Publications

For an ecological monitoring program to be successful over the long-term, the perceived benefits of the information must justify the cost. Financial limitations will always restrict the scope of a monitoring program, hence the program’s focus must be carefully prioritized. Clearly identifying the costs and benefits of a program will assist in this prioritization process, but this is...

The controversy (Berger 1990, 1999; Wehausen 1999) over rapid extinction in bighorn sheep (Ovis canadensis) has focused on population size alone as a correlate to persistence time. We report on the persistence and population performance of 24 translocated populations of bighorn sheep. Persistence in these sheep was strongly correlated with larger patch sizes, greater distance to domestic...

An important component of ecological assessments is the ability to predict and display changes in ecosystem structure and function over a variety of spatial and temporal scales. These changes can occur over short (less than 1 year) or long time frames (over 100 years). Models may emphasize structural responses (changes in species composition, growth forms, canopy height, amount of old...

Human recreation has been implicated in the decline of several populations of desert bighorn sheep (Ovis canadensis nelsoni). Managers are concerned about the impact of increased recreation on desert bighorn sheep in Canyonlands National Park (NP), Utah, USA, where visitation increased 325% from 1979 to 1994. We compared behavioral responses of sheep to recreational activity between a...

The decline in abundance of the newly recognized Gunnison sage grouse (Centrocercus minimus) in southwestern Colorado is thought to be linked to loss and fragmentation of its habitat, sagebrush (Artemisia) vegetation. We documented changes in sagebrush-dominated areas between the 1950s and 1990s by comparing low level aerial photographs taken in these time periods. We documented a loss...

In western North America, the alien Elaeagnus angustifolia L. invades riparian habitats usually dominated by pioneer woody species such as Populus deltoides Marshall ssp. monilifera (Aiton) Eckenwalder. We conducted manipulative field experiments to compare the importance of physical disturbance and granivory for seedling establishment of these two species. We planted seeds of both...

Alternative water management scenarios for a portion of the mainstem Klamath River from Keno, Oregon, to Seiad Valley, California, were evaluated using computer models of water quantity (MODSIM) and quality (HEC-5Q). These models were used to explore the potential for changing system operations to improve summer/fall water quality conditions to benefit declining anadromous fish...

To determine if the Siberian polecat (Mustela eversmannii) represents a suitable model for the study of plague pathogenesis and prevention in the black-footed ferret (Mustela nigripes), polecats were exposed to 103, 107, or 1010 Yersinia pestis organisms by subcutaneous injection; an additional group was exposed to Y. pestis via ingestion of a plague-killed mouse. Plague killed 88% of...

In the late summer of 2000, we canvassed a random sample of residents in the 11-sate short grass prairie region of the United States. We asked about people's attitude toward and knowledge of black-tailed prairie dogs and their management. The survey received 1,933 useable responses with a response rate of 56.4% (margin of error ±2.2%). We developed a questionnaire (OMB Control Number...

Historic patterns of fire occurrence and vegetation change in the Jemez Mountains of northern New Mexico have been described in detail by using multiple lines of evidence. Data sources include old aerial and ground-based photographs, historic records, charcoal deposits from bogs, fire-scarred trees (Figure 1), tree-ring reconstructions of precipitation, and field sampling of vegetation...

This document is a combined self-study textbook and reference manual. The material is presented in the general order of a PHABSIM study placed within the context of an IFIM application. The document may also be used as reading material for a lecture-based course. This manual provides documentation of the various PHABSIM programs so every option of each program is treated. This text is...

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