David J. Mattson

Tree rubbing by Yellowstone grizzly bears Ursus arctos

Tree rubbing or marking by bears has been observed throughout the northern hemisphere. Even so, this behaviour has rarely been studied. We documented 93 sites where grizzly bears Ursus arctos horribilis rubbed on 116 trees during 1986–1992, in the Yellowstone Ecosystem. We used logistic regression and information-based estimation and selection criteria to specify models that explained selection of sites and individual trees for rubbing by bears in our study area. The probability of rubbing peaked during May and June, the period of mating and moult, and declined thereafter. At the landscape level, grizzly bears selected for gentle south-facing slopes, forest/non-forest ecotones with sparse deadfall, and forest stands dominated by lodgepole pine Pinus contorta or Douglas-fir Pseudotsuga menziesii. Among the trees at sites where bears rubbed, we found strong selection for large diameters but no indication of selection for species. Rubbed trees were highly associated with travel routes likely used by bears, including game trails, recreation trails and forest edges. Rubbing was often oriented towards these likely travel routes. Short trails of entrenched pad-shaped marks leading up to rubbed trees were recorded at 58% of the sites where rubbing occurred. Contrary to reports of black bears Ursus americanus clawing and biting trees, we found shredded or bitten bark at only 9% of sites with rubbed or otherwise marked trees. Circumstantial evidence suggests that bears used trees primarily for rubbing their back and shoulders. Our findings are consistent with previous arguments that rubbing serves as a means of chemical communication.

Natural landscape features, human-related attractants, and conflict hotspots: a spatial analysis of human–grizzly bear conflicts

Abstract There is a long history of conflict in the western United States between humans and grizzly bears (Ursus arctos) involving agricultural attractants. However, little is known about the spatial dimensions of this conflict and the relative importance of different attractants. This study was undertaken to better understand the spatial and functional components of conflict between humans and grizzly bears on privately owned agricultural lands in Montana. Our investigations focused on spatial associations of rivers and creeks, livestock pastures, boneyards (livestock carcass dump sites), beehives, and grizzly bear habitat with reported human–grizzly bear conflicts during 1986–2001. We based our analysis on a survey of 61 of 64 livestock producers in our study in the Rocky Mountain East Front, Montana. With the assistance of livestock and honey producers, we mapped the locations of cattle and sheep pastures, boneyards, and beehives. We used density surface mapping to identify seasonal clusters of conflicts that we term conflict hotspots. Hotspots accounted for 75% of all conflicts and encompassed approximately 8% of the study area. We also differentiated chronic (4 or more years of conflicts) from non-chronic hotspots (fewer than 4 years of conflict). The 10 chronic hotpots accounted for 58% of all conflicts. Based on Monte Carlo simulations, we found that conflict locations were most strongly associated with rivers and creeks followed by sheep lambing areas and fall sheep pastures. Conflicts also were associated with cattle calving areas, spring cow–calf pastures, summer and fall cattle pastures, and boneyards. The Monte Carlo simulations indicated associations between conflict locations and unprotected beehives at specific analysis scales. Protected (fenced) beehives were less likely to experience conflicts than unprotected beehives. Conflicts occurred at a greater rate in riparian and wetland vegetation than would be expected. The majority of conflicts occurred in a small portion of the study area, where concentrations of attractants existed that overlapped with bear habitat. These hotspots should be the target of management and conservation efforts that focus on removing or protecting attractants using non-lethal techniques.

College and University Environmental Programs as a Policy Problem (Part 1): Integrating Knowledge, Education, and Action for a Better World?

The environmental sciences/studies movement, with more than 1000 programs at colleges and universities in the United States and Canada, is unified by a common interest—ameliorating environmental problems through empirical enquiry and analytic judgment. Unfortunately, environmental programs have struggled in their efforts to integrate knowledge across disciplines and educate students to become sound problem solvers and leaders. We examine the environmental program movement as a policy problem, looking at overall goals, mapping trends in relation to those goals, identifying the underlying factors contributing to trends, and projecting the future. We argue that despite its shared common interest, the environmental program movement is disparate and fragmented by goal ambiguity, positivistic disciplinary approaches, and poorly rationalized curricula, pedagogies, and educational philosophies. We discuss these challenges and the nature of the changes that are needed in order to overcome them. In a subsequent article (Part 2) we propose specific strategies for improvement.

College and University Environmental Programs as a Policy Problem (Part 2): Strategies for Improvement

Environmental studies and environmental sciences programs in American and Canadian colleges and universities seek to ameliorate environmental problems through empirical enquiry and analytic judgment. In a companion article (Part 1) we describe the environmental program movement (EPM) and discuss factors that have hindered its performance. Here, we complete our analysis by proposing strategies for improvement. We recommend that environmental programs re-organize around three principles. First, adopt as an overriding goal the concept of human dignity—defined as freedom and social justice in healthy, sustainable environments. This clear higher-order goal captures the human and environmental aspirations of the EPM and would provide a more coherent direction for the efforts of diverse participants. Second, employ an explicit, genuinely interdisciplinary analytical framework that facilitates the use of multiple methods to investigate and address environmental and social problems in context. Third, develop educational programs and applied experiences that provide students with the technical knowledge, powers of observation, critical thinking skills and management acumen required for them to become effective professionals and leaders. Organizing around these three principles would build unity in the EPM while at the same time capitalizing on the strengths of the many disciplines and diverse local conditions involved.

Selection of microsites by grizzly bears to excavate biscuitroots

Roots of the biscuitroot ( Lomatium cous ) are a common food of grizzly bears ( Ursus arctos horribilis ) in drier parts of their southern range. I used random sampling and locations of radiomarked bears in the Yellowstone ecosystem to investigate the importance of mass and starch content of roots, digability of the site, and density of plants relative to selection of sites by grizzly bears to dig biscuitroots. Where biscuitroots were present, most differences between dug and undug sites were related to digability of the site and mass and starch content of roots. Grizzly bears more often dug in sites where average milligrams of starch per kilogram of pull per root (≈energy gain) was high. Density of biscuitroots was not related to selection of sites by grizzly bears. Mass of biscuitroot stems also provided relatively little information about mass of roots. Distribution of biscuitroots was associated with increased cover of rocks and exposure to wind, and with decreased slopes and cover of forbs. Digs by grizzly bears were associated with the presence of biscuitroots, proximity to edge of forest, and increased cover of rocks. Results were consistent with previously observed tendencies of grizzly bears to concentrate their feeding within 50–100 m of cover.

Use of lodgepole pine cover types by yellowstone grizzly bears

Lodgepole pine (Pinus contorta) forests are a large and dynamic part of grizzly bear (Ursus arctos) habitat in the Yellowstone ecosystem. Research in other areas suggests that grizzly bears select for young open forest stands, especially for grazing and feeding on berries. Management guidelines accordingly recommend timber harvest as a technique for improving habitat in areas potentially dominated by lodgepole pine. In this paper I examine grizzly bear use of lodgepole pine forests in the Yellowstone area, and test several hypotheses with relevance to a new generation of management guidelines. Differences in grizzly bear selection of lodgepole pine cover types (defined on the basis of stand age and structure) were not pronounced. Selection furthermore varied among years, areas, and individuals. Positive selection for any lodgepole pine type was uncommon. Estimates of selection took 5-11 years or 4-12 adult females to stabilize, depending upon the cover type. The variances of selection estimates tended to stabilize after 3-5 sample years, and were more-or-less stable to slightly increasing with progressively increased sample area. There was no conclusive evidence that Yellowstones grizzlies favored young (<40 yr) stands in general or for their infrequent use of berries. On the other hand, these results corroborated previous observations that grizzlies favored open and/or young stands on wet and fertile sites for grazing. These results also supported the proposition that temporally and spatially robust inferences require extensive, long-duration studies, especially for wide-ranging vertebrates like grizzly bears.

A model-based appraisal of habitat conditions for grizzly bears in the Cabinet–Yaak region of Montana and Idaho

Abstract We used a broad-scale model based on observations of grizzly bears (Ursus arctos) or their sign, calibrated to reported putative death rate, to appraise current habitat conditions in the Cabinet–Yaak region of Montana. Habitat capability (i.e., potential grizzly bear densities) and regional human population sizes had the greatest effects in this model. We predicted the effects of (1) human population increases (+150% anticipated by 2023), (2) changes in lethality of humans (i.e., the probability that a human would kill a bear given an encounter), and (3) differences in the ratio of unknown to known bear deaths on the extent and location of potential source areas. We predicted densities of 1.0 and 2.1 grizzly bears/100 km2 with and without human impacts, respectively. Under our baseline scenario (3% sustainable mortality and 1:1 ratio of unknown to known bear deaths), we predicted that 2 source areas totaling 9,156 km2 and potentially supporting 123 bears occurred in our study area. With projected human population increases, potential source areas and bear populations declined by 33% and 45%, respectively. A spatially uniform increase of 1% in annual death rate (as a surrogate for increased human lethality) reduced potential source areas and bear numbers by 41% and 36%. Source areas and bear numbers declined by 39% and 34% if the ratio of unknown to known grizzly bear deaths was 2:1 versus 1:1. We obtained the best match with current population estimates (about 35 bears) assuming a 2:1 ratio of unknown to known deaths and a very low sustainable death rate of 2%. This implies either high levels of illegal human-caused mortality and low birth and recruitment rates or a population smaller than currently estimated. We conclude that human numbers and human lethality will likely govern the fate of grizzly bears in this region.

Exploitation of pocket gophers and their food caches by grizzly bears

Abstract I investigated the exploitation of pocket gophers (Thomomys talpoides) by grizzly bears (Ursus arctos horribilis) in the Yellowstone region of the United States with the use of data collected during a study of radiomarked bears in 1977–1992. My analysis focused on the importance of pocket gophers as a source of energy and nutrients, effects of weather and site features, and importance of pocket gophers to grizzly bears in the western contiguous United States prior to historical extirpations. Pocket gophers and their food caches were infrequent in grizzly bear feces, although foraging for pocket gophers accounted for about 20–25% of all grizzly bear feeding activity during April and May. Compared with roots individually excavated by bears, pocket gopher food caches were less digestible but more easily dug out. Exploitation of gopher food caches by grizzly bears was highly sensitive to site and weather conditions and peaked during and shortly after snowmelt. This peak coincided with maximum success by bears in finding pocket gopher food caches. Exploitation was most frequent and extensive on gently sloping nonforested sites with abundant spring beauty (Claytonia lanceolata) and yampah (Perdieridia gairdneri). Pocket gophers are rare in forests, and spring beauty and yampah roots are known to be important foods of both grizzly bears and burrowing rodents. Although grizzly bears commonly exploit pocket gophers only in the Yellowstone region, this behavior was probably widespread in mountainous areas of the western contiguous United States prior to extirpations of grizzly bears within the last 150 years.

Values in Natural Resource Management and Policy

Values are considered by many people to be central to human interactions, yet the meaning of “values” is rarely clear in most applications. We offer our thoughts on how values might be usefully construed in a policy context, with relevance to design and appraisal of social and decision-making processes. We differentiate values from preferences, attitudes, worldviews, and interests because of the extent to which this surrounding field of concepts has been contested by sociologists and psychologists, and to highlight the comparative utility of focusing on values. We find it useful to apply the term “values” to the fundamental and abiding non-linguistic ways that people orient to the world, arising from antecedent attraction. Shalom Schwartz and Harold Lasswell developed values schema which, when used together, constitute a powerful frame for generating insights about human behaviors and decision-making in specific contexts. Schwartz posited the values of universalism, benevolence, self-direction, stimulation, hedonism, achievement, power, security, conformity, and tradition. Lasswell posited the related values of rectitude, respect, affection, enlightenment, skill, power, wealth, and well-being. We illustrate the utility of a values frame through an appraisal of social and decision-making processes in the Glen Canyon Dam Adaptive Management Program.

Consumption of voles and vole food caches by Yellowstone grizzly bears: exploratory analyses

Abstract Previously published observations of bears consuming murid rodents have been limited to short anecdotes. Only 2 studies reported bears consuming rodent food caches. I investigated the consumption of voles (Microtus spp.) and vole food caches by grizzly bears (Ursus arctos) in the Yellowstone region, 1977–92, using data collected during a study of 140 radiomarked bears. Study bears excavated vole nests, burrows, or food caches at 45 different sites. Excavations of nests (n = 37) were more common than excavations of food caches (n = 15). The remains of voles were found in 62 bear feces. Occurrences of voles in bear feces and excavations by bears for vole nests or food caches were essentially uncorrelated over time, suggesting that total consumption of voles and pursuit of voles or vole food caches by excavation were affected by different factors. Excavations by bears were largest in size and peaked in number during the driest months of the study period and were most likely to occur on gently sloping sites with abundant grasses, especially of the genus Phleum, and sedges (Carex). Bear excavations were more common during drought, probably because voles increased their burrowing in response to drying of wet soils, decreased above-ground security, and decreased abundance of above-ground foods. Food caching by voles has been documented in Canada and at high latitudes in the U.S., but prior to this study, only once in the U.S. Rocky Mountains. Bears consumed vole food caches primarily during September and were most successful finding caches at sites where yampah (Perideridia gairdneri) was abundant. Study bears excavated vole nests most often during spring and fall. Although voles were not a major source of energy for Yellowstones grizzly bears, some individuals frequently foraged for voles during certain years.