes on the presence of Allee effects. In the laboratory, we measured brood production and individual survival in experimental colonies that differed in the initial numbers of queens and workers. 4. Our results highlight the differential effect of queens and workers on survival and productivity. We found three positive density-dependent relationships indicative of component Allee effects at the colony level: both workers and queens had a positive effect on the productivity of the other caste, and queens had a positive effect on worker survivorship. 5. Our experimental results suggest a potential positive feedback between worker and queen abundance, which may have contributed to the evolution of large colony sizes. Our study provides the first evidence of Allee effects in eusocial insects and highlights the need to consider castes separately in population dynamics. Division of labour and differential reproductive rates are factors that should be integrated into the study of Allee effects.

As climatically suitable range projections become increasingly used to assess distributions of species, we recommend systematic assessments of the quality of habitat in addition to the classical binary classification of habitat. We devised a method to assess occurrence probability, captured by a climatic suitability index, through which we could determine variations in the quality of potential habitat. This relative risk assessment circumvents the use of an arbitrary suitability threshold. We illustrated our method with 2 case studies on invasive ant species. We estimated invasion potential of the destroyer ant (Monomorium destructor) and the European fire ant (Myrmica rubra) on a global scale currently and by 2080 with climate change. We found that 21.1% of the world's landmass currently has a suitable climate for the destroyer ant and 16% has a suitable climate for European fire ant. Our climatic suitability index showed that both ant species would benefit from climate change, but in different ways. The size of the potential distribution increased by 35.8% for the destroyer ant. Meanwhile, the total area of potential distribution remained the same for the European fire ant (0.05%), but the level of climatic suitability within this range increased greatly and led to an improvement in habitat quality (i.e., of invasive species' establishment likelihood). Either through quantity or quality of suitable areas, both invasive ant species are likely to increase the extent of their invasion in the future, following global climate change. Our results show that species may increase their range if either more areas become suitable or if the available areas present improved suitability. Studies in which an arbitrary suitability threshold was used may overlook changes in area quality within climatically suitable areas and as a result reach incorrect predictions. Incremento de la Cantidad y Calidad de Áreas Idóneas para Especies Invasoras a Medida que Cambia el Clima.

Since the middle of the 20th century, the Tibetan antelope (Pantholops hodgsonii) has been poached for its wool to make luxury shawls, shahtoosh. This direct overexploitation caused a drastic decline in their population, with a loss of more than 90% compared to the baseline population a few decades ago. Assuming this is an anthropogenic Allee effect (AAE), human attraction for rarity can drive rare species to extinction, which could explain the increasing rates of antelope harvests, paralleling the escalating prices of shahtoosh as the species got rarer. Since 1999, international concern led to conservation actions and the population soon started increasing. This unique situation allowed the presence of an AAE in Tibetan antelope to be tested, as well as an assessment of the potential effects of conservation actions in the presence of this process. We developed a theoretical discrete-time population dynamics model and examined effects of variation in shahtoosh prices. Furthermore, we tested the effects of major conservation actions into our models assessing their relative contribution to population recovery. During the exploitation phase, we found some evidence supporting the presence of an AAE compared to non-AAE models when hunting ceased at antelope population sizes below 10% of the initial population size. Regarding the conservation phase, our results suggested that poacher numbers reduction had the most likely positive impact on Tibetan antelope population dynamics. As many other species are similarly declining and/or close to extinction, our results suggest that adequate conservation actions could counter the most dramatic declines, even when populations have entered an extinction vortex.

Climate change and invasive species are two of the most serious threats of biodiversity. A general concern is that these threats interact, and that a globally warming climate could favour invasive species. In this study we investigate the invasive potential of one of the “100 of the world’s worst invasive species”, the big-headed ant Pheidole megacephala. Using ecological niche models, we estimated the species’ potential suitable habitat in 2020, 2050 and 2080. With an ensemble forecast obtained from five different modelling techniques, 3 Global Circulation Models and 2 CO2 emission scenarios, we generated world maps with suitable climatic conditions and assessed changes, both qualitatively and quantitatively. Almost one-fifth (18.5 %) of the landmass currently presents suitable climatic conditions for P. megacephala. Surprisingly, our results also indicate that the invasion of big-headed ants is not only unlikely to benefit from climate change, but may even suffer from it. Our projections show a global decrease in the invasive potential of big-headed ants as early as 2020 and becoming even stronger by 2080 reaching a global loss of 19.4 % of area with favourable climate. The decrease is observable in all 6 broad regions, being greatest in the Oceania and lowest in Europe.