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The annual trade in exotic vertebrates as pets is a multi-billion-dollar global business. Thousands of species, and tens of millions of individual animals, are shipped both internationally and within countries to satisfy this demand. Most research on the exotic pet trade has focused on its contribution to native biodiversity loss and disease spread. Here, we synthesize information across taxa and research disciplines to document the exotic pet trade's contribution to vertebrate biological invasions. We show recent and substantial worldwide growth in the number of non-native animal populations introduced via this invasion pathway, which demonstrates a strong potential to increase the number of invasive animals in the future. Key to addressing the invasion threat of exotic pets is learning more about the socioeconomic forces that drive the massive growth in the exotic pet market and the socioecological factors that underlie pet release by owners. These factors likely vary according to cultural pet-keeping traditions across regions and whether purchases were legal or illegal. These gaps in our understanding of the exotic pet trade must be addressed in order to implement effective policy solutions.

AimInternational trade in plants and animals generates significant economic benefits. It also leads to substantial unintended impacts when introduced species become invasive, causing environmental disturbance or transmitting diseases that affect people, livestock, other wildlife or the environment. Policy responses are usually only implemented after these species become established and damages are already incurred. International agreements to control trade are likewise usually based on selection of species with known impacts. We aim to further develop quantitative invasive species risk assessment for bird imports and extend the tool to explicitly address disease threats.LocationUnited States of America.MethodsWe use a two-step approach for rapid risk assessment based on the expected biological risks due to both the environmental and health impact of a potentially invasive wildlife species in trade. We assess establishment probability based on a model informed by historical observations and then construct a model of emerging infectious disease threat based on economic and ecological characteristics of the exporting country.ResultsWe illustrate how our rapid assessment tool can be used to identify high-priority species for regulation based on a combination of the threat they pose for becoming established and vectoring emerging infectious diseases.Main conclusionsOur approach can be executed for a species in a matter of days and is nested in an economic decision-making framework for determining whether the biological risk is justified by trade benefits.

Intentional introductions of nonindigenous fishes are increasing globally. While benefits of these introductions are easily quantified, assessments to understand the negative impacts to ecosystems are often difficult, incomplete, or absent. Grass carp (Ctenopharyngodon idella) was originally introduced to the United States as a biocontrol agent, and recent observations of wild, diploid individuals in the Great Lakes basin have spurred interest in re-evaluating its ecological risk. Here, we evaluate the ecological impact of grass carp using expert opinion and a suite of the most up-to-date analytical tools and data (ploidy assessment, eDNA surveillance, species distribution models (SDMs), and meta-analysis). The perceived ecological impact of grass carp by fisheries experts was variable, ranging from unknown to very high. Wild-caught triploid and diploid individuals occurred in multiple Great Lakes waterways, and eDNA surveillance suggests that grass carp are abundant in a major tributary of Lake Michigan. SDMs predicted suitable grass carp climate occurs in all Great Lakes. Meta-analysis showed that grass carp introductions impact both water quality and biota. Novel findings based on updated ecological impact assessment tools indicate that iterative risk assessment of introduced fishes may be warranted. Le nombre d'introductions intentionnelles de poissons non indigenes augmente a l'echelle planetaire. Si les avantages qu'offrent ces introductions peuvent facilement etre quantifies, des evaluations permettant d'en comprendre les impacts negatifs sur les ecosystemes sont souvent difficiles, incompletes ou non existantes. L'amour blanc (Ctenopharyngodon idella) a, a l'origine, ete introduit aux Etats-Unis comme agent de lutte biologique, et des observations recentes d'individus diploides dans le bassin des Grands Lacs ont suscite un interet envers la reevaluation du risque ecologique qu'il presente. Nous evoluons l'impact ecologique de l'amour blanc a la lumiere d'opinions de specialistes et d'un ensemble d'outils et de donnees analytiques les plus recents (evaluation de la diploidie, surveillance basee sur l'ADNe, modeles de repartition des especes (MRE) et meta-analyse). L'impact ecologique de l'amour blanc perqu par les specialistes des peches etait variable, allant d'inconnu a tres fort. Des individus triploides et diploides ont ete captures a l'etat sauvage dans de multiples cours d'eau du bassin des Grands Lacs et la surveillance basee sur l'ADNe donne a penser que l'amour blanc est abondant dans un grand affluent du lac Michigan. Des MRE ont predit que tous les Grands Lacs presentent un climat convenant a l'amour blanc. La meta-analyse montre que les introductions de cette espece ont une incidence tant sur la qualite de l'eau que sur le biote. De nouvelles constatations reposant sur des outils devaluation de l'impact ecologique a jour indiquent qu'il pourrait etre pertinent d'effectuer une evaluation iterative du risque presente par les poissons introduits. [Traduit par la Redaction], Introduction The introduction of nonindigenous species has brought both environmental and economic benefits and harms (Keller et al. 2009). Globally, nonindigenous fishes continue to be introduced for commercial, recreational, or [...]

Non-native crayfishes can have large impacts on biodiversity and the provisioning of ecosystem services in freshwaters. In 2015 we discovered an established population of the globally widespread red swamp crayfish (Procambarus clarkii) in the North Shore Channel of the Chicago Area Waterway System. This population overlaps with a population of rusty crayfish (Faxonius rusticus), a previous invader that is widely distributed and usually the dominant crayfish species across the Great Lakes region. If P. clarkii continues to spread in the Great Lakes region it will frequently encounter F. rusticus. Factors such as water clarity, competition for food when limited, and susceptibility to predation may alter P. clarkii's ability to become established and spread. We sampled the overlapping populations and found that P. clarkii are significantly larger than F. rusticus. Next, we conducted lab experiments to examine the outcomes of competition between these species for shelter and food. F. rusticus were significantly more likely to seek shelter when threatened, while P. clarkii were significantly more likely to respond aggressively. P. clarkii won more competitions for food. Finally, we conducted field experiments to investigate rates of predation on each species and found that P. clarkii are predated significantly more often. Our results suggest that P. clarkii is dominant in interactions with F. rusticus but that higher rates of predation, likely occurring because P. clarkii is less likely to flee from threats, mitigate these benefits. We suggest that P. clarkii will dominate crayfish communities in water with low clarity, but not in clear-water habitats where visual predators are more effective. [ABSTRACT FROM AUTHOR]