Kim Keating's Research Projects

Landscape-level Modeling and Decision Support

• Modeling utilization distributions in space and time

In his 1975 paper, Van Winkle established an enduring cornerstone of modern home range analysis when he defined the utilization distribution (UD) as a probability density that gives an animal’s relative frequency of occurrence in 2-dimensional (x,y) space. We extend Van Winkle’s work to all 4 dimensions of space and time, and describe a method for estimating this expanded model. Our method allows scientists to include circularly distributed temporal covariates (like day of year) in UD models for the first time. Performance of the method is explored using simulations, and is illustrated in an empirical example in which we estimate the expected UD in 3 dimensions (x, y, and t) for animals belonging to each of 2 distinct bighorn sheep (Ovis canadensis) social groups in Glacier National Park, Montana, USA. Videos showing how use of space varies with time are an important product made possible by this method and provide a new tool for visualizing the inherently dynamic nature of animal distributions.

Associated Publications:
Keating, K. A., and S. Cherry. 2009. Modeling utilization distributions in space and time. Ecology. 90:1971-1980.
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Associated Uses:
Calenge, C., M. Basille, S. Dray, and S. Fortmann-Roe. 2009. Package ‘adehabitat’. Version 1.8.3. http://cran.fhcrc.org/web/packages/adehabitat/adehabitat.pdf. Accessed 10 August 2009.



• Use of logistic regression in wildlife habitat-selection modeling

Logistic regression is one of the most widely used statistical tools for modeling wildlife-habitat relationships. However, frequent misapplication of this method by wildlife scientists reflects an inadequate understanding of the logistic model, its interpretation, and the influence of sampling design. To encourage proper application, the correct use and interpretation of logistic regression was reviewed for 3 common sampling designs, and guidelines for applying logistic regression were offered for each. A particularly controversial finding was that logistic regression is generally inappropriate for modeling habitat selection in studies that employ a use–availability design, whereby 2 random samples are drawn independently, one from habitats available to the animal, another from habitats used by the animal. Because this is perhaps the most common sampling design in wildlife-habitat research, results of this study underscore the need for further work to develop credible statistical methods for modeling habitat selection in the use-availability setting.

Associated Publications:
Keating, K. A., and S. Cherry. 2004. Use and interpretation of logistic regression in habitat-selection studies. Journal of Wildlife Management 68:774-789.
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• Robust methods for modeling probability of use

Habitat selection models have become an important wildlife conservation tool that, ideally, allow one to estimate expected relative densities of animal use over a landscape, and to forecast likely effects of habitat change. Unfortunately, no generally robust method for building such models has yet been proposed. Working from first principles, a simple conceptual model of the habitat-selection process suggests that nonparametric methods may offer important advantages for modeling probability of use. In this study, the accuracy and precision of selected nonparametric approaches is being examined to test this prediction.

Wildlife Conservation

• Bighorn sheep in Waterton-Glacier International Peace Park

Despite its pristine appearance, the Waterton-Glacier area harbors a fauna that has been greatly affected by human activities. Historical periods of trapping, mining, logging, agriculture and unregulated hunting resulted in the extirpation of some species, while greatly reducing numbers and distributions of others. Today, human population growth and tourism have led to accelerated rates of land development and increased recreational use in and near both parks, further affecting critical ungulate habitats and the populations dependent on them. Bighorn sheep are among those species that face serious risk of further decline. Bighorns occupy patchily distributed habitats, particularly during the critical winter period. Decades of fire suppression have decreased the size and increased the insularity of many of these habitat patches, while disease has caused recurrent catastrophic mortality, exacerbated by legal and illegal hunting. Such factors have combined to extirpate bighorn sheep from some important historical winter ranges in and adjacent to the parks, and are a continuing concern into the future. To provide park managers with a better understanding of bighorn populations, this study will document seasonal ranges and migration routes, evaluate patterns of habitat use and selection, and model bighorn-habitat relationships to predict occurrences of critical habitats and provide managers with rigorous decision-support tools to aid planning and impact assessment.

• Bighorn sheep in Dinosaur National Monument

Originally established to protect paleontological resources, Dinosaur National Monument was expanded in 1938 to include the Green and Yampa River corridors, and the bighorn sheep population that occupied them. It is a population with an unsteady history. By the early 1940s, bighorn sheep were extirpated from the Monument through overgrazing, disease, and hunting. Reintroduced in 1952, bighorns thrived initially, but then languished after a period of decline in the mid-1970s. Following releases of additional animals in the 1980s and 1990s, the herd again expanded, but current numbers and distribution remain largely unknown. Monument managers need better information about herd size and distribution, as well as factors that might limit population growth and expansion into new areas. This project is focused foremost on documenting seasonal ranges and travel routes, evaluating patterns of habitat use and selection, and modeling bighorn-habitat relationships to predict the distribution of suitable habitats. Relationships between bighorn distribution and the presence of domestic sheep on federal lands adjacent to the Monument are a particular concern. In addition, this project provides an opportunity to study genetic diversity in a population whose founders were drawn from diverse sources, and to test for possible exposure to a range of diseases that might limit population growth.