Publications

No abstract available.

We evaluated nesting habitat selection (disproportionate use compared to availability) by plains sharp-tailed grouse (Tympanuchus phasianellus jamesi) on rangelands grazed by cattle (Bos taurus) relative to height, density, and heterogeneity of residual herbaceous vegetation remaining from previous growing seasons. Residual cover is critical for nesting sharp-tailed grouse and can be...

SALMOD is a computer model that simulates the dynamics of freshwater salmonid populations, both anadromous and resident. The conceptual model was developed in a workshop setting (Williamson et al. 1993) using fish experts concerned with Trinity River chinook restoration. The model builds on the foundation laid by similar models (see Cheslak and Jacobson 1990). The model’s premise that...

The systematic relationship between Myotis lucifugus carissima and Myotis occultus has been the subject of multiple studies. Although several studies, including a recent allozyme study, concluded that M. occultus is a subspecies of M. lucifugus, this view has not been universally accepted. We reexamined the relationships of these 2 taxa by sequencing the mitochondrial cytochrome-b (cyt-b...

A new species of the genus Echinosaura is described from the Pacific drainages of northern Ecuador and adjacent Colombia. Evaluation of variation among congeners justifies their recognition as distinct species instead of subspecies as previously proposed. The new lizard occurs in close proximity to Echinosaura horrida and Teuchocercus keyi.

No abstract available.

"Today was another record-breaking day," the evening radio or television declares. High temperatures, low temperatures, floods, drought - take your choice. But how can we put these pronouncements in perspective? What do they really mean? We present two types of information in this article: 1) an analysis of daily air temperature and precipitation for Fort Collins and 2) an analysis of...

The subspecific status of the Louisiana black bear (Ursus americanus luteolus) and Florida black bear (U. a. floridanus) were assessed using morphologic features to determine their distinctness in relation to one another and to the black bear (U. a. americanus). Forty-four dimensions were recorded from skulls of 125 male and 127 female adult (4.5 years or older) bears. Results showed...

America is under siege by invasive species of plants and animals, and by diseases. The current environmental, economic, and health-related costs of invasive species could exceed $138 billion per year-more than all other natural disasters combined. Notorious examples include West Nile virus, Dutch elm disease, chestnut blight, and purple loose- strife in the Northeast; kudzu, Brazilian...

This Circular provides a basic understanding of the characteristics, location, distribution, and quality of infrastructure resources (natural aggregate, energy, and water) in the Colorado Front Range urban corridor between Denver and Ft. Collins. With this understanding, the reader explores the many factors that affect the current and future availability of those resources, including the

We used regression quantiles to model potentially limiting relationships between the standing crop of cutthroat trout Oncorhynchus clarki and measures of stream channel morphology. Regression quantile models indicated that variation in fish density was inversely related to the width:depth ratio of streams but not to stream width or depth alone. The spatial and temporal stability of model...

The Rocky Mountain West is largely arid and steep, with ecological scars from past human use visible for hundreds of years. Just how damaging were the past 150 years of activity? How do current rates of disturbance compare with past mining, grazing, and water diversion activities? In the face of constant change, what constitutes a "natural" ecosystem? And can a high quality of life be...