Networks of global bird invasion altered by regional trade ban

Structure, conservation and health implications of urban wild meat value chains: A case study of Lagos, Nigeria

Urban wild meat value chains represent a vital source of protein and livelihood intertwined with culture and complex market systems. Against the backdrop of escalating zoonotic disease concerns linked to wild meat, this research aimed to unravel the structure, governance, species composition and actor characteristics of the wild meat value chain in Lagos, Africa's most populated city. We employed a cross-sectional study design incorporating qualitative and quantitative approaches. Interviews (n = 22) were conducted and structured questionnaires were administered to participants (n = 257) across 15 sites in Lagos. Participants' activities were also observed, and field notes were taken. Descriptive statistics and inductive thematic approach were used for data analysis. Findings revealed five main value chain nodes: hunter, processor, wholesale, retail and consumer; and five major geographical areas from which wild meat flowed into the city. Governance structures showed a blend of informal and formal mechanisms sustained through trust, cultural beliefs and informal regulations. The main motivation was income (88.1 %), and period of optimum activity was at night times (53 %) during the dry season (≥ 62 %). Women (62.2 %) dominated the value chain, prevalent at the wholesaler (61.7 %), processor (89.7 %) and retailer (83 %) nodes. Hunters (40 %) were able to supply wild meat directly to consumers, and the large-scale retailers (26 %) were responsible for exportation of wild meat. A total of 35 species were traded in the value chain, and the most commonly traded species were: grasscutters, duikers, porcupines, and giant-pouched rats (≥90.7 % participants). Pottos, buffalos, tortoises and house snakes were the least traded (≤ 7.0 % participants). This study provides an understanding of Lagos wildlife trade from a value chain perspective, paving the way for interventions to address wildlife conservation challenges and spillover risks. Species traded in the value chain have been globally reported as reservoirs of zoonotic pathogens, representing a source of zoonotic spillover risks to actors. Also, the ability of hunters to supply wild meat directly to consumers signals an increase in the speed of zoonotic pathogen spread, and portends a greater risk for public health. Formal governance should be integrated into the value chain to aid effective monitoring and regulation. Conservation and public health interventions should be node-specific and gender-sensitive, targeting the dry seasons when actors' activities peak, and risks of human-wild meat contact are greater. There is need for the re-assessment of the conservation statuses of West Africa's wildlife species to reflect current realities foisted by wild meat trade.

Alien range size, habitat breadth, origin location, and domestication of alien species matter to their impact risks

Invasive alien species are a major driver of biodiversity loss. Currently, the process of biological invasions is experiencing a constant acceleration, foreshadowing a future increase in the threat posed by invasive alien species to global biodiversity. Therefore, it is necessary to assess the impact risks of invasive alien species and related factors. Here, we constructed a dataset of negative environmental impact events to evaluate the impact risks of alien species. We collected information on 1071 established alien terrestrial vertebrates and then gathered negative environmental impacts for 108 of those species. Generalized linear mixed-effects model and phylogenetic generalized least-squares regression model were used to examine the characteristic (including life-history traits, characteristics related to distribution, and introduction event characteristics) correlates of species' impact risks at the global scale for 108 established alien terrestrial vertebrates (mammals, birds, reptiles and amphibians). Our results showed that a total of 3158 negative environmental impacts were reported for 108 harmful species across 71 countries worldwide. Factors associated with impact risks varied slightly among taxa, but alien range size, habitat breadth, origin location, and domestication were significantly correlated with impact risks. Our study aims to identify the characteristics of alien species with high-impact risks to facilitate urgent assessment of alien species and to protect the local ecological environment and biodiversity.

The magnitude of legal wildlife trade and implications for species survival

The unsustainable use of wildlife is a primary driver of global biodiversity loss. No comprehensive global dataset exists on what species are in trade, their geographic origins, and trade's ultimate impacts, which limits our ability to sustainably manage trade. The United States is one of the world's largest importers of wildlife, with trade data compiled in the US Law Enforcement Management Information System (LEMIS). The LEMIS provides the most comprehensive publicly accessible wildlife trade database of non-the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) listed species. In total, 21,097 species and over 2.85 billion individuals were traded over the past 22 y (2000-2022). When LEMIS data are combined with CITES records, the United States imported over 29,445 wild species, including over 50% of all globally described species in some taxonomic groups. For most taxa, around half of the individuals are declared as sourced from the wild. Although the LEMIS provides the only means to assess trade volumes for many taxa, without any associated data on most wild populations, it is impossible to assess the impact on biodiversity, sustainability of trade, or any potential risk of pest or pathogen spread. These insights underscore the considerable underestimation of trade and the urgent need for other countries to adopt similar mechanisms to accurately record trade.

Preventing zoonotic spillover through regulatory frameworks governing wildlife trade: A scoping review

Wildlife trade can create adverse impacts for biodiversity and human health globally, including increased risks for zoonotic spillover that can lead to pandemics. Institutional responses to zoonotic threats posed by wildlife trade are diverse; understanding regulations governing wildlife trade is an important step for effective zoonotic spillover prevention measures. In this review, we focused on peer-reviewed studies and grey literature conducted on regulatory approaches that govern domestic and international wildlife trade in order to assess the role of local, national and global-level institutions in the prevention of zoonotic spillover and infection transmission between humans. The five-stage scoping review protocol described by Arksey and O'Malley to map key concepts and main sources and types of evidence available was followed to understand and analyze empirical evidence from peer-reviewed studies and grey literature conducted on regulatory approaches that govern domestic and international wildlife. Sources were included if they discuss at least one of three points: regulatory approaches governing the wild animal trade, including wild animal markets, traditional medicine or exotic pets; regulatory approaches governing importation of wild animals and the international wildlife supply chain; or the role of local, national, and global-level institutions in regulating wild animal trade for food, traditional medicine or exotic pets. A total of 1598 sources were retrieved, from which 32 sources were included in the final review (30 studies + 2 grey literature reports). Based on published literature, regulations governing wildlife trade are inconsistent within and between countries. Organizations regulating wildlife trade may have competing interests, which can lead to fragmentation and a lack in coordination and oversight. National compliance with international regulations can be an issue. Reducing the probability of spillover events in wildlife trade is key to prevent future pandemics. Our results indicate a need for enhanced regulatory harmonization within and between national and supranational regulations. Coordination and collaboration for prevention of zoonotic infection and spillover may be enhanced through future research focused on the effectiveness of timely Information sharing and global- and national- level harmonization of wildlife trade regulations.

China's International Trade of Parrots from 1981 to 2022 Based on the CITES Trade Database

Parrots are popular with pet consumers and are one of the most traded groups of live birds around the world. China has been considered as an important country in bird trades, but we know little about China's import and export of parrots. Using the latest data available from the CITES Trade Database, we analyzed China's import and export of CITES-listed live parrots from 1981-2022 to better understand the patterns and dynamics of these trades. China imported 155,339 parrots of 173 species and exported 608,987 parrots of 42 species during the study period with an annual average of about 18,500 individuals, accounting for c. 5% of the global average number. The most imported parrots to China were Grey Parrot (Psittacus erithacus) and Monk Parakeet (Myiopsitta monachus), while the most exported ones were Fisher's Lovebirds (Agapornis fischeri), Rosy-faced Lovebirds (Agapornis roseicollis), and Yellow-collared Lovebird (Agapornis personatus). Since the early 21st century, China's imports of parrots gradually increased, but exports decreased more pronouncedly, making China's international parrot trade volume declining in the past 20 years. China's international parrot trade routes also changed over time, with the destination of parrot exports shifting from Europe to Africa and the Arabian region, while more parrots being gradually imported from countries in South America and Africa. The vast majority of parrots exported from China were captive-bred non-native species like Fisher's Lovebirds, while a substantial proportion of imported parrots were wild-sourced and the proportion has been increasing in the last decade. The fact that China exported much more parrots than imported suggests existence of large-scale parrot farming and domestic parrot trade in China. Attention needs to be paid to monitoring China's import of increasing proportion of wild-sourced parrots from South America countries and its potential impacts on their wild populations. Close monitoring of and more studies on domestic and illegal parrot trade are essential to fully understand the role China plays in the international trade of parrots.

Global invasion and biosecurity risk from the online trade in ornamental crayfish

Trade in undomesticated ornamental animals has rapidly expanded beyond brick-and-mortar retail stores to now include growing numbers of internet marketplaces. The growing volume, diversity, and origins of invasive non-native species in trade challenge already weak national biosecurity policies. Despite widespread focus on vertebrates, many knowledge gaps exist regarding the online global trade of ornamental invertebrates. We conducted the first global assessment of the online trade in and associated invasion risk of freshwater crayfishes, which are increasingly popular aquarium animals. We systematically examined e-commerce marketplaces in multiple languages, scrapping information that included species identity, price, quantity, and shipping designation from each crayfish listing. Next, we combined geographic pathways of shipping associated with online trade (introduction risk) and environmental suitability modeling (establishment risk) to estimate global risk of non-native crayfish invasion risk. We identified hundreds of online marketplaces and thousands of sale listings in 33 countries (5 continents) involving 60 species and representing a selling value of ∼US$1.5 million. Invasion risk of non-native crayfish in trade was widespread, with geographic hotspots coinciding with both elevated opportunities for introduction (greater shipping offerings) and establishment. Precise characterization of the online species trade is fundamental to support new and reformed biosecurity policies, build industry partnerships, and design educational campaigns to prevent species invasions through trade. We found that the taxonomy, geography, and economics of the global online ornamental crayfish trade are vast and require greater attention.

Rethinking ecological niches and geographic distributions in face of pervasive human influence in the Anthropocene

Species are distributed in predictable ways in geographic spaces. The three principal factors that determine geographic distributions of species are biotic interactions (B), abiotic conditions (A), and dispersal ability or mobility (M). A species is expected to be present in areas that are accessible to it and that contain suitable sets of abiotic and biotic conditions for it to persist. A species' probability of presence can be quantified as a combination of responses to B, A, and M via ecological niche modeling (ENM; also frequently referred to as species distribution modeling or SDM). This analytical approach has been used broadly in ecology and biogeography, as well as in conservation planning and decision-making, but commonly in the context of 'natural' settings. However, it is increasingly recognized that human impacts, including changes in climate, land cover, and ecosystem function, greatly influence species' geographic ranges. In this light, historical distinctions between natural and anthropogenic factors have become blurred, and a coupled human-natural landscape is recognized as the new norm. Therefore, B, A, and M (BAM) factors need to be reconsidered to understand and quantify species' distributions in a world with a pervasive signature of human impacts. Here, we present a framework, termed human-influenced BAM (Hi-BAM, for distributional ecology that (i) conceptualizes human impacts in the form of six drivers, and (ii) synthesizes previous studies to show how each driver modifies the natural BAM and species' distributions. Given the importance and prevalence of human impacts on species distributions globally, we also discuss implications of this framework for ENM/SDM methods, and explore strategies by which to incorporate increasing human impacts in the methodology. Human impacts are redefining biogeographic patterns; as such, future studies should incorporate signals of human impacts integrally in modeling and forecasting species' distributions.

Parrots in the wild in Polish cities

Amateur breeding of parrots as pets has contributed to many species being found in areas where they never occurred in the wild, particularly in warmer regions, but also in the temperate climates of North America and Europe. Climate change is likely to exacerbate this process. We hypothesised that parrots occurred in the wild in the cities of Poland, especially the rose-ringed parakeet, as there are reports of breeding sites in the literature. Using information on lost, found and sighted parrots posted on social media, we have analysed the extent of parrot emergence in Poland. In a period of less than two years (from October 2018, through 2019 and from June to the end of December 2021), 2,675 parrot specimens of 49 species were found in the wild. The most frequently observed species were cockatiel Nymphicus hollandicus (N = 962), budgerigar Melopsittacus undulatus (N = 884) and rose-ringed parakeet Psittacula krameri (N = 182). Parrots were most frequently observed in urban areas, in regions characterized by a higher population size, a higher income and a higher proportion of people with a university degree. Our study shows that the occurrence of parrots, especially rose-ringed parakeets in the wild, needs to be monitored as new breeding sites may appear.

Quantifying global colonization pressures of alien vertebrates from wildlife trade

The global trade in live wildlife elevates the risk of biological invasions by increasing colonization pressure (the number of alien species introduced to an area). Yet, our understanding of species traded as aliens remains limited. We created a comprehensive global database on live terrestrial vertebrate trade and use it to investigate the number of traded alien species, and correlates of establishment richness for aliens. We identify 7,780 species involved in this trade globally. Approximately 85.7% of these species are traded as aliens, and 12.2% of aliens establish populations. Countries with greater trading power, higher incomes, and larger human populations import more alien species. These countries, along with island nations, emerge as hotspots for establishment richness of aliens. Colonization pressure and insularity consistently promote establishment richness across countries, while socio-economic factors impact specific taxa. Governments must prioritize policies to mitigate the release or escape of traded animals and protect global biosecurity.

Biophysical models accurately characterize the thermal energetics of a small invasive passerine bird

Effective management of invasive species requires accurate predictions of their invasion potential in different environments. By considering species' physiological tolerances and requirements, biophysical mechanistic models can potentially deliver accurate predictions of where introduced species are likely to establish. Here, we evaluate biophysical model predictions of energy use by comparing them to experimentally obtained energy expenditure (EE) and thermoneutral zones (TNZs) for the common waxbill Estrilda astrild, a small-bodied avian invader. We show that biophysical models accurately predict TNZ and EE and that they perform better than traditional time-energy budget methods. Sensitivity analyses indicate that body temperature, metabolic rate, and feather characteristics were the most influential traits affecting model accuracy. This evaluation of common waxbill energetics represents a crucial step toward improved parameterization of biophysical models, eventually enabling accurate predictions of invasion risk for small (sub)tropical passerines.

Determining the sustainability of legal wildlife trade

Exploitation of wildlife represents one of the greatest threats to species survival according to the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. Whilst detrimental impacts of illegal trade are well recognised, legal trade is often equated to being sustainable despite the lack of evidence or data in the majority of cases. We review the sustainability of wildlife trade, the adequacy of tools, safeguards, and frameworks to understand and regulate trade, and identify gaps in data that undermine our ability to truly understand the sustainability of trade. We provide 183 examples showing unsustainable trade in a broad range of taxonomic groups. In most cases, neither illegal nor legal trade are supported by rigorous evidence of sustainability, with the lack of data on export levels and population monitoring data precluding true assessments of species or population-level impacts. We propose a more precautionary approach to wildlife trade and monitoring that requires those who profit from trade to provide proof of sustainability. We then identify four core areas that must be strengthened to achieve this goal: (1) rigorous data collection and analyses of populations; (2) linking trade quotas to IUCN and international accords; (3) improved databases and compliance of trade; and (4) enhanced understanding of trade bans, market forces, and species substitutions. Enacting these core areas in regulatory frameworks, including CITES, is essential to the continued survival of many threatened species. There are no winners from unsustainable collection and trade: without sustainable management not only will species or populations become extinct, but communities dependent upon these species will lose livelihoods.

Mechanistic models project bird invasions with accuracy

Invasive species pose a major threat to biodiversity and inflict massive economic costs. Effective management of bio-invasions depends on reliable predictions of areas at risk of invasion, as they allow early invader detection and rapid responses. Yet, considerable uncertainty remains as to how to predict best potential invasive distribution ranges. Using a set of mainly (sub)tropical birds introduced to Europe, we show that the true extent of the geographical area at risk of invasion can accurately be determined by using ecophysiological mechanistic models that quantify species' fundamental thermal niches. Potential invasive ranges are primarily constrained by functional traits related to body allometry and body temperature, metabolic rates, and feather insulation. Given their capacity to identify tolerable climates outside of contemporary realized species niches, mechanistic predictions are well suited for informing effective policy and management aimed at preventing the escalating impacts of invasive species.

Seasonal variation in thermoregulatory capacity of three closely related Afrotropical Estrildid finches introduced to Europe

A species' potential geographical range is largely determined by how the species responds physiologically to its changing environment. It is therefore crucial to study the physiological mechanisms that species use to maintain their homeothermy in order to address biodiversity conservation challenges, such as the success of invasions of introduced species. The common waxbill Estrilda astrild, the orange-cheeked waxbill E. melpoda, and the black-rumped waxbill E. troglodytes are small Afrotropical passerines that have established invasive populations in regions where the climate is colder than in their native ranges. As a result, they are highly suitable species for studying potential mechanisms for coping with a colder and more variable climate. Here, we investigated the magnitude and direction of seasonal variation in their thermoregulatory traits, such as basal (BMR), summit (M_sum) metabolic rates and thermal conductance. We found that, from summer to autumn, their ability to resist colder temperatures increased. This was not related to larger body masses or higher BMR and M_sum, but instead, species downregulated BMR and M_sum toward the colder season, suggesting energy conservation mechanisms to increase winter survival. BMR and M_sum were most strongly correlated with temperature variation in the week preceding the measurements. Common waxbill and black-rumped waxbill, whose native ranges encompass the highest degree of seasonality, showed the most flexibility in metabolic rates (i.e., stronger downregulation toward colder seasons). This ability to adjust thermoregulatory traits, combined with increased cold tolerance, may facilitate their establishment in areas characterized by colder winters and less predictable climates.

A Review of the Trade in Toucans (Ramphastidae): Levels of Trade in Species, Source and Sink Countries, Effects from Governance Actions and Conservation Concerns

Utilising wildlife as natural resources has a long history and wide appeal for many nations, while seeking international wildlife that is sustainably managed is the primary responsibility of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, data-driven trade reviews are required, utilising CITES data to increase our understanding of the trade and facilitate evidence-based conservation planning. This study presents the first trade review for Toucans utilising CITES import reported data. The total number of Toucans exported was over 22,000, which subsequently generated a retail ‘real price’ value of nearly US $72 million. The countries accounting for the majority of Toucan exports were Guyana (39%), Suriname (33%) and Nicaragua (14%), while the main importing country was The Netherlands (nearly 25%). Toucan species traded were Ramphastos vitellinus (accounting for 21.5%), Ramphastos toco (19%) and Ramphastos tucanus (17%), making the top three while trade was recorded in 10 species. However, successfully identifying economic values for 15 species highlights that trade exists within non-CITES listed Toucan species too. Therefore, the levels of trade in non-CITES-listed Toucan species need urgent attention, as do the non-detrimental findings that underpin the CITES quotas set for each species, given the species’ importance ecologically.

Investigation and sequence analysis of psittacine beak and feather disease virus and avian polyomavirus from companion birds in Windhoek, Namibia

The commercial farming and trading of parrots and ornamental birds as companion animals are important economic activities in many countries. Some of the bird species farmed/traded are captured from the wild or are closely related to wild birds and therefore represent a risk of pathogen exchange/introduction. Beak and feather disease virus (BFDV) and avian poliomavirus (APV) are among the viruses with the biggest impact on companion bird populations and have been detected in different hosts worldwide. Despite their relevance for both domesticated and wild birds, our knowledge of BFDV and APV epidemiology remains limited in several African countries. In the present study, 143 cloacal swabs were collected from companion birds in Windhoek, Namibia, and tested by polymerase chain reaction for BFDV and APV. Of the samples tested, 35/143 (24.48%) tested positive for BFDV; 11/143 (7.69%) were positive for APV; and 6/143 (4.2%) tested positive for both pathogens. Positive amplicons, consisting of segments of the ORF1 and VP1 genes, were sequenced and compared with sequences from viruses identified in other countries. Four Namibian-only clades of BFDV were identified, loosely related to foreign strains, which suggest the occurrence of multiple introduction events in the past, potentially from South Africa, followed by local, independent evolution. In contrast, the Namibian APV sequences were identical to each other and form a single clade. In both instances, no correlation was observed between the sampling host and the viral phylogeny, suggesting the absence of host-specific adaptation and a remarkable, unconstrained viral circulation within Namibian borders. Therefore, while regulations and control measures developed against foreign strain introduction have proven to be effective over time, the spread of BFDV and APV within Namibia's borders appears undeterred. Additional resources should be dedicated to limit strain circulation in commercial farming facilities, markets and small-scale traders.

Mobile Zoos and Other Itinerant Animal Handling Events: Current Status and Recommendations for Future Policies

Mobile zoos are events in which non-domesticated (exotic) and domesticated species are transported to venues such as schools, hospitals, parties, and community centres, for the purposes of education, entertainment, or social and therapeutic assistance. We conducted literature searches and surveyed related government agencies regarding existing provisions within laws and policies, number of mobile zoos, and formal guidance issued concerning operation of such events in 74 countries or regions. We also examined governmental and non-governmental guidance standards for mobile zoos, as well as websites for mobile zoo operations, assessed promotional or educational materials for scientific accuracy, and recorded the diversity of species in use. We used the EMODE (Easy, Moderate, Difficult, or Extreme) algorithm, to evaluate identified species associated with mobile zoos for their suitability for keeping. We recorded 14 areas of concern regarding animal biology and public health and safety, and 8 areas of false and misleading content in promotional or educational materials. We identified at least 341 species used for mobile zoos. Mobile zoos are largely unregulated, unmonitored, and uncontrolled, and appear to be increasing. Issues regarding poor animal welfare, public health and safety, and education raise several serious concerns. Using the precautionary principle when empirical evidence was not available, we advise that exotic species should not be used for mobile zoos and similar itinerant events.

The ecological drivers and consequences of wildlife trade

Wildlife trade is a key driver of extinction risk, affecting at least 24% of terrestrial vertebrates. The persistent removal of species can have profound impacts on species extinction risk and selection within populations. We draw together the first review of characteristics known to drive species use - identifying species with larger body sizes, greater abundance, increased rarity or certain morphological traits valued by consumers as being particularly prevalent in trade. We then review the ecological implications of this trade-driven selection, revealing direct effects of trade on natural selection and populations for traded species, which includes selection against desirable traits. Additionally, there exists a positive feedback loop between rarity and trade and depleted populations tend to have easy human access points, which can result in species being harvested to extinction and has the potential to alter source-sink dynamics. Wider cascading ecosystem repercussions from trade-induced declines include altered seed dispersal networks, trophic cascades, long-term compositional changes in plant communities, altered forest carbon stocks, and the introduction of harmful invasive species. Because it occurs across multiple scales with diverse drivers, wildlife trade requires multi-faceted conservation actions to maintain biodiversity and ecological function, including regulatory and enforcement approaches, bottom-up and community-based interventions, captive breeding or wildlife farming, and conservation translocations and trophic rewilding. We highlight three emergent research themes at the intersection of trade and community ecology: (1) functional impacts of trade; (2) altered provisioning of ecosystem services; and (3) prevalence of trade-dispersed diseases. Outside of the primary objective that exploitation is sustainable for traded species, we must urgently incorporate consideration of the broader consequences for other species and ecosystem processes when quantifying sustainability.

The U.S. market for imported wildlife not listed in the CITES multilateral treaty

The international wildlife trade presents severe conservation and environmental security risks, yet no international regulatory framework exists to monitor the trade of species not listed in the appendices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). We explored the composition and dynamics of internationally regulated versus nonregulated trade, with a focus on importations of wild-caught terrestrial vertebrates entering the United States from 2009 to 2018. We used 10 years of species-level trade records of the numbers of live, wild-caught animals imported to the United States and data on International Union for the Conservation of Nature (IUCN) estimates of extinction risk to determine whether there were differences in the diversity, abundance, and risk to extinction among imports of CITES-listed versus unlisted species. We found 3.6 times the number of unlisted species in U.S. imports compared with CITES-listed species (1366 vs. 378 species). The CITES-listed species were more likely to face reported conservation threats relative to unlisted species (71.7% vs. 27.5%). However, 376 unlisted species faced conversation threats, 297 species had unknown population trends, and 139 species were without an evaluation by the IUCN. Unlisted species appearing for the first time in records were imported 5.5 times more often relative to CITES-listed species. Unlisted reptiles had the largest rate of entry, averaging 53 unique species appearing in imports for the first time per year. Overall trade quantities were approximately 11 times larger for imports of unlisted species relative to imports of CITES-listed species. Countries that were top exporters of CITES-listed species were mostly different from exporters of unlisted species. Because of the vulnerabilities of unlisted, traded species entering the United States and increasing global demand, we strongly recommend governments adapt their policies to monitor and report on the trade of all wildlife.

Polymorphisms of CRELD1 and DNAJC30 and their relationship with chicken carcass traits

Carcass traits play important roles in the broiler industry and single nucleotide polymorphism (SNP) can be efficient molecular markers for marker-assisted breeding of chicken carcass traits. Based on our previous RNA-seq data (accession number GSE58755), cysteine rich with epidermal growth factor like domains 1 (CRELD1) and DnaJ heat shock protein family member C30 (DNAJC30) are differentially expressed in breast muscle between white recessive rock chicken (WRR) and Xinghua chicken (XH). In this study, we further characterize the potential function and SNP mutation of CRELD1 and DNAJC30 in chicken for the first time. According to protein interaction network and enrichment analysis, CRELD1 and DNAJC30 may play some roles in chicken muscle development and fat deposition. In WRR and XH, the results of the relative tissue expression pattern demonstrated that CRELD1 and DNAJC30 are not only differentially expressed in breast muscle but also leg muscle and abdominal fat. Therefore, we identified 5 SNP sites of CRELD1 and 7 SNP sites of DNAJC30 and genotyped them in an F₂ chicken population. There are 4 sites of CRELD1 and 3 sites of DNAJC30 are associated with chicken carcass traits like breast muscle weight, body weight, dressed weight, leg weight percentage, eviscerated weight with giblet percentage, intermuscular adipose width, shank length, and girth. These results suggest that the SNP sites of CRELD1 and DNAJC30 can be potential molecular markers to improve the chicken carcass traits and lay the foundation for marker-assisted selection.

Wildlife trade targets colorful birds and threatens the aesthetic value of nature

A key component of nature's contribution to people is aesthetic value.^1,2 Charismatic species rally public support and bolster conservation efforts.^3,4 However, an insidious aspect to humanity's valuation of nature is that high value also drives wildlife trade,^5,6 which can spearhead the demise of prized species.^7-9 Here, we explore the antagonistic roles of aesthetic value in biodiversity conservation by using novel metrics of color to evaluate the aesthetics of the most speciose radiation of birds: passerines (i.e., the perching birds). We identify global color hotspots for passerines and highlight the breadth of color in the global bird trade. The tropics emerge as an epicentre of color, encompassing 91% and 65% of the world's most diverse and most uniquely colored passerine assemblages, respectively. We show that the pet trade, which currently affects 30% of passerines (1,408/5,266), traverses the avian phylogeny and targets clusters of related species that are uniquely colored. We identify an additional 478 species at risk of future trade based on their coloration and phylogenetic relationship to currently traded species-together totaling 1,886 species traded, a 34% increase. By modeling future extinctions based on species' current threat status, we predict localized losses of color diversity and uniqueness in many avian communities, undermining their aesthetic value and muting nature's color palette. Given the distribution of color and the association of unique colors with threat and trade, proactive regulation of the bird trade is crucial to conserving charismatic biodiversity, alongside recognition and celebration of color hotspots.

Potential for invasion of traded birds under climate and land-cover change

Humans have moved species away from their native ranges since the Neolithic, but globalization accelerated the rate at which species are being moved. We fitted more than half million distribution models for 610 traded bird species on the CITES list to examine the separate and joint effects of global climate and land-cover change on their potential end-of-century distributions. We found that climate-induced suitability for modelled invasive species increases with latitude, because traded birds are mainly of tropical origin and much of the temperate region is 'tropicalizing.' Conversely, the tropics are becoming more arid, thus limiting the potential from cross-continental invasion by tropical species. This trend is compounded by forest loss around the tropics since most traded birds are forest dwellers. In contrast, net gains in forest area across the temperate region could compound climate change effects and increase the potential for colonization of low-latitude birds. Climate change has always led to regional redistributions of species, but the combination of human transportation, climate, and land-cover changes will likely accelerate the redistribution of species globally, increasing chances of alien species successfully invading non-native lands. Such process of biodiversity homogenization can lead to emergence of non-analogue communities with unknown environmental and socioeconomic consequences.

A Local Approach to Better Understand the Spread and Population Growth of the Monk Parakeet as an Invasive Species

Invasive exotic species are currently a topic of interest for environmental management agencies and the media. This is due to the socio-economic and environmental problems that they are causing or may cause. The Monk Parakeet is a clear example of this, especially in some large cities, where populations are growing quickly, and their distribution continues to expand. In our study, we focused on a population that has been closely monitored during the last 25 years to understand its growth and change on a local scale to determine the maximum sustainable population size in the invaded area and to check when this population began to act as a source of new breeding colonies to adjacent areas. The first breeding of the species occurred in 2002, and from then, the average growth rate (r) of the population was 0.191 until 2016, when it stabilized and declined slightly (r = −0.043). The maximum growth rate occurred during the years 2002 and 2007 and was 0.314. The results obtained give us information about the carrying capacity of the study area, allowing us to explain the dispersal process of the species to neighbouring areas, with populations that have reached maximum size serving as sources of individuals dispersing to suitable areas. In our study area, the species shows a strong preference for building its nests in palm trees and electric utility structures. Our study’s local focus on studying the population dynamics of an invasive species may allow us to understand the increased range of the species on a larger scale, which is necessary in order to be able to design appropriate and effective management strategies.

Avian species richness and tropical urbanization gradients: Effects of woodland retention and human disturbance

Urbanization is a major driver of tropical biodiversity loss. In temperate regions avian species richness-urbanization intensity relationships typically exhibit unimodal patterns, with peak richness at intermediate urbanization levels. In tropical regions, the form of such relationships and the extent to which they are moderated by patches of seminatural habitat are unclear. We address these questions in Bangkok, Thailand (one of the largest and most rapidly expanding tropical mega-cities) and generate conservation recommendations for tropical biodiversity in urban locations. We use repeated point count surveys at a random location, and the largest available woodland patch, in 150 1 km × 1 km grid cells selected along the urbanization gradient. Woodland patches support higher species richness compared with randomized locations (except for non-natives), and avian species richness declines linearly with increasing urbanization. The contrast with unimodal patterns in temperate regions is probably driven by divergent patterns of habitat heterogeneity along tropical and temperate urbanization gradients. Moreover, we provide novel evidence that retaining patches of urban woodland moderates adverse impacts of urbanization on avian species richness. For most species groups, the benefits of woodland increase as urbanization intensifies, despite such woodland patches being very small (mean of 0.38 ha). Avian species richness in woodland patches is maximized, and community composition less similar to that in randomized locations, when woodland patches are larger and visited by fewer people. Assemblages of forest-dependent species (which provide additional ecological functions) have higher richness, and are less similar to those in randomized locations, in patches of woodland with higher tree species richness and biomass. Finally, species richness in randomized sites is greatest when they are closer to woodland patches, and such assemblages more closely resemble those of woodland sites. Our work highlights four strategies for tropical urban bird conservation: (1) conserving woodland patches across the urbanization gradient regardless of patch size, (2) improving the quality of existing woodland by increasing tree biomass and diversity, (3) creating additional woodland that is well distributed throughout the urban area to minimize effects of habitat isolation and (4) reducing human disturbance, especially in areas of the highest habitat quality, while ensuring that the benefits of connecting people to nature are realized in other locations.

Phylodynamic and phylogeographic reconstruction of beak and feather disease virus epidemiology and its implications for the international exotic bird trade

Beak and feather disease virus (BFDV) infects domestic and wild psittacine species and is able to cause progressive beak, claw and feather malformation and necrosis. In addition to having an impact on the health and welfare of domesticated birds, BFDV represents a significant threat to wild endangered species. Understanding the epidemiology, dynamics, viral migration rate, interaction between wild and domestic animals and the effect of implemented control strategies is fundamental in controlling the spread of the disease. With this in mind, a phylodynamic and phylogeographic analysis has been performed on a database of more than 400 replication-associated protein (Rep) gene (ORF1) sequences downloaded from Genbank including some recently generated sequences from fifteen samples collected in Namibia. The results allowed us to reconstruct the variation of viral population size and demonstrated the effect of enforced international bans on these dynamics. A good correlation was found between viral migration rate and the intensity of animal trade between regions over time. A dominant flux of viral strains was observed from wild to domestic populations, highlighting the directionality of viral transmission and the risk associated with the capturing and trade of wild birds. Nevertheless, the flow of viruses from domestic to wild species was not negligible and should be considered as a threat to biodiversity. Therefore, considering the strong relationship demonstrated in this study between animal trade and BFDV viral fluxes more effort should be made to prevent contact opportunities between wild and domestic populations from different countries in order to control disease spread.

Exploring the Effects of Geopolitical Shifts on Global Wildlife Trade

International wildlife trade is a major driver of species extinction and biological invasions. Anticipating environmental risks requires inferences about trade patterns, which are shaped by geopolitics. Although the future cannot be predicted, scenarios can help deal with the uncertainty of future geopolitical dynamics. We propose a framework for generating and analyzing scenarios based on four geopolitical storylines, distinguished by combinations of international trade barrier strength and domestic law enforcement degree across countries supplying and demanding wildlife. We then use historical data on bird trade to classify countries into geopolitical profiles and confirm that trade barriers and law enforcement allow predicting bird trade patterns, supporting our scenarios' plausibility and enabling projections for future global bird trade. Our framework can be used to examine the consequences of geopolitical changes for wildlife trade and to advise policy and legislation. Reducing demand for wildlife and ameliorating global inequality are key for curbing trade related risks.

Impacts of the SARS-CoV-2 pandemic on the global demand for exotic pets: An expert elicitation approach

The SARS-CoV-2 pandemic has caused immense social and economic costs worldwide. Most experts endorse the view that the virus has a zoonotic origin with the final spillover being associated with wildlife trade. Besides human consumption, wild animals are also extensively traded as pets. Information on zoonotic diseases has been reported to reduce consumer demand for exotic pets. We conducted a global survey and collected 162 responses from international experts on exotic pet trade (traders, academics, NGOs, enforcement entities) to understand how the legal and illegal trade of exotic pets is expected to be affected by the ongoing coronavirus pandemic. Our results suggest that legal purchase of exotic pets is perceived as decreasing during the first pandemic wave due to: lower availability of animals for trade, suppliers' inability to reach consumers and social distancing measures. The general perception is that in the future (i.e., next five years), both demand and supply of legally traded exotic pets are expected to either remain unchanged or decrease only temporarily. The consumer demand for illegal exotic pets is also expected to remain unchanged following the outbreak. The top two challenges reported by respondents, when considering the consequences of the pandemic for the exotic pet trade, are inadequate enforcement of national regulations and increased illegal trade. Our results suggest that the negative consequences of a zoonotic outbreak may not dissuade consumers of exotic pets. Worldwide, the transit/storing conditions and lack of health screenings of traded live animals are conducive to spreading diseases. Consumer demand is a key driver of trade, and enforcement of trade regulations will remain challenging, unless factors driving consumer demand are adequately incorporated in problem-solving frameworks. We emphasize the complexity of trade dynamics and the need to go beyond bans on wildlife trade. Stronger law enforcement, implemented along with initiatives dissuading consumption of wild exotic pets, are essential to sustainably satisfy the market demand.

Wildlife trade and the establishment of invasive alien species in Indonesia: management, policy, and regulation of the commercial sale of songbirds

In Southeast Asia, mynas (genus Acridotheres) are amongst the most invasive bird species. Information is largely lacking as to where they have established themselves. The spread of invasive, non-native mynas is partially or largely driven by the massive trade in these species as songbirds. While preventing unintentional introductions early is the most effective management option, these species continue to be traded in bird markets throughout the region. We focus on the trade of native and non-native species of mynas, and the establishment of non-native mynas on the Indonesian islands of Java, Bali, and Lombok. Between 2016 and 2019, through field surveys and use of citizen science data (e.g., Burungnesia, iNaturalist, birding reports), we assessed where non-native mynas have been recorded in the wild on these three islands; through bird market surveys we established in which cities these birds are traded. We recorded common myna in Yogyakarta, one of our three survey areas. Combining all records, the areas where alien invasive mynas are established are Greater Jakarta (common and jungle myna), Yogyakarta (common myna), Bali (common and bank myna) and Lombok (common and Javan myna). Two-thirds of the records come from farmlands, home gardens and urbanised areas. In the bird markets, we recorded ~ 23,000 mynas of five species for sale, with Greater Jakarta, Bali and Lombok standing out as areas with high numbers of potentially invasive alien species offered for sale. Restrictions on the sale of wild-caught birds are not adhered to. Well-intended policies concerning the breeding and sale of legally protected species, whereby 10% of the stock is bred to be released in the wild, exacerbate the risk of the establishment of non-native species. We surmise that one of the most effective ways to reduce the risk of the accidental or deliberate release of potentially invasive alien mynas (and indeed other birds) into the wild is for governments and conservationists to work more closely with the retailers who hold the key to informing and educating consumers.

Identifying opportunities for expert-mediated triangulation in monitoring wildlife trade on social media

Wildlife trade has rapidly expanded on social media platforms in recent years, offering an easy means for traders to access international markets. Investigating this trade activity poses a complex challenge to researchers seeking to understand online trade and moderators seeking to disrupt illicit and harmful activity. Current survey methods frequently rely on text-based searches and focus on posts in which the advertisement is explicit. However, such approaches risk overlooking a growing volume of relevant content, particularly outside social media groups. We used posts from pages promoting West African birds for trade as a case study to explore the availability of information for making inferences about trade activity on social media, specifically information indicating that trade activity was occurring or that could be used to infer trade routes. We recorded 400 posts from 12 pages that we inferred either promoted or facilitated wildlife trade, of which 19.7% were explicit advertisements and 23.8% contained taxa-related terms. In the remaining 341 posts, profile information was the most common indicator of trade activity, but a variety of indicators (e.g., images of birds in trade and trade enquiries) were identified across imagery, text, and comments. We identified multiple types of geographical information that could help infer trade routes and thus the likely legality of trade, although most were relatively rare and sometimes contradictory. Our findings suggest that triangulating multiple types of information from within, across, and beyond posts is vital for effectively identifying and interpreting wildlife trade content on social media. Therefore, were commend that expert-mediated triangulation should be integrated in and used alongside automated detection systems and moderating practices of social media companies.

Mixed protection of threatened species traded under CITES

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulates international legal trade to prevent the detrimental harvest of wildlife. We assess the volumes of threatened and non-threatened bird, mammal, amphibian, and reptile species in the CITES-managed trade and how this trade responded to category changes of species in the IUCN Red List between 2000 and 2018. In this period, over a thousand wild-sourced vertebrate species were commercially traded. Species of least conservation concern had the highest yearly trade volumes (excluding birds), whereas species in most Red List categories showed an overall decrease in trade reoccurrence and volume through time, with most species unlikely to reoccur in recent trade. Charismatic species with populations split-listed between Appendices I and II were traded in substantially lower yearly volumes when sourced from the more-threatened Appendix I populations. Species trade volumes did not systematically respond to changes in the Red List category, with 31.0% of species disappearing from trade before changing category and the majority of species revealing no difference in trade volumes from pre- to post-change. Just 2.7% (12/432) of species volumes declined and 2.1% (9/432) of volumes increased after a category change. Our findings highlight that non-threatened species dominate trade but reveal small numbers of highly threatened species in trade and a disconnect between species trade volumes and changing extinction risk. We highlight potential drawbacks in the current regulation of trade in listed species and urgently call for open and accessible assessments-non-detriment findings-robustly evidencing the sustainable use of threatened and non-threatened species alike.

Drivers of alien species composition in bird markets across the world

The global pet trade is a major pathway for the introduction of invasive alien species. The composition of species selected for transport is driven by market demands, which may be influenced by a combination of both historical and cultural factors. We compared Eastern (Taiwan) and Western (Australia and the Iberian Peninsula) bird markets to explore factors associated with the species composition and geographic origin of the birds for sale. We used a bespoke randomization test to compare species composition, geographic origins, and species overlap at different taxonomic levels among bird markets across countries. Alien species identified in the study accounted for more than 10% of the world's bird species. Parrots and songbirds were the most common alien bird taxa traded across all markets. In both Iberian and Australian markets, there was a strong bias toward parrots, waxbills, gamebirds, and finches. In Taiwan, species traded more than expected were parrots, waxbills, starlings, and leafbirds. Neotropical species were the most traded group in the three markets. Afrotropical species were also traded more than expected in Iberian and Australian markets, while the Taiwanese traded more alien species from neighboring Asian regions. The bird trade focuses on the same few bird groups worldwide. The composition and origin of species preferred in the Western markets may be influenced by colonial histories, cultural similarity, and strict regulations on wildlife importation, while species preferences in Eastern markets are strongly influenced by regional culture and proximity. Propagule pressure is a dominant factor influencing the success of biological invasions; it is important to recognize differences in the composition of bird markets among regions because they can translate into different invasion risks, among other factors.

The International Vertebrate Pet Trade Network and Insights from US Imports of Exotic Pets

The international trade in exotic vertebrate pets provides key social and economic benefits but also drives associated ecological, ethical, and human health impacts. However, despite its clear importance, we currently lack a full understanding of the structure of the pet trade, hampering efforts to optimize its benefits while mitigating its negative effects. In the present article, we represent and review the structure of the pet trade as a network composed of different market actors (nodes) and trade flows (links). We identify key data gaps in this network that, if filled, would enable network analyses to pinpoint targets for management. As a case study of how data-informed networks can realize this goal, we quantified spatial and temporal patterns in pets imported to the United States. Our framework and case study illustrate how network approaches can help to inform and manage the effects of the growing demand for exotic pets.

International socioeconomic inequality drives trade patterns in the global wildlife market

The wildlife trade is a major cause of species loss and a pathway for disease transmission. Socioeconomic drivers of the wildlife trade are influential at the local scale yet rarely accounted for in multinational agreements aimed at curtailing international trade in threatened species. In recent decades (1998-2018), approximately 421,000,000 threatened (i.e., CITES-listed) wild animals were traded between 226 nations/territories. The global trade network was more highly connected under conditions of greater international wealth inequality, when rich importers may have a larger economic advantage over poorer exporting nations/territories. Bilateral trade was driven primarily by socioeconomic factors at the supply end, with wealthier exporters likely to supply more animals to the global market. Our findings suggest that international policies for reducing the global wildlife trade should address inequalities between signatory states, possibly using incentive/compensation-driven programs modeled after other transnational environmental initiatives (e.g., REDD+).

Wildlife-pet markets in a one-health context

Background and Aim: Wildlife markets are centers of trade involving live animals and their derivatives from wild-caught and captive-bred non-domesticated animals, including for the culinary, fashion, traditional medicine, curio, and pet sectors. These markets occur in Southeast Asia, India, North America, Latin America, Europe, Africa, and elsewhere. This study aims to address a diversity of related issues that have a one-health bearing while focusing on wildlife markets in relation to the pet trade. Across relevant regions and countries, all major animal classes are traded at wildlife-pet markets. Wildlife markets, in general, are considered distinct from so-called "wet markets" at which domesticated animals, fish, and other "seafood" are offered only for consumption. Several aspects of wildlife markets have attracted scientific and popular scrutiny, including animal welfare concerns, species conservation threats, legality, ecological alteration, introduction of invasive alien species, presence of undescribed species, and public and agricultural animal health issues. Materials and Methods: Onsite inspections were conducted for markets in the United States, Spain, Germany, The Netherlands, and the UK, as well as observational research of visual imagery of market conditions, and we compared these conditions with evidence-based standards for animal welfare and public health management. Results: Wildlife markets globally shared common similar structures and practices including the presence of sick, injured, or stressed animals; mixing of animals of uncertain origin and health state; and no specific or any hygiene protocols, with issues of animal welfare, public health and safety, agricultural animal health, and other one-health concerns being inherently involved. Conclusion: We conclude that wildlife markets are incompatible with responsible standards and practices, and we recommend that such events are banned globally to ameliorate inherent major problems.

Trading Tactics: Time to Rethink the Global Trade in Wildlife

The Covid-19 outbreak has brought about fresh and intensified scrutiny of the wildlife trade, which substantively involves commerce in exotic pets. In response, major policy decisions involving trade bans have ensued, with calls for similar such action to be applied across the trade chain. Yet, these measures have been criticised, largely based on concerns that they risk exacerbating poverty, undermining human rights, damaging conservation incentives, and otherwise harming sustainable development and conservation efforts. Instead, many critics propose improved regulation of the status quo, with the intention of nurturing a legal, sustainable, safe, humane, and equitable wildlife trade. Herein, we provide a countering view that outlines how the risks presented by the wildlife trade are becoming increasingly recognised as being both manifold and severe; and raise concerns that the goal of a well-regulated wildlife trade is becoming increasingly exposed as a mirage. We conclude that while pursuing the United Nation's Sustainable Development Goals (with their focus on poverty alleviation, food security, public health, and conservation) is enduringly vital, a flourishing wildlife trade is not. Given that the exploitation of wildlife, including for the pet trade, has been identified as one of the dominant drivers of biodiversity loss, emergence of zoonotic infectious disease, animal suffering, and financial instability, perpetuating the concept of utilising a regulated wildlife trade as the default approach to protect people and planet is in urgent need of re-evaluation.

Thousands of reptile species threatened by under-regulated global trade

Wildlife trade is a key driver of the biodiversity crisis. Unregulated, or under-regulated wildlife trade can lead to unsustainable exploitation of wild populations. International efforts to regulate wildlife mostly miss ‘lower-value’ species, such as those imported as pets, resulting in limited knowledge of trade in groups like reptiles. Here we generate a dataset on web-based private commercial trade of reptiles to highlight the scope of the global reptile trade. We find that over 35% of reptile species are traded online. Three quarters of this trade is in species that are not covered by international trade regulation. These species include numerous endangered or range-restricted species, especially hotspots within Asia. Approximately 90% of traded reptile species and half of traded individuals are captured from the wild. Exploitation can occur immediately after scientific description, leaving new endemic species especially vulnerable. Pronounced gaps in regulation imply trade is having unknown impacts on numerous threatened species. Gaps in monitoring demand a reconsideration of international reptile trade regulations. We suggest reversing the status-quo, requiring proof of sustainability before trade is permitted.

There are gaps in international efforts to monitor the wildlife trade, with many species potentially being undetected by the established monitoring groups. Here the authors use an automated web search to document the sale of reptiles online, revealing over 36% of all known reptile species are in trade, including many missing from official databases.

Drivers of future alien species impacts: An expert-based assessment

Understanding the likely future impacts of biological invasions is crucial yet highly challenging given the multiple relevant environmental, socio-economic and societal contexts and drivers. In the absence of quantitative models, methods based on expert knowledge are the best option for assessing future invasion trajectories. Here, we present an expert assessment of the drivers of potential alien species impacts under contrasting scenarios and socioecological contexts through the mid-21st century. Based on responses from 36 experts in biological invasions, moderate (20%-30%) increases in invasions, compared to the current conditions, are expected to cause major impacts on biodiversity in most socioecological contexts. Three main drivers of biological invasions-transport, climate change and socio-economic change-were predicted to significantly affect future impacts of alien species on biodiversity even under a best-case scenario. Other drivers (e.g. human demography and migration in tropical and subtropical regions) were also of high importance in specific global contexts (e.g. for individual taxonomic groups or biomes). We show that some best-case scenarios can substantially reduce potential future impacts of biological invasions. However, rapid and comprehensive actions are necessary to use this potential and achieve the goals of the Post-2020 Framework of the Convention on Biological Diversity.

Early warning systems in biosecurity; translating risk into action in predictive systems for invasive alien species

Invasive alien species (IAS) are one of the most severe threats to biodiversity and are the subject of varying degrees of surveillance activity. Predictive early warning systems (EWS), incorporating automated surveillance of relevant dataflows, warning generation and dissemination to decision makers are a key target for developing effective management around IAS, alongside more conventional early detection and horizon scanning technologies. Sophisticated modelling frameworks including the definition of the ‘risky’ species pool, and pathway analysis at the macro and micro-scale are increasingly available to support decision making and to help prioritise risks from different regions and/or taxa. The main challenges in constructing such frameworks, to be applied to border inspections, are (i) the lack of standardisation and integration of the associated complex digital data environments and (ii) effective integration into the decision making process, ensuring that risk information is disseminated in an actionable way to frontline surveillance staff and other decision makers. To truly achieve early warning in biosecurity requires close collaboration between developers and end-users to ensure that generated warnings are duly considered by decision makers, reflect best practice, scientific understanding and the working environment facing frontline actors. Progress towards this goal will rely on openness and mutual understanding of the role of EWS in IAS risk management, as much as on developments in the underlying technologies for surveillance and modelling procedures.

CITES and the Zoonotic Disease Content in International Wildlife Trade

International trade in wildlife is one contributing factor to zoonotic disease risk. Using descriptive statistics, this paper shows that in the last decades, the volume and pattern of internationally traded wildlife has changed considerably and, with it, the zoonotic pathogens that are traded. In an econometric analysis, we give evidence that an international environmental trade agreement could be used to limit the spread of zoonotic pathogens and disease. More specifically, combining zoonotic disease data with wildlife trade data from the Convention on International Trade in Endangered Species of Wildlife and Fauna (CITES), we show that making trade requirements more stringent leads to a decrease in the number of animals traded and, incidentally, also the number of zoonotic diseases that are traded. Our results contribute to the discussion of policy measures that manage the spread of zoonotic diseases.

Ecological networks: Pursuing the shortest path, however narrow and crooked

Representing data as networks cuts across all sub-disciplines in ecology and evolutionary biology. Besides providing a compact representation of the interconnections between agents, network analysis allows the identification of especially important nodes, according to various metrics that often rely on the calculation of the shortest paths connecting any two nodes. While the interpretation of a shortest paths is straightforward in binary, unweighted networks, whenever weights are reported, the calculation could yield unexpected results. We analyzed 129 studies of ecological networks published in the last decade that use shortest paths, and discovered a methodological inaccuracy related to the edge weights used to calculate shortest paths (and related centrality measures), particularly in interaction networks. Specifically, 49% of the studies do not report sufficient information on the calculation to allow their replication, and 61% of the studies on weighted networks may contain errors in how shortest paths are calculated. Using toy models and empirical ecological data, we show how to transform the data prior to calculation and illustrate the pitfalls that need to be avoided. We conclude by proposing a five-point check-list to foster best-practices in the calculation and reporting of centrality measures in ecology and evolution studies.

Human-mediated dispersal in insects

Central to the problem of biological invasions, human activities introduce species beyond their native ranges and participate in their subsequent spread. Understanding human-mediated dispersal is therefore crucial for both predicting and preventing invasions. Here, we show that decomposing human-mediated dispersal into three temporal phases: departure, transport and arrival, allows to understand how the characteristics of human activities and the biological traits of species influence each phase of the dispersal process, and ultimately govern invasion pathways in insects. Integrating these precise mechanisms into future invasion models should increase their realism and generalization for any potential insect invader. Moreover, understanding these mechanisms can provide insight into why some invasive insects are more widely distributed than others, and to estimate risks posed by species that have not yet been introduced.

Thirty-six years of legal and illegal wildlife trade entering the USA

The USA is the largest consumer of legally, internationally-traded wildlife. A proportion of this trade consists of species listed in the Appendices of CITES, and recorded in the CITES Trade Database. Using this resource, we quantified wildlife entering the USA for 82 of the most frequently recorded wildlife products and a range of taxonomic groups during 1979–2014. We examined trends in legal trade and seizures of illegally traded items over time, and relationships between trade and four national measures of biodiversity. We found that: (1) there is an overall positive relationship between legal imports and seizures; (2) Asia was the main region exporting CITES-listed wildlife products to the USA; (3) bears, crocodilians and other mammals (i.e. other than Ursidae, Felidae, Cetacea, Proboscidea, Primates or Rhinocerotidae) increased in both reported legal trade and seizures over time; (4) legal trade in live specimens was reported to be primarily from captive-produced, artificially-propagated or ranched sources, whereas traded meat was primarily wild sourced; (5) both seizures and legally traded items of felids and elephants decreased over time; and (6) volumes of both legally traded and seized species were correlated with four attributes of exporting countries: species endemism, species richness, number of IUCN threatened species, and country size. The goal of our analysis was to inform CITES decision-making and species conservation efforts.