Bruce W. Dale's research while affiliated with Alaska Department of Fish and Game and other places

Publications (31)

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There is a long and contentious history of brown bear (Ursus arctos) harvest management in Alaska, USA, the state that hosts the largest brown bear population in North America. In the mid‐1990s, the Alaska Board of Game set the population objective for brown bears in Game Management Unit 13 A, located in interior southcentral Alaska, to be reduced...
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Predation of moose (Alces alces) and caribou (Rangifer tarandas) calves by brown bears (Ursus arctos) has been extensively studied, because predation has population implications for both predator and prey species. Existing methods have provided estimates of population-level predation rates, but they have not been able to estimate kill rates by indi...
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North American caribou (Rangifer tarandus) herds commonly exhibit little nuclear genetic differentiation among adjacent herds, although available evidence supports strong demographic separation, even for herds with seasonal range overlap. During 1997—2003, we studied the Mentasta and Nelchina caribou herds in south-central Alaska using radiotelemet...
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The role of wildland fire in the winter habitat use of caribou (Rangifer tarandus) has long been debated. Fire has been viewed as detrimental to caribou because it destroys the slow-growing climax forage lichens that caribou utilize in winter. Other researchers argued that caribou were not reliant on lichens and that fire may be beneficial, even in...
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In the early 1990s the Nelchina Caribou (Rangifer tarandus) Herd (NCH) began a dramatic shift to its current winter range, migrating at least an additional 100 km beyond its historic range. We evaluated the impacts of fire and grazing history on lichen abundance and subsequent use and distribution by the NCH. Historic (prior to 1990) and current (2...
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We focused on describing low nutritional status in an increasing moose (Alces alces gigas) population with reduced predation in Game Management Unit (GMU) 20A near Fairbanks, Alaska, USA. A skeptical public disallowed liberal antlerless harvests of this moose population until we provided convincing data on low nutritional status. We ranked nutritio...
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Most wolf Canis lupus studies have been conducted in inland regions and comparatively little data are available for wolves inhabiting coastal areas. We monitored four members of a coastal wolf pack on the Alaska Peninsula during 2006-2008. Habitat selection ratios indicated a strong association with the coastline, and we documented pack members and...
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A program to control wolves (Canis lupus) in interior Alaska in 1993 and 1994 did not result in expected increases in calf survival in the Delta caribou (Rangifer tarandus) herd (DCH). Therefore, the Alaska Department of Fish and Game conducted a study to determine causes of calf mortality during 1995–1997 and monitored recruitment, mortality, and...
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Nutritional restriction during growth can have short- and long-term effects on fitness; however, animals inhabiting uncertain environments may exhibit adaptations to cope with variation in food availability. We examined changes in body mass in free-ranging female caribou (Rangifer tarandus) by measuring mass at birth and at 4, 11, and 16 months of...
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ABSTRACT  Our understanding of wolf (Canis lupus) population dynamics in North America comes largely from studies of protected areas, at-risk populations, and wolf control programs, although most North American wolves experience moderate levels of regulated harvest. During 1986–1992, we investigated the population dynamics and harvests of wolves in...
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Caribou are an integral component of high-latitude ecosystems and represent a major subsistence food source for many northern people. The availability and quality of winter habitat is critical to sustain these caribou populations. Caribou commonly use older spruce woodlands with adequate terrestrial lichen, a preferred winter forage, in the underst...
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We document the accuracy, efficacy, and safety of ultrasound in estimating reproductive characteristics of gray wolves (Canis lupus) in central Alaska. We examined 68 adult female wolves with ultrasound during late March and early April to diagnose pregnancy and litter size. Seventy-two percent were pregnant. We compared ultrasound diagnoses with p...
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Although historic literature is replete with anecdotes about atypical and far-reaching movements of caribou (Rangifer tarandus granti) herds in Alaska, very few such events have been described since the late 1970s proliferation of radiotelemetry studies in the region. In September 1992, several herds in Alaska made unusual movements away from their...
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We studied natality in the Northern Alaska Peninsula (NAP) and Southern Alaska Peninsula (SAP) caribou (Rangifer tarandus granti) herds during 1996-1999, and mortality and weights of calves during 1998 and 1999- Natality was lower in the NAP than the SAP primarily because most 3-year-old females did not produce calves in the NAP Patterns of calf mo...
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The five naturally occurring and one transplanted caribou (Rangifer tarandus granti) herd in southwestern Alaska composed about 20% of Alaska's caribou population in 2001. All five of the naturally occurring herds fluctuated considerably in size between the late 1800s and 2001 and for some herds the data provide an indication of long-term periodic...
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We studied body mass of female calves and natality rate of adult females in two adjacent Interior Alaskan cari-bou (Rangifer tarandus granti) herds during 1991-2001. Mass of newborn calves was similar in both herds, but Delta calves gained significantly more mass over summer than Nelchina calves. In contrast, Nelchina calves consistently maintained...
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Wolves (Canis lupus) were captured in three areas of Interior Alaska (USA). Four hundred twenty-five sera were tested for evidence of exposure to canine coronavirus by means of an indirect fluorescent antibody procedure. Serum antibody prevalence averaged 70% (167/240) during the spring collection period and 25% (46/185) during the autumn collectio...
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We studied life-history characteristics of Alaskan moose (Alces alces gigas) including the effects of maternal condition of adult females (>33 months old) on survival and physical condition of young during their first year-of-life. We also examined the relation between maternal condition and reproductive parameters of individual adult moose, and te...
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Normal serum biochemistry values are frequently obtained from studies of captive sedentary (zoo) or free-ranging (wild) animals. It is frequently assumed that values obtained from these two populations are directly referable to each other. We tested this assumption using 20 captive gray wolves (Canis lupus) in Minnesota, USA, and 11 free-ranging gr...
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We examined the reproductive performance of female caribou (Rangifer tarandus granti) in relation to age, physical condition, and reproductive experience for 9 consecutive years (1987-95) at Denali National Park, Alaska, during a period of wide variation in winter snowfall. Caribou in Denali differed from other cervid populations where reproductive...
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Cardiac chamber enlargement and hypertrophy are normal physiologic responses to repetitive endurance exercise activity in human beings and domestic dogs. Whether similar changes occur in wild animals as a consequence of increased activity is unknown. We found that free-ranging gray wolves (Canis lupus, n = 11), the archetypical endurance athlete, h...
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Timing of parturition of caribou (Rangifer tarandus) varies within populations, but the relative influences of nutritional condition of females during the autumn breeding season and during gestation on that variation is not known. We determined timing of parturition of caribou in Denali National Park, Alaska, during 1984-1995, which had wide variat...
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Calf mortality is a major component of caribou (Rangifer tarandus) population dynamics, but little is known about the timing or causes of calf losses, or of characteristics that predispose calves to mortality. During 1984-87, we radiocollared 226 calves (≤3 days old) in the Denali Caribou Herd (DCH), an unhunted population utilized by a natural com...
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1. We investigated the functional response of wolves (Canis lupus) to varying abundance of ungulate prey to test the hypothesis that switching from alternate prey to preferred prey results in regulation of a caribou (Rangifer tarandus) population at low densities. 2. We determined prey selection, kill rates, and prey abundance for four wolf packs d...
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Interior Alaska contains 140 million burnable acres and includes the largest National Parks and National Wildlife Refuges in the country. On average, wildland fires burn 1,000,000 acres in Interior Alaska each year and threaten the lives, property, and timber resources of Alaska's sparse but growing population. Wildland fires threaten human values,...

Citations

... Density estimates in a relatively remote portion of 13E indicated no change during a period of liberalized hunting regulations between 1985 and 1995 but detected a change in population composition favoring females [37,38]. Replicate density estimates in more accessible 13A during 1998 and 2011 reported a decline in density of 20-45% (4% per year) and, based on harvest data, a shift in population composition toward adult females [39]. In contrast to brown bears, most hunting regulations for black bear in GMU 13 were liberal prior to 1980 but also exhibited a trend toward becoming increasingly more liberal. ...
... It is notable that while several recent studies provide guidance to improve the design and analysis of functional response experiments (Zhang et al., 2018;Moffat et al., 2020;Uszko et al., 2020;Coblentz and DeLong, 2021), novel approaches and models are still needed to better characterize these relationships in natural systems and to capture variation in them occurring across various temporal, spatial, and ecological scales (Novak et al., 2017;Barbier et al., 2021). Technological advances such as camera-traps, biotelemetry and biologgers, and genetic and genomic methods are greatly improving our ability to estimate densities of various predators and prey (Bravington et al., 2016;Ruzzante et al., 2019;Green et al., 2020;Ruprecht et al., 2021), diets (Galan et al., 2018), and kill rates (Merrill et al., 2010;Hubel et al., 2016;Brockman et al., 2017;Wilmers et al., 2017;Studd et al., 2021), while collecting ancillary data from natural systems (Wilmers et al., 2015;Tosa et al., 2021). Such tools and approaches will be essential to furthering our understanding of functional responses and their role in community and ecosystem dynamics. ...
... Wolves in Alaska prey primarily on large ungulates (Dale et al., 1995;Mech and Peterson, 2003), whereas coyotes prey mostly on snowshoe hares and other smaller prey, including neonatal ungulates (Prugh, 2004). Longterm (mean ± SE) densities of Dall's sheep (Ovis dalli) were 810 ± 80 sheep/1000 km 2 (n = 12 surveys, 1949 -2002) or ~ 605 -750 sheep in the study area. ...
... We suspect nonpredation perinatal losses regularly occur and the magnitude we noted (5%) was not unusual. Adams et al. (1995a) studied caribou calf mortality by locating parturient radiocollared females daily and collaring their calves; they noted 11 of 147 calves (7%) were lost to stillbirths (n = 3) and unspecified perinatal causes within 24 hours of birth (n = 8), although some of the unspecified deaths may have resulted from predation (L. G. Adams, unpublished data). ...
... The species were all ungulates and the data were chosen because they were long time series (15-97 yr) that showed evidence of eruptive dynamics, allowing us to examine the characteristics of population eruptions among species with a wider range of life histories than represented in the Australian data. We obtained abundance data for the five translocated populations analysed in Forsyth and Caley (2006) and abundance data for translocations of wood bison in northern Canada (Larter et al. 2000) and reindeer on the Nushagak Peninsula in Alaska (Valkenburg et al. 2003). Our final dataset comprised a total of 176 time series of 24 mammal species (Table 1 and Metadata S1). ...
... En este sentido, se ha detectado una importante variabilidad en la dieta del lobo en distintos puntos de nuestro país (Fernández, 2004). Las razones que explican los factores que determinan las diferencias en la dieta entre unas áreas loberas y otras, e incluso entre grupos dentro de territorios cercanos, comenzaron a estudiarse en la década de 1990 en Norte América (Dale et al., 1995;Mech et al., 1996), y más recientemente en el continente europeo (Muller, 2006). ...
... The population dynamics of large ungulates and the densitydependent processes that promote resilience of their populations to predation (or harvest) have been well-documented ( [4,5] for reviews). Gray wolves (Canis lupis), brown (grizzly) (hereafter brown bears) (Ursus arctos), and black bears (U. americanus) can be important predators on young (<1 year old) moose (Alces alces) [6][7][8][9][10][11][12]. Survivorship of young often is a critical density-dependent mechanism regulating ungulate populations [13][14][15][16]. ...
... Alternatively, calves may sometimes avoid predation when synchronization of birth dilutes predation risk by swamping predators (Estes 1976, Rutberg 1987, Ims 1990, whereas when born outside the peak parturition period, they may either avoid predation (Testa 2002, Barber-Meyer et al. 2008 or be targets for high predation. For example, bear (Ursus spp.) predation on neonatal ungulates has been reported to occur before that of other predators (Gasaway et al. 1992, Adams et al. 1995, Griffin et al. 2011. Therefore, if the timing of parturition relative to predator distribution or overall exposure differs among migratory tactics, elk following different migratory tactics may be subject to differential predation (Linnell et al. 1995, Griffin et al. 2011. ...
... We sampled birth mass each year on a single day near the historic median date of calving (22-25 May) using previously described methods (Adams et al. 1995;Sellers et al. 2003). In previous studies most captured calves were ,2 days of age (Adams 2005). ...
... Similar examples exist for other Alaska caribou herds, e.g., an extraordinarily heavy August-September snowfall near the Arctic coast and in Anaktuvuk Pass in 1960 and 1961 triggered migration of Western Arctic Herd (WAH) caribou south of the BR [34]. In interior Alaska, the Denali Herd caribou made an unusual movement 200 km north of their regular winter range following a record September snowfall in 1992 [132]. In Canada, Le Corre et al. [133] found that caribou arrived earlier on winter range in years with early fall snow. ...