Urbanisation can negatively impact biodiversity, often resulting in smaller and more isolated populations-which can be particularly detrimental for habitat specialists. Yet, under the right ecological conditions, urbanised greenspaces can also act as refugia for remnant populations to persist. The Four-toed Salamander (Hemidactylium scutatum) is an example of a macrohabitat specialist; it is an amphibian which relies specifically on habitat with bogs/fens and adjacent upland forests. In New Brunswick, Canada, this salamander is presumed to be critically imperilled as it had previously only been observed in a single location, a protected national park. A second population, however, was recently discovered within an urbanised greenspace in Riverview, New Brunswick. Notably, this area is enveloped by anthropogenic landscape features (e.g., roads, parking lots, housing, businesses), which demonstrates how this species can also occur in more urbanised areas. Our study aims to understand the population ecology of Four-toed Salamanders at this newly described site and investigate how its habitat use allows it to persist in an area with strong anthropogenic disturbance. We estimated the current relative abundance and density, and quantified the demographics, of Four-toed Salamanders at the Riverview site, while also testing to see if these salamanders favoured specific microhabitats within both fen and upland forest habitats. We contrasted a wide range of suitable environmental variables (e.g., substrate temperature, acidity, canopy cover, humidity, and plant percent coverage) between locations containing a salamander to nearby, unoccupied locations. We found a total of 67 salamanders across all surveys, which translates to a conservative relative population density estimate of 2.12 individuals/ha. We observed few differences in microhabitats between where salamanders were seen and random locations, which suggests that suitable microhabitats were not limited for these amphibians at this site. These differences were that salamanders preferred higher slopes within moss hummocks in fens, cooler substrates in the forest, and the presence of woody debris in the forest. Our study provides key insights into the habitat characteristics of Four-toed Salamanders at the northern extent of their range, a species with a cryptic lifestyle that is widely considered to be a macrohabitat specialist. By quantifying the ecological features of an urban habitat being used by Four-toed Salamanders in New Brunswick, we expand the types of ecosystems conservation biologists and wildlife managers should consider viable when conducting additional surveys and assessments for this species. This study increases our knowledge about the niche of an amphibian whose conservation and protection in New Brunswick, and more broadly in Canada, is hindered by a lack of foundational natural history data.
Changes in gene expression during host-pathogen interactions reveal species' functional responses and provide insight into the mechanisms by which pathogens impact biodiversity. The pathogen Batrachochytrium salamandrivorans (Bsal) poses a major threat to salamander diversity, particularly in global biodiversity hotspots. In the most species-rich salamander family, Plethodontidae, infection outcomes vary markedly, suggesting that hosts play a role in mediating susceptibility. Despite this variation, salamander defence mechanisms against Bsal, as well as the pathogen's capacity to facilitate multi-host infection, remain largely unexplored. Here, I characterised gene expression changes associated with salamander-Bsal interactions using a multispecies comparative framework that integrated host and pathogen functional mechanisms. I identified variation in host responses alongside a conserved expression pattern among plethodontid salamanders, and uncovered Bsal's capacity to adjust its genetic machinery in relation to host susceptibility and, potentially, co-infection with its sister taxon, Batrachochytrium dendrobatidis (Bd). These findings provide insight into the biological mechanisms underlying salamander-Bsal interactions, highlighting a pathway involved in Bsal virulence mediated by calmodulin. This study underscores the need to characterise gene expression changes in both host and pathogen simultaneously to better understand species interactions, and proposes that these changes should be modelled within the parasite-mutualist continuum. Comparative frameworks incorporating multiple host species are also essential for characterising conserved responses to infection, and ultimately for anticipating, preventing and mitigating the potential negative impacts of Bsal on salamander biodiversity.
The conservation of stream salamanders relies on effective monitoring of these cryptic species in freshwater habitats increasingly affected by human activities. Environmental DNA (eDNA) and environmental RNA (eRNA) offer non-invasive alternatives to conventional active search methods. However, knowledge gaps remain regarding how eDNA and eRNA (collectively environmental nucleic acids; eNA) signals vary across space and time under natural field conditions, limiting their integration into monitoring programs. We evaluated eNA signals in small headwater streams in Quebec (Canada), focusing on the northern two-lined salamander (Eurycea bislineata) and the spring salamander (Gyrinophilus porphyriticus). We collected water samples over three consecutive days during fall and winter, and we assessed eNA detection and concentration using species-specific qPCR assays targeting mitochondrial markers. Detection rates of eDNA were consistently high across seasons, highlighting its suitability for rapid presence-absence surveys. In contrast, eRNA detection rates were lower in the fall, but increased with repeated sampling. In winter, eRNA detection rates were near zero, consistent with salamanders' markedly reduced metabolic rate during overwintering, suggesting that mitochondrial eRNA primarily represents metabolically active individuals rather than species presence alone. The concentrations of eNA were positively associated with salamander abundance in fall. Our results demonstrate the value of eNA-based approaches for the monitoring of stream salamanders under natural field conditions.
To address the challenges posed by traditional tracking algorithms in adapting to complex underwater environments characterized by nonlinear motion, drastic morphological changes, mimicry camouflage, and frequent occlusions in wild Chinese giant salamanders, this study proposes a multi-object tracking and behavior analysis method based on the TransTrack-OC-SORT algorithm. The algorithm employs a dual-branch Transformer motion predictor to replace linear Kalman filtering, effectively capturing nonlinear motion patterns such as velocity changes and directional turns exhibited by salamanders. Simultaneously, it introduces the BIOU matching metric, which integrates center distance and aspect ratio penalties with overlap degree, thereby enhancing the robustness of associations in scenarios involving occlusion and mimicry camouflage. The results indicate that the multi-object tracking accuracy (MOTA) based on the TransTrack-OC-SORT algorithm reaches 80.9%, while the identity preservation metric (IDF1) achieves 83.7%. Quantitative behavioral analysis based on continuous trajectory data obtained from this algorithm revealed significant diurnal behavioral rhythms in the Chinese giant salamander. During the daytime, stationary behavior accounted for 95.5% of the total behavioral duration, while swimming for ventilation and foraging behaviors constituted only 4.1% and 0.4%, respectively. At night, the salamander's behavioral patterns underwent fundamental changes; although stationary behavior remained dominant (approximately 72.6%), the proportions of swimming for ventilation and foraging behaviors significantly increased to 15.1% and 12.3% of the nocturnal period, respectively. These findings enhance our understanding of the salamander's ecological habits from the perspectives of visual adaptation, energy allocation, and predation strategies. This study provides a reliable technical tool for non-invasive behavioral monitoring and rhythm research in endangered amphibians.
Morphological evolution can be explosive, producing visually spectacular adaptive radiations like Caribbean anoles, Malagasy vangas, and African Rift Lake cichlids. Yet morphological stasis, the long-term retention of a conserved body plan, is often observed across evolutionary radiations. Woodland salamanders (Plethodon) are a classic example of such "nonadaptive" radiation, characterized by prolific speciation alongside morphological stasis (i.e., limited morphological divergence), often attributed to phylogenetic conservatism in their climatic and microhabitat niches. However, the multidimensional nature of phenotypes and the niche means that adaptive evolution in less apparent traits can occur even when morphology appears static. We investigated whether woodland salamanders exhibit adaptive divergence in a less conspicuous phenotypic axis-specifically, physiology-and compared patterns and rates of trait evolution to those of morphological traits. We found that most physiological traits are associated with climatic variation and exhibit elevated rates of evolution, high trait disparity, and more frequent shifts in adaptive optima than morphological traits. In particular, skin resistance to water loss, metabolic rate, and cold tolerance exhibit evolutionary signatures of adaptive radiation. Notably, morphology is not entirely static: Some traits show climatic associations, several exhibit localized shifts, and evolutionary rates exceed those of slower evolving physiological traits, such as heat tolerance. Biological systems, as evidenced by woodland salamanders, are not exclusively "conserved" or "labile" in their evolution, and this system illustrates how the same features that limit morphological divergence may also facilitate physiological evolution. Woodland salamanders exemplify how adaptive radiation can proceed despite outward similarity.
This study aimed to investigate and report ocular findings in a group of healthy captive African Clawed Frogs (Xenopus laevis) and Tiger Salamanders (Ambystoma tigrinum) and to establish reference data for commonly performed ocular diagnostic tests. Seven female adult captive African Clawed Frogs (ACF) and seven adult captive Tiger Salamanders (TS) were included. All animals underwent ophthalmic examination, Cochet-Bonnet corneal esthesiometry, rebound tonometry (Tonovet Plus), and conjunctival bacterial aerobic culture. Mann-Whitney tests were used for comparisons between species. Significance was set at p < 0.05. One frog exhibited a typical iris coloboma bilaterally and 2/7 frogs exhibited unilateral punctate cortical cataracts. Retinal evaluation was unremarkable in 13/14 frog eyes. One frog exhibited a large chorioretinal scar in one eye. Tonometry was (median, min-max) 24 mmHg (18-36) and corneal touch threshold (CTT) was (median, min-max) 2.25 mm, (1.0-3.0). Five of seven frogs had positive culture results. Four of the 7 salamanders had bilateral nuclear cataracts and 2 of those 4 also had cortical cataracts. Retinal exam in this species was precluded. Tonometry was (median, min-max) 19.5 mmHg, (14-23) and CTT were > 5.0 cm in all individuals. All TS had positive bacterial cultures, mostly gram-negative rods. ACF had significantly less corneal sensitivity and a significantly higher IOP than TS (p < 0.0001 and p = 0.0003, respectively). TS and ACF can be manageable for ophthalmic examination and minimal diagnostic testing without chemical restraint. This study provides preliminary baseline ophthalmic data in captive Tiger Salamanders and African Clawed Frogs examined without sedation.
The Chinese giant salamander (Andrias davidianus) is a nationally protected species in China, and its respiratory behavior serves as a key indicator of its physiological state, health status, and biological rhythm. However, research on intelligent monitoring of its respiratory behavior remains limited due to several challenges, including the species' nocturnal habits, resulting in low image contrast and poor quality in dark environments; extremely subtle breathing movements; and high-cost manual annotation, leading to a scarcity of high-quality annotated visual data. These factors severely constrain the application of deep learning techniques in this field. To support research on respiratory behavior monitoring in the Chinese giant salamander, this study constructs and releases the CGS-BR dataset, which is the first vision-based dataset dedicated specifically to respiratory behavior detection in this species. The dataset was collected under controlled simulated breeding conditions and consists of 1732 images extracted from 215 high-definition video clips. Following a standardized procedure, each complete respiratory cycle is manually annotated into four stages: head-up, diving, exhalation, and inhalation. To validate the effectiveness of this dataset, this study selects YOLOv8n as the baseline model, which balances detection accuracy, speed, and parameter count, enabling efficient giant salamander respiratory detection under limited resources. By comparing it with several representative models, we provide a reliable evaluation of the dataset's applicability. CGS-BR aims to provide fundamental data support for research on respiratory monitoring in the Chinese giant salamander, laying the foundation for subsequent applications in conservation management, captive breeding, health monitoring, and early disease warning.
Hundreds of plethodontid salamander species can climb vertical structures, despite lacking morphological adaptations typically found in other climbing tetrapods. To compensate, salamanders likely rely more on behavioral modifications to mediate the relationship between their relatively generalist morphologies and climbing performance. Here, we examined four plethodontid species (Aneides aeneus, Aneides lugubris, Aneides hardii and Plethodon glutinosus) that differ in their habitat preferences, climbing tendencies and limb morphologies. Using 3D high-speed videography, we compared how these species adjust their gait and limb kinematics while traversing a flat surface inclined at 0, 45, 80 and 90 deg. We found that all species could climb vertically (or near vertically for A. hardii) using similar gait and kinematic changes that increase stability. For instance, all species used a single-step gait, increased duty factor, reduced stride length and reduced stride frequency while their bodies were positioned closer to the substrate at the highest inclines compared with 0 or 45 deg inclines. However, highly scansorial species (A. aeneus and A. lugubris) climbed faster than the other species. The enhanced abilities of scansorial species may be attributable to their longer limbs that enable longer strides as well as their unique foot morphologies - coupled with changes in foot orientation - that facilitate better attachment through grasping. Overall, we propose that behavioral changes are sufficient for adequate climbing, but subtle morphological changes promote exceptional climbing performance. This likely explains the prevalence of climbing abilities across ecologically and morphologically diverse plethodontid salamanders.
Amphibians are particularly vulnerable to climate change, with many species projected to experience significant reductions in their current distributional ranges due to ongoing climatic impacts. Mediterranean biodiversity hotspots, characterised by exceptionally high species richness, including rare and endemic species, are especially susceptible. Here, we employed an ensemble of eight advanced distribution modelling algorithms to model and explain the spatial distribution of the seven closely related salamander species and one documented hybrid lineage, all belonging to the genus Lyciasalamandra, within a Mediterranean hotspot in Türkiye. We explored how their spatial distributions are linked to both climate and anthropogenic activities and examined the projected changes in suitable habitat. Projected habitat suitability maps, under various climate change scenarios for the coming decades, indicate a severe decline in the quality and extent of habitats for Lycian salamanders, raising concerns about their long-term survival. Overall, our findings emphasise the urgency of species-specific conservation actions that prioritise the protection of microrefugia and the maintenance of ecological connectivity to enhance the long-term persistence of Lycian salamanders under accelerating climate change.
The family Cryptobranchidae, commonly known as giant salamanders, originated at least by the Late Paleocene and has persisted to the present day. However, its fossil record is, extremely fragmentary, with few occurrences known from East Asia after the Miocene. Here we report three vertebral specimens of a cryptobranchid salamander from the Upper Pliocene Tsubusagawa Formation (around 3.5 Ma) of Oita Prefecture, Japan. These specimens were previously identified as Andrias sp., including extant species, but their taxonomic status remained unresolved. In this study, we re-examine the material and provide a more detailed description and attempt to resolve its taxonomic status. Our study demonstrates that it is a new taxon, Limnospondylus ajimuensis gen. et sp. nov., because it shows a unique combination of characters in the mid-trunk vertebra. This new giant salamander inhabited freshwater lacustrine environments and may have reached a total length of approximately 110 cm by around 18 years of age. The discovery of this new taxon helps to fill a significant gap in the Asian fossil record of this group. It also highlights the morphological and ecological diversity of Cryptobranchidae and provides essential implications for understanding their evolutionary history.
Baseline information on terrestrial wildlife communities and their activity patterns is essential for protected-area management, but such information remains limited for Hunan Zhangjiajie Giant Salamander National Nature Reserve, where conservation attention has historically focused on the Chinese giant salamander and associated aquatic ecosystems. From March 2024 to August 2025, we conducted a camera-trap survey in broad-leaved and coniferous forest habitats of the reserve to document terrestrial mammals and ground-dwelling birds, evaluate taxonomic completeness, and describe diel and seasonal activity patterns. Across 43 camera-trap stations and 16,314 effective camera-trap days, we recorded 59 wildlife species, including 18 mammals and 41 ground-dwelling birds. The assemblage included nationally protected, threatened, and Chinese endemic species, indicating that the reserve's forest habitats support important terrestrial biodiversity in addition to its aquatic conservation target. Taxonomic completeness curves suggested that the current survey captured most camera-detectable mammal and ground-dwelling bird taxa under the present sampling design, although the results should not be interpreted as a complete inventory of the reserve's total vertebrate diversity. Annual diel activity analysis of 11 focal species showed clear temporal differentiation among ecological groups: small and medium-sized carnivores were mainly nocturnal, ground-dwelling birds, and red-hipped squirrel were primarily diurnal, and ungulates showed mixed or crepuscular-to-nocturnal tendencies. Seasonal analyses based on bioclimatic periods showed interspecific differences in activity-density distributions between the cool-dry and warm-wet seasons. However, peak-shift reliability analysis indicated that most focal species retained broadly similar main activity peaks across seasons; masked palm civet was the only species showing reliable seasonal displacement of its main activity peak. Pairwise temporal overlap analyses described temporal co-occurrence patterns among selected sympatric species but should not be interpreted as evidence of direct interaction or niche differentiation. Overall, this study provides baseline data on camera-detected terrestrial vertebrates in the reserve and supports long-term monitoring, forest habitat management, and disturbance control for terrestrial mammals and ground-dwelling birds.
The Chinese giant salamander (Andrias davidianus) is a critically endangered living fossil species that is highly sensitive to changes in water temperature. However, systematic studies on the heat shock protein (HSP) gene family and its response mechanisms to environmental stress in this species remain limited. This study utilized transcriptome data from captive-bred salamanders exposed to combined temperature and pathogen stress. Bioinformatics tools were employed to identify the HSP gene family of A. davidianus (AndHSP) and to analyze their evolution, structure, and function, thereby revealing their regulatory mechanisms in response to environmental stress. A total of 72 AndHSPs were identified and classified into five subfamilies. Phylogenetic analysis revealed that each subfamily is evolutionarily conserved and functionally related. Gene expression analysis demonstrated that pathogen infection induced the expression of AndHSPs, and elevated temperature significantly intensified this response. Nine key differentially expressed genes were identified, predominantly from the AndHSP70 subfamily, with AndHSP70-18 exhibiting rapid heat-induced expression. Tissue-specific analysis showed high expression of AndHSP60 in the spleen. A qPCR validation confirmed the reliability of the transcriptome expression results. This study presents the first systematic identification of the AndHSP gene family and elucidates its cooperative stress response mechanisms under combined temperature and pathogen stress. These findings provide a molecular basis for understanding the species' environmental adaptation and have important implications for its conservation and artificial breeding.
The Chinese giant salamander (Andrias davidianus), a species of high ecological and conservation value, shows abnormal respiratory behaviors as early signs of health decline. Accurate assessment of its pulmonary respiration is crucial for improving captive breeding and post-breeding parental care-key strategies for its survival and population recovery. However, its nocturnal and cave-dwelling nature makes traditional observation extremely difficult. Manual monitoring suffers from poor visibility at night, while conventional detection methods often miss subtle respiratory movements, limiting behavioral and health research. To address these challenges, this study presents the first automated method for monitoring respiratory behaviors in this species. We propose Mamba-YOLO-SRC, a novel hybrid detection framework that combines Mamba and YOLO architectures to accurately identify four key behaviors: diving (Dive), head-raising (HeadUP), inhalation (Inhale), and exhalation (Exhale). The proposed model achieves a mean average precision (mAP@0.5) of 0.944, with per-class average precision scores of 0.975 for Dive, 0.925 for HeadUP, 0.948 for Exhale, and 0.928 for Inhale. Mamba-YOLO-SRC provides a feasible and referable technical solution for advancing research on the Chinese giant salamander in both captive and natural settings.
The new genus Pseudoangiostoma gen. n. (Nematoda: Angiostomatidae) was established on the basis of the type species Pseudoangiostoma onychodactyla comb. n. (syn. Angiostoma onychodactyla), which parasitizes the stomach and intestine of some species of the genus Onychodactylus (Amphibia: Hynobiidae) in Japan. Pseudoangiostoma gen. n. differs from the genus Angiostoma by having a lower inverted truncated cone-shaped buccal cavity, a thicker and strongly curved buccal wall, and for parasitizing hosts of the order Caudata. The phylogenetic pattern provided substantial suppot for the new genus, exhibiting two major divergent lineages (diverged in terrestrial gastropods vs. salamanders). This study indicated that P. onychodactyla comb. n. did not originate from host-switching event from terrestrial gastropods to salamanders. However, other species of Angiostoma parasitic in amphibians and reptiles are still considered insertae sedis.
Population-specific variation in animal microbiomes is well documented, yet the functional consequences and underlying mechanisms remain poorly understood. To address this, we conducted genome-resolved metagenomic analyses on gut and skin microbiomes from four populations of Pyrenean brook salamanders (Calotriton asper) inhabiting two distinct environments: Pyrenean subalpine brooks and Atlantic montane streams. From paired faecal and skin swab samples, we reconstructed 539 and 43 metagenome-assembled genomes, respectively, and examined taxonomic composition, metabolic capacity, and microdiversity across environments. Although alpha diversity remained similar across environments, both gut and skin microbiomes exhibited significant differences in community composition and functional potential between environments. Partitioning the gut microbiome into core, endemic, and marginal fractions revealed a dominant core community-shared across environments and accounting for over 85% of reads-that did not drive functional divergence. Instead, functional differences were primarily shaped by low-abundance, population-specific endemic bacteria. Atlantic salamanders hosted endemic taxa with significantly greater metabolic potential and higher strain-level microdiversity than those at the Pyrenees. These patterns were not associated with broad-scale dietary differences and may reflect environmental influences such as temperature and nutrient availability. Our findings highlight the relevance of rare, endemic bacteria in driving microbiome function and underscore the power of genome-resolved metagenomics to uncover functional and evolutionary dynamics in wild host-microbe systems.
Starvation is one of the common survival stresses frequently encountered by wildlife, and the adaptive strategies of animals to starvation stress exhibit significant interspecific differences. This study investigated the effects of different starvation periods (1-4 weeks) on the growth characteristics, locomotor performance, foraging behavior, and hypoxia tolerance of Chinese giant salamander (Andrias davidianus) larvae (5.41 ± 0.06 g; 9.78 ± 0.03 cm). Our results showed that the final body weight of A. davidianus larvae decreased significantly with prolonged starvation time, with a more pronounced rate of decrease during the early starvation period. However, the final body length of A. davidianus larvae was less significantly affected by starvation stress. Starvation had no significant effects on the relative induction flow speed, relative burst swimming speed, total foraging distance, relative foraging speed, and foraging time of A. davidianus larvae. The resting metabolic rate of A. davidianus larvae decreased significantly as the starvation period lengthened. Starvation lasting 2-4 weeks significantly increased the dissolved oxygen level at which A. davidianus larvae exhibited the loss of equilibrium (ventral side facing upward). These results indicate that (1) starvation has a more significant negative impact on body mass than on body length in A. davidianus larvae; (2) starvation stress does not significantly affect the locomotor performance or foraging behavior of A. davidianus larvae, but it does lead to a significant reduction in their extreme hypoxia tolerance.
Salamanders have the remarkable ability of regenerating complex tissues such as their limbs, brain, and spinal cord. While the requirement of nerve supply to the damaged tissue has been known for centuries, emerging work has emphasized the possibility of a "brain-limb" axis, in which signals from the brain and spinal cord assist in coordinating local responses to injury. Understanding the molecular underpinnings of how regeneration is coordinated on a body-wide scale may provide further insights into how complex vertebrate regeneration is achieved.
Amphibian metamorphosis is a dramatic thyroid hormone (TH) mediated process involving the transformation of aquatic larvae into more-terrestrial adults. But some salamanders, referred to as larval-form paedomorphs, completely or partially forgo metamorphosis, retaining their aquatic larval features and lifestyle into adulthood. This developmental pattern can be facultative or obligate and can manifest from lowering circulating TH and/or reducing TH-responsiveness of larval tissues. Obligate larval-form paedomorphs display varying degrees of responsiveness to TH-treatment; some species exhibit complete metamorphosis, while others show no overt transformation of larval-form tissues. Investigations of the latter species have shown that they have a functional TH-axis, but their tissues have become deregulated (decoupled) from ancestral TH-induced transformation. Obligate paedomorphosis is thought to evolve from facultative paedomorphosis through genetic assimilation followed by canalization. However, the developmental and physiological advantages of full TH-deregulation of larval-form tissues have not been discussed in detail. Since TH is intertwined with many processes such as stress-response, growth, and reproduction, we propose that directional selection for deregulation may allow TH and other interacting hormones to be utilized more effectively without compromising the larval-form. Furthermore, it is unclear whether facultative paedomorphosis is a necessary prerequisite step to becoming obligate. We propose alternative scenarios leading to TH-deregulation such as a rapid rate of directional selection after secondarily colonizing more divergent adaptive zones (e.g., aquifers), and relaxed selection from disusing ancestral TH-pathways for metamorphosis over many generations. Deregulating hormone pathways may be a more generalizable evolutionary phenomenon, reinforcing developmental evolution and perhaps generating novel signaling pathways.
The balance between thromboembolic complications and bleeding risk in anticoagulated patients with atrial fibrillation remains challenging, with left atrial appendage occlusion (LAAO) representing a potential alternative. Our prospective multicenter study aimed to evaluate the feasibility, safety, technical, and procedural outcomes of the contemporary practice of stand-alone LAAO. The SALAMANDER (Stand-Alone Left Atrial Appendage Occlusion for Thromboembolism Prevention in Nonvalvular Atrial Fibrillation Disease) registry is a real-world, multicenter, observational cohort study conducted at 16 cardiac centers in Europe between 2010 and 2024, evaluating the safety and efficacy of LAAO using contemporary devices. A total of 1660 patients were enrolled, with a median age of 76 (interquartile range, 70-81) years and 38% being women. The median CHA2DS2-VASc score was 4 (interquartile range, 3-5). The most common indication for LAAO was significant bleeding (83.7% of patients), most frequently during treatment with direct oral anticoagulants (68.8%) more than vitamin K antagonists (24.9%). The predominant bleeding sites were the lower (27.9%) and upper (21.7%) gastrointestinal tracts, with 17.4% having a history of hemorrhagic stroke. The most common antithrombotic regimen before the procedure was direct oral anticoagulants (48.9%), while postprocedural therapy most often included dual antiplatelet therapy (50%). The technical success rate was 95.5%, with residual leak (2.2%) and tamponade (1.4%) as the main causes of failure. Procedural success was 90.5%, most often limited by vascular complications (3.7%), periprocedural death (1.1%), and major bleeding (0.7%). Technical and procedural success rates did not differ significantly between the devices used. In this large prospective cohort, technical and procedural success rates were similar across all LAAO devices, suggesting comparable safety and efficacy. Postprocedural therapy typically involves dual antiplatelet therapy, with all patients requiring some pharmacological treatment. URL: https://www.clinicaltrials.gov; Unique identifier: NCT05144958.
Biological invasions provide unique opportunities to examine how populations cope with rapid ecological change, as well as the influence of human activity on our natural world. The island of Newfoundland, Canada, has no native amphibians; however, five species have established non-native populations, including one caudatan, the Eastern Red-backed Salamander (Plethodon cinereus). We posit that this salamander's successful colonisation may have been mediated by dietary shifts that allowed them to capitalize on a greater variety of prey, as well as by exploiting pre-existing invasive prey communities - both these mechanisms could limit the likelihood of competitive exclusion and promote establishment in a novel environment. To examine this, we identified stomach contents of Newfoundland Eastern Red-backed salamanders, characterised the prey as native or invasive, and compared the dietary composition of the invasive population to that of conspecifics in the native range through a systematic literature review. As predicted, the invasive salamander population's diet is more generalised (i.e., a broader dietary niche) than the native salamanders, and invasive invertebrates comprised two thirds of the volume of prey eaten by invasive salamanders. Our research provides insight into the Niche Breadth Invasion Hypothesis as well as the Invasional Meltdown Hypothesis, which are mechanisms that may have allowed this species to establish a population in an island ecosystem. Furthermore, our research suggests that prior invasions of a diverse invertebrate community to Newfoundland may have bolstered the invasive potential of this novel, non-native salamander.