CamTrapAsia: A dataset of tropical forest vertebrate communities from 239 camera trapping studies.

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remain scattered across a wide array of sources, including published scientific literature, gray literature, and unpublished works, making it challenging for researchers to harness the full potential of cameras for ecology, conservation, and management.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.

Deep biogeographic barriers explain divergent global vertebrate communities.

Biogeographic history can lead to variation in biodiversity across regions, but it remains unclear how the degree of biogeographic isolation among communities may lead to differences in biodiversity. Biogeographic analyses generally treat regions as discrete units, but species assemblages differ in how much biogeographic history they share, just as species differ in how much evolutionary history they share. Here, we use a continuous measure of biogeographic distance, phylobetadiversity, to analyze the influence of biogeographic isolation on the taxonomic and functional diversity of global mammal and bird assemblages. On average, biodiversity is better predicted by environment than by isolation, especially for birds. However, mammals in deeply isolated regions are strongly influenced by isolation; mammal assemblages in Australia and Madagascar, for example, are much less diverse than predicted by environment alone and contain unique combinations of functional traits compared to other regions. Neotropical bat assemblages are far more functionally diverse than Paleotropical assemblages, reflecting the different trajectories of bat communities that have developed in isolation over tens of millions of years. Our results elucidate how long-lasting biogeographic barriers can lead to divergent diversity patterns, against the backdrop of environmental determinism that predominantly structures diversity across most of the world.

Mammal responses to global changes in human activity vary by trophic group and landscape.

Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in human-wildlife interactions along gradients of human influence.

Combining camera trap surveys and IUCN range maps to improve knowledge of species distributions.

Reliable maps of species distributions are fundamental for biodiversity research and conservation. The International Union for Conservation of Nature (IUCN) range maps are widely recognized as authoritative representations of species' geographic limits, yet they might not always align with actual occurrence data. In recent area of habitat (AOH) maps, areas that are not habitat have been removed from IUCN ranges to reduce commission errors, but their concordance with actual species occurrence also remains untested. We tested concordance between occurrences recorded in camera trap surveys and predicted occurrences from the IUCN and AOH maps for 510 medium- to large-bodied mammalian species in 80 camera trap sampling areas. Across all areas, cameras detected only 39% of species expected to occur based on IUCN ranges and AOH maps; 85% of the IUCN only mismatches occurred within 200 km of range edges. Only 4% of species occurrences were detected by cameras outside IUCN ranges. The probability of mismatches between cameras and the IUCN range was significantly higher for smaller-bodied mammals and habitat specialists in the Neotropics and Indomalaya and in areas with shorter canopy forests. Our findings suggest that range and AOH maps rarely underrepresent areas where species occur, but they may more often overrepresent ranges by including areas where a species may be absent, particularly at range edges. We suggest that combining range maps with data from ground-based biodiversity sensors, such as camera traps, provides a richer knowledge base for conservation mapping and planning.

Combinación de censos con fototrampas y mapas de extensión de la UICN para incrementar el conocimiento sobre la distribución de las especies Resumen Los mapas confiables de la distribución de las especies son fundamentales para la investigación y conservación de la biodiversidad. Los mapas de distribución de la Unión Internacional para la Conservación de la Naturaleza (UICN) están reconocidos como representaciones de autoridad de los límites geográficos de las especies, aunque no siempre se alinean con los datos actuales de su presencia. En los mapas recientes de área de hábitat (ADH), las áreas que no son hábitat han sido eliminadas de la distribución de la UICN para reducir los errores de comisión, pero su concordancia con la presencia actual de las especies tampoco ha sido analizada. Analizamos la concordancia entre la presencia registrada por los censos de fototrampas y pronosticamos la presencia a partir de los mapas de la UICN y de ADH de 510 especies de mamíferos de talla mediana a grande en 80 áreas de muestreo de fototrampas. Las cámaras detectaron sólo el 39% de las especies esperadas con base en la distribución de la UICN y los mapas de ADH en todas las áreas; el 85% de las disparidades con la UICN ocurrieron dentro de los 200 km a partir del borde de la distribución. Sólo el 4% de la presencia de las especies fue detectada por las cámaras ubicadas fuera de la distribución de la UICN. La probabilidad de disparidad entre las cámaras y la UICN fue significativamente mayor para los mamíferos de talla pequeña y para los especialistas de hábitat en las regiones Neotropical e Indomalaya y en áreas con doseles forestales más bajos. Nuestros hallazgos sugieren que los mapas de distribución y ADH pocas veces subrepresentan las áreas con presencia de las especies, pero con frecuencia pueden sobrerrepresentar la distribución al incluir áreas en donde las especies pueden estar ausentes, en particular los bordes de la distribución. Sugerimos que la combinación de los mapas de distribución con los sensores de biodiversidad en tierra, como las fototrampas, proporciona una base más rica de conocimiento para el mapeo y la planeación de la conservación.

Landscape-scale benefits of protected areas for tropical biodiversity.

The United Nations recently agreed to major expansions of global protected areas (PAs) to slow biodiversity declines1. However, although reserves often reduce habitat loss, their efficacy at preserving animal diversity and their influence on biodiversity in surrounding unprotected areas remain unclear2-5. Unregulated hunting can empty PAs of large animals6, illegal tree felling can degrade habitat quality7, and parks can simply displace disturbances such as logging and hunting to unprotected areas of the landscape8 (a phenomenon called leakage). Alternatively, well-functioning PAs could enhance animal diversity within reserves as well as in nearby unprotected sites9 (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.

Fruit Size in Indo-Malayan Island Plants Is More Strongly Influenced by Filtering than by In Situ Evolution.

AbstractCommunity trait assembly, the formation of distributions of phenotypic characteristics across coexisting species, can occur via two main processes: filtering of trait distributions from the regional pool and in situ phenotypic evolution in local communities. But the relative importance of these processes remains unclear, largely because of the difficulty in determining the timing of evolutionary trait changes and biogeographic dispersal events in phylogenies. We assessed evolutionary and biogeographic transitions in woody plant species across the Indo-Malay archipelago, a series of island groups where the same plant lineages interact with different seed disperser and seed predator assemblages. Fruit size in 2,650 taxa spanning the angiosperm tree of life tended to be smaller in the Sulawesi and Maluku island groups, where frugivores are less diverse and smaller bodied, than in the regional source pool. While numerous plant lineages (not just small-fruited ones) reached the isolated islands, colonists tended to be the smaller-fruited members of each clade. Nearly all of the evolutionary transitions to smaller fruit size predated, often substantially, organismal dispersal to the islands. Our results suggest that filtering rather than within-island evolution largely determined the distribution of fruit sizes in these regions.

The hierarchy of factors predicting the latitudinal diversity gradient.

The numerous explanations for why Earth's biodiversity is concentrated at low latitudes fail to explain variation in the strength and even direction of the gradient through deep time. Consequently, we do not know if today's gradient is representative of what might be expected on other planets or is merely an idiosyncrasy of Earth's history. We propose a hierarchy of factors driving the latitudinal distribution of diversity: (i) over geologically long time spans, diversity is largely predicted by climate; (ii) when climatic gradients are shallow, diversity tracks habitat area; and (iii) historical contingencies linked to niche conservatism have geologically short-term, transient influence at most. Thus, latitudinal diversity gradients, although variable in strength and direction, are largely predictable on our planet and possibly others.

Predicting how defaunation-induced changes in seed predation and dispersal will affect tropical tree populations.

The loss of large animals due to overhunting and habitat loss potentially affects tropical tree populations and carbon cycling. Trees reliant on large-bodied seed dispersers are thought to be particularly negatively affected by defaunation. But besides seed dispersal, defaunation can also increase or decrease seed predation. It remains unclear how these different defaunation effects on early life stages ultimately affect tree population dynamics. We reviewed the literature on how tropical animal loss affects different plant life stages, and we conducted a meta-analysis of how defaunation affects seed predation. We used this information to parameterize models that altered matrix projection models from a suite of tree species to simulate defaunation-caused changes in seed dispersal and predation. We assessed how applying these defaunation effects affected population growth rates. On average, population-level effects of defaunation were negligible, suggesting that defaunation may not cause the massive reductions in forest carbon storage that have been predicted. In contrast to previous hypotheses, we did not detect an effect of seed size on changes in seed predation rates. The change in seed predation did not differ significantly between exclosure experiments and observational studies, although the results of observational studies were far more variable. Although defaunation surely affects certain tree taxa, species that benefit or are harmed by it and net changes in forest carbon storage cannot currently be predicted based on available data. Further research on how factors such as seed predation vary across tree species and defaunation scenarios is necessary for understanding cascading changes in species composition and diversity.

Predicciones de cómo los cambios inducidos en la dispersión y depredación de semillas por la pérdida de fauna afectará a las poblaciones de árboles tropicales Resumen La pérdida de animales grandes debido a la caza excesiva y la pérdida del hábitat afecta potencialmente a las poblaciones de árboles tropicales y al ciclo del carbono. Se considera que los árboles que dependen de dispersores de semillas de talla grande son los más afectados negativamente por la pérdida de fauna. La defaunación también puede incrementar o disminuir la depredación de semillas, además de su dispersión. Todavía no está claro cómo afectan al final a las dinámicas poblaciones de los árboles los diferentes efectos de la pérdida de fauna en las etapas temprana de vida. Revisamos la literatura sobre cómo la pérdida de animales tropicales afecta las diferentes etapas de vida de las plantas y realizamos un metaanálisis sobre cómo la pérdida de fauna afecta a la depredación de semillas. Usamos esta información para definir los parámetros de los modelos que alteraron los modelos de proyección de matriz a partir de un conjunto de especies de árboles y así simular los cambios causados por la pérdida de fauna en la dispersión y depredación de semillas. Analizamos cómo la aplicación de estos efectos de pérdida de fauna afectó las tasas de crecimiento poblacional. En promedio, los efectos de la pérdida de fauna a nivel poblacional fueron no significativas, lo que sugiere que la pérdida de fauna puede no ser la causa de las reducciones masivas que se han pronosticado en el almacenamiento de carbono forestal. Contrario a las hipótesis previas, no detectamos ningún efecto del tamaño de las semillas sobre los cambios en las tasas de depredación. El cambio en la depredación de semillas no difirió significativamente entre los experimentos de encierro y los estudios de observación, aunque los resultados de los últimos fueron mucho más variables. Mientras que la pérdida de fauna seguramente afecta a ciertos taxones de árboles, actualmente no se pueden pronosticar, con base en los datos disponibles, las especies que se benefician o perjudican por esta pérdida y los cambios netos en el almacenamiento de carbono forestal. Se necesita una investigación más avanzada sobre cómo varían los factores, como la depredación de semillas, entre especies de árboles y escenarios de pérdida de fauna para entender los cambios en cascada en la composición y diversidad de las especies.

Food availability alters community co-occurrence patterns at fine spatiotemporal scales in a tropical masting system.

Patterns of co-occurrence among species can help reveal the structure and assembly of ecological communities. However, studies have been limited by measuring co-occurrence in either space or time but not both simultaneously. This is especially problematic in systems such as masting forests where resources are highly variable, meaning that spatial use and co-occurrence patterns can change on fine spatiotemporal scales. We develop an analytical framework for assessing species co-occurrence at fine spatial and temporal scales simultaneously and apply these models to a camera trapping dataset from Borneo. We sought to determine how substantial variation in food availability across space and time affects co-occurrence among terrestrial vertebrates. We detect many significant, mostly positive, co-occurrence patterns among species, but almost entirely in unlogged forest and during dipterocarp mast years. The most strongly co-occurring pair of species, bearded pig (Sus barbatus) and sambar (Rusa unicolor), only positively co-occur in areas and years when fruit is locally abundant. Species occurrences in logged forest and non-mast years are mostly random with respect to other species. This suggests that frugivore-granivore species positively co-occur when resources are plentiful (i.e., large trees are present and fruiting), likely because they use the same resources; these patterns disappear when food availability is lower. Our approach demonstrates the utility of measuring co-occurrence in space and time together and highlights the importance of resource abundance for driving the co-occurrence structure of communities. Furthermore, our method could be broadly applied to other systems to assess fine-scale spatiotemporal patterns across a range of taxa.

Tropical forest dung beetle-mammal dung interaction networks remain similar across an environmental disturbance gradient.

Conservation outcomes could be greatly enhanced if strategies addressing anthropogenic land-use change considered the impacts of these changes on entire communities as well as on individual species. Examining how species interactions change across gradients of habitat disturbance allows us to predict the cascading consequences of species extinctions and the response of ecological networks to environmental change. We conducted the first detailed study of changes in a commensalist network of mammals and dung beetles across an environmental disturbance gradient, from primary tropical forest to plantations, which varied in above-ground carbon density (ACD) and mammal communities. Mammal diversity changed only slightly across the gradient, remaining high even in oil palm plantations and fragmented forest. Dung beetle species richness, however, declined in response to lower ACD and was particularly low in plantations and the most disturbed forest sites. Three of the five network metrics (nestedness, network specialization and functionality) were significantly affected by changes in dung beetle species richness and ACD, but mammal diversity was not an important predictor of network structure. Overall, the interaction networks remained structurally and functionally similar across the gradient, only becoming simplified (i.e. with fewer dung beetle species and fewer interactions) in the most disturbed sites. We suggest that the high diversity of mammals, even in disturbed forests, combined with the generalist feeding patterns of dung beetles, confer resilience to the commensalist dung beetle-mammal networks. This study highlights the importance of protecting logged and fragmented forests to maintain interaction networks and potentially prevent extinction cascades in human-modified systems.

Fungi and insects compensate for lost vertebrate seed predation in an experimentally defaunated tropical forest.

Overhunting reduces important plant-animal interactions such as vertebrate seed dispersal and seed predation, thereby altering plant regeneration and even above-ground biomass. It remains unclear, however, if non-hunted species can compensate for lost vertebrates in defaunated ecosystems. We use a nested exclusion experiment to isolate the effects of different seed enemies in a Bornean rainforest. In four of five tree species, vertebrates kill many seeds (13-66%). Nonetheless, when large mammals are excluded, seed mortality from insects and fungi fully compensates for the lost vertebrate predation, such that defaunation has no effect on seedling establishment. The switch from seed predation by generalist vertebrates to specialist insects and fungi in defaunated systems may alter Janzen-Connell effects and density-dependence in plants. Previous work using simulation models to explore how lost seed dispersal will affect tree species composition and carbon storage may require reevaluation in the context of functional redundancy within complex species interactions networks.

The decline of mammal functional and evolutionary diversity worldwide.

Biodiversity is declining worldwide. Because species interact with one another and with their environment, losses of particular organisms alter the function of ecosystems. Our understanding of the global rates and specific causes of functional decline remains limited, however. Species losses also reduce the cumulative amount of extant evolutionary history ("phylogenetic diversity" [PD]) in communities-our biodiversity heritage. Here we provide a global assessment of how each known anthropogenic threat is driving declines in functional diversity (FD) and PD, using terrestrial mammals as a case study. We find that habitat loss and harvest (e.g., legal hunting, poaching, snaring) are by far the biggest drivers of ongoing FD and PD loss. Declines in FD in high-biodiversity countries, particularly in Southeast Asia and South America, are greater than would be expected if species losses were random with respect to ecological function. Among functional guilds, herbivores are disproportionately likely to be declining from harvest, with important implications for plant communities and nutrient cycling. Frugivores are particularly likely to be declining from both harvest and habitat loss, with potential ramifications for seed dispersal and even forest carbon storage. Globally, phylogenetically unique species do not have an elevated risk of decline, but in areas such as Australia and parts of Southeast Asia, both habitat loss and harvest are biased toward phylogenetically unique species. Enhanced conservation efforts, including a renewed focus on harvest sustainability, are urgently needed to prevent the deterioration of ecosystem function, especially in the South American and equatorial Asian tropics.

Understanding the distribution of bushmeat hunting effort across landscapes by testing hypotheses about human foraging.

Mitigating the massive impacts of defaunation on natural ecosystems requires understanding and predicting hunting effort across the landscape. But such understanding has been hindered by the difficulty of assessing the movement patterns of hunters in thick forests and across complex terrain. We statistically tested hypotheses about the spatial distribution of hunting with circuit theory and structural equation models. We used a data set of >7000 known kill locations in Guyana and hunter movement models to test these methods. Comparing models with different resistance layers (i.e., different estimates of how terrain and land cover influence human movement speed) showed that rivers, on average, limited movement rather than serving as transport arteries. Moreover, far more kills occurred close to villages than in remote areas. This, combined with the lack of support for structural equation models that included latent terms for prey depletion driven by past overhunting, suggests that kill locations in this system tended to be driven by where hunters were currently foraging rather than by influences of historical harvest. These analyses are generalizable to a variety of ecosystems, species, and data types, providing a powerful way of enhancing maps and predictions of hunting effort across complex landscapes.

Comprensión de la Distribución de los Esfuerzos por Obtener Carne de Caza a lo largo de un Paisaje Mediante la Comprobación de Hipótesis sobre el Forrajeo Humano Resumen La mitigación de los impactos masivos de la defaunación sobre los ecosistemas naturales requiere de comprensión y predicción de los esfuerzos de caza a lo largo del paisaje. Dicha comprensión se ha visto obstaculizada por la dificultad que representa la evaluación de los patrones de movimiento de los cazadores en bosques densos y a través de un terreno complejo. Analizamos estadísticamente las hipótesis sobre la distribución espacial de la cacería mediante una teoría de circuito y modelos de ecuaciones estructurales. Usamos un conjunto de datos de más de 7000 localidades conocidas de sacrificios en Guayana y los modelos de movimiento de los cazadores para probar estos modelos. La comparación entre modelos con diferentes capas de resistencia (es decir, diferentes estimaciones de cómo el terreno y la cobertura de suelo influyen sobre la velocidad del movimiento humano) mostró que los ríos, en promedio, limitaron el movimiento en lugar de funcionar como arterias de transporte. Además, ocurrieron mucho más sacrificios cerca de las aldeas que en las áreas remotas. Lo anterior, combinado con la falta de apoyo para los modelos de ecuaciones estructurales que incluyeron los términos latentes para la reducción de presas causada por la sobrecaza pasada, sugiere que las localidades de sacrificios en este sistema tendieron a ser seleccionadas por la ubicación actual en la que los cazadores se encontraban forrajeando y no por la influencia de la cosecha histórica. Estos análisis son generalizables para una variedad de ecosistemas, especies y tipos de datos, lo que proporciona una manera poderosa de mejorar los mapas y las predicciones de los esfuerzos de cacería a través de paisajes complejos.

Advancing an interdisciplinary framework to study seed dispersal ecology.

Although dispersal is generally viewed as a crucial determinant for the fitness of any organism, our understanding of its role in the persistence and spread of plant populations remains incomplete. Generalizing and predicting dispersal processes are challenging due to context dependence of seed dispersal, environmental heterogeneity and interdependent processes occurring over multiple spatial and temporal scales. Current population models often use simple phenomenological descriptions of dispersal processes, limiting their ability to examine the role of population persistence and spread, especially under global change. To move seed dispersal ecology forward, we need to evaluate the impact of any single seed dispersal event within the full spatial and temporal context of a plant's life history and environmental variability that ultimately influences a population's ability to persist and spread. In this perspective, we provide guidance on integrating empirical and theoretical approaches that account for the context dependency of seed dispersal to improve our ability to generalize and predict the consequences of dispersal, and its anthropogenic alteration, across systems. We synthesize suitable theoretical frameworks for this work and discuss concepts, approaches and available data from diverse subdisciplines to help operationalize concepts, highlight recent breakthroughs across research areas and discuss ongoing challenges and open questions. We address knowledge gaps in the movement ecology of seeds and the integration of dispersal and demography that could benefit from such a synthesis. With an interdisciplinary perspective, we will be able to better understand how global change will impact seed dispersal processes, and potential cascading effects on plant population persistence, spread and biodiversity.

Predicting defaunation: accurately mapping bushmeat hunting pressure over large areas.

Unsustainable hunting is emptying forests of large animals around the world, but current understanding of how human foraging spreads across landscapes has been stymied by data deficiencies and cryptic hunter behaviour. Unlike other global threats to biodiversity like deforestation, climate change and overfishing, maps of wild meat hunters' movements-often based on forest accessibility-typically cover small scales and are rarely validated with real-world observations. Using camera trapping data from rainforests across Malaysian Borneo, we show that while hunter movements are strongly correlated with the accessibility of different parts of the landscape, accessibility measures are most informative when they integrate fine-scale habitat features like topography and land cover. Measures of accessibility naive to fine-scale habitat complexity, like distance to the nearest road or settlement, generate poor approximations of hunters' movements. In comparison, accessibility as measured by high-resolution movement models based on circuit theory provides vastly better reflections of real-world foraging movements. Our results highlight that simple models incorporating fine-scale landscape heterogeneity can be powerful tools for understanding and predicting widespread threats to biodiversity.