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Federal Way, MT, United States

Fortin J.K.,Washington State University | Ware J.V.,Washington State University | Jansen H.T.,Washington State University | Schwartz C.C.,2327 University Way | Robbins C.T.,Washington State University
Journal of Mammalogy | Year: 2013

Grizzly bears (Ursus arctos) have been reported as either nocturnal or diurnal in various studies, but have not been known to switch between the 2 times unless disturbed by humans. Black bears (Ursus americanus) are almost solely diurnal in studies unless human influences occur. Because human disturbance is often difficult to control, the relative temporal niche of both species remains ill-defined. Thus, the present study examined bears in Yellowstone National Park (Wyoming) where hunting does not occur, human activities are relatively benign, and bear species are sympatric to determine if niche occupancy was a stable feature of the species. Onset of activity was anticipatory of both sunrise or morning civil twilight (illumination sufficient for human vision) for individuals of either species. The peak hour of activity in black bears was consistently midday, but fluctuated in grizzly bears from midday during early spring, late summer, and fall to evening during late spring and early summer. Black bears did not temporally avoid the times when the more dominant grizzly bears were active. Mean activity levels were higher for male black bears than for both male and female grizzly bears. Together, results suggest that the foraging needs of black bears necessitate ingestion of less-digestible, lower-quality foods requiring longer foraging time during daytime hours, whereas grizzly bears adapt their diet to seasonally available food sources, necessitating greater temporal flexibility. © 2013 American Society of Mammalogists. © 2013 American Society of Mammalogists. Source

Ryan S.J.,New York University | Cross P.C.,2327 University Way | Winnie J.,Montana State University | Hay C.,Southern African Wildlife College | And 3 more authors.
Journal of Wildlife Management | Year: 2012

Many studies of mammalian herbivores have employed remotely sensed vegetation greenness, in the form of Normalized Difference Vegetation Index (NDVI) as a proxy for forage quality. The assumption that reflected greenness represents forage quality often goes untested, and limited data exist on the relationships between remotely sensed and traditional forage nutrient indicators. We provide the first study connecting NDVI and forage nutrient indicators within a free-ranging African herbivore ecosystem. We examined the relationships between fecal nutrient levels (nitrogen and phosphorus), forage nutrient levels, body condition, and NDVI for African buffalo (Syncerus caffer) in a South African savanna ecosystem over a 2-year period (2001 and 2002). We used an information-theoretic approach to rank models of fecal nitrogen (N f) and phosphorus (P f) as functions of geology, season, and NDVI in each year separately. For each year, the highest ranked models for N f accounted for 61% and 65% of the observed variance, and these models included geology, season, and NDVI. The top-ranked model for P f in 2001, although capturing 54% of the variability, did not include NDVI. In 2002, we could not identify a top ranking model for phosphorus (i.e.; all models were within 2 AIC c of each other). Body condition was most highly correlated (R adj 2 = 0.75; P≤0.001) with NDVI at a 1 month time lag and with f at a 3 months time lag (R adj 2 = 0.65; P≤0.001), but was not significantly correlated with P f. Our findings suggest that NDVI can be used to index nitrogen content of forage and is correlated with improved body condition in African buffalo. Thus, NDVI provides a useful means to assess forage quality where crude protein is a limiting resource. We found that NDVI accounted for more than a seasonal effect, and in a system where standing biomass may be high but of low quality, understanding available nutrients is useful for management. © 2012 The Wildlife Society. Copyright © The Wildlife Society, 2012. Source

Hopkins III J.B.,Montana State University | Herrero S.,University of Calgary | Shideler R.T.,Alaska Department of Fish and Game | Gunther K.A.,Bear Management Office | And 2 more authors.
Ursus | Year: 2010

We believe that communication within and among agency personnel in the United States and Canada about the successes and failures of their humanbear (Ursidae) management programs will increase the effectiveness of these programs and of bear research. To communicate more effectively, we suggest agencies clearly define terms and concepts used in humanbear management and use them in a consistent manner. We constructed a humanbear management lexicon of terms and concepts using a modified Delphi method to provide a resource that facilitates more effective communication among humanbear management agencies. Specifically, we defined 40 terms and concepts in humanbear management and suggest definitions based on discussions with 13 other professionals from the United States and Canada. Although new terms and concepts will emerge in the future and definitions will evolve as we learn more about bear behavior and ecology, our purpose is to suggest working definitions for terms and concepts to help guide humanbear management and research activities in North America. Applications or revisions of these definitions may be useful outside of North America. © 2010 International Association for Bear Research and Management. Source

Layhee M.,U.S. Geological Survey | Sepulveda A.,U.S. Geological Survey | Ray A.,U.S. Geological Survey | Ray A.,2327 University Way | And 2 more authors.
Science of the Total Environment | Year: 2015

Managers often nest sections of water bodies together into assessment units (AUs) to monitor and assess water quality criteria. Ideally, AUs represent an extent of waters with similar ecological, watershed, habitat and land-use conditions and no overlapping characteristics with other waters. In the United States, AUs are typically based on political or hydrologic boundaries rather than on ecologically relevant features, so it can be difficult to detect changes in impairment status. Our goals were to evaluate if current AU designation criteria of an impaired water body in southeastern Idaho, USA that, like many U.S. waters, has three-quarters of its mainstem length divided into two AUs. We focused our evaluation in southeastern Idaho's Portneuf River, an impaired river and three-quarters of the river is divided into two AUs. We described biological and environmental conditions at multiple reaches within each AU. We used these data to (1) test if variability at the reach-scale is greater within or among AUs and, (2) to evaluate alternate AU boundaries based on multivariate analyses of reach-scale data. We found that some biological conditions had greater variability within an AU than between AUs. Multivariate analyses identified alternative, 2- and 3-group, AUs that reduced this variability. Our results suggest that the current AU designations in the mainstem Portneuf River contain ecologically distinct sections of river and that the existing AU boundaries should be reconsidered in light of the ecological conditions measured at the reach scale. Variation in biological integrity within designated AUs may complicate water quality and biological assessments, influence management decisions or affect where monitoring or mitigation resources are directed. © 2015. Source

Schwartz C.C.,2327 University Way | Cain S.L.,National Park Service | Podruzny S.,2327 University Way | Cherry S.,Montana State University | Frattaroli L.,National Park Service
Journal of Wildlife Management | Year: 2010

The distribution of grizzly (Ursus arctos) and American black bears (U. americanus) overlaps in western North America. Few studies have detailed activity patterns where the species are sympatric and no studies contrasted patterns where populations are both sympatric and allopatric. We contrasted activity patterns for sympatric black and grizzly bears and for black bears allopatric to grizzly bears, how human influences altered patterns, and rates of grizzlyblack bear predation. Activity patterns differed between black bear populations, with those sympatric to grizzly bears more day-active. Activity patterns of black bears allopatric with grizzly bears were similar to those of female grizzly bears; both were crepuscular and day-active. Male grizzly bears were crepuscular and night-active. Both species were more night-active and less day-active when ≤1 km from roads or developments. In our sympatric study area, 2 of 4 black bear mortalities were due to grizzly bear predation. Our results suggested patterns of activity that allowed for intra- and inter-species avoidance. National park management often results in convergence of locally high human densities in quality bear habitat. Our data provide additional understanding into how bears alter their activity patterns in response to other bears and humans and should help park managers minimize undesirable bearhuman encounters when considering needs for temporal and spatial management of humans and human developments in bear habitats. © 2010 The Wildlife Society. Source

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