J. ANDREW ROYLE results 44
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Abundance‐mediated species interactionsNARA Subscribed
Species interactions shape biodiversity patterns, community assemblage, and the dynamics of wildlife populations. Ecological theory posits that the strength of interspecific interactions is fundamentally underpinned by the population sizes of the involved species. Nonetheless, prevalent approaches for modeling species interactions predominantly center around occupancy states. Here, we use simulations to illuminate the inadequa...
Integrated distance sampling models for simple point countsNARA Subscribed
Point counts (PCs) are widely used in biodiversity surveys but, despite numerous advantages, simple PCs suffer from several problems: detectability, and therefore abundance, is unknown; systematic spatiotemporal variation in detectability yields biased inferences, and unknown survey area prevents formal density estimation and scaling‐up to the landscape level. We introduce integrated distance sampling (IDS) models that combine...
Long-term trends of local bird populations based on monitoring schemes: are they suitable for justifying management measures?NARA Subscribed
Local biodiversity monitoring is important to assess the effects of global change, but also to evaluate the performance of landscape and wildlife protection, since large-scale assessments may buffer local fluctuations, rare species tend to be underrepresented, and management actions are usually implemented on local scales. We estimated population trends of 58 bird species using open-population N-mixture models based on count d...
Modeling spatiotemporal abundance and movement dynamics using an integrated spatial capture–recapture movement modelNARA Subscribed
Animal movement is a fundamental ecological process affecting the survival and reproduction of individuals, the structure of populations, and the dynamics of communities. Methods to quantify animal movement and spatiotemporal abundances, however, are generally separate and therefore omit linkages between individual‐level and population‐level processes. We describe an integrated spatial capture–recapture (SCR) movement model to...
Optimal sampling design for spatial capture–recaptureNARA Subscribed
Spatial capture–recapture (SCR) has emerged as the industry standard for estimating population density by leveraging information from spatial locations of repeat encounters of individuals. The precision of density estimates depends fundamentally on the number and spatial configuration of traps. Despite this knowledge, existing sampling design recommendations are heuristic and their performance remains untested for most practic...
Ecological distance‐based spatial capture–recapture models (SCR) are a promising approach for simultaneously estimating animal density and connectivity, both of which affect spatial population processes and ultimately species persistence. We explored how SCR models can be integrated into reserve‐design frameworks that explicitly acknowledge both the spatial distribution of individuals and their space use resulting from landsca...
Incorporating citizen science data in spatially explicit integrated population modelsNARA Subscribed
Information about population abundance, distribution, and demographic rates is critical for understanding a species’ ecology and for effective conservation and management. To collect data over large spatial and temporal extents for such inferences, especially for species with low densities or wide distributions, citizen science can be an efficient approach. Integrated models have also emerged as an important methodology to est...
Brain cortical characteristics of lifetime cognitive ageingNARA Subscribed
An open‐population hierarchical distance sampling modelNARA Subscribed
Modeling population dynamics while accounting for imperfect detection is essential to monitoring programs. Distance sampling allows estimating population size while accounting for imperfect detection, but existing methods do not allow for estimation of demographic parameters. We develop a model that uses temporal correlation in abundance arising from underlying population dynamics to estimate demographic parameters from repeat...
The study of population dynamics requires unbiased, precise estimates of abundance and vital rates that account for the demographic structure inherent in all wildlife and plant populations. Traditionally, these estimates have only been available through approaches that rely on intensive mark–recapture data. We extended recently developed N ‐mixture models to demonstrate how demographic parameters and abundance can be estimated...
Markov models are dynamic models that characterize transitions among discrete ecological states with transition probability matrices. Such models are widely used to infer community dynamics of sessile organisms because transition probabilities (the elements of transition probability matrices) can be estimated with time series data from “grid sampling,” where species occupancy states are assessed at multiple fixed points in a q...
Current approaches using genetic distances produce poor estimates of landscape resistance to interindividual dispersalNARA Subscribed
Landscape resistance reflects how difficult it is for genes to move across an area with particular attributes (e.g. land cover, slope). An increasingly popular approach to estimate resistance uses M antel and partial M antel tests or causal modelling to relate observed genetic distances to effective distances under alternative sets of resistance parameters. Relatively few alternative sets of resistance parameters are tested, l...
Spatial capture–recapture models for jointly estimating population density and landscape connectivityNARA Subscribed
Population size and landscape connectivity are key determinants of population viability, yet no methods exist for simultaneously estimating density and connectivity parameters. Recently developed spatial capture–recapture (SCR) models provide a framework for estimating density of animal populations but thus far have not been used to study connectivity. Rather, all applications of SCR models have used encounter probability mode...
A productive way forward in studies of animal populations is to efficiently make use of all the information available, either as raw data or as published sources, on critical parameters of interest. In this study, we demonstrate two approaches to the use of multiple sources of information on a parameter of fundamental interest to ecologists: animal density. The first approach produces estimates simultaneously from two differen...
Assessing hypotheses about nesting site occupancy dynamicsNARA Subscribed
Use of Spatial Capture‐Recapture Modeling and DNA Data to Estimate Densities of Elusive AnimalsNARA Subscribed
Assessment of abundance, survival, recruitment rates, and density (i.e., population assessment) is especially challenging for elusive species most in need of protection (e.g., rare carnivores). Individual identification methods, such as DNA sampling, provide ways of studying such species efficiently and noninvasively. Additionally, statistical methods that correct for undetected animals and account for locations where animals...