DOI: 10.3897/neobiota.107.178668

Authors: Hedi Schloddarick, Frederic Griesbaum, Melita Vamberger, Johannes Penner

Abstract: The introduction of non-native species has created significant global biodiversity challenges, both directly and indirectly, affecting native ecosystems and biodiversity. Since the 1930s, with a peak in the 1980s and early 1990s, human activities have facilitated the global spread of the North American pond slider (Trachemys scripta), which seems to be widespread in Germany, occupying numerous waterbodies. However, knowledge on other non-native chelonian species in Germany remains sparse. This study aims to assess the current diversity and distribution of non-native freshwater chelonians in Germany. Using a dataset of 1770 records of non-native terrapins in Germany, derived from the published sources and publicly available citizen-science data, we examine the distributions and their relationship to anthropogenic factors. Herein, we confirm the presence of 14 free-ranging non-native terrapin species in Germany, namely Chelydra serpentina, Chrysemys dorsalis, Chrysemys picta, Graptemys ouachitensis, Graptemys pseudogeographica, Mauremys leprosa, Mauremys reevesii, Mauremys sinensis, Pelodiscus sinensis, Pseudemys concinna, Pseudemys nelsoni, Pseudemys peninsularis, Sternotherus odoratus and Trachemys scripta and provide a comprehensive overview of their currently known distribution patterns. We also report occurrences of Emys orbicularis, which is native to Germany, but, with the exception of the Brandenburg populations, nearly all populations are allochthonous. Our study reveals that species diversity and abundance are highest in and in close proximity to urban areas, confirming a strong correlation between terrapin distribution and anthropogenic presence.

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DOI: 10.3897/neobiota.107.175797

Authors: Bettina Pintér-Szajbert, András Weiperth, Zsombor Márk Bányai, Gábor Herczeg

Abstract: Global declines in amphibians and reptiles have been well documented for decades, with invasive species being one of the major threats. In the Pannonian Biogeographical Region (PBR) of Central Europe, which includes the whole territory of Hungary and peripheral areas of Austria, Croatia, Czech Republic, Romania, Slovakia, Slovenia, Serbia, and Ukraine, there is currently no systematic overview of the occurrence and potential risk of invasiveness of non-native amphibians and aquatic reptiles. Here, we (i) collated observations on non-native species occurrence in the PBR, (ii) ran a monitoring program focused on the urban areas around Budapest, the capital of Hungary, and (iii) screened 16 amphibian and 28 aquatic reptile non-native species found across the PBR and in the local pet trade market for risk of invasiveness under both current and predicted future climate conditions. The risk screening was carried out using the Aquatic Species Invasiveness Screening Kit v2.4 (AS-ISK). We collected 5,134 observations of five amphibian and 14 aquatic reptile non-native species in the PBR, with the highest diversity and densities observed in urban areas. Screening revealed that six amphibians and 23 aquatic reptiles can be regarded as posing a high to very high risk of invasiveness, especially after accounting for the effects of climate change. Combining occurrence data and screening results, the highest-risk taxa include the three subspecies of pond slider Trachemys scripta, the common snapping turtle Chelydra serpentina, the Eastern river cooter Pseudemys concinna, the Chinese soft-shelled turtle Pelodiscus sinensis, the false map turtle Graptemys pseudogeographica, the African clawed frog Xenopus laevis, and the western dwarf clawed frog Hymenochirus curtipes. Trachemys scripta elegans and T. s. scripta can already be considered invasive. We conclude that pet keeping presents a serious conservation threat for the PBR, where urban areas act as incubators for potential invasion. We emphasize the importance of public campaigns aimed at raising awareness of the risk posed by invasive species and of continuous targeted monitoring of urban areas to prevent future invasions.

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DOI: 10.3897/neobiota.104.159611

Authors: Edvárd Mizsei, Csongor Adorjáni, Barnabás Bancsik, Gergő Kovács, Gergő Rák, Gergely Babocsay, Mátyás Budai

Abstract: Grasslands have undergone significant loss of area and species diversity worldwide. The spread of invasive alien plant species further exacerbates the degradation of these ecosystems. Reptile populations are particularly affected by changes caused by invasive plants. Pannonian sand steppe grasslands, typical of the lowland regions within the Central European Carpathian Basin, are distinctive habitats that are rapidly shrinking in extent. These grasslands provide habitats for numerous grassland specialists, such as the Balkan wall lizard (Podarcis tauricus). Over the last few years, a new invader, the sand dropseed (Sporobolus cryptandrus), native to the North American prairies, has appeared in this community and spread aggressively. In addition, shrub encroachment due to pasture abandonment and reforestation has further reduced the area of these communities. In this study, we explored how the densities of two lizard species, the Balkan wall lizard and the Eastern green lizard (Lacerta viridis), a potential competitor of the Balkan wall lizard inhabiting these open grasslands, respond to increasing coverage of non-native invasive plants and the encroachment of woody vegetation. We surveyed lizard populations at six sites and assessed the effects of these threats using single-visit N-mixture models. The results showed varied effects on the abundance of the two lizard species: sand dropseed negatively affected the Balkan wall lizard, while woody encroachment positively influenced the Eastern green lizard.

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DOI: 10.3897/neobiota.102.143330

Authors: João Rato, Pedro Brandão, Mafalda Gama, Filipe Banha, Pedro Anastácio

Abstract: Invasive species pose significant threats to biodiversity, human health, and economic systems. Freshwater turtles are popular as pets, but when released or allowed to escape into the wild, they can become invasive. A prominent example is the red-eared slider Trachemys scripta, which is recognized as a globally invasive species. Legislative tools, such as the European Union Regulation 1143/2014 on the prevention and management of invasive alien species, aim to combat these threats. This framework includes the implementation of Commission Implementing Regulation 1141/2016, which banned the trade of listed invasive species, including T. scripta. This study evaluates the effectiveness of Regulation 1143/2014 on T. scripta invasion and its consequences on other freshwater turtle invasions, using data from the CITES database and the GBIF platform. While T. scripta imports into the EU ceased after 2016, the species continues to establish and expand in the wild. This suggests that the trade ban had minimal impact on already established populations, highlighting the need for additional measures to reduce and control its spread. Simultaneously, imports and records of other freshwater turtle species have risen, indicating a shift in trade dynamics. These species are increasingly being introduced, potentially exacerbating the biological invasion problem. Despite limitations inherent to CITES and GBIF data, our findings suggest that the current European legislation has not been effective in mitigating T. scripta invasions and may have unintentionally contributed to the introduction of other invasive turtles. We recommend that the European Union develop invasive species lists tailored to each biogeographic regions of Europe to enhance the effectiveness of legislation.

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DOI: 10.3897/neobiota.100.147371

Authors: Isabell M. Kuhn, Benoît Quintard, Kathrin Theissinger, Jean-Yves Georges

Abstract: Biological invasions contrast with reintroduction projects, where native species are deliberately returned to their natural habitat to restore local biodiversity. Such a reintroduction project is being carried out in the Upper Rhine Valley with the European pond turtle (Emys orbicularis) in the transbordering region between Lauterbourg (France) and Neuburg am Rhein (Germany), hereafter referred as Neu-Woerr. Several ponds have been created to benefit the dispersal of reintroduced turtles. However, this pondscape has been recently widely invaded by the calico crayfish (Faxonius immunis) and partly by the zebra mussel (Dreissena polymorpha). These two invasive non-native species decrease the overall habitat quality due to the massive exploitation of phytoplankton by the zebra mussel as well as macrophytes and macroinvertebrates by the calico crayfish. However, these invasive non-native species are also potential novel prey for the reintroduced turtles. Here, we investigated the trophic interactions under captive conditions between the turtle and the two invasive non-native species. We conducted prey choice tests of turtles with calico crayfish of different sex, size, and shell hardness, as well as with zebra mussels of different size. Additionally, faecal samples of wild caught turtles on Neu-Woerr were sampled and analysed for calico crayfish DNA. Our results demonstrated that the turtles were capable of preying on the calico crayfish in the wild and in captivity, preferring small crayfish individuals, with no sexual preference for the less aggressive female crayfish. For the zebra mussels, turtles preyed preferably on small alive individuals, while they also preyed on larger, yet dead mussels. This study provides new insights into the feeding ecology of the European pond turtle and highlights added benefits and values of reintroduction projects when the reintroduced species additionally acts as a novel predator of invasive species.

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DOI: 10.3897/neobiota.100.148230

Authors: Andrew M. Durso, Shane R. Siers, Robert N. Reed, Julie A. Savidge

Abstract: Predation by Brown Treesnakes (Boiga irregularis) has caused the decline or extinction of all native forest vertebrates on Guam, including birds, lizards, and bats. Loss of the highest-quality prey has caused shifts in Brown Treesnake size and life history. We sought to understand how reproductive condition varies among habitats island-wide, particularly comparing urban and savanna habitats (where some primarily non-native large prey remain) with prey-depauperate forest habitats. We dissected 100 snakes from each of 18 sites stratified by 6 habitat types and calculated a body condition index, relative follicle size (for females; N = 817) and relative testes size (for males; N = 992) for each. Low detection of reproductive females continues to hamper research on their biology, as only 11% of females had secondary vitellogenic follicles (N = 89). Although variation among sites within habitats was high, above-average reproductive development of both males and females was most frequently observed in urban and savanna habitats, emphasizing the potential for prey subsidies in these habitats to fuel population growth and affect invasive snake management objectives. Furthermore, the trade-off between body condition and reproductive condition appeared to be more severe in forested habitats and less severe in urban habitats for both males and females. There were few obvious seasonal patterns, although there was a slightly lower probability of females having secondary vitellogenic follicles in the wet season compared to the dry season.

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DOI: 10.3897/neobiota.99.148521

Authors: Gretchen E. Anderson, McKayla M. Spencer, Ray W. Snow, Andrea F. Currylow, Frank N. Ridgley, Bryan G. Falk, Amy A. Yackel Adams

Abstract: Burmese pythons (Python molurus bivittatus) and African rock pythons (Python sebae) have established invasive populations in southern Florida, severely disrupting local ecosystems. We analysed necropsy data from 2,179 pythons captured between 2006 and 2022, revealing nine cases of coelomic foreign bodies, primarily consisting of bird beaks, which presumably entered the coelom following gastrointestinal perforations during prey consumption. Despite the presence of foreign bodies, most examined pythons exhibited no obvious health issues. These findings indicate that the consumption of prey with sharp morphological features, such as wading birds, may not impede the pythons’ survival or health significantly, thereby underscoring their adaptability as apex predators in the Greater Everglades Ecosystem.

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DOI: 10.3897/neobiota.96.128038

Authors: Alexandra Meira, Francisco Carvalho, Paulo Castro, Ronaldo Sousa

Abstract: Technological advances have boosted the ability to obtain large and high-quality ecological data. These new technological tools have the potential to rapidly develop knowledge on how species behave and interact in ecosystems at relevant spatial and temporal scales. Comprehensive time-series datasets on the in situ behaviour and dispersal of wild organisms are essential for addressing fundamental ecological and physiological questions regarding non-native freshwater species. In this review, we address how biosensors, hereby defined as a tool for electronic tagging and tracking, can be useful in assessing movement, internal states and behaviour in non-native freshwater species, plus information about the surrounding environment and discuss possibilities of future research. We performed a systematic review of the available literature and retrieved a total of 132 scientific studies (from 1996 to 2023) detailing 140 examples of sensor use. Most studies used radio telemetry (40%; n = 53) followed by acoustic telemetry (34%; n = 45) and PIT telemetry (20%; n = 26) to study non-native freshwater species. The taxonomic group most studied was fish (72%; n = 109), followed by crustaceans (14%; n = 21) and amphibians (5%; n = 8). The most addressed topics included species behaviour assessment (72%; n = 101), species physiology (10%; n = 14) and management (9%; n = 12). As expected, the number of studies noticeably increased since 2006, with the majority performed in North America (55%; n = 73), followed by Europe (30%; n = 40) and Oceania (7%; n = 9). Information provided by biosensors can be used to better understand the dynamics and impacts of cryptic non-native species and can be applied in the management of biological invasions. We also addressed future directions concerning the use of biosensors in non-native freshwater species (e.g. underwater internet systems, artificial intelligence, crittercams). Overall, these technologies provide unique possibilities in the field of biological invasions in freshwater ecosystems and the development of new technologies to address their limitations will increase the amount and reliability of the data gathered to provide information for management actions.

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DOI: 10.3897/neobiota.96.114925

Authors: Christina N. De Jesús Villanueva, Gabriela P. Massanet Prado, Steven M. Van Belleghem, William Gould, Jason J. Kolbe

Abstract: Losses in crop yield due to invasive insects, weeds, pathogens, and herbivores cost trillions of dollars per year globally. To prevent further spread of invasive agricultural pest species, continuous monitoring and prevention are crucial. Once introduced, however, assessing the impact of an invasive pest on agricultural production and testing management strategies are essential. The green iguana (Iguana iguana), a globally widespread invasive herbivore, is considered a possible agricultural pest although no quantitative data on its impact are available. In this study, we evaluated the impact of the invasive green iguana on cucumber (Cucumis sativus, var. Dasher II) and lettuce (Lactuca sativa, var. Black-seeded Simpson) yield by testing the efficacy of two management strategies – Neem-based pesticide and mesh fencing – compared to open field cultivation in Puerto Rico. Mesh fencing led to 20% more growth and doubled cucumber yield compared to open field cultivation, while spraying Neem led to an 18% increase in plant growth but no effect on cucumber yield. We found no difference in lettuce growth or yield among treatment and control plots. This study supports categorizing the green iguana as an invasive agricultural pest species and demonstrates the reptile’s potential to reduce crop yield. It also shows that Neem application at the manufacturer’s suggested concentration is not an effective mitigation technique for reducing crop loss due to green iguana herbivory. Government agencies in regions where the green iguana has the potential to be introduced should consider the species a threat to food production when developing monitoring programs and drafting regulations.

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DOI: 10.3897/neobiota.91.109403

Authors: Elizabeth F. Pienaar, Diane J. E. Sturgeon

Abstract: The exotic pet trade has resulted in substantial invasion and disease risks, owing to the release of pets into new environments. Scientists have conjectured that pet owners acquire and release species with undesirable traits because they are imperfectly informed about the traits of these animals. However, few studies have used social science methods to elicit pet owners’ preferences for exotic pets. In 2019 we administered a best-worst choice survey to 1,055 exotic pet owners in the United States (who own pet reptiles, amphibians, fish, or invertebrates) to examine how human preferences and incomplete information may contribute to the risks of the exotic pet trade. Respondents preferred colorful and patterned species. On average, respondents preferred medium-sized amphibians and reptiles, small fish, and large invertebrates, although they demonstrated heterogeneity in preferences with respect to the adult size of pets. Respondents also preferred amphibians and reptiles with medium life expectancies and fish and invertebrates with long life expectancies, although they again demonstrated heterogeneity in preferences with respect to pets’ life span. Respondents preferred docile animals, and were more likely to purchase lower-cost pets. We found some evidence that respondents’ decision to purchase exotic pets depended on whether these animals were native, rare, had unusual morphological features, and breed easily. Respondents’ decision to purchase specific taxa as exotic pets also depended on their age, education, and housing. Most respondents stated that they searched for information on pets’ diet, behavior, adult size, life span, costs of care such as equipment or veterinary costs, and whether the animal was captive bred before purchasing these animals. Excepting pets’ diets, fewer than half of respondents had been offered information on pets’ traits by sellers. On average, respondents rated the information they had been offered as average. Respondents typically obtained additional information about pets from online searches. Our results suggest that certification systems that provide critical information on exotic pets’ behaviors, adult size, longevity, fecundity, and husbandry needs should be implemented to prevent pet owners acquiring animals that they may subsequently abandon.

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DOI: 10.3897/neobiota.90.103041

Authors: Shane R. Siers, Melia G. Nafus, Jeried E. Calaor, Rachel M. Volsteadt, Matthew S. Grassi, Megan Volsteadt, Aaron F. Collins, Patrick D. Barnhart, Logan T. Huse, Amy A. Yackel Adams, Diane L. Vice

Abstract: In October 2020, a new population of invasive brown treesnakes (Boiga irregularis) was discovered on the 33-ha Cocos Island, 2.5 km off the south coast of Guam. Cocos Island is a unique conservation resource, providing refuge for many lizards and birds, including endangered species, which were extirpated from mainland Guam by invasive predators including brown treesnakes. We sought to evaluate the usefulness of toxic baiting with acetaminophen-treated carrion baits and cage trapping, common tools for the control of brown treesnakes on mainland Guam, as potential eradication tools on Cocos Island. We evaluated multiple bait types and bait presentations: on the ground, suspended in the canopy emulating aerial bait applications and in four plastic-tube bait station configurations intended to exclude non-target species. We monitored all baits with time-lapse cameras. Despite improved exclusion of non-targets by bait station design, most baits were quickly removed by non-target species, particularly coconut crabs (Birgus latro) and Mariana monitors (Varanus tsukamotoi). Monitoring of 1,250 baits available for 2,427 bait nights resulted in no observations of brown treesnakes taking any bait. Subsequently, we tested two trap types commonly used on Guam and compared trapping success with live versus dead mouse lures. In 10,553 trap nights using live and dead mouse lures, we only captured one brown treesnake, in a trap with a live mouse lure. These baiting and trapping rates are so low as to be ineffectual for all practical purposes. Concurrent visual searching and hand capture of brown treesnakes during initial rapid response efforts demonstrates that these low baiting and trapping success rates are not a result of low snake density. We make a case for our assumption that the ineffectiveness of these tools on Cocos Island is due to the context of extremely high abundance of preferred live prey, primarily large geckos and birds. Our results have profound conservation ramifications, because any future island invasions by brown treesnakes are likely to occur within similarly prey-rich environments where these baiting and trapping methods might be similarly ineffective.

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DOI: 10.3897/neobiota.87.102969

Authors: Lance D. McBrayer, Daniel Haro, Michael Brennan, Bryan G. Falk, Amy A. Yackel Adams

Abstract: Excluding non-target species from invasive species control efforts can be challenging due to non-target attraction to trap structure, baits, and lures. Various methods have been used to deter non-target species from entering or disturbing traps including altered features (e.g., mesh size, trip mechanism, or entrances), staking traps, and chemical deterrents. Invasive populations of Argentine Black and White Tegu lizards (Salvator merianae) occur in several locations across Florida and Georgia, and there are ongoing trapping efforts to control them. At sites in Georgia, non-target mammals disturb most of the lizard traps (>80%), consume egg bait/lures, and thus reduce trap efficacy. In contrast, our Florida site has fewer problems with non-target mammals. Our goal was to quantify the efficacy of capsaicin-coated eggs, a known distasteful irritant to mammals, as a non-target bait deterrent in live traps set for tegus in both Georgia and Florida. We conducted feeding assays on three tegus and found that individuals readily consumed food coated in capsaicin. We then conducted a three-part, live trapping experiment to test 1) if trap disturbance by mammals habituated to eggs without capsaicin decreased when capsaicin-coated eggs were deployed in Georgia, 2) if mammals not habituated to eggs as bait (treated or untreated) disturbed live traps at the same rate as those habituated to eggs in Georgia, and 3) if tegu capture rates were different when capsaicin treated eggs were deployed in Florida. In Georgia, we found that trap disturbance by non-target mammals did not decrease when capsaicin was applied to eggs in an area previously habituated to trapping with this bait nor when applied in a novel area. In Florida, we found no significant difference in tegu captures using capsaicin-treated vs. untreated bait. Tegus were tolerant of capsaicin, but capsaicin treated eggs did not reduce non-target mammal disturbance to traps. Therefore, removal of invasive populations could be problematic if methods to reduce trap disturbance by non-targets are not identified and deployed.

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DOI: 10.3897/neobiota.82.87264

Authors: Benno Tietz, Johannes Penner, Melita Vamberger

Abstract: Biological invasions by alien species have substantial economic impacts and are a major driver of the ongoing decline and loss of biodiversity. Through humans, the North American pond slider (Trachemys scripta) has acquired a global distribution over the last decades and is currently listed among the worst invasive reptile species. However, in more recent times, other freshwater chelonian species have increasingly been recorded far outside their native distribution ranges as well, not only on the same continent but also on others. Despite that, the impact of alien chelonians on their respective new ecosystems remains unclear. The long-term effects and severity of impacts of alien populations mostly depend on whether they ultimately succeed in establishing themselves. This is not entirely resolved for chelonians in Central Europe. To answer that, we investigated wild populations of three non-native chelonian species from North America in Germany (Pseudemys concinna, Graptemys pseudogeographica and Trachemys scripta) applying population genetic approaches. We revealed the successful reproduction of all three species in Germany and provide the very first record for the reproduction of P. concinna and G. pseudogeographica in a temperate continental climate zone outside their native distribution. Based on our unambiguous evidence of natural reproduction, we call for dedicated studies to verify how widespread established populations are and to investigate the existing and potential impacts of all three species in a range of ecosystems along a climatic gradient. Such data is urgently needed to revise the current risk assessments of non-native chelonians, especially in Central European countries.

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DOI: 10.3897/neobiota.80.90439

Authors: Jacquelyn C. Guzy, Bryan G. Falk, Brian J. Smith, John David Willson, Robert N. Reed, Nicholas G. Aumen, Michael L. Avery, Ian A. Bartoszek, Earl Campbell, Michael S. Cherkiss, Natalie M. Claunch, Andrea F. Currylow, Tylan Dean, Jeremy Dixon, Richard Engeman, Sarah Funck, Rebekah Gibble, Kodiak C. Hengstebeck, John S. Humphrey, Margaret E. Hunter, Jillian M. Josimovich, Jennifer Ketterlin, Michael Kirkland, Frank J. Mazzotti, Robert McCleery, Melissa A. Miller, Matthew McCollister, M. Rockwell Parker, Shannon E. Pittman, Michael Rochford, Christina Romagosa, Art Roybal, Ray W. Snow, McKayla M. Spencer, J. Hardin Waddle, Amy A. Yackel Adams, Kristen M. Hart

Abstract: Burmese pythons (Python molurus bivittatus) are native to southeastern Asia, however, there is an established invasive population inhabiting much of southern Florida throughout the Greater Everglades Ecosystem. Pythons have severely impacted native species and ecosystems in Florida and represent one of the most intractable invasive-species management issues across the globe. The difficulty stems from a unique combination of inaccessible habitat and the cryptic and resilient nature of pythons that thrive in the subtropical environment of southern Florida, rendering them extremely challenging to detect. Here we provide a comprehensive review and synthesis of the science relevant to managing invasive Burmese pythons. We describe existing control tools and review challenges to productive research, identifying key knowledge gaps that would improve future research and decision making for python control.

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DOI: 10.3897/neobiota.78.93788

Authors: Andrea F. Currylow, Bryan G. Falk, Amy A. Yackel Adams, Christina M. Romagosa, Jillian M. Josimovich, Michael R. Rochford, Michael S. Cherkiss, Melia G. Nafus, Kristen M. Hart, Frank J. Mazzotti, Ray W. Snow, Robert N. Reed

Abstract: The design of successful invasive species control programs is often hindered by the absence of basic demographic data on the targeted population. Establishment of invasive Burmese pythons (Python molurus bivittatus) in the Greater Everglades Ecosystem, Florida USA has led to local precipitous declines (> 90%) of mesomammal populations and is also a major threat to native populations of reptiles and birds. Efforts to control this species are ongoing but are hampered by the lack of access to and information on the expected biological patterns of pythons in southern Florida. We present data from more than 4,000 wild Burmese pythons that were removed in southern Florida over 26 years (1995–2021), the most robust dataset representing this invasive population to date. We used these data to characterize Burmese python size distribution, size at maturity, clutch size, and seasonal demographic and reproductive trends. We broadened the previously described size ranges by sex and, based on our newly defined size-stage classes, showed that males are smaller than females at sexual maturity, confirmed a positive correlation between maternal body size and potential clutch size, and developed predictive equations to facilitate demographic predictions. We also refined the annual breeding season (approx.100 days December into March), oviposition timing (May), and hatchling emergence and dispersal period (July through October) using correlations of capture morphometrics with observations of seasonal gonadal recrudescence (resurgence) and regression. Determination of reproductive output and timing can inform population models and help managers arrest population growth by targeting key aspects of python life history. These results define characteristics of the species in Florida and provide an enhanced understanding of the ecology and reproductive biology of Burmese pythons in their invasive Everglades range.

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DOI: 10.3897/neobiota.76.84268

Authors: Lorenzo Vilizzi, Marina Piria, Dariusz Pietraszewski, Oldřich Kopecký, Ivan Špelić, Tena Radočaj, Nikica Šprem, Kieu Anh T. Ta, Ali Serhan Tarkan, András Weiperth, Baran Yoğurtçuoğlu, Onur Candan, Gábor Herczeg, Nurçin Killi, Darija Lemić, Bettina Szajbert, David Almeida, Zainab Al-Wazzan, Usman Atique, Rigers Bakiu, Ratcha Chaichana, Dimitriy Dashinov, Árpad Ferincz, Guillaume Flieller, Allan S. Gilles Jr, Philippe Goulletquer, Elena Interesova, Sonia Iqbal, Akihiko Koyama, Petra Kristan, Shan Li, Juliane Lukas, Seyed Daryoush Moghaddas, João G. Monteiro, Levan Mumladze, Karin H. Olsson, Daniele Paganelli, Costas Perdikaris, Renanel Pickholtz, Cristina Preda, Milica Ristovska, Kristína Slovák Švolíková, Barbora Števove, Eliza Uzunova, Leonidas Vardakas, Hugo Verreycken, Hui Wei, Grzegorz Zięba

Abstract: Electronic decision-support tools are becoming an essential component of government strategies to tackle non-native species invasions. This study describes the development and application of a multilingual electronic decision-support tool for screening terrestrial animals under current and future climate conditions: the Terrestrial Animal Species Invasiveness Screening Kit (TAS-ISK). As an adaptation of the widely employed Aquatic Species Invasiveness Screening Kit (AS-ISK), the TAS-ISK question template inherits from the original Weed Risk Assessment (WRA) and related WRA-type toolkits and complies with the ‘minimum requirements’ for use with the recent European Regulation on invasive alien species of concern. The TAS-ISK consists of 49 basic questions on the species’ biogeographical/historical traits and its biological/ecological interactions, and of 6 additional questions to predict how climate change is likely to influence the risks of introduction, establishment, dispersal and impact of the screened species. Following a description of the main features of this decision-support tool as a turnkey software application and of its graphical user interface with support for 32 languages, sample screenings are provided in different risk assessment areas for one representative species of each of the main taxonomic groups of terrestrial animals supported by the toolkit: mammals, birds, reptiles, amphibians, annelids, insects, molluscs, nematodes, and platyhelminths. The highest-scoring species were the red earthworm Lumbricus rubellus for the Aegean region of Turkey and the New Zealand flatworm Arthurdendyus triangulatus for Croatia. It is anticipated that adoption of this toolkit will mirror that of the worldwide employed AS-ISK, hence allowing to share information and inform decisions for the prevention of entry and/or dispersal of (high-risk) non-native terrestrial animal species – a crucial step to implement early-stage control and eradication measures as part of rapid-response strategies to counteract biological invasions.

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DOI: 10.3897/neobiota.74.82250

Authors: Magda Vodrážková, Irena Šetlíková, Josef Navrátil, Michal Berec

Abstract: The presence of a predator affects prey populations either by direct predation or by modifying various parts of their life history. We investigated whether the hatching time, developmental stage, and body size at hatching of common frog (Rana temporaria) embryos would alter in the presence of a red-eared slider (Trachemys scripta elegans) as a predator. The presence of a predator affected all factors examined. We found that in the absence of the slider, the embryos hatched in 12 days, while hatching was accelerated by two days in slider treatment. At the same time, the embryos hatched smaller and at a lower stage of development with the slider than without it. Our study extends the range of predators studied, including the effect on different phases of development of potential amphibian prey.

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DOI: 10.3897/neobiota.70.71379

Authors: Staci M. Amburgey, Amy A. Yackel Adams, Beth Gardner, Bjorn Lardner, Adam J. Knox, Sarah J. Converse

Abstract: Early detection and rapid response (EDRR) are essential to identifying and decisively responding to the introduction or spread of an invasive species, thus avoiding population establishment and improving the probability of achieving eradication. However, detection can be challenging at the onset of a species invasion as low population densities can reduce the likelihood of detection and conceal the true extent of the situation until the species is well established. This is doubly challenging if the invading species displays cryptic behavior or is nocturnal, thus further limiting opportunities for its discovery. Survey methods that maximize a searcher’s ability to detect an incipient population are therefore critical for successful EDRR. Brown treesnakes (Boiga irregularis) on Guåhan are a classic cautionary example of the dangers of not detecting an invasion early on, and the risk of their introduction to other islands within the Marianas, Hawai’i and beyond remains. Nocturnal visual surveys are known to detect brown treesnakes of all sizes and are the primary detection tool used by the Brown Treesnake Rapid Response Team, but detection probability remains low in complex forest habitats. As such, we investigated the use of two potential enhancements to nocturnal visual surveys – a live mouse lure and spray scent attractant – that may create hotspots of increased detection probability during surveys. We found that, while brown treesnake detection probabilities were low for all surveys, visual surveys conducted on transects with live mouse lures resulted in detection probabilities that were 1.3 times higher than on transects without live mouse lures. Conversely, the spray scent attractant did not increase the probability of detecting brown treesnakes compared to transects without scent, and in fact had detection probabilities that were 0.66 times lower, though the reasons for this phenomenon are unclear. Unlike scent attractants, live mouse lures likely provide both visual and olfactory cues that attract brown treesnakes to transects and thus provide more opportunities to detect and capture them. These enhancements were trialed on Guåhan, where prey populations are depressed. It remains unclear whether live mouse lures will be as effective for EDRR applications in prey-rich settings.

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DOI: 10.3897/neobiota.64.55597

Authors: Fernando Ascensão, Marcello D'Amico, Ricardo C. Martins, Rui Rebelo, A. Márcia Barbosa, Joana Bencatel, Rafael Barrientos, Pedro Abellán, José L. Tella, Laura Cardador, José D. Anadón, Martina Carrete, Enrique Murgui, Pedro Fernandes, Sara M. Santos, António Mira, Maria da Luz Mathias, Patrícia Tiago, Eduardo Casabella, Luís Reino, Octávio S. Paulo, Henrique M. Pereira, César Capinha

Abstract: We present a dataset that assembles occurrence records of alien tetrapods (amphibians, reptiles, birds and mammals) in the Iberian Peninsula, a coherent biogeographically unit where introductions of alien species have occurred for millennia. These data have important potential applications for ecological research and management, including the assessment of invasion risks, formulation of preventive and management plans, and research at the biological community level on alien species. This dataset summarizes inventories and data sources on the taxonomy and distribution of alien tetrapods in the Iberia Peninsula, comprising known locations from published literature, expert knowledge and citizen science platforms. An expert-based assessment process allowed the identification of unreliable records (misclassification or natural dispersion from native range), and the classification of species according to their status of reproduction in the wild. Distributional data was harmonized into a common area unit, the 10 × 10 km Universal Transverse Mercator (UTM) system (n = 6,152 cells). The year of observation and/or year of publication were also assigned to the records. In total, we assembled 35,940 unique distribution records (UTM × species × Year) for 253 species (6 amphibians, 16 reptiles, 218 birds and 13 mammals), spanning between 1912 and 2020. The species with highest number of distribution records were the Mediterranean painted frog Discoglossus pictus (n = 59 UTM), the pond slider Trachemys scripta (n = 471), the common waxbill Estrilda astrild (n = 1,275) and the house mouse Mus musculus (n = 4,043), for amphibians, reptiles, birds and mammals, respectively. Most alien species recorded are native to Africa (33%), followed by South America (21%), Asia (19%), North America (12%) and Oceania (10%). Thirty-six species are classified by IUCN as threatened in their native range, namely 2 Critically Endangered (CR), 6 Endangered (EN), 8 Vulnerable (VU), and 20 species Near Threatened (NT). Species maps are provided in DataSet1, as well R code and GIS layers to update them as new records are obtained.

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DOI: 10.3897/neobiota.59.53671

Authors: Katherine G. W. Hill, Kristine E. Nielson, Jonathan J. Tyler, Francesca A. McInerney, Zoe A. Doubleday, Greta J. Frankham, Rebecca N. Johnson, Bronwyn M. Gillanders, Steven Delean, Phillip Cassey

Abstract: The illegal pet trade facilitates the global dispersal of invasive alien species (IAS), providing opportunities for new pests to establish in novel recipient environments. Despite the increasing threat of IAS to the environment and economy, biosecurity efforts often lack suitable, scientifically-based methods to make effective management decisions, such as identifying an established IAS population from a single incursion event. We present a proof-of-concept for a new application of a stable isotope technique to identify wild and captive histories of an invasive pet species. Twelve red-eared slider turtles (Trachemys scripta elegans) from historic Australian incursions with putative wild, captive and unknown origins were analysed to: (1) present best-practice methods for stable isotope sampling of T. s. elegans incursions; (2) effectively discriminate between wild and captive groups using stable isotope ratios; and (3) present a framework to expand the methodology for use on other IAS species. A sampling method was developed to obtain carbon (δ13C) and nitrogen (δ15N) stable isotope ratios from the keratin layer of the carapace (shells), which are predominantly influenced by dietary material and trophic level respectively. Both δ13C and δ15N exhibited the potential to distinguish between the wild and captive origins of the samples. Power simulations demonstrated that isotope ratios were consistent across the carapace and a minimum of eight individuals were required to effectively discriminate wild and captive groups, reducing overall sampling costs. Statistical classification effectively separated captive and wild groups by δ15N (captive: δ15N‰ ≥ 9.7‰, minimum of 96% accuracy). This study outlines a practical and accessible method for detecting IAS incursions, to potentially provide biosecurity staff and decision-makers with the tools to quickly identify and manage future IAS incursions.

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DOI: 10.3897/neobiota.45.31009

Authors: Pablo García-Díaz, Joshua V. Ross, Miquel Vall-llosera, Phillip Cassey

Abstract: When we assume that contemporary management actions will be effective against the global rise of emerging alien species, we can develop management complacency, which leads to potentially disastrous outcomes for native biodiversity. Here, we propose the use of the probability of detection as a metric to assess the feasibility of management actions for alien species. We explore how detectability can influence the management of alien reptiles, a group of emergent alien vertebrates globally. We use a Rapid Biological Assessment method (time-limited transects) to estimate the probability of detection for alien reptiles present on Christmas Island (Australia). Across the five species studied, we found low probabilities of detection and poor explanatory capacity of the individual covariates included in our models. These findings indicate that management options to deal with alien reptiles are limited due to the potential high cost and low efficacy associated with low probabilities of detection. Strict preventive strategies, firmly espousing the principles of adaptiveness and precautionary policies, combined with early detection and biosecurity response activities are needed to address the emergence of alien reptiles. Our research was focussed on alien reptiles on islands, but the rise of new pools of alien species from all taxonomic realms across the world suggests that our conclusions may be applicable more generally. Further research is called for to explore the applicability of our conclusions and recommendations to other taxonomic groups and regions of the world.

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DOI: 10.3897/neobiota.40.28519

Authors: James W.E. Dickey, Ross N. Cuthbert, Michael Rea, Ciaran Laverty, Kate Crane, Josie South, Elizabeta Briski, Xuexiu Chang, Neil E. Coughlan, Hugh J. MacIsaac, Anthony Ricciardi, Gillian E. Riddell, Meng Xu, Jaimie T.A. Dick

Abstract: Invasive alien species (IAS) cause myriad negative impacts, such as ecosystem disruption, human, animal and plant health issues, economic damage and species extinctions. There are many sources of emerging and future IAS, such as the poorly regulated international pet trade. However, we lack methodologies to predict the likely ecological impacts and invasion risks of such IAS which have little or no informative invasion history. This study develops the Relative Impact Potential (RIP) metric, a new measure of ecological impact that incorporates per capita functional responses (FRs) and proxies for numerical responses (NRs) associated with emerging invaders. Further, as propagule pressure is a determinant of invasion risk, we combine the new measure of Pet Propagule Pressure (PPP) with RIP to arrive at a second novel metric, Relative Invasion Risk (RIR). We present methods to calculate these metrics and to display the outputs on intuitive bi- and triplots. We apply RIP/RIR to assess the potential ecological impacts and invasion risks of four commonly traded pet turtles that represent emerging IAS: Trachemys scripta scripta, the yellow-bellied slider; T. s. troostii, the Cumberland slider; Sternotherus odoratus, the common musk turtle; and Kinosternon subrubrum, the Eastern mud turtle. The high maximum feeding rate and high attack rate of T. s. scripta, combined with its numerical response proxies of lifespan and fecundity, gave it the highest impact potential. It was also the second most readily available according to our UK surveys, indicating a high invasion risk. Despite having the lowest maximum feeding rate and attack rate, S. odoratus has a high invasion risk due to high availability and we highlight this species as requiring monitoring. The RIP/RIR metrics offer two universally applicable methods to assess potential impacts and risks associated with emerging and future invaders in the pet trade and other sources of future IAS. These metrics highlight T. s. scripta as having high impact and invasion risk, corroborating its position on the EU list of 49 IAS of Union Concern. This suggests our methodology and metrics have great potential to direct future IAS policy decisions and management. This, however, relies on collation and generation of new data on alien species functional responses, numerical responses and their proxies, and imaginative measures of propagule pressure.

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DOI: 10.3897/neobiota.38.23940

Authors: Daniel Escoriza

Abstract: The fluvial systems in the north-east of the Iberian Peninsula are highly disturbed habitats, with widespread occurrence of alien species. Previous studies have shown that alien species have a major impact on native freshwater fauna, but it is not known what effect they have on semi-aquatic reptiles. Here the author investigated the factors that influence the occurrence of three species of semi-aquatic reptiles, one turtle (Mauremys leprosa) and two snakes (Natrix astreptophora and Natrix maura), at 261 sites in seven rivers/streams in Girona (north-eastern Spain). The studied semi-aquatic reptiles are habitat generalists which can occupy sections of rivers with altered regimes. The relationships of reptile presence to abiotic niche parameters and the presence of alien species were evaluated, as well as the patterns of pairwise co-occurrence between the reptiles. The presence of alien species did impact one out of three reptiles in this community. The association between both species of natricines was weakly negative, suggesting that interspecific competition does not structure their co-occurrences. The removal of alien species is the most appropriate strategy to preserve the complete diversity of native semi-aquatic reptiles.

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DOI: 10.3897/neobiota.27.5437

Authors: Omar Torres-Carvajal

Abstract: Hemidactylus frenatus is an Asian gecko species that has invaded many tropical regions to become one of the most widespread lizards worldwide. This species has dispersed across the Pacific Ocean to reach Hawaii and subsequently Mexico and other Central American countries. More recently, it has been reported from northwestern South America. Using 12S and cytb mitochondrial DNA sequences I found that South American and Galápagos haplotypes are identical to those from Hawaii and Papua New Guinea, suggesting a common Melanesian origin for both Hawaii and South America. Literature records suggest that H. frenatus arrived in Colombia around the mid-‘90s, dispersed south into Ecuador in less than five years, and arrived in the Galápagos about one decade later.

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