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KEEPING THE HEAT ON: WEIGHTED SURVEILLANCE FOR CHYTRID FUNGUS (BATRACHOCHYTRIUM DENDROBATIDIS) IN DIXIE VALLEY TOADS (ANAXYRUS [= BUFO] WILLIAMSI).

Introduced fungal pathogens have caused declines and extinctions of naïve wildlife populations across vertebrate classes. Consequences of introduced pathogens to hosts with small ranges might be especially severe because of limited redundancy to rescue populations and lower abundance that may limit the resilience of populations to perturbations like disease introduction. As a complement to biosecurity measures to prevent the spread of pathogens, surveillance programs may enable early detection of pathogens, when management actions to limit the effects of pathogens on naïve hosts might be most beneficial. We analyzed surveillance data for the endangered and narrowly endemic Dixie Valley toad (Anaxyrus [= Bufo] williamsi) from two time periods (2011-2014 and 2019-2021) to estimate the minimum detectable prevalence of the amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd). We assessed if detection efficiency could be improved by using samples from both Dixie Valley toads and co-occurring introduced American bullfrogs (Lithobates catesbeianus) and literature-derived surveillance weights. We further evaluated a weighted surveillance design to increase the efficiency of surveillance efforts for Bd within the toad's small (<6 km2) range. We found that monitoring adult and larval American bullfrogs would probably detect Bd more efficiently than monitoring Dixie Valley toads alone. Given that no Bd was detected, minimum detectable prevalence of Bd was <3% in 2011-2014, and <5% (Dixie Valley toads only) and <10% (American bullfrogs only) in 2019-2021. Optimal management for Bd depends on the mechanisms underlying its apparent absence from the range of Dixie Valley toads, but a balanced surveillance scheme that includes sampling American bullfrogs to increase the likelihood of detecting Bd, and adult Dixie Valley toads to ensure broad spatial coverage where American bullfrogs do not occur, would probably result in efficient surveillance, which might permit timely management of Bd if it is detected.

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A window into the forest: post-release behaviour of rehabilitated Bornean Sun bears (Helarctos malayanus euryspilus) in Sabah, Malaysia

Abstract As the number of threatened wildlife species increases globally, captive rehabilitation and release of wild caught animals plays an increasingly significant role in conservation efforts, particularly where poaching threatens wild populations. Sun bear (Helarctos malayanus) populations are decreasing globally, with habitat loss and fragmentation and poaching as key threats to the species. This study aimed to assess post-release behaviour of rehabilitated Sun bears (n = 12) using GPS-collar data to inform ongoing efforts to rehabilitate wild caught bears. We assessed spatial patterns of movement using kernel density estimates and utilisation distributions. We utilised an information theory (IT) and generalised linear modelling approach to assess temporal patterns of sun bear movement (n = 9). Home range estimates (mean = 56.68 km2, range:1.9 – 202.4) and post-release behaviour varied widely between bears, with no significant difference in home range size between males (n = 3) and females (n = 6). Home ranges of most bears stabilised within the first month and bears that were rehabilitated and released together did not spend a significant amount of time together following release. Bears were most active during daytime hours and most established a home range encompassing the riverside. The ultimate success of the releases is unknown, due to collar malfunction and damage, and the inaccessibility of the study terrain. We find that future releases of Sun bears would benefit from soft-release and in-situ rehabilitation techniques. This study provides important insights into the complexity of bear reintroductions informing future rehabilitation and releases for threatened bear species.

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Why Toxicocalamus longhagen Roberts, Iova &amp; Austin, 2022 (Serpentes, Elapidae) is a taxonomic nomen dubium

Roberts et al. (2022) presented a taxonomic decision, in which they proposed the species name longhagen for a single, poorly preserved specimen of elapid New Guinean snake in the species assemblage known as the Toxicocalamus loriae Group. Geographically widespread populations in this species group had long been united under a single name even though some character variation had been noted, and only a thorough morphological study by Kraus et al. (2022), published shortly after the description of T. longhagen, confirmed additional species-level diversity and the detail of character analysis needed to differentiate species in this group. Their work made clear that only examination of many specimens would allow an assessment of interspecific variation and species boundaries, and this had been explained to the authors of the Roberts et al. paper ahead of their manuscript submission. The authors of the Kraus et al. paper had examined the specimen used to diagnose T. longhagen, as well as a series of similar specimens, and found it impossible to make a reliable species-level determination. Our detailed evaluation of the taxon longhagen reveals that it is insufficiently differentiated from the now-known species of the T. loriae Group, that it cannot confidently be assigned to any of these species, and that none of the existing specimens of snakes in this group can be assigned to T. longhagen. It follows that T. longhagen as currently defined is a taxonomic nomen dubium. It will retain this status until such time when additional data or additional material can lead to a resolution of its taxonomy.

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Bewildering biogeography: Waves of dispersal and diversification across southern Wallacea by bent-toed geckos (genus: Cyrtodactylus)

Bent-toed Geckos, genus Cyrtodactylus, are one of the most diverse terrestrial vertebrate groups, and their range extends from South Asia into Australo-Papua and adjacent Pacific islands. Given the generally high faunal endemism on Wallacean islands, it is rather paradoxical that the diversity in these geckos appears to be so low (21 species in Wallacea, 15 in the Philippines) compared with continental shelf assemblages (>300 species on Sunda + Sahul Shelves + adjacent islands). To determine whether this shortfall was real or an artifact of historical undersampling, we analyzed mitochondrial DNA sequences of hundreds of southern Wallacean samples (Lesser Sundas + southern Maluku). After screening to guide sample selection for target capture data collection, we obtained a 1150-locus genomic dataset (1,476,505 bp) for 119 samples of southern Wallacean and closely related lineages. The results suggest that species diversity of Cyrtodactylus in southern Wallacea is vastly underestimated, with phylogenomic and clustering analyses suggesting as many as 25 candidate species, in contrast to the 8 currently described. Gene exchange between adjacent candidate species is absent or minimal across the archipelago with only one case of > 0.5 migrants per generation. Biogeographical analysis suggests that the hitherto unrecognized diversity is the result of at least three independent dispersals from Sulawesi or its offshore islands into southern Wallacea between 6 and 14 Ma, with one invasion producing small-bodied geckos and the other two or three producing larger-bodied geckos. The smaller-bodied laevigatus group appears to be able to coexist with members of either larger-bodied clade, but we have yet to find members of the two larger-bodied clades occurring in sympatry, suggesting that ecological partitioning or competitive exclusion may be shaping individual island assemblages.

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Method for controlling invasive <scp><i>Ammophila arenaria</i></scp> in coastal dunes alters restoration trajectory

Coastal dune restoration often focuses on weed removal to reestablish native vegetation communities. Point Reyes National Seashore (PRNS) initiated large‐scale dune restoration after becoming concerned about loss of dune and rare species habitat from spread of non‐native Ammophila arenaria (European beachgrass). Two projects removed beachgrass from 146 ha of heavily invaded dunes using either mechanical removal or herbicide treatment. PRNS conducted pre‐ and post‐restoration vegetation monitoring for 10 years post‐implementation, evaluating success in (1) eradicating beachgrass and (2) reestablishing vegetation communities similar to native dunes in cover, diversity, and species composition. Both methods eradicated beachgrass with annual retreatment. However, they were less successful in rebuilding vegetation communities with comparable native species cover and/or richness. Mechanical removal areas remained largely barren expanses of sand that struggled to support native plants except for a rare perennial, Tidestrom's lupine (Lupinus tidestromii). Tidestrom's lupine and other rare plants now number in the hundreds of thousands. Conversely, herbicide‐treated backdunes were dominated by standing dead beachgrass that resisted decomposition even after 7 years, which hampered native and rare plant establishment. Delayed decomposition was less of an issue in herbicide‐treated foredunes, because sand overwash buried necromass. Restored areas also contended with subsequent invasion by secondary plant invaders. By 2021, only older herbicide‐treated backdunes, and to a lesser extent, mechanical backdunes, showed signs of convergence with native dunes. Successful convergence may be hindered by lingering physical and microbial legacy effects of beachgrass invasion and treatment method. Adaptive restoration may be needed to counter effects and improve project success.

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Sierra Nevada amphibians demonstrate stable occupancy despite precipitation volatility in the early 21st Century

Climate can have a strong influence on species distributions, and amphibians with different life histories might be affected by annual variability in precipitation in different ways. The Sierra Nevada of California, United States, experienced some of the driest and wettest years on record in the early 21st Century, with variability in annual precipitation predicted to increase with climate change. We examined the relationship between adult occupancy dynamics of three high elevation anurans and site and annual variation in measures of winter severity, summer wetness, and cumulative drought. We further evaluated how these weather conditions affected the probability that each species would reproduce, conditional on their occurrence at a site. We found that although different aspects of weather affected the occupancy dynamics of each species differently, adult occupancy probabilities were generally stable throughout our 15-year study period. The probability of reproduction, although slightly more variable than adult occupancy, was similarly stable throughout the study. Although occurrence of the three species was resilient to recent extremes in precipitation, more detailed demographic study would inform the extent to which amphibian populations will remain resilient to increasing severity, duration, and frequency of drought and flood cycles.

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