Geology topics

Shannon M. Barber-Meyer

Publications and source records attributed to Shannon M. Barber-Meyer.

10 recordsLinked to original sources

USGS2024

Intrinsic and environmental drivers of pairwise cohesion in wild Canis social groups

Animals within social groups respond to costs and benefits of sociality by adjusting the proportion of time they spend in close proximity to other individuals in the group (cohesion). Variation in cohesion between individuals, in turn, shapes important group-level processes such as subgroup formation and fission–fusion dynamics. Although critical to animal sociality, a comprehensive understanding of the factors influencing cohesion remains a gap in our knowledge of cooperative behavior in animals. We tracked 574 individuals from six species within the genus Canis in 15 countries on four continents with GPS telemetry to estimate the time that pairs of individuals within social groups spent in close proximity and test hypotheses regarding drivers of cohesion. Pairs of social canids ( Canis spp.) varied widely in the proportion of time they spent together (5%–100%) during seasonal monitoring periods relative to both intrinsic characteristics and environmental conditions. The majority of our data came from three species of wolves (gray wolves, eastern wolves, and red wolves) and coyotes. For these species, cohesion within social groups was greatest between breeding pairs and varied seasonally as the nature of cooperative activities changed relative to annual life history patterns. Across species, wolves were more cohesive than coyotes. For wolves, pairs were less cohesive in larger groups, and when suitable, small prey was present reflecting the constraints of food resources and intragroup competition on social associations. Pair cohesion in wolves declined with increased anthropogenic modification of the landscape and greater climatic variability, underscoring challenges for conserving social top predators in a changing world. We show that pairwise cohesion in social groups varies strongly both within and across Canis species, as individuals respond to changing ecological context defined by resources, competition, and anthropogenic disturbance. Our work highlights that cohesion is a highly plastic component of animal sociality that holds significant promise for elucidating ecological and evolutionary mechanisms underlying cooperative behavior.

Ecology↗

USGS2017

A serosurvey of diseases of free-ranging gray wolves (Canis lupus) in Minnesota

We tested serum samples from 387 free-ranging wolves ( Canis lupus ) from 2007 to 2013 for exposure to eight canid pathogens to establish baseline data on disease prevalence and spatial distribution in Minnesota's wolf population. We found high exposure to canine adenoviruses 1 and 2 (88% adults, 45% pups), canine parvovirus (82% adults, 24% pups), and Lyme disease (76% adults, 39% pups). Sixty-six percent of adults and 36% of pups exhibited exposure to the protozoan parasite Neospora caninum . Exposure to arboviruses was confirmed, including West Nile virus (37% adults, 18% pups) and eastern equine encephalitis (3% adults). Exposure rates were lower for canine distemper (19% adults, 5% pups) and heartworm (7% adults, 3% pups). Significant spatial trends were observed in wolves exposed to canine parvovirus and Lyme disease. Serologic data do not confirm clinical disease, but better understanding of disease ecology of wolves can provide valuable insight into wildlife population dynamics and improve management of these species.

Minnesota↗

USGS2016

Wolf ( Canis lupus ) generation time and proportion of current breeding females by age

Information is sparse about aspects of female wolf ( Canis lupus ) breeding in the wild, including age of first reproduction, mean age of primiparity, generation time, and proportion of each age that breeds in any given year. We studied these subjects in 86 wolves (113 captures) in the Superior National Forest (SNF), Minnesota (MN), during 1972–2013 where wolves were legally protected for most of the period, and in 159 harvested wolves from throughout MN wolf range during 2012–2014. Breeding status of SNF wolves were assessed via nipple measurements, and wolves from throughout MN wolf range, by placental scars. In the SNF, proportions of currently breeding females (those breeding in the year sampled) ranged from 19% at age 2 to 80% at age 5, and from throughout wolf range, from 33% at age 2 to 100% at age 7. Excluding pups and yearlings, only 33% to 36% of SNF females and 58% of females from throughout MN wolf range bred in any given year. Generation time for SNF wolves was 4.3 years and for MN wolf range, 4.7 years. These findings will be useful in modeling wolf population dynamics and in wolf genetic and dog-domestication studies.

Minnesota↗

USGS2016

White-tailed Deer ( Odocoileus virginianus ) fawn risk from Gray Wolf ( Canis lupus ) predation during summer

Little is known about how often various prey animals are at risk of predation by Gray Wolves ( Canis lupus ). We used a system to monitor the presence during the day of two radio-collared Gray Wolves within 2 km of a radio-collared White-tailed Deer ( Odocoileus virginianus ) with a fawn or fawns in August 2013 in the Superior National Forest of northeastern Minnesota. We concluded that the fawn or fawns were at risk of predation by at least one wolf at least daily.

Minnesota↗

USGS2016

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

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 (p<0.01). The SNF differences could be related to the wolves’ risk when hunting primary prey, for those packs (N=3) hunting moose ( Alces americanus ) were significantly larger than those (N=10) hunting white-tailed deer ( Odocoileus virginianus ) (F1,8=16.50, p=0.004). 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. 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 (p<0.01). The SNF differences could be related to the wolves’ risk when hunting primary prey, for those packs (N=3) hunting moose ( Alces americanus ) were significantly larger than those (N=10) hunting white-tailed deer ( Odocoileus virginianus ) (F1,8=16.50, p=0.004). 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.

Behaviour↗

USGS2015

Evaluation of a formula that categorizes female gray wolf breeding status by nipple size

The proportion by age class of wild Canis lupus (Gray Wolf) females that reproduce in any given year remains unclear; thus, we evaluated the applicability to our long-term (1972–2013) data set of the Mech et al. ( 1993 ) formula that categorizes female Gray Wolf breeding status by nipple size and time of year. We used the formula to classify Gray Wolves from 68 capture events into 4 categories (yearling, adult non-breeder, former breeder, current breeder). To address issues with small sample size and variance, we created an ambiguity index to allow some Gray Wolves to be classed into 2 categories. We classified 20 nipple measurements ambiguously: 16 current or former breeder, 3 former or adult non-breeder, and 1 yearling or adult non-breeder. The formula unambiguously classified 48 (71%) of the nipple measurements; based on supplemental field evidence, at least 5 (10%) of these were incorrect. When used in conjunction with an ambiguity index we developed and with corrections made for classifications involving very large nipples, and supplemented with available field evidence, the Mech et al. ( 1993 ) formula provided reasonably reliable classification of breeding status in wild female Gray Wolves.

Minnesota↗

USGS2015

Trophic cascades from wolves to grizzly bears or changing abundance of bears and alternate foods?

This is a Forum article commenting on: Ripple, W. J., Beschta, R. L., Fortin, J. K., & Robbins, C. T. (2014) Trophic cascades from wolves to grizzly bears in Yellowstone. Journal of Animal Ecology, 83, 223–233. Comparisons Ripple et al. (2014) used to demonstrate increased fruit availability and consumption by grizzly bears post-wolf reintroduction are flawed and tenuous at best. Importantly, a more parsimonious (than trophic cascades) hypothesis, not sufficiently considered by Ripple et al., exists and is better supported by available data I review.

Journal of Animal Ecology↗

USGS2015

Gray Wolf ( Canis lupus ) dyad monthly association rates by demographic group.

Preliminary data from GPS-collared wolves (Canis lupus) in the Superior National Forest of northeastern Minnesota indicated wolves had low association rates with packmates during summer. However, aerial-telemetry locations of very high frequency (VHF)-radioed wolves in this same area showed high associations among packmates during winter. We analyzed aerial-telemetry-location data from VHF-collared wolves in several packs (n=18 dyads) in this same area from 1994-2012 by month, and found lowest association rates occurred during June. While other studies have found low association among wolf packmates during summer, information on differences in association patterns depending on the wolf associates’ demographics is sparse. During May-July, association rates were greatest for breeding pairs, followed by sibling dyads, and lowest for parent– offspring dyads. Our findings improve our understanding of how individual wolf relationships affect monthly association rates. We highlight some important remaining questions regarding wolf packmate associations.

Minnesota↗

USGS2014

How hot is too hot? Live-trapped gray wolf rectal temperatures and 1-year survival

The ability of physically restrained and anesthetized wolves to thermoregulate is lessened and could lead to reduced survival, yet no information is available about this subject. Therefore, we analyzed rectal temperatures related to survival 1 year post-capture from 173 adult (non-pup) gray wolves ( Canis lupus ) captured in modified foot-hold traps for radiocollaring during June–August, 1988–2011, in the Superior National Forest of northeastern Minnesota, USA. The maximum observed rectal temperature (“maxtemp,” ° F, ° C) in each wolf during capture ( x  = 104.0, 40.0; SD = 2.0, 1.1; min. = 95.9, 35.5; max. = 108, 42.2) was not a significant predictor of survival to 1 year post-capture. Although no weather or morphometric variable was a significant predictor of maxtemps, wolves initially anesthetized with ketamine–xylazine rather than telazol®–xylazine averaged higher maxtemps. This information does not fully address possible effects of high body temperatures related to live-capture and handling of wolves, but it does provide a useful waypoint for future assessments of this relationship and a reassurance to wildlife practitioners that the maxtemps observed in our study did not appear to affect 1-year survival.

Minnesota↗

USGS2014

Preliminary data used to assess the accuracy of estimating female white-tailed deer diel birthing-season home ranges using only daytime locations

Because many white-tailed deer (Odocoileus virginianus) home-range and habitat-use studies rely only on daytime radio-tracking data, we were interested in whether diurnal data sufficiently represented diel home ranges. We analyzed home-range and core-use size and overlap of 8 adult-female Global-Positioning-System-collared deer during May and June 2001 and 2002 in the Superior National Forest, Minnesota, USA. We used 2 traditional means of analysis: minimum-convex polygons (MCP) and fixed kernels (95% FK, home range and 50% FK, core use) and two methods to partition day and night location data: (1) daytime = 0800-2000 h versus nighttime = 2000-0800 h and (2) sunup versus sundown. We found no statistical difference in size of home-range and core-use areas across day and night comparisons; however, in terms of spatial overlap, approximately 30% of night-range areas on average were not accounted for using daytime locations, with even greater differences between core-use areas (on average approximately 50%). We conclude that diurnal data do not adequately describe diel adult-female-deer, May-June home-ranges due to differences in spatial overlap (location). We suggest research to determine (1) if our findings hold in other circumstances (e.g., exclusive of the parturition period, other age classes, etc.), (2) if our conclusions generalize under other conditions (e.g., across deer range, varying seasons, etc.), (3) if habitat-use conclusions are affected by the incomplete overlap between diurnal and diel data, (4) how many nocturnal locations must be included to generate sufficient overlap, and (5) the influence of using other kernel sizes (e.g., 75%, 90%).

Wildlife Biology in Practice↗