Patrick A. Jansen

Smithsonian Tropical Research Institute · Center for Tropical Forest Science

Biodiversity loss and the emergence of zoonotic diseases are two major global challenges. An urgent question is how ecosystems and wildlife communities can be restored whilst minimizing the risk of zoonotic diseases carried by wildlife. Here, we evaluate how current ambitions to restore Europe's natural ecosystems may affect the hazard of diseases...

Ungulates play an important role in temperate systems. Through their feeding behaviour, they can respond to vegetation by selecting patches or modify vegetation composition by herbivory. The degree in which they interact with vegetation can either reinforce landscape heterogeneity by creating disturbance or reduce heterogeneity in case of overbrows...

An animal’s daily use of time (their “diel activity”) reflects their adaptations, requirements, and interactions, yet we know little about the underlying processes governing diel activity within and among communities. Here we examine whether community-level activity patterns differ among biogeographic regions, and explore the roles of top-down vers...

Hunting impacts tropical vertebrate populations, causing declines of species that function as seed dispersers and predators, or that browse seedlings and saplings. Whether and how the resulting reductions in seed dispersal, seed predation and browsing translate to changes in the tree composition is poorly understood. Here, we assess the effect of d...

The structure of forest mammal communities appears surprisingly consistent across the continental tropics, presumably due to convergent evolution in similar environments. Whether such consistency extends to mammal occupancy, despite variation in species characteristics and context, remains unclear. Here we ask whether we can predict occupancy patte...

Most animals follow distinct daily activity patterns reflecting their adaptations1, requirements, and interactions2-4. Specific communities provide specific opportunities and constraints to their members that further shape these patterns3,4. Here, we ask whether community-level diel activity patterns among long-separated biogeographic regions diffe...

The establishment of protected areas (PAs) is a central strategy for global biodi- versity conservation. While the role of PAs in protecting habitat has been high- lighted, their effectiveness at protecting mammal communities remains unclear. We analyzed a global dataset from over 8671 camera traps in 23 countries on four continents that detected 3...

p>Recruitment limitation—the failure of a species to establish recruits at an available site—is a potential determinant of plant communities’ structure, causing local communities to be a limited subset of the regional species pool. Recruitment limitation results from three mechanisms: (i) lack of seed sources (i.e., source limitation), (ii) failure...

Predation risk is a major driver of the distribution of prey animals, which typically show strong responses to cues for predator presence. An unresolved question is whether naïve individuals respond to mimicked cues, and whether such cues can be used to deter prey. We investigated whether playback of wolf sounds induces fear responses in naïve ungu...

Wildlife monitoring is essential for conservation science and data‐driven decision‐making. Tropical forests pose a particularly challenging environment for monitoring wildlife due to the dense vegetation, and diverse and cryptic species with relatively low abundances. The most commonly used monitoring methods in tropical forests are observations ma...

Allometric equations for calculation of tree aboveground biomass (AGB) form the basis for estimates of forest carbon storage and exchange with the atmosphere. While standard models exist to calculate forest biomass across the tropics, we lack a standardized tool for computing AGB across boreal and temperate regions that comprise the global extratro...

Arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) associations are critical for host-tree performance. However, how mycorrhizal associations correlate with the latitudinal tree beta-diversity remains untested. Using a global dataset of 45 forest plots representing 2,804,270 trees across 3840 species, we test how AM and EcM trees contribute to t...

Daily activity in herbivores reflects a balance between finding food and safety. The safety‐in‐numbers theory predicts that living in higher population densities increases safety, which should affect this balance. High‐density populations are thus expected to show a more even distribution of activity—that is, spread—and higher activity levels acros...

In a scenario where escalating human activities lead to several environmental changes and, consequently, affect mammal abundance and distribution, β-diversity may increase due to differences among sites. Using the ecological uniqueness approach, we analyzed β-diversity patterns of ground-dwelling mammal communities recorded through comprehensive ca...

A variety of factors can affect the biodiversity of tropical mammal communities, but their relative importance and directionality remain uncertain. Previous global investigations of mammal functional diversity have relied on range maps instead of observational data to determine community composition. We test the effects of species pools, habitat he...

Blood-feeding arthropod microbiomes often play important roles in disease transmission, yet the factors that structure tick microbial communities in the Neotropics are unknown. Utilizing ticks collected from live animals in neotropical forest fragments, this study teases apart the contributions of intrinsic and extrinsic tick-associated factors on...

Wild deer exert strong top-down control on forest composition by browsing on palatable trees, and these effects are exacerbated as red, fallow, and roe deer populations increase in northern temperate forests. However, the relationship between deer abundance and plant recruitment remains poorly documented. Here, we combined camera trap and vegetatio...

Ungulates have become abundant in many temperate forests, shifting tree species composition by browsing and altering soil physical conditions by trampling. Whether these effects cascade down to other trophic levels and ecosystem processes is poorly understood. Here, we assess the paths through which ungulates have cascading effects on other trophic...

Wild deer exert strong top–down control on forest composition by browsing on palatable trees, and these effects are exacerbated as red, fallow, and roe deer populations increase in northern temperate forests. However, the relationship between deer abundance and plant recruitment remains poorly documented. Here, we combined camera trap and vegetatio...

ForestGEO is a network of scientists and long-term forest dynamics plots (FDPs) spanning the Earth's major forest types. ForestGEO's mission is to advance understanding of the diversity and dynamics of forests and to strengthen global capacity for forest science research. ForestGEO is unique among forest plot networks in its large-scale plot dimens...

Camera traps deployed in grids or stratified random designs are a well‐established survey tool for wildlife but there has been little evaluation of study design parameters. We used an empirical subsampling approach involving 2225 camera deployments run at 41 study areas around the world to evaluate three aspects of camera trap study design (number...

Activity range ‐ the amount of time spent active per day ‐ is a fundamental aspect contributing to the optimization process by which animals achieve energetic balance. Based on their size and the nature of their diet, theoretical expectations are that larger carnivores need more time active to fulfil their energetic needs than do smaller ones and a...

The understanding of global diversity patterns has benefitted from a focus on functional traits and how they relate to variation in environmental conditions among assemblages. Distant communities in similar environments often share characteristics, and for tropical forest mammals, this functional trait convergence has been demonstrated at coarse sc...

Bushmeat hunting is widely cited as cause for declines of wildlife populations throughout Africa. Forest duikers (Bovidae, Cephalophinae) are among the most exploited species. Whether current harvest rates imperil duikers is debated because of the difficulty of accurately assessing population trends. To assess population trends, we first reviewed l...

(1) Camera trapping allows scientists to study activity patterns of animals under natural conditions. However, comparisons of activity patterns across seasons or latitudes can be biased, because activity is often attuned to sunrise and sunset, the timing of which varies with latitude and season. Existing transformation methods to solve this problem...

Habitat fragmentation is a primary driver of wildlife loss, and establishment of biological corridors is a common strategy to mitigate this problem. A flagship example is the Mesoamerican Biological Corridor (MBC), which aims to connect protected forest areas between Mexico and Panama to allow dispersal and gene flow of forest organisms. Because fo...

Symbiotic nitrogen (N)‐fixing trees can provide large quantities of new N to ecosystems, but only if they are sufficiently abundant. The overall abundance and latitudinal abundance distributions of N‐fixing trees are well characterised in the Americas, but less well outside the Americas. Here, we characterised the abundance of N‐fixing trees in a n...

Identifying the underlying drivers of species’ distributional dynamics is critical for predicting change and managing biological diversity. While anthropogenic factors such as climate change can affect species distributions through time, other naturally occurring ecological processes can also have an influence. Theory predicts that interactions bet...

Carnivores have long been used as model organisms to examine mechanisms that allow coexistence among ecologically similar species. Interactions between carnivores, including competition and predation, comprise important processes regulating local community structure and diversity. We use data from an intensive camera-trapping monitoring program acr...

Model selection analysis for occupancy (Ψ) and detection probability (p) used to evaluate the effect of time (sampling period) and study site on the habitat use of three sympatric felids, the jaguar (Panthera onca), puma (Puma concolor) and ocelot (Leopardus pardalis) in Neotropical forests. (DOCX)

Prey species list and relative abundance index (images/100 ctdays) of small (< 15 Kg) and large prey (> 15Kg) of carnivores in our eight Neotropical study sites. (DOCX)

Spearman’s rank correlation to test for collinearity among continuous covariates (ρ> 0.70). (DOCX)

Coefficient of overlap (Δ1) with confidence intervals (CI lower/CI upper) and Watson’s two-sample test (two-sample U2) performed on pairwise comparisons between study sites. (DOCX)

Single-species detection models used to evaluate the effects of covariates on the detection probability (p) of three sympatric felids, the jaguar (Panthera onca), puma (Puma concolor) and ocelot (Leopardus pardalis) in Neotropical forests. Detection probability was modelled as a function of elevation, NDVI, study site (site), large prey availabilit...

Single-species occupancy models used to evaluate the effects of elevation (Elev.), distance to nearest water source (water), NDVI (ndvi), small prey’s availability (small) and large prey’s availability (large) on the habitat use of jaguar (Panthera onca), puma (Puma concolor) and ocelot (Leopardus pardalis) in Neotropical forests. (DOCX)

Coefficient of overlap (Δ) with confidence intervals (CI lower/CI upper) and Watson’s two-sample test (two-sample U2) performed on pairwise comparisons between cat species per site. (DOCX)

Single-species occupancy models used to evaluate best habitat factors and species interactions. Occupancy probability was modelled as a function of elevation (Elev.), distance to water (water), NDVI (ndvi), small prey’s availability (small), large prey’s availability (large) and occupancy estimates of each cat species (jaguar, puma and ocelot). (DO...

Differences in the daily activity level (i. e., proportion of hours per day that an animal is active), standard errors (SE), Wald test (W) of Neotropical cats across the eight study sites (*Significant difference <0.05). (DOCX)

Spatial variation in habitat riskiness has a major influence on the predator–prey space race. However, the outcome of this race can be modulated if prey shares enemies with fellow prey (i.e., another prey species). Sharing of natural enemies may result in apparent competition, and its implications for prey space use remain poorly studied. Our objec...

Ticks are obligatory parasites with complex life cycles that often depend on larger bodied vertebrates as final hosts. These traits make them particularly sensitive to local coextinction with their host. Loss of wildlife abundance and diversity should thus lead to loss of tick abundance and diversity to the point where only generalist tick species...

Ungulates in temperate regions are increasing in range and abundance, leading to concerns that browsing and trampling reach levels that hamper tree recruitment and forest regeneration. However, studies that actually quantify the long-term effects of ungulates on forest succession are scarce. Here, we use a chronosequence of ungulate exclosures (fen...

Identifying optimal sampling designs for detecting population-level declines is critical for optimizing expenditures by research and monitoring programmes. The Tropical Ecology Assessment and Monitoring (TEAM) network is the most extensive tropical camera-trap monitoring programme, but the effectiveness of its sampling protocol has not been rigorou...

Significance Identifying and explaining regional differences in tropical forest dynamics, structure, diversity, and composition are critical for anticipating region-specific responses to global environmental change. Floristic classifications are of fundamental importance for these efforts. Here we provide a global tropical forest classification tha...

Background Understanding which factors drive population densities of disease vectors is an important step in assessing disease risk. We tested the hypothesis that the density of ticks from the Ixodes ricinus complex, which are important vectors for tick-borne diseases, is determined by the density of deer, as adults of these ticks mainly feed on de...

Metabarcoding of vertebrate DNA derived from carrion flies has been proposed as a promising tool for biodiversity monitoring. To evaluate its efficacy, we conducted metabarcoding surveys of carrion flies on Barro Colorado Island (BCI), Panama, which has a well-known mammal community, and compared our results against diurnal transect counts and came...

The availability of vertebrate hosts is a major determinant of the occurrence of ticks and tick-borne zoonoses in natural and anthropogenic ecosystems, and thus drives disease risk for wildlife, livestock and humans. However, it remains challenging to quantify the availability of vertebrate hosts in field settings, particularly for medium-sized to...

Predators and competitors of vertebrates can in theory reduce the density of infected nymphs (DIN)—an often-used measure of tick-borne disease risk—by lowering the density of reservoir-competent hosts and/or the tick burden on reservoir-competent hosts. We investigated this possible indirect effect of predators by comparing data from 20 forest plot...

The availability of vertebrate hosts is a major determinant of the occurrence of ticks and tick-borne zoonoses in natural and anthropogenic ecosystems and thus drives disease risk for wildlife, livestock, and humans. However, it remains challenging to quantify the availability of vertebrate hosts in field settings, particularly for medium-sized to...

Camera traps that capture photos of animals are a valuable tool for monitoring biodiversity. The use of camera traps is rapidly increasing and there is an urgent need for standardization to facilitate data management, reporting and data sharing. Here we offer the Camera Trap Metadata Standard as an open data standard for storing and sharing camera t...

Identifying the factors that influence the species diversity and distribution of ticks (Acari: Ixodida) across vertebrate host taxa is of fundamental ecological and medical importance. Host body size is considered one of the most important determinants of tick abundance, with larger hosts having higher tick burdens. The species diversity of tick as...

Context Many arboreal mammals in Neotropical forests are important seed dispersers that influence the spatial patterns of tree regeneration via their movement patterns, which in turn are determined by the canopy structure of the forest itself. However, the relationship between arboreal mammal movement and canopy structure is poorly understood, due...

Synthesis: We show that two species of insect seed predators relying on the same host plant species are niche differentiated in their reproductive strategies such that one species has the advantage when fruits are handled promptly by vertebrates and the other when they aren't. Defaunation disrupts this mediating influence of vertebrates and strong...

Estimates of animal abundance are essential for understanding animal ecology. Camera traps can be used to estimate the abundance of terrestrial mammals, including elusive species, provided that the sensitivity of the sensor, estimated as the effective detection distance (EDD), is quantified. Here, we show how the EDD can be inferred directly from c...