Decision Science and Quantitative Methods

Protected area managers provide formal trail systems to accommodate recreational visitation on resistant “hardened” treads, while protecting off-trail vegetation, soils, and wildlife. When formal trail networks fail to provide visitors the access and experiences they require, visitors frequently venture “off-trail” to fish, hunt, explore, climb, or engage in other off-trail activities. Even...

These systems are characterized as 4th order and larger nontidal riverine systems, which includes many of the intermediate and larger size rivers, such as the Penobscot, Connecticut, Hudson, Delaware, and Susquehanna Rivers and their larger tributaries of the northeastern U.S. Fish passage, thermal stress, and ecological flows are likely important issues in these systems. Fish health issues and...

Research in population biology is concerned with factors affecting the change in a population over time, including births, deaths, immigration and emigration. Despite the potential importance of immigration and emigration, empirical data on movement patterns are lacking in many systems.

The Challenge: Traditionally, bee identification has relied on taxonomic methods centered on descriptions of morphological differences between species. However, for many species, separate keys are required for identifying adult males and females and immature life stages. These keys are commonly unavailable. The lack of distinguishing morphological characters useful for separating closely related...

Protected natural areas, including parks, forests, wilderness, and wildlife refuges, have a dual mandate to protect natural resources and accommodate recreational visitation. Recreational activities that occur on trails (hiking, mountain biking, horseback riding) and on recreation sites (picnicking, camping) can benefit from the development of a sustainable infrastructure of facilities that...

It is (relatively) easy to construct complex hierarchical models for analysis of the North American Breeding Bird Survey (BBS), but deciding which model best describes population change is difficult. We are developing methods for model selection for BBS and other important survey data sets, and using them to refine our estimates of population change from this important survey.

The boreal forest in the northeastern United States and eastern Canada contains most of the breeding range of the American black duck ( Anas rubripes ). We collaborate with scientists from the U. S. Fish and Wildlife Service to design and analyze waterfowl surveys in this large and often inaccessible area.

Designing and analyzing large-scale animal surveys is an important focus of our research. Although we conduct research into analysis methods for many surveys, the primary focus of this project is to conduct analyses and develop web-based summaries of data from the North American Breeding Bird Survey (BBS).

The Challenge: Research goals of this project are to develop models, statistical methods, sampling strategies and tools for inference about animal population status from survey data. Survey data are always subject to a number of observation processes that induce bias and error. In particular, inferences are based on spatial sampling – we can only ever sample a subset of locations where species...

The Challenge: For decades, capture-recapture methods have been the cornerstone of ecological statistics as applied to population biology. While capture-recapture has become the standard sampling and analytical framework for the study of population processes (Williams, Nichols & Conroy 2002) it has advanced independent of and remained unconnected to the spatial structure of the population or the...

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 Challenge: Much of wildlife research consists of the description of variation in data. Some of the variation results from spatial and temporal change in populations, while some results from biologically irrelevant sampling variation induced by the process of data collection. Distinguishing relevant from irrelevant variation is the first task of statistical analysis, but the job does not end...