scholarly journals Differential wolf-pack-size persistence and the role of risk when hunting dangerous prey

Behaviour ◽  
2016 ◽  
Vol 153 (12) ◽  
pp. 1473-1487 ◽  
Author(s):  
Shannon M. Barber-Meyer ◽  
L. David Mech ◽  
Wesley E. Newton ◽  
Bridget L. Borg

Risk to predators hunting dangerous prey is an emerging area of research and could account for possible persistent differences in gray wolf (Canis lupus) pack sizes. We documented significant differences in long-term wolf-pack-size averages and variation in the Superior National Forest (SNF), Denali National Park and Preserve, Yellowstone National Park, and Yukon, Canada (). The SNF differences could be related to the wolves’ risk when hunting primary prey, for those packs () hunting moose (Alces americanus) were significantly larger than those () hunting white-tailed deer (Odocoileus virginianus) (, ). Our data support the hypothesis that differential pack-size persistence may be perpetuated by differences in primary prey riskiness to wolves, and we highlight two important extensions of this idea: (1) the potential for wolves to provision and defend injured packmates from other wolves and (2) the importance of less-risky, buffer prey to pack-size persistence and year-to-year variation.

2003 ◽  
Vol 81 (6) ◽  
pp. 985-993 ◽  
Author(s):  
T Adam Switalski

Coyotes (Canis latrans) in Yellowstone National Park (YNP) have lived in the absence of wolves (Canis lupus) for over 60 years. I examined whether wolf reintroduction in 1995 and 1996 in YNP influenced coyote vigilance and foraging ecology. From December 1997 to July 2000, my co-workers and I collected 1708 h of coyote activity budgets. Once wolves became established in the Park, they once again provided a continuous source of carrion in the Lamar Valley and we found that coyotes began feeding on carcasses throughout the year. Although we documented that wolves killed coyotes, it also became clear that surviving coyotes quickly adjusted their behaviors when wolves were present. When coyotes were near wolves or in areas of high wolf use, they fed on carcasses much more; however, they increased the amount of time spent in vigilance activities and decreased rest. There appears to be a trade-off in which wolf kills provide a quick source of food that is energetically advantageous to coyotes; however, attendant costs included increased vigilance, decreased rest, and a higher risk of being killed. Changes in the behavior of coyotes in response to the reintroduction of this large carnivore may ultimately have wide-ranging cascading effects throughout the ecosystem.


2006 ◽  
Vol 136 (7) ◽  
pp. 1923S-1926S ◽  
Author(s):  
Daniel R. Stahler ◽  
Douglas W. Smith ◽  
Debra S. Guernsey

ARCTIC ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 51-66
Author(s):  
Bridget L. Borg ◽  
Stephen M. Arthur ◽  
Jeffrey A. Falke ◽  
Laura R. Prugh

Wildlife viewing within protected areas is an increasingly popular recreational activity. Management agencies are often tasked with providing these opportunities, yet quantitative analyses of factors influencing wildlife sightings are lacking. We analyzed locations of GPS-collared wolves and wolf sightings from 2945 trips in Denali National Park and Preserve, Alaska, USA, to provide a mechanistic understanding of how viewing opportunities are influenced by attributes of wolves and physical, biological, and harvest characteristics. We found that the presence of masking vegetation, den site proximity to the road, pack size, and presence of a wolf harvest closure adjacent to the park affected wolf sightings, and the influence of den proximity on sightings depended on harvest management. Wolf sightings increased with den site proximity to the road in years with a harvest closure adjacent to the park but not in the absence of the closure. The effect of the harvest closure on sightings was similar in magnitude to an increase in pack size by two wolves or a more than a two-fold decrease in masking vegetation. These findings were consistent across a 10-fold change in spatial resolution. Quantitative analysis of the factors influencing wildlife sightings provides valuable insight for agencies tasked with managing viewing opportunities. 


Author(s):  
Elaine M. Brice ◽  
Daniel MacNulty

Predation is commonly cited as a top-down effect that structures food webs, with the reintroduction of wolves to Yellowstone as perhaps the most famous example. However, despite two decades of research, there is still debate as to whether wolves (Canis lupus) have indirectly benefited aspen (Populus tremuloides) by reducing herbivory from elk (Cervus canadensis). As such, the purpose of this study was to investigate the role of top-down and bottom-up forces on aspen recruitment in northern Yellowstone. The UW-NPS grant funds were used to conduct a genetic analysis of 59 aspen stands in an effort to determine whether genetic variation is one control of aspen recruitment. During summer 2018, 122 leaves were collected and sent to the Mock Lab at Utah State University. The samples will undergo DNA extractions at 12 microsatellite loci, which will provide us with genotype and ploidy level, with the genotype at a resolution to distinguish clones. Concurrently, we measured aspen heights and browse rates, as well as soil moisture. The median aspen height in 2018 was 110 cm (SD=135), and the browse rate was 0.45. Stands varied in volumetric water content (VWC), ranging from a mean VWC of 2.7% to 45.2%.   Featured photo by Yellowstone National Park on Flickr. https://flic.kr/p/efXLV2


2003 ◽  
Vol 40 (11) ◽  
pp. 1611-1642 ◽  
Author(s):  
Donald R Lowe ◽  
Deena Braunstein

Slightly alkaline hot springs and geysers in Yellowstone National Park exhibit distinctive assemblages of high-temperature (>73 °C) siliceous sinter reflecting local hydrodynamic conditions. The main depositional zones include subaqueous pool and channel bottoms and intermittently wetted subaerial splash, surge, and overflow areas. Subaqueous deposits include particulate siliceous sediment and dendritic and microbial silica framework. Silica framework forms thin, porous, microbe-rich films coating subaqueous surfaces. Spicules with intervening narrow crevices dominate in splash zones. Surge and overflow deposits include pool and channel rims, columns, and knobs. In thin section, subaerial sinter is composed of (i) dark brown, nearly opaque laminated sinter deposited on surfaces that evaporate to dryness; (ii) clear translucent silica deposited subaqueously through precipitation driven by supersaturation; (iii) heterogeneous silica representing silica-encrusted microbial filaments and detritus; and (iv) sinter debris. Brownish laminations form the framework of most sinter deposited in surge and overflow zones. Pits and cavities are common architectural features of subaerial sinter and show concave-upward pseudo-cross-laminations and micro-unconformities developed through migration. Marked birefringence of silica deposited on surfaces that evaporate to dryness is probably a strain effect. Repeated wetting and evaporation, often to dryness, and capillary effects control the deposition, morphology, and microstructure of most high-temperature sinter outside of the fully subaqueous zone. Microbial filaments are abundant on and within high-temperature sinter but do not provide the main controls on morphology or structuring except in biofilms developed on subaqueous surfaces. Millimetre-scale lamination cyclicity in much high-temperature sinter represents annual layering and regular seasonal fluctuations in silica sedimentation.


Author(s):  
JULIO R GUTIÉRREZ ◽  
PETER L MESERVE ◽  
DOUGLAS A KELT ◽  
ANDREW ENGILIS JR ◽  
M. ANDREA PREVITALI ◽  
...  

2016 ◽  
Vol 46 (4) ◽  
pp. 548-556 ◽  
Author(s):  
Robert L. Beschta ◽  
Luke E. Painter ◽  
Taal Levi ◽  
William J. Ripple

We report long-term patterns of quaking aspen (Populus tremuloides Michx.) recruitment for five ungulate exclosures in the northern ungulate winter range of Yellowstone National Park. Aspen recruitment was low (<3 aspen·ha−1·year−1) in the mid-1900s prior to exclosure construction due to herbivory by Rocky Mountain elk (Cervus elaphus Linnaeus, 1758) but increased more than 60-fold within 25 years after exclosure construction despite a drying climatic trend since 1940. Results support the hypothesis that long-term aspen decline in Yellowstone’s northern range during the latter half of the 20th century was caused by high levels of ungulate herbivory and not a drying climate. Gray wolves (Canis lupus Linnaeus, 1758) were reintroduced during 1995–1996. For the period 1995–2012, we summarized annual predator–prey ratios, ungulate biomass, and drought severity. The average density of young aspen increased from 4350 aspen·ha−1 in 1997–1998 to 8960 aspen·ha−1 in 2012; during the same time period, those >1 m in height increased over 30-fold (from 105 to 3194 aspen·ha−1). Increased heights of young aspen occurred primarily from 2007 to 2012, a period with relatively high predator–prey ratios, declining elk numbers, and decreasing browsing rates. Consistent with a re-established trophic cascade, aspen stands in Yellowstone’s northern range have increasingly begun to recover.


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