Information on tropical Asian vertebrates has traditionally been sparse, particularly when it comes to cryptic species inhabiting the dense forests of the region. Vertebrate populations are declining globally due to land-use change and hunting, the latter frequently referred as "defaunation." This is especially true in tropical Asia where there is extensive land-use change and high human densities. Robust monitoring requires that large volumes of vertebrate population data be made available for use by the scientific and applied communities. Camera traps have emerged as an effective, non-invasive, widespread, and common approach to surveying vertebrates in their natural habitats. However, camera-derived datasets remain scattered across a wide array of sources, including published scientific literature, gray literature, and unpublished works, making it challenging for researchers to harness the full potential of cameras for ecology, conservation, and management. In response, we collated and standardized observations from 239 camera trap studies conducted in tropical Asia. There were 278,260 independent records of 371 distinct species, comprising 232 mammals, 132 birds, and seven reptiles. The total trapping effort accumulated in this data paper consisted of 876,606 trap nights, distributed among Indonesia, Singapore, Malaysia, Bhutan, Thailand, Myanmar, Cambodia, Laos, Vietnam, Nepal, and far eastern India. The relatively standardized deployment methods in the region provide a consistent, reliable, and rich count data set relative to other large-scale pressence-only data sets, such as the Global Biodiversity Information Facility (GBIF) or citizen science repositories (e.g., iNaturalist), and is thus most similar to eBird. To facilitate the use of these data, we also provide mammalian species trait information and 13 environmental covariates calculated at three spatial scales around the camera survey centroids (within 10-, 20-, and 30-km buffers). We will update the dataset to include broader coverage of temperate Asia and add newer surveys and covariates as they become available. This dataset unlocks immense opportunities for single-species ecological or conservation studies as well as applied ecology, community ecology, and macroecology investigations. The data are fully available to the public for utilization and research. Please cite this data paper when utilizing the data.

Habitat loss and fragmentation profoundly impact Southeast Asian rainforest biodiversity and ecosystem functioning. While many larger herbivores are hunted and area-demanding apex predators are lost from degraded forests (logged forests, forest fragments and forest edges), smaller herbivore species may be comparatively resilient or even benefit from a release from competition and predation in degraded forests. Mousedeer (or chevrotains) in the Tragulus genus are some of the world's smallest ungulates (1.5-4.5 kg) and are widespread in Southeast Asia. We evaluated mousedeer habitat associations at three spatial scales. At the regional scale, presence-only species distribution modelling suggested mousedeer are negatively associated with aridity and elevation. At the landscape scale, variation capture rates among 186 published camera trapping studies suggested mousedeer are negatively associated with forest degradation and elevation. At the local scale (within landscapes), mousedeer abundance sampled with 1218 cameras at 10 landscapes and analysed with hierarchical abundance modelling suggested mousedeer are negatively associated with humans and elevation. Mousedeer diel activity patterns shifted towards increased nocturnality in degraded forests, possibly to avoid interactions with diurnal humans. Taken together, mousedeer prefer wet lowland forests and they persist - but decline - in degraded habitats and near humans. One exception was degraded forest fragments of Singapore where mousedeer are very abundant, likely due to the absence of hunting and predators. Our results emphasize that small herbivores persisting in fragmented rainforests decline relative to intact forests and thus are unlikely to be experiencing significant release from competition or predation. They also differ from small omnivorous generalists who experience beneficial foraging opportunities at edges. In degraded forests where larger wildlife has been lost, even low densities of small herbivores may perpetuate important ecological interactions such as herbivory, seed dispersal, or as prey for remaining predators. Mousedeer habitat associations were evaluated at multiple spatial scales. Mousedeer abundance is associated with low-altitude areas, with high forest integrity and low human presence. Nevertheless, mousedeer can persist in low-integrity forests surrounded by densely populated matrix.image

Some animal species shift their activity towards increased nocturnality in disturbed habitats to avoid predominantly diurnal humans. This may alter diel overlap among species, a precondition to most predation and competition interactions that structure food webs. Here, using camera trap data from 10 tropical forest landscapes, we find that hyperdiverse Southeast Asian wildlife communities shift their peak activity from early mornings in intact habitats towards dawn and dusk in disturbed habitats (increased crepuscularity). Our results indicate that anthropogenic disturbances drive opposing behavioural adaptations based on rarity, size and feeding guild, with more nocturnality among the 59 rarer specialists’ species, more diurnality for medium-sized generalists, and less diurnality for larger hunted species. Species turnover also played a role in underpinning community- and guild-level responses, with disturbances associated with markedly more detections of diurnal generalists and their medium-sized diurnal predators. However, overlap among predator-prey or competitor guilds does not vary with disturbance, suggesting that net species interactions may be conserved.

The United Nations recently agreed to major expansions of global protected areas (PAs) to slow biodiversity declines 1 .But while reserves often reduce habitat loss, their efficacy at preserving animal diversity is unclear, as is their influence on biodiversity in surrounding unprotected areas 2-5 .Unregulated hunting can empty PAs of larger animals 6 , illegal tree felling can degrade habitat quality 7 , and parks can simply displace disturbances such as logging and hunting to unprotected areas of the landscape ('leakage') 8 .Alternatively, well-functioning PAs could enhance animal diversity within reserves as well as in nearby unprotected sites ('spillover') 9 .Here we test if PAs across mega-diverse Southeast Asia contribute to vertebrate conservation inside and outside their boundaries.Reserves increased all facets of bird diversity.Large reserves also had substantially enhanced mammal diversity in the adjacent unprotected landscape.Rather than PAs generating leakage that deteriorated ecological conditions elsewhere, our results are consistent with PAs inducing spillover that benefits biodiversity in surrounding areas.These findings support the 2030 United Nations goals of achieving 30% PA coverage by demonstrating that protected areas are associated with higher vertebrate diversity both inside their boundaries and in the broader landscape.

The persistence of seed-dispersing animals in degraded habitats could be critical for ensuring the long-term conservation value and restoration of forests. This is particularly important in Southeast Asia, where > 70% of the remaining forest areas are within 1 km of a forest edge, and many are degraded (e.g. logged). We synthesized information on the habitat associations of the binturong Arctictis binturong , a large, semi-arboreal, frugivorous civet and one of the most important seed dispersers in the region, especially for figs ( Ficus spp). We adopted a multiscale approach by employing ensemble species distribution modelling from presence-only records, assessing landscape-scale variation in detection rates in published camera-trap studies and using hierarchical occupancy modelling to assess local (i.e. within-landscape) patterns observed from 20 new camera-trap surveys. Contrary to prior reports that binturongs are strongly associated with intact forests, the species was equally present in degraded forests and near forest edges where sufficient forest cover was maintained (> 40% forest cover within a 20-km radius). The species also tolerates moderate incursions of oil palm plantations (< 20% of the area within a 20-km radius covered by oil palm plantations). The relative resilience of binturongs to habitat degradation could be in part because of behavioural adaptations towards increased nocturnal activity. These results support the notion that key seed dispersers can persist and maintain their ecological function in degraded forests.

Fragments and edges account for most remaining forest habitats globally. Apex predators and megaherbivores often decline in these degraded habitats while smaller generalist omnivores can persist or thrive in forest edges, especially if they can utilize nonnative resources (“cross‐boundary food subsidies”). Outcomes for small‐medium carnivores (mesopredators) remain unclear or idiosyncratic. We tested responses of a widespread and common forest mesopredator to edges and the composition of the adjacent nonforested areas using 91 camera trapping surveys in Southeast Asia. Leopard cats ( Prionailurus bengalensis and Prionailurus javanensis ) showed a hump‐shaped relationship with forest cover and a positive association with oil palm plantations, but they did not increase near other types of nonnative land cover. Leopard cats' success in edges appears due to their hunting abundant rodent prey inside oil palm plantations, providing natural pest management for farmers. Abundant leopard cats also hunt and suppress native small vertebrates, which may trigger negative ecological cascades and suppress biodiversity in forest edges.

Southeast Asia supports the greatest diversity of felids globally, but this diversity is threatened by the severe forest loss and degradation occurring in the region. The response of felids to disturbances appears to differ depending on their ecology. For example, the largely terrestrial and nocturnal leopard cat (Prionailurus bengalensis) thrives near forest edges and in oil palm plantations where it hunts rodents (Muridae) at night, thereby avoiding human activity peaks. Conversely, we hypothesized that the sympatric and similar-sized marbled cat (Pardofelis marmorata) would respond negatively to edges and relatively open oil palm plantations as they are more arboreal than leopard cats, rely on tree connectivity for hunting, and are diurnal so have less potential to temporally avoid humans. We used camera trapping from Southeast Asia to test habitat associations at multiple spatial scales using zero-inflated Poisson generalized linear mixed models and hierarchical occupancy modeling. We found that marbled cats were positively associated with large intact forests and, in contrast to leopard cats, negatively associated with oil palm plantations. Furthermore, we found preliminary evidence suggesting marbled cats may adapt their diel activity to become more crepuscular in degraded forests, likely shifting their activity to avoid humans. These findings suggest that the marbled cat's International Union for Conservation of Nature (IUCN) Red List conservation status should potentially be upgraded from Near Threatened to Vulnerable, matching other forest-dependent felids in the region. We posit our findings may be generalizable such that semi-arboreal and diurnal felids could face greater threats from habitat degradation than their terrestrial and nocturnal relatives.

ABSTRACT In many disturbed terrestrial landscapes, a subset of native generalist vertebrates thrives. The population trends of these disturbance‐tolerant species may be driven by multiple factors, including habitat preferences, foraging opportunities (including crop raiding or human refuse), lower mortality when their predators are persecuted (the ‘human shield’ effect) and reduced competition due to declines of disturbance‐sensitive species. A pronounced elevation in the abundance of disturbance‐tolerant wildlife can drive numerous cascading impacts on food webs, biodiversity, vegetation structure and people in coupled human–natural systems. There is also concern for increased risk of zoonotic disease transfer to humans and domestic animals from wildlife species with high pathogen loads as their abundance and proximity to humans increases. Here we use field data from 58 landscapes to document a supra‐regional phenomenon of the hyperabundance and community dominance of Southeast Asian wild pigs and macaques. These two groups were chosen as prime candidates capable of reaching hyperabundance as they are edge adapted, with gregarious social structure, omnivorous diets, rapid reproduction and high tolerance to human proximity. Compared to intact interior forests, population densities in degraded forests were 148% and 87% higher for wild boar and macaques, respectively. In landscapes with >60% oil palm coverage, wild boar and pig‐tailed macaque estimated abundances were 337% and 447% higher than landscapes with <1% oil palm coverage, respectively, suggesting marked demographic benefits accrued by crop raiding on calorie‐rich food subsidies. There was extreme community dominance in forest landscapes with >20% oil palm cover where two pig and two macaque species accounted for >80% of independent camera trap detections, leaving <20% for the other 85 mammal species >1 kg considered. Establishing the population trends of pigs and macaques is imperative since they are linked to cascading impacts on the fauna and flora of local forest ecosystems, disease and human health, and economics (i.e., crop losses). The severity of potential negative cascading effects may motivate control efforts to achieve ecosystem integrity, human health and conservation objectives. Our review concludes that the rise of native generalists can be mediated by specific types of degradation, which influences the ecology and conservation of natural areas, creating both positive and detrimental impacts on intact ecosystems and human society.

Despite mounting evidence on the ecological impacts of damming for biodiversity, little is known regarding its consequences in the hyper-diverse Southeast Asian tropical forests. Here we assess the effects of habitat loss and fragmentation on the diversity and activity of insectivorous bats within the hydroelectric Kenyir Lake in peninsular Malaysia. We surveyed bat assemblages on 26 islands and two mainland continuous forest sites using passive acoustic monitoring. Echolocation calls were classified into sonotypes, each corresponding to either one or multiple species, and grouped into foraging guilds. We then examined bat overall assemblage (sonotype richness, activity, and composition), guild- and sonotype-specific activity. From 9360 h of recordings, we identified 16 bat sonotypes, including 10 forest (2854 bat passes), three edge (13703) and three open-space foragers (3651). Sonotype richness increased towards denser canopy structures, as indicated by higher Normalized Difference Vegetation Index values (NDVI). Sonotype composition varied across the gradient of forest area. Forest foragers were positively affected by NDVI and negatively affected by distance to the closest neighbour, whereas edge foragers' activity increased in smaller islands. Of the six sonotypes analysed, the activity of one forest sonotype increased with forest area, while that of one edge sonotype decreased. Ensuring habitat quality within insular forest remnants, in addition to their functional connectivity, maximises bat diversity, including the persistence of forest foraging species. Future hydropower development should therefore avoid the creation of a myriad of small, isolated, and habitat-degraded islands further characterised by altered levels of bat diversity and guild-level activity.

Species Distribution Models (SDMs) are a powerful tool to derive habitat suitability predictions relating species occurrence data with habitat features. Two of the most frequently applied algorithms to model species-habitat relationships are Generalised Linear Models (GLM) and Random Forest (RF). The former is a parametric regression model providing functional models with direct interpretability. The latter is a machine learning non-parametric algorithm, more tolerant than other approaches in its assumptions, which has often been shown to outperform parametric algorithms. Other approaches have been developed to produce robust SDMs, like training data bootstrapping and spatial scale optimisation. Using felid presence-absence data from three study regions in Southeast Asia (mainland, Borneo and Sumatra), we tested the performances of SDMs by implementing four modelling frameworks: GLM and RF with bootstrapped and non-bootstrapped training data. With Mantel and ANOVA tests we explored how the four combinations of algorithms and bootstrapping influenced SDMs and their predictive performances. Additionally, we tested how scale-optimisation responded to species' size, taxonomic associations (species and genus), study area and algorithm. We found that choice of algorithm had strong effect in determining the differences between SDMs' spatial predictions, while bootstrapping had no effect. Additionally, algorithm followed by study area and species, were the main factors driving differences in the spatial scales identified. SDMs trained with GLM showed higher predictive performance, however, ANOVA tests revealed that algorithm had significant effect only in explaining the variance observed in sensitivity and specificity and, when interacting with bootstrapping, in Percent Correctly Classified (PCC). Bootstrapping significantly explained the variance in specificity, PCC and True Skills Statistics (TSS). Our results suggest that there are systematic differences in the scales identified and in the predictions produced by GLM vs. RF, but that neither approach was consistently better than the other. The divergent predictions and inconsistent predictive abilities suggest that analysts should not assume machine learning is inherently superior and should test multiple methods. Our results have strong implications for SDM development, revealing the inconsistencies introduced by the choice of algorithm on scale optimisation, with GLM selecting broader scales than RF.

Deforestation and poaching in Southeast Asia have driven a stark decline in the region's apex predators, including large felids like tigers and leopards. Meanwhile, some small felids thrive in the region's human-modified landscapes. The extent to which medium-sized felids cope with anthropogenic disturbances remains poorly understood, but this information is crucial for the conservation of threatened felids and key trophic interactions that maintain high-diversity food webs. Here, we use the largest camera-trap dataset from Southeast Asia to conduct a multi-scale synthesis of the habitat associations of two cryptic felids, the Near-Threatened Asiatic golden cat (Catopuma temminckii) and the Endangered bay cat (Catopuma badia). Unlike many mesopredators, both species exhibited poor tolerance to habitat degradation (i.e. selective logging, edges or fragmentation). The golden cat was positively associated with forest patch size and elevation, and negatively associated with degraded forests, and the bay cat was negatively associated with human population density. Our habitat suitability model suggests that ongoing forest fragmentation and degradation have critically reduced suitable habitat for the golden cat, giving reason to suspect a population decline that calls for a revision of the species' IUCN Red List status to Vulnerable. There is also evidence that the bay cat may be more widely distributed in Borneo than previously thought, including in areas currently threatened by deforestation. Our results indicate both species face a high risk of becoming extirpated from many of the region's remaining forests. In areas where apex predators have been extirpated, these charismatic mid-sized felids can become umbrella species to protect forests with high biodiversity value.

Pangolins are the most trafficked animals worldwide and are presumed to be restricted to pristine habitats due to poaching intensity in more accessible degraded areas or intrinsic habitat preferences. We tested the hypothesis that pangolins' could persist in degraded areas and near humans if poaching is controlled. We used occurrence records from new and published camera trapping studies from across Southeast Asia to conduct a multiscale analysis of habitat associations for the Critically Endangered Sunda pangolin, encompassing poached and non-poached areas. Our results were highly influenced by Singapore, where pangolins are common in urban settings and there is minimal poaching. Excluding Singapore, there were no significant landscape-level habitat associations, reflecting pangolins are habitat generalists. At local scales (including and excluding Singapore), occupancy was negatively correlated with active deforestation but not previously degraded forests. We conclude that with strong antipoaching enforcement, pangolins are unexpectedly adaptable, with Singapore exemplifying the potential for species recovery.

Southeast Asia is experiencing a biodiversity crisis driven by the synergistic forces of deforestation and poaching. The mainland serow (Capricornis sumatraensis) is a large rainforest goat threatened by habitat loss, hunting for bushmeat, and poaching for traditional medicine. Serow have been considered to be montane forest specialists and preferring limestone karsts, but this has never been rigorously evaluated. If the species is restricted to high elevations, climate change and the upward expansion of deforestation and agriculture would threaten the species, but less so if serows are more closely associated with landscape roughness (i.e., rough topography including at low elevations such as in karst landscapes). We collated and synthesised new and existing camera-trap data from 29 landscapes across Southeast Asia to determine the serow's habitat associations at regional, landscape, and local scales. Serow occurrence was negatively associated with oil palm plantation cover and positively associated with landscape roughness across all scales; elevation was not a top-performing variable in model selection. With just 16% of their forested range under some form of declared protection, climate change and expansion of oil palm plantations into higher elevations will further reduce habitat and facilitate poaching into the species' core habitat. However, the serow's preference for rough landscapes, where mechanised agriculture is infeasible, may be its saving grace. An improved understanding of megafauna habitat associations provides conservationists, enforcement agencies, and policymakers with practical and applicable guidance to ensure their persistence in Asia.

Asia's wild pigs are ecosystem engineers and a key food for predators and people. The arrival of African swine fever (ASF) in 2018 induced near-100% fatality in domestic pigs and decimated the Chinese pork industry in 2020 but outcomes for wild pigs have been delayed and unclear. Here we report on the mass mortality of native wild boar ( Sus scrofa ) in Peninsular Malaysia. ASF was confirmed at our long-term study site in February 2022 and wild boar carcasses increased >100-fold in June 2022 compared to prior years. Camera trapping revealed an 87% decline in wild boar activity in 2022 compared to five prior surveys. Wild boars retired in old birthing nests and pairs of animals died next to each other in the open. Similar results are being anecdotally reported across the region with immense repercussions suspected on ecology and conservation. We urge a rapid research response to take advantage of this unique natural experiment.

The United Nations recently agreed to major expansions of global protected areas (PAs) to slow biodiversity declines 1 . However, although reserves often reduce habitat loss, their efficacy at preserving animal diversity and their influence on biodiversity in surrounding unprotected areas remain unclear 2 – 5 . Unregulated hunting can empty PAs of large animals 6 , illegal tree felling can degrade habitat quality 7 , and parks can simply displace disturbances such as logging and hunting to unprotected areas of the landscape 8 (a phenomenon called leakage). Alternatively, well-functioning PAs could enhance animal diversity within reserves as well as in nearby unprotected sites 9 (an effect called spillover). Here we test whether PAs across mega-diverse Southeast Asia contribute to vertebrate conservation inside and outside their boundaries. Reserves increased all facets of bird diversity. Large reserves were also associated with substantially enhanced mammal diversity in the adjacent unprotected landscape. Rather than PAs generating leakage that deteriorated ecological conditions elsewhere, our results are consistent with PAs inducing spillover that benefits biodiversity in surrounding areas. These findings support the United Nations goal of achieving 30% PA coverage by 2030 by demonstrating that PAs are associated with higher vertebrate diversity both inside their boundaries and in the broader landscape.

Analysis of small mammal diversity patterns on island fragments in Chiew Larn reservoir, Thailand

Habitat loss and degradation threaten forest specialist wildlife species, but some generalist mesopredators exploit disturbed areas and human-derived food, which brings them into closer contact with humans. Mesopredator release is also important for human health for known zoonotic disease reservoirs, such as Asian civets (Viverridae family), since this group includes the intermediator species for the SARS-CoV-1 outbreak. Here we use camera trapping to evaluate the habitat associations of the widespread banded civet (Hemigalus derbyanus) across its range in Southeast Asia. At the regional scale, banded civet detections among published studies were positively associated with forest cover and negatively associated with human population. At the local scale (within a landscape), hierarchical modeling of new camera trapping showed that abundance was negatively associated with forest loss and positively associated with distance to rivers. These results do not support mesopredator release and suggest a low likelihood overlap with humans in degraded habitats and, therefore, a low risk of zoonotic disease transmission from this species in the wild. We also estimate that banded civet distribution has contracted to under 21% of its currently recognized IUCN Red List range, only 12% of which falls within protected areas, and a precipitous recent decline in population size. Accordingly, we suggest the banded civet's Red List status should be re-evaluated in light of our findings.

Habitat loss and degradation can undermine wildlife communities and ecosystem functioning. However, certain generalist wildlife species like mesopredators and omnivores can exploit these disturbed habitats, sometimes leading to population increases (e.g. 'mesopredator release' in degraded areas). Although mesopredator release may cause negative effects on food webs and zoonotic disease management, some disturbance-tolerant species may help perpetuate important ecological interactions, such as seed dispersal. We evaluated the habitat associations of common palm civets Paradoxurus hermaphroditus, which are widespread generalist mesopredators in Southeast Asia. Common palm civets are also high-quality seed dispersers, and potential zoonotic disease hosts. We used published and new camera trapping data to map their probability of presence across Southeast Asia and evaluate regional-scale associations between capture rates and habitat variables such as elevation, ecoregion intactness and Human Footprint Index, among others. We also assessed the influence of habitat variables on their relative abundance at the local scale. At the regional scale, we found that common palm civets showed significant positive associations with landscapes characterized by lower ecoregion intactness, higher Human Footprint Index and lower elevations. At the local scale, their relative abundance showed a significant positive association with higher Human Footprint Index, but only to a certain point, after which it started decreasing. They also favoured lower elevations at the local scale. These multi-scale results indicate that common palm civets' abundance can increase under certain levels of human disturbances, consistent with the 'mesopredator release' hypothesis. This suggests they may be crucial seed dispersers in degraded forest landscapes, especially where more sensitive seed dispersers have disappeared. Our results are also consistent with previous studies reporting that habitat degradation increases populations of potential zoonotic disease hosts, and thus risks of transmission to humans.

The "trophic downgrading of planet Earth" refers to the systematic decline of the world's largest vertebrates. However, our understanding of why megafauna extinction risk varies through time and the importance of site- or species-specific factors remain unclear. Here, we unravel the unexpected variability in remaining terrestrial megafauna assemblages across 10 Southeast Asian tropical forests. Consistent with global trends, every landscape experienced Holocene and/or Anthropocene megafauna extirpations, and the four most disturbed landscapes experienced 2.5 times more extirpations than the six least disturbed landscapes. However, there were no consistent size- or guild-related trends, no two tropical forests had identical assemblages, and the abundance of four species showed positive relationships with forest degradation and humans. Our results suggest that the region's megafauna assemblages are the product of a convoluted geoclimatic legacy interacting with modern disturbances and that some megafauna may persist in degraded tropical forests near settlements with sufficient poaching controls.