“BioInvasions Records” (BIR) is an international journal founded in 2011, with its primary focus the publication of new records of non-native species. We analyzed all published articles in BIR between 2012 and 2019, aiming to: make all georeferenced records openly available; investigate spatio-temporal patterns in reported records, methodologies for species identification, and pathways of invasion; and identify possible biases in reporting alien species occurrences and distributions. In total, 10457 georeferenced records were retrieved from 467 published articles, reporting 628 different species. Terrestrial species were under-represented in the dataset. Chordata dominated in the list of reported species, followed by Arthropoda, Mollusca, and Tracheophyta. Europe was the continent with most recorded species, followed by North America. In terms of species reported by country, USA ranked on top. This geographic bias is in accordance with global patterns of research output, related to the fact that North America and Western Europe are leaders in funding research and development, and this is where the majority of highly ranked universities are situated. The country diversity of reported species exhibited an increasing trend from 28 countries in 2012 to 49 countries in 2019. Single-author papers represented only ~ 5% of all published papers, and the median number of authors has increased from 3 in 2012–2013, to 4 in 2015–2019, following global trends of increased collaborations. The frequency of conducting molecular analyses for species identification has increased from 4.5% of published articles in 2012 to 25.2% in 2019, and is expected to further increase with the continuing development of molecular tools, in particular rapid advances and cost reduction in eDNA, next-generation sequencing, barcoding and metabarcoding analyses. The most common pathway of introduction (based on the CBD classification) was “transport-stowaway”, followed by “escape from confinement” and “corridor”. However, the importance of pathways significantly differed by environment. “Transport-stowaway” was the most important pathway for marine and transitional species, whereas “escape from confinement” was the most important pathway for terrestrial and freshwater species. The most important CBD pathway subcategory was “ship/boat ballast water”, followed by “interconnected waterways/basins/seas”, “natural dispersal across borders”, “ship/boat hull fouling”, “aquaculture/mariculture”, and “pet/aquarium/terrarium species (including live food for such species)”. BIR has provided the means for publishing valuable information on the distribution of alien species, the dynamics of invasions, and pathways of introduction, therefore substantially supporting invasion science and management.

In their 2019 study, Molina et al. evaluate a cell proliferation assay that fluorescently quantifies DNA for assessing ballast water treatment efficacy of organisms ≥ 10 to 50 µm. Because of concerns with the overall experimental design, procedures, and authors’ interpretations, their conclusions do not appear to be justified and the assay used to arrive at those conclusions is not proven appropriate. Specific concerns we highlight include UV and chlorine dose calculations and exposure conditions, bacterial contamination issues, poor agreement between controls, high detection limit of the assay, and mismatch between conclusions in the abstract and statistical significance of the data. Their conclusions that “population maintenance or growth was evident … after UV treatment” and “photoreactivation could have been attributed to increased mean DNA concentrations” are therefore not scientifically defensible without further experimentation and verification. These concerns call into serious question the use of this study by the US Coast Guard or other governing bodies to (1) determine the applicability of this cell proliferation assay for assessing ballast water disinfection or (2) make conclusions regarding the suitability of UV treatment for inactivating organisms in ballast water.

We appreciate Natalie M. Hull and Karl G. Linden’s interest in our recent article in which we examined a novel application of a CyQuant®-based approach for examining DNA concentrations of UV- and chlorination-treated organisms. Hull and Linden questioned our work, which was conducted to inform considerations of regulating ballast water discharges on the basis of the number of viable organisms, and several concerns were identified. Here we provide our response to the specific concerns raised about experimental design, procedure, and interpretation.

Although there is a sizeable budget for biosecurity management in New Zealand, there will never be sufficient resources to intervene in all incursions of harmful species, including invasive freshwater plants. Given the inherent complexity in making decisions on interventions, responses are often decided in relation to specific incursions as they happen within their particular context. This paper uses New Zealand case studies to test if there are general economic principles related to intervention in invasive freshwater plants which can be used to improve decision-making. The general principles were; the sooner eradication is started and/or the smaller the incursion size, the lower the cost will be; eradication is more expensive than alternative responses in the short term but is cheaper than long term impacts of no intervention and/or ongoing control programs; and preventing new incursions is cheaper in the long run than eradication. The three principles were considered to be logical in an economic sense and can contribute to supporting intervention decision-making at a macro-level (i.e. across the majority of incursions) and provide more holistic outcomes for society in relation to management programs.

In an effort to harmonize multi-jurisdictional surveillance and detection of aquatic invasive species, regional stakeholders have called for the development of a Great Lakes Aquatic Invasive Species Surveillance Framework to identify species that pose a risk to the basin, quantify the relative risk of various pathways of introduction, provide guidance on monitoring protocols for surveillance, and identify priority locations for surveillance based on this pathway assessment. Here, we screen 448 species to develop a surveillance list of 144 species that are relevant for Great Lakes surveillance: are not yet widespread throughout the basin, have a pathway through which they can arrive, are able to establish and are predicted to cause impacts. Using the Great Lakes Aquatic Nonindigenous Species Risk Assessment for consistent assessment across taxa, the surveillance species list consisted of 144 species: 64 plants, 4 algae, 40 fish, 5 mollusks, 28 crustaceans, 1 platyhelminthes and 2 bryozoans. While pathway risk varies by taxon, the highest risk pathways across all taxonomic groups are natural dispersal, hitchhiking/fouling, and intentional release. The taxonomic group predicted to have the most severe impacts on a per species basis is algae, followed by mollusks, and plants. However, the large number of plant and fish species on the surveillance species list means that overall predicted impact (from a taxonomic perspective) is greatest from these two groups. We recommend ways that the surveillance list could be applied to improve aquatic invasive species management efforts: engage in community-based surveillance, inform taxonomic and species surveillance priorities, provide guidance on monitoring protocols for surveillance, quantify the relative risk of various pathways of introduction and identify priority locations for surveillance based on this pathway assessment.

Non-native small mammals are amongst the most popular species traded as pets around the world. Some of these mammals have become invasive through various pet trade releases and escapees in most countries. In South Africa, several non-native small mammals have been introduced for pet trade purposes. We assessed the sale of non-native small mammals in South Africa from September 2018 to 2019 to determine their abundance and degree of trade online and in pet shops. A total of seven websites were recorded selling 2,681 individuals representing 24 species belonging to seven taxonomic orders. For physical pet shops, 19,391 individuals representing 16 species and seven orders were recorded from 122 pet shops. Rodents and primates were the most dominant groups in both online and pet shops. The most common small mammal species traded were the Norwegian rat Rattus norvegicus, the guinea pig Cavia porcellus, the European rabbit Oryctolagus cuniculus and the house mouse Mus musculus. Prices ranged from ZAR9.00 to ZAR12,000.00, with rodents offered at relatively low prices. The most abundant species traded were relatively cheap when compared with the least abundant species and CITES species were more expensive than non-CITES species. Species with high abundances traded at low prices and have a history of invasion through pet trade releases and escapes pose an invasion risk in South Africa. Therefore, their trade should be strictly regulated.

The East Maui Watershed (EMW) is a > 60,000-ha forested watershed with wide temperature and precipitation gradients being invaded by miconia (Miconia calvescens DC.). Current miconia management efforts focus on protecting important watershed and critical habitat areas from miconia invasion. Herein, we report on a miconia species distribution model to predict unoccupied areas that may be still vulnerable to invasion. This suitable habitat model was developed from an ensemble of five algorithms associating five physical features of EMW with miconia occurrence data from a 26-yr management history (1991–2016; n = 114,953). All of the algorithms performed well based on model evaluation statistics (e.g. AUC ≥ 0.83; TSS ≥ 0.36). Elevation, slope and rainfall were consistently important predictors, while aspect indices were non-contributors. The binary ensemble model suggests a total of ~ 56.9% of the area of interest is susceptible to invasion by miconia. An independent dataset collected in 2017–2018 (n = 5,222) was used to field validate the ensemble habitat suitability model (EHSM) and found that the model could correctly predict suitable habitat 94% of the time. All five of the model algorithms were updated using this new management data, and the predicted suitable area decreased 2.3%. While binary models are useful for risk assessment, the classification of an area as suitable or not suitable has limitations for land managers adopting for management activities. Utilizing the mean weighted consensus probability surface representation of the model allows for more scrutiny of potential suitable habitat. We suggest using this approach when planning future monitoring efforts, especially if specific areas have a higher prioritization for conservation than others.

The invasive brown marmorated stink bug Halyomorpha halys is native to East Asia and was first detected in Switzerland, Europe in 2004. It is now widespread throughout continental Europe and has recently been reported on several islands in the Mediterranean Sea. In the Eastern Mediterranean, it has been recorded in Greece, Turkey and most probably Egypt, but there is no information regarding its occurrence in the Republic of Cyprus. Therefore, in September 2019, a survey at potential points of entry and arrivals was carried out by setting pheromone traps of the pest in the vicinity of airports, harbours as well as next to importers’ trade warehouses in the country. This stink bug monitoring programme in September and October was completed with an awareness campaign, which consisted of the establishment of a citizen science initiative for the early warning of this alien pest by disseminating an alert letter titled “Bug Alert Cyprus” in English and Greek to various target groups. To the best of our knowledge, this is the first CS initiative in Cyprus focusing on the early detection of a polyphagous agricultural and nuisance pest. The lack of H. halys captured during the trapping period, and the absence of reports from citizens seem to indicate that H. halys had not reached this European island country up to January 2020. The methodology we applied and our further recommendations may foster further CS activities combined with targeted trappings to give an early warning and enable the detection of H. halys as effectively as possible on European islands as well as on other remote or isolated parts of the world not yet invaded by this pest.

Early detection of an invasive species is the first critical step to managing their invasion. New Zealand mudsnails (Potamopyrgus antipodarum; hereafter NZMS) are a small gastropod native to New Zealand and a documented worldwide invader. Although many approaches for sampling NZMS have been used, no protocol has emerged as a standard for early detection monitoring in lotic environments. In order to document the occurrence of NZMS, we developed a qualitative sampling methodology and evaluated its effectiveness. The sampling methodology involved conducting two searcher visual surveys along stream margins in a 50-meter search range for a standard 20-minute search time. Qualitative estimates of abundance and the time when the first detection was made were documented by each searcher. We conducted a total of 227 surveys in 12 rivers in Michigan, USA in 2017. Survey data were analyzed using an occupancy model framework, resulting in a per survey detectability exceeding 96%. We ran the occupancy model in an atypical fashion to explore the impact that relative abundance had on detectability. As relative abundance increased, detectability of NZMS increased. We modeled shorter survey durations (i.e., 15, 10, and 5 minutes) to determine their impact on detectability and found that less than 2% of detections were lost when reducing the survey length from 20 to 5 minutes. We developed a novel decision support tool to help understand how the number of sites surveyed, the site level detection probability, and the occupancy level of a rare species interact to determine the overall probability of detection of a new invader. The decision support table can help guide sampling design choices by giving insight into what combination of choices provides the overall highest probability of detection across all sites combined.

The movement of live fish for use as bait in recreational angling has been identified as a high-risk pathway for the spread of aquatic invasive species and disease in the Great Lakes region. To better understand the hazards present in Minnesota’s live baitfish pathway, we employed both conventional and advanced diagnostic approaches to detect non-target species and pathogens in golden shiners (Notemigonus crysoleucas), a common baitfish sold in retail bait shops. Golden shiners were purchased from bait shops (n = 34 total; n = 15 sampled once, n = 19 sampled twice) in 2014 and 2015 across Minnesota. Of the 53 lots examined, non-target species were observed in 24/53 lots and included nine different fish species and one frog species, however, none of the non-target species found are listed as invasive in Minnesota. Nine parasite taxa were observed by wet mounts of the gills, epidermal mucus, and fin clips in 27/53 lots. The microsporidian parasite, Ovipleistophora ovariae, was detected in 24/53 lots by qPCR. While many bacterial species were identified by culture dependent and independent methods, two notable species including, Aeromonas salmonicida and Yersinia ruckeri, were confirmed in ten and five lots, respectively. Detection of replicating virus in culture was low, with only 2/53 lots positive for the golden shiner reovirus. No other viruses were detected with the standard culture-based assays; however, a total of eight novel viruses were detected by next-generation sequencing. These findings underscore the need for a proactive surveillance approach that includes advanced diagnostic tools for the detection of emerging aquatic pathogens, to better understand and manage the risks associated with the use of live baitfish.

Reliable, inexpensive, and publicly accessible decontamination techniques are needed for equipment used in waters infested with aquatic invasive species. One such aquatic invasive species is the faucet snail (Bithynia tentaculata) that hosts several parasitic trematodes which have caused mass waterfowl die-offs in the United States and Canada. We examined freezing as a potential decontamination method using a household chest freezer. Snails were frozen in time increments of 0, 5, 10, 30, 60, 120, 180, and 240 min in dry conditions (water removed) and in water. Snails in dry conditions reached 100% mortality after 30 min while snails in water reached 80% mortality after 240 min. Snail mortality was inversely related to size, with larger snails requiring longer times to achieve mortality. Snails in water could tolerate freezing temperatures longer than snails in dry conditions. We determined that freezing is a viable decontamination method for contaminated equipment, but longer freezing times will be necessary for larger snails, especially when equipment is wet.

Protected areas (PAs) are important tools for biodiversity conservation. In developing countries, incomplete information about the presence of non-native species makes it difficult to develop strategies to manage this threat to biodiversity. Although a list of non-native species for continental Ecuador has recently been published, information on the status of these species in PAs in terms of invasiveness and impacts is scarce. This study presents a method that proposes criteria to prioritize the management of non-native phanerogam plants and terrestrial vertebrate species in eight PAs in the coastal region of Ecuador, based on the minimal information available. The study area covers 79.6% of all coastal PAs. For the non-native species inventory, we collated information from global biodiversity databases, research papers, theses and project repositories from local private and public universities, public institutions, and management plans for the selected PAs. To categorize the monitoring priority of the non-native species from the selected PAs, we used a pipeline scheme based on species invasion risk principles. We registered 78 non-native species within the eight PAs, consisting of 64 phanerogam plants and 14 terrestrial vertebrates. The PA with the highest non-native plant species richness is Manglares Churute Ecological Reserve (ER) with 25 species (39.1%; n = 64). For terrestrial vertebrates, the highest non-native species richness was in Isla Santay National Recreation Area (NRA) (71.4%; n = 14). 15.6% of the phanerogam plants and 78.5% of the terrestrial vertebrates were classified in the high priority category. The majority of non-native plants are categorized as “more studies required”, reflecting the state of art of invasion ecology in this country. This method allowed us to classify the species based on theoretical and occurrence data. It can potentially be replicated throughout the country and used as a rapid assessment method, complemented with specific invasion/impact studies on PAs in Ecuador.

The Asian water buffalo was introduced in Brazil in in the late nineteenth century. Today the country harbours one of the largest populations in the world, most of it in the Amazon basin. The majority of populations are domesticated, but feral populations have established in several protected areas. One of the largest, comprising both feral and free-living domestic individuals, is in Lago Piratuba Biological Reserve (LPBR) and Maracá-Jipioca Ecological Station (MJES) in Amapá state. Water buffalo cause serious damage to floodplains in both areas and their population control has been recommended. In 2017, we conducted aerial surveys using the double-count technique to estimate the size and distribution of the water buffalo population at LPBR and MJES. To assess population trends, we compared our results with two previous population estimates (2007 and 2013) for the same areas as well as with data from the Brazilian agricultural census (2007 to 2017) for the region. We estimated a population of 17,782 and 686 buffalo at LPBR and MJES, respectively. Compared to previous surveys, the population at MJES has remained stable, but the LPBR population declined by more than 40% compared to the last survey. The decline was virtually limited to one survey sector at LPBR. The decline is mirrored by the agricultural census data, but its reasons are unclear. We recommend continued monitoring, as the population can quickly rebound to previous numbers if left unchecked.

Volunteers are extensively involved in monitoring and controlling invasive species. Most research has examined volunteer activity in groups organized “top-down”, but we examined a local community-based group removing lionfish in the British Virgin Islands (BVI) with a specific focus on the use of social media by the group. Indo-Pacific lionfish (Pterois miles, P. lunulate and P. russelii) are invasive in the Western Atlantic Ocean and can impact the composition and function of coral reef communities. In response, resource managers and scientists have organized programs using divers and snorkelers to remove lionfish. In the volunteer-led BVI program, participants searched for and culled lionfish in their spare time and used a public Facebook group to record their activity. We compiled all lionfish-related posts from 2012 to 2014 (n = 654). Lionfish were reported at 147 sites, and 1451 lionfish were culled from 117 sites, but activity was concentrated at 35 established dive/snorkeling sites. We also performed SCUBA surveys (n = 27 sites). Survey results were consistent with Facebook reports in suggesting that culling made lionfish wary but did not consistently reduce lionfish abundance or size-distributions. Most removals were conducted by a core group of locals whereas a much larger group of locals and visitors, some of whom apparently participated after seeing the Facebook page, contributed mainly by reporting the location of sightings. Those removing lionfish frequently followed-up on posted sightings, suggesting that social networking facilitated information sharing by guiding the selection of hunting sites. Posts were also used by participants to encourage one another and share negative attitudes about lionfish. Community-based groups are challenged by limited resources, however social-media networks may facilitate communication among participants in ways that help motivate, coordinate and direct group activity.

A good understanding of the public’s knowledge and perceptions of alien fish species can guide policymakers to gain support for conservation and management programs. Using online and hardcopy questionnaires (n = 304), this study investigated public knowledge and perceptions of the impacts and importance of alien fish species in Malaysia, as well as information about relevant practices related to keeping and consuming fish. We correlated items measuring respondents’ knowledge, perception, and practices regarding alien fishes and associated these items with selected socio-demographic variables (education, ethnicity, gender and age). Significant relationships (p < 0.05) were found between different items measuring respondent knowledge versus perceptions regarding alien fishes, and between items measuring knowledge and perception versus practices regarding alien fishes. Seventy-six percent of the respondents considered alien fish species as economically valuable, while 91% knew their ecological impacts. Arapaima (Arapaima sp.) was the most well-known alien fish species among the public. Chi-square (χ²) tests showed that education, ethnicity, gender and age were important factors influencing public knowledge and perceptions of alien fish in Malaysia. Information from this study can inform future planning of conservation programs for native fish species in Malaysia.

The combination of snake-proof barriers and an aerial toxicant-delivery system for snake suppression may allow large-scale control of invasive brown treesnakes (Boiga irregularis) on Guam. However, suppression or local eradication of several other species (e.g., introduced ungulates, cats, rodents) may be required for successful restoration and recovery of forest habitat and reintroduction of native fauna. Island-wide eradication of invasive species is unlikely on Guam, and existing snake-proof barriers are largely ineffective against cats, rodents, shrews, or monitor lizards. Improved barrier technology and pest-control tools may together provide a viable solution to support localized restoration of species and habitats. We designed and tested prototype multispecies barriers using materials known to repel ungulates, cats, and rodents, with a focus on testing the ability of a rolled hood installed over three different mesh designs to repel brown treesnakes and black rats (Rattus rattus). Woven wire (4.9 × 12 mm aperture, 2.5 mm dia. wire) repelled 99.1% of all snakes, including ≥ 1031 breach attempts by 106 individuals and 2 successful breaches by 1 small individual. Woven wire (6 × 6 mm aperture, 2.7 mm dia. wire) repelled 100% of all snakes, including 611 breach attempts by 65 individuals. Mini chain link mesh (7 × 9 mm aperture, 1 mm dia. wire) repelled 100% of all snakes, including 1053 breach attempts by 97 individuals. Brown treesnakes were unable to climb either of the two woven wire designs (1642 breach attempts by 171 individuals), making the rolled hood serve as a redundant secondary snake barrier. The rolled hood repelled 100% of all snakes when individuals were provided a climbable surface to access the hood (94 breach attempts by 39 snakes). The probability of a snake being able to climb the mini chain link mesh was inversely related to snout-vent length. The rolled hood repelled 100% of all rats, with 5080 breach attempts by 21 individuals. Recommended next steps include consultation with engineers to address wind loading, structural integrity, material interactions, and integration of decision-support tools to optimize cost and efficacy of barrier designs on the landscape.

The brown treesnake (Boiga irregularis) was accidentally introduced to Guam and caused severe ecological and economic damages. Acetaminophen is an effective, low-risk oral toxicant for invasive brown treesnakes, and an automated aerial delivery system (ADS) has been developed for landscape-scale toxic bait distribution. A fixed dose of 80 mg of acetaminophen within a tablet inserted into a dead neonatal mouse (DNM) was lethal for all brown treesnakes in previous trials; however, these trials did not include very large individuals which are difficult to acquire for testing. Because most reptiles continue to grow throughout their lifespan, a small number reach much greater than average body sizes. Here, we tested effectiveness of 80 mg acetaminophen DNM baits for unusually large brown treesnakes as they became available. Our results confirmed that an 80 mg dose is lethal for the vast majority of snakes on Guam, but efficacy starts to diminish around 200 g of body mass. We also tested an alternative mouse bait configuration with 160 mg of acetaminophen that could be incorporated into the ADS to improve control of unusually large snakes. The 160 mg dose is expected to be effective for nearly all female snakes; males grow much larger and additional methods will be needed for extraordinarily large individuals. We describe a full dose-response curve for brown treesnakes to acetaminophen tablets and estimate the LD₉₀ at 299 mg/kg and the LD₉₉ at 578 mg/kg. To our knowledge, this is the first published dose-response curve for an invasive vertebrate with indeterminate growth.