William Link, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 44
No results found.
Filter Total Items: 122
Tigers and their prey: Predicting carnivore densities from prey abundance
The goal of ecology is to understand interactions that determine the distribution and abundance of organisms. In principle, ecologists should be able to identify a small number of limiting resources for a species of interest, estimate densities of these resources at different locations across the landscape, and then use these estimates to predict the density of the focal species at these locations
Authors
K. U. Karanth, J. D. Nichols, S. Kumar, W. A. Link, J. E. Hines
Testing life history predictions in a long-lived seabird: A population matrix approach with improved parameter estimation
Life history theory and associated empirical generalizations predict that population growth rate (λ) in long-lived animals should be most sensitive to adult survival; the rates to which λ is most sensitive should be those with the smallest temporal variances; and stochastic environmental events should most affect the rates to which λ is least sensitive. To date, most analyses attempting to examine
Authors
P.F. Doherty, E.A. Schreiber, J. D. Nichols, J. E. Hines, W. A. Link, G.A. Schenk, R.W. Schreiber
Statistical analyses make the Christmas Bird Count relevant for conservation
No abstract available.
Authors
J.R. Sauer, W. A. Link, D.K. Niven
Nonidentifiability of population size from capture-recapture data with heterogeneous detection probabilities
Heterogeneity in detection probabilities has long been recognized as problematic in mark-recapture studies, and numerous models developed to accommodate its effects. Individual heterogeneity is especially problematic, in that reasonable alternative models may predict essentially identical observations from populations of substantially different sizes. Thus even with very large samples, the analyst
Authors
W. A. Link
Demographic analysis from summaries of an age-structured population
Demographic analyses of age-structured populations typically rely on life history data for individuals, or when individual animals are not identified, on information about the numbers of individuals in each age class through time. While it is usually difficult to determine the age class of a randomly encountered individual, it is often the case that the individual can be readily and reliably assig
Authors
William A. Link, J. Andrew Royle, Jeff S. Hatfield
Hierarchical models and the analysis of bird survey information
Management of birds often requires analysis of collections of estimates. We describe a hierarchical modeling approach to the analysis of these data, in which parameters associated with the individual species estimates are treated as random variables, and probability statements are made about the species parameters conditioned on the data. A Markov-Chain Monte Carlo (MCMC) procedure is used to fi
Authors
J.R. Sauer, W. A. Link
Estimation of change in populations and communities from monitoring survey data
Monitoring surveys provide fundamental information for use in environmental decision making by permitting assessment of both current population (or community) status and change in status, by providing a historical context of the present status, and by documenting response to ongoing management. Conservation of species and communities has historically been based upon monitoring information, and pr
Authors
J.R. Sauer, W. A. Link, J. D. Nichols
Of bugs and birds: Markov Chain Monte Carlo for hierarchical modeling in wildlife research
Markov chain Monte Carlo (MCMC) is a statistical innovation that allows researchers to fit far more complex models to data than is feasible using conventional methods. Despite its widespread use in a variety of scientific fields, MCMC appears to be underutilized in wildlife applications. This may be due to a misconception that MCMC requires the adoption of a subjective Bayesian analysis, or perhap
Authors
William A. Link, Emmanuelle Cam, James D. Nichols, Evan G. Cooch
Using Christmas Bird Count data in analysis of population change
The scientific credibility of Christmas Bird Count (CBC) results depend on the development and implementation of appropriate methods of statistical analysis. The key to any successful analysis of CBC data is to begin with a careful review of how the limitations of the data are likely to influence the results of the analysis, then to choose methods of analysis that accommodate as much as possible
Authors
J.R. Sauer, W. A. Link
Model-based estimation of individual fitness
Fitness is the currency of natural selection, a measure of the propagation rate of genotypes into future generations. Its various definitions have the common feature that they are functions of survival and fertility rates. At the individual level, the operative level for natural selection, these rates must be understood as latent features, genetically determined propensities existing at birth. Thi
Authors
William A. Link, Evan G. Cooch, Emmanuelle Cam
Individual covariation in life-history traits: Seeing the trees despite the forest
We investigated the influence of age on survival and breeding rates in a long-lived species Rissa tridactyla using models with individual random effects permitting variation and covariation in fitness components among individuals. Differences in survival or breeding probabilities among individuals are substantial, and there was positive covariation between survival and breeding probability; birds
Authors
E. Cam, W. A. Link, E.G. Cooch, J. -Y. Monnat, E. Danchin
Occam's shadow: levels of analysis in evolutionary ecology - where to next?
Evolutionary ecology is the study of evolutionary processes, and the ecological conditions that influence them. A fundamental paradigm underlying the study of evolution is natural selection. Although there are a variety of operational definitions for natural selection in the literature, perhaps the most general one is that which characterizes selection as the process whereby heritable variation
Authors
E.G. Cooch, E. Cam, W. A. Link
Science and Products
Filter Total Items: 44
No results found.
Filter Total Items: 122
Tigers and their prey: Predicting carnivore densities from prey abundance
The goal of ecology is to understand interactions that determine the distribution and abundance of organisms. In principle, ecologists should be able to identify a small number of limiting resources for a species of interest, estimate densities of these resources at different locations across the landscape, and then use these estimates to predict the density of the focal species at these locations
Authors
K. U. Karanth, J. D. Nichols, S. Kumar, W. A. Link, J. E. Hines
Testing life history predictions in a long-lived seabird: A population matrix approach with improved parameter estimation
Life history theory and associated empirical generalizations predict that population growth rate (λ) in long-lived animals should be most sensitive to adult survival; the rates to which λ is most sensitive should be those with the smallest temporal variances; and stochastic environmental events should most affect the rates to which λ is least sensitive. To date, most analyses attempting to examine
Authors
P.F. Doherty, E.A. Schreiber, J. D. Nichols, J. E. Hines, W. A. Link, G.A. Schenk, R.W. Schreiber
Statistical analyses make the Christmas Bird Count relevant for conservation
No abstract available.
Authors
J.R. Sauer, W. A. Link, D.K. Niven
Nonidentifiability of population size from capture-recapture data with heterogeneous detection probabilities
Heterogeneity in detection probabilities has long been recognized as problematic in mark-recapture studies, and numerous models developed to accommodate its effects. Individual heterogeneity is especially problematic, in that reasonable alternative models may predict essentially identical observations from populations of substantially different sizes. Thus even with very large samples, the analyst
Authors
W. A. Link
Demographic analysis from summaries of an age-structured population
Demographic analyses of age-structured populations typically rely on life history data for individuals, or when individual animals are not identified, on information about the numbers of individuals in each age class through time. While it is usually difficult to determine the age class of a randomly encountered individual, it is often the case that the individual can be readily and reliably assig
Authors
William A. Link, J. Andrew Royle, Jeff S. Hatfield
Hierarchical models and the analysis of bird survey information
Management of birds often requires analysis of collections of estimates. We describe a hierarchical modeling approach to the analysis of these data, in which parameters associated with the individual species estimates are treated as random variables, and probability statements are made about the species parameters conditioned on the data. A Markov-Chain Monte Carlo (MCMC) procedure is used to fi
Authors
J.R. Sauer, W. A. Link
Estimation of change in populations and communities from monitoring survey data
Monitoring surveys provide fundamental information for use in environmental decision making by permitting assessment of both current population (or community) status and change in status, by providing a historical context of the present status, and by documenting response to ongoing management. Conservation of species and communities has historically been based upon monitoring information, and pr
Authors
J.R. Sauer, W. A. Link, J. D. Nichols
Of bugs and birds: Markov Chain Monte Carlo for hierarchical modeling in wildlife research
Markov chain Monte Carlo (MCMC) is a statistical innovation that allows researchers to fit far more complex models to data than is feasible using conventional methods. Despite its widespread use in a variety of scientific fields, MCMC appears to be underutilized in wildlife applications. This may be due to a misconception that MCMC requires the adoption of a subjective Bayesian analysis, or perhap
Authors
William A. Link, Emmanuelle Cam, James D. Nichols, Evan G. Cooch
Using Christmas Bird Count data in analysis of population change
The scientific credibility of Christmas Bird Count (CBC) results depend on the development and implementation of appropriate methods of statistical analysis. The key to any successful analysis of CBC data is to begin with a careful review of how the limitations of the data are likely to influence the results of the analysis, then to choose methods of analysis that accommodate as much as possible
Authors
J.R. Sauer, W. A. Link
Model-based estimation of individual fitness
Fitness is the currency of natural selection, a measure of the propagation rate of genotypes into future generations. Its various definitions have the common feature that they are functions of survival and fertility rates. At the individual level, the operative level for natural selection, these rates must be understood as latent features, genetically determined propensities existing at birth. Thi
Authors
William A. Link, Evan G. Cooch, Emmanuelle Cam
Individual covariation in life-history traits: Seeing the trees despite the forest
We investigated the influence of age on survival and breeding rates in a long-lived species Rissa tridactyla using models with individual random effects permitting variation and covariation in fitness components among individuals. Differences in survival or breeding probabilities among individuals are substantial, and there was positive covariation between survival and breeding probability; birds
Authors
E. Cam, W. A. Link, E.G. Cooch, J. -Y. Monnat, E. Danchin
Occam's shadow: levels of analysis in evolutionary ecology - where to next?
Evolutionary ecology is the study of evolutionary processes, and the ecological conditions that influence them. A fundamental paradigm underlying the study of evolution is natural selection. Although there are a variety of operational definitions for natural selection in the literature, perhaps the most general one is that which characterizes selection as the process whereby heritable variation
Authors
E.G. Cooch, E. Cam, W. A. Link