The Challenge: Wildlife science and management are guided by data, and it is unquestionably the case that the greatest success occurs when good data are analyzed by good statistical methods.
The Science:
This study provides the basis for collaboration between a mathematical statistician and quantitative ecologists. One such collaboration led to the development of techniques for aging Dwarf crocodiles (Osteolaemus tetraspis), informed by model based analysis of two data sets, one consisting of young crocodiles of known age, another consisting of recapture data for older crocodiles of unknown age. Methods developed for these crocodiles have been applied to wildebeest (Connochaetes taurinus albojubotus), frogs (Rana sierra) and even trees (Juniperus ashei).
A major product of the study has been publication of the book Bayesian Inference, with Ecological Applications by W.A. Link and R.J. Barker. The Bayesian approach to statistical inference was first described in Thomas Bayes’ “An Essay towards solving a Problem in the Doctrine of Chances” published posthumously in 1763. Bayesian methods were largely ignored in the early twentieth century, but their usefulness for describing complex models, in concert with advances in computational capacity, has led to a surge of interest, which is revolutionizing statistical analysis. A wildcard search for “Bayes*” in the text of publications of the Ecological Society of America provides an index to the phenomenon: 17, 29, 46, 69 and 85 publications are found for 1990-1994, 1995-1999, 2000-2004, 2005-2009 and 20101-2014. Link and Barker's text has been well received, not only as an introduction to the Bayesian paradigm, but also for its presentations of Bayesian analysis of a variety of ecological and wildlife data.
The Future: The Bayesian paradigm is a mathematically sound and reliable basis for multimodel inference. Bayesian multimodel inference has been and continues to be an important component of this study. This study has addressed practical difficulties associated with choices of objective prior distributions, and computational difficulties associated with Reversible Jump Markov chain Monte Carlo.
Research also continues on computational methods for Bayesian models describing complex latent structures. Widely available and popular software packages such as OpenBUGS and JAGS are usually effective, but not always. Latent multinomial structures are problematic, requiring the selection of Markov bases for implementation of Gibbs sampling. Applications have included models for growth and movement in closed populations based on removal data, and mark-recapture models accounting for misidentification.
Below are publications associated with this project.
Bayesian cross-validation for model evaluation and selection, with application to the North American Breeding Bird Survey
Tarangire revisited: Consequences of declining connectivity in a tropical ungulate population
Individual heterogeneity in growth and age at sexual maturity: A gamma process analysis of capture–mark–recapture data
Truth, models, model sets, AIC, and multimodel inference: a Bayesian perspective
Modeling participation duration, with application to the North American Breeding Bird Survey
On thinning of chains in MCMC
Decision analysis for conservation breeding: Maximizing production for reintroduction of whooping cranes
Book review: Bayesian analysis for population ecology
Modeling misidentification errors that result from use of genetic tags in capture-recapture studies
Uncovering a latent multinomial: Analysis of mark-recapture data with misidentification
A Bayesian approach to identifying structural nonlinearity using free-decay response: Application to damage detection in composites
Spatial patterns of bee captures in North American bowl trapping surveys
- Overview
The Challenge: Wildlife science and management are guided by data, and it is unquestionably the case that the greatest success occurs when good data are analyzed by good statistical methods.
The Science:
This study provides the basis for collaboration between a mathematical statistician and quantitative ecologists. One such collaboration led to the development of techniques for aging Dwarf crocodiles (Osteolaemus tetraspis), informed by model based analysis of two data sets, one consisting of young crocodiles of known age, another consisting of recapture data for older crocodiles of unknown age. Methods developed for these crocodiles have been applied to wildebeest (Connochaetes taurinus albojubotus), frogs (Rana sierra) and even trees (Juniperus ashei).
A major product of the study has been publication of the book Bayesian Inference, with Ecological Applications by W.A. Link and R.J. Barker. The Bayesian approach to statistical inference was first described in Thomas Bayes’ “An Essay towards solving a Problem in the Doctrine of Chances” published posthumously in 1763. Bayesian methods were largely ignored in the early twentieth century, but their usefulness for describing complex models, in concert with advances in computational capacity, has led to a surge of interest, which is revolutionizing statistical analysis. A wildcard search for “Bayes*” in the text of publications of the Ecological Society of America provides an index to the phenomenon: 17, 29, 46, 69 and 85 publications are found for 1990-1994, 1995-1999, 2000-2004, 2005-2009 and 20101-2014. Link and Barker's text has been well received, not only as an introduction to the Bayesian paradigm, but also for its presentations of Bayesian analysis of a variety of ecological and wildlife data.
The Future: The Bayesian paradigm is a mathematically sound and reliable basis for multimodel inference. Bayesian multimodel inference has been and continues to be an important component of this study. This study has addressed practical difficulties associated with choices of objective prior distributions, and computational difficulties associated with Reversible Jump Markov chain Monte Carlo.
Research also continues on computational methods for Bayesian models describing complex latent structures. Widely available and popular software packages such as OpenBUGS and JAGS are usually effective, but not always. Latent multinomial structures are problematic, requiring the selection of Markov bases for implementation of Gibbs sampling. Applications have included models for growth and movement in closed populations based on removal data, and mark-recapture models accounting for misidentification.
- Publications
Below are publications associated with this project.
Filter Total Items: 15Bayesian cross-validation for model evaluation and selection, with application to the North American Breeding Bird Survey
The analysis of ecological data has changed in two important ways over the last 15 years. The development and easy availability of Bayesian computational methods has allowed and encouraged the fitting of complex hierarchical models. At the same time, there has been increasing emphasis on acknowledging and accounting for model uncertainty. Unfortunately, the ability to fit complex models has outstrAuthorsWilliam A. Link, John R. SauerTarangire revisited: Consequences of declining connectivity in a tropical ungulate population
The hyper-abundance of migratory wildlife in many ecosystems depends on maintaining access to seasonally available resources. In Eastern and Southern Africa, land-use change and a loss of connectivity have coincided with widespread declines in the abundance and geographic range of ungulate populations. Using photographic capture-mark-recapture, we examine the historical pattern of loss of connectiAuthorsThomas A. Morrison, William A. Link, William D. Newmark, Charles A.H. Foley, Douglas T. BolgerIndividual heterogeneity in growth and age at sexual maturity: A gamma process analysis of capture–mark–recapture data
Knowledge of organisms’ growth rates and ages at sexual maturity is important for conservation efforts and a wide variety of studies in ecology and evolutionary biology. However, these life history parameters may be difficult to obtain from natural populations: individuals encountered may be of unknown age, information on age at sexual maturity may be uncertain and interval-censored, and growth daAuthorsWilliam A. Link, Kyle Miller HesedTruth, models, model sets, AIC, and multimodel inference: a Bayesian perspective
Statistical inference begins with viewing data as realizations of stochastic processes. Mathematical models provide partial descriptions of these processes; inference is the process of using the data to obtain a more complete description of the stochastic processes. Wildlife and ecological scientists have become increasingly concerned with the conditional nature of model-based inference: what if tAuthorsRichard J. Barker, William A. LinkModeling participation duration, with application to the North American Breeding Bird Survey
We consider “participation histories,” binary sequences consisting of alternating finite sequences of 1s and 0s, ending with an infinite sequence of 0s. Our work is motivated by a study of observer tenure in the North American Breeding Bird Survey (BBS). In our analysis, j indexes an observer’s years of service and Xj is an indicator of participation in the survey; 0s interspersed among 1s correspAuthorsWilliam A. Link, John R. SauerOn thinning of chains in MCMC
1. Markov chain Monte Carlo (MCMC) is a simulation technique that has revolutionised the analysis of ecological data, allowing the fitting of complex models in a Bayesian framework. Since 2001, there have been nearly 200 papers using MCMC in publications of the Ecological Society of America and the British Ecological Society, including more than 75 in the journal Ecology and 35 in the Journal of AAuthorsWilliam A. Link, Mitchell J. EatonDecision analysis for conservation breeding: Maximizing production for reintroduction of whooping cranes
Captive breeding is key to management of severely endangered species, but maximizing captive production can be challenging because of poor knowledge of species breeding biology and the complexity of evaluating different management options. In the face of uncertainty and complexity, decision-analytic approaches can be used to identify optimal management options for maximizing captive production. BuAuthorsDes H.V. Smith, Sarah J. Converse, Keith Gibson, Axel Moehrenschlager, William A. Link, Glenn H. Olsen, Kelly MaguireBook review: Bayesian analysis for population ecology
Brian Dennis described the field of ecology as “fertile, uncolonized ground for Bayesian ideas.” He continued: “The Bayesian propagule has arrived at the shore. Ecologists need to think long and hard about the consequences of a Bayesian ecology. The Bayesian outlook is a successful competitor, but is it a weed? I think so.” (Dennis 2004) Review info: Bayesian Analysis for Population Ecology. By RuAuthorsWilliam A. LinkModeling misidentification errors that result from use of genetic tags in capture-recapture studies
Misidentification of animals is potentially important when naturally existing features (natural tags) such as DNA fingerprints (genetic tags) are used to identify individual animals. For example, when misidentification leads to multiple identities being assigned to an animal, traditional estimators tend to overestimate population size. Accounting for misidentification in capture–recapture models rAuthorsJ. Yoshizaki, C. Brownie, K.H. Pollock, William A. LinkUncovering a latent multinomial: Analysis of mark-recapture data with misidentification
Natural tags based on DNA fingerprints or natural features of animals are now becoming very widely used in wildlife population biology. However, classic capture-recapture models do not allow for misidentification of animals which is a potentially very serious problem with natural tags. Statistical analysis of misidentification processes is extremely difficult using traditional likelihood methods bAuthorsW.A. Link, J. Yoshizaki, L.L. Bailey, K.H. PollockA Bayesian approach to identifying structural nonlinearity using free-decay response: Application to damage detection in composites
This work discusses a Bayesian approach to approximating the distribution of parameters governing nonlinear structural systems. Specifically, we use a Markov Chain Monte Carlo method for sampling the posterior parameter distributions thus producing both point and interval estimates for parameters. The method is first used to identify both linear and nonlinear parameters in a multiple degree-of-freAuthorsJ.M. Nichols, W.A. Link, K.D. Murphy, C.C. OlsonSpatial patterns of bee captures in North American bowl trapping surveys
1. Bowl and pan traps are now commonly used to capture bees (Hymenoptera: Apiformes) for research and surveys. 2. Studies of how arrangement and spacing of bowl traps affect captures of bees are needed to increase the efficiency of this capture technique. 3. We present results from seven studies of bowl traps placed in trapping webs, grids, and transects in four North American ecoregions (Mid-AtAuthorsSam Droege, Vincent J. Tepedino, Gretchen Lebuhn, William Link, Robert L. Minckley, Qian Chen, Casey Conrad