Publications

We report the first abundance and density estimates for American black bears (Ursus americanus) in Glacier National Park (NP),Montana, USA.We used data from 2 independent and concurrent noninvasive genetic sampling methods—hair traps and bear rubs—collected during 2004 to generate individual black bear encounter histories for use in closed population mark–recapture models. We improved...

Global climate change threatens to affect negatively the structure, function, and diversity of aquatic ecosystems worldwide. In alpine systems, the thermal tolerances of stream invertebrates can be assessed to understand better the potential effects of rising ambient temperatures and continued loss of glaciers and snowpack on alpine stream ecosystems. We measured the critical thermal...

Mobile elements are powerful agents of genomic evolution and can be exceptionally informative markers for investigating species and population-level evolutionary history. While several studies have utilized retrotransposon-based insertional polymorphisms to resolve phylogenies, few population studies exist outside of humans. Endogenous retroviruses are LTR-retrotransposons derived from...

The Yellowstone grizzly bear (Ursus arctos) was listed as a threatened species in 1975 (Federal Register 40 FR:31734-31736). Since listing, recovery efforts have focused on increasing population size, improving habitat security, managing bear mortalities, and reducing bear-human conflicts. The Interagency Grizzly Bear Committee (IGBC; partnership of federal and state agencies responsible...

Mark-resight designs for estimation of population abundance are common and attractive to researchers. However, inference from such designs is very limited when faced with sparse data, either from a low number of marked animals, a low probability of detection, or both. In the Greater Yellowstone Ecosystem, yearly mark-resight data are collected for female grizzly bears with cubs-of-the...

Despite the high profile of amphibian declines and the increasing threat of drought and fragmentation to aquatic ecosystems, few studies have examined long-term rates of change for a single species across a large geographic area. We analyzed growth in annual egg-mass counts of the Columbia spotted frog (Rana luteiventris) across the northwestern United States, an area encompassing 3...

The potential for invasion of Asian carp into the Great Lakes has ecological and socio-economic implications. If they become established, Asian carp are predicted to alter lake ecosystems and impact commercial and recreational fisheries. The Chicago Sanitary and Shipping Canal is an important biological conduit between the Mississippi River Basin, where invasive Asian carp are abundant...

A framework to monitor mountain summit vegetation (The Global Observation Research Initiative in Alpine Environments, GLORIA) was initiated in 1997. GLORIA results should be taken within a regional context of the spatial variability of alpine tundra. Changes observed at GLORIA sites in Glacier National Park, Montana, USA are quantified within the context of the range of variability...

Negative effects of global warming are predicted to be most severe for species that occupy a narrow range of temperatures, have limited dispersal abilities or have long generation times. These are characteristics typical of many species that occupy small, cold streams.Habitat use, vulnerabilities and mechanisms for coping with local conditions can differ among populations and...

Plains bison (Bison b. bison) centered on Yellowstone National Park are chronically infected with brucellosis (Brucella abortus) and culled along the park boundaries to reduce the probability of disease transmission to domestic livestock. We evaluated the relationship between pregnancy rates and age, dressed carcass weight, and serological status for brucellosis among bison culled from...

We combine large observed data sets and dynamically downscaled climate data to explore historic and future (2050–2069) stream temperature changes over the topographically diverse Greater Yellowstone Ecosystem (elevation range = 824–4017 m). We link future stream temperatures with fish growth models to investigate how changing thermal regimes could influence the future distribution and...

Commonly in environmental and ecological studies, species distribution data are recorded as presence or absence throughout a spatial domain of interest. Field based studies typically collect observations by sampling a subset of the spatial domain. We consider the effects of six different adaptive and two non-adaptive sampling designs and choice of three binary models on both predictions...