Age-Mass Relationships for Beavers in Montana

Beavers (Castor spp.) are receiving increased attention due to their impact on ecosystems and potential for use in stream restoration. Beaver research and relocation projects are especially common in the western United States, and professionals using live-captured animals for projects will benefit from a reliable technique for aging live-caught beavers. The only reliable technique for aging live beavers without sedation is to estimate age based on mass, but estimates of the age-mass relationship for beavers vary regionally and are not adequately quantified in the western United States. We collected beaver carcasses and skulls from trappers throughout southwest Montana to estimate the age-mass relationship using a robust sample collected from a large geographic area. We weighed beaver carcasses and extracted molar teeth from the mandibles to estimate age by counting cementum annuli on cross-sections of the teeth. We collected 193 beaver carcasses and hanging weights from nine major river drainages in Montana. Multiple regression analysis indicated the top prediction equation was mass = 9.4611 + 8.2234 x log(age) + drainage, indicating drainage-level differences in the average mass of beavers. Beavers from the Ruby, Jefferson, and Yellowstone River drainages were larger than those from the other river drainages in Montana. We could reliably separate beavers into four age classes: kits, yearlings, two-year-olds, and adults (>3 years). Our results are useful for researchers who need to estimate beaver age to understand population dynamics and age-specific life history characteristics, as well as restoration practitioners who need to determine colony compositions and recruitment rates to evaluate the success of restoration projects

Habitat Selection, Movements and Survival of Dispersing Juvenile Beavers in Southwestern Montana

The natural activities of beavers (Castor canadensis) effectively create or expand, and maintain, healthy riparian and wetland areas. Therefore, interest has increased among land and wildlife managers in the reintroduction of beavers into degraded riparian habitats as a proactive management option for natural restoration of these areas. However, there is a need for information regarding habitat selection by beavers in novel habitats to increase the likelihood that reintroduced beavers will colonize the area targeted for restoration. We are using cable snares to capture and radio tag dispersal age beavers in headwater streams of the Madison and Gallatin River drainages. We will relocate tagged beavers via handheld telemetry to obtain movement data from the moment the beavers leave their natal colony in the spring until they settle in a new location in the late summer and fall. Habitat characteristics representing vegetation, hydrology and geomorphology will be assessed at settlement locations as well as locations encountered but not settled to make inference on habitat conditions most important to dispersing beavers in selecting settlement sites. Eighteen beavers were radio tagged in the fall of 2015 representing 6 different streams in the study area. The 18 tagged beavers will be tracked through the spring and summer of 2016 and habitat conditions will be assessed based on their movements before another season of beaver trapping in the fall of 2016. Our analysis of habitat selection by juvenile beavers will guide future beaver restoration projects in this region by identifying release sites with the highest probability of success

Effects of Grazing Management on Sharp-Tailed Grouse Nest Survival in Mixed Grass Prairies

Grazing is the predominant land use across western North America and directly affects the structure, composition, and productivity of native grasslands. Thus, grazing management has a significant impact on the quality and extent of wildlife habitat. Sharp-tailed grouse (Tympanuchus phasianellus) have large home ranges and utilize a wide range of habitat types, allowing them to serve as an ideal indicator species for grassland habitats. To better understand the relationship between rangeland management, habitat conditions, and nesting ecology, we monitored 50 radio-collared sharp-tailed grouse in eastern Montana to assess the effects of grazing management, local habitat, and female attributes on nest survival. In the first year of a three-year study, we monitored 73 nests, 27 of which successfully hatched at least one chick. Probability of daily nest survival was 0.96 ± 0.006 and overall nest survival during the nesting period was 0.24 ± 0.05. Variables at the home-range scale, including grazing system and grassland shape complexity, were better predictors of nest survival than variables at the nest-scale. Nest survival declined with female age, and was higher for nests located in pastures managed with season-long grazing than for pastures managed with rotation and rest-rotation grazing. However, confidence intervals of effects overlapped 0 and a null model was considered parsimonious, suggesting little to no direct effect of grazing system on nest survival during our first year of study. By evaluating the influence of different rangeland management practices on demographic rates, this project will develop specific management recommendations for the conservation of sharp-tailed grouse

Grizzly Bear Use of Forest Service Grazing Allotments in The Greater Yellowstone Ecosystem (Poster)

Range expansion of the Greater Yellowstone Ecosystem (GYE) grizzly bear (Ursus arctos) population has led to increased human-bear conflicts, including livestock depredation. In 2015, we began a study to evaluate spatio-temporal patterns between public land livestock grazing, grizzly bear habitat use and livestock depredations. In collaboration with the U.S. Forest Service and the Interagency Grizzly Bear Study Team, we will obtain 25 years (1989-2014) of data related to Forest Service grazing allotments, including livestock stocking and on-off dates, locations of individual collared bears, grizzly bear depredations and management removals, bear density and habitat characteristics pertinent to bear space use (e.g. landcover, elevation, human activity) within the GYE. Bear and conflict locations will be related to allotment information, habitat characteristics, and bear density using generalized linear models to evaluate what factors are influencing grizzly bear space use and depredation events, and how they have changed across seasons and years. Habitat selection by individual bears will be evaluated at two scales, home range selection within the landscape and selection within the home range, to give more insight into factors affecting space use and how they differ among individual bears. Our results should facilitate the development of adaptive approaches to conserve grizzly bears while also conserving the economic viability of livestock operations, and should have utility for bear and land management in the GYE

Effects of Livestock Grazing Management on Grassland Bird Abundance in the Northern Mixed-Grass Prairie

Grassland bird populations have been declining throughout a majority of their range in the United States and Canada over the past 40 years, and currently have the most accelerated declines of any guild of terrestrial birds in this region. Rangelands used for domestic cattle grazing are important for maintaining large tracts of native grassland that may otherwise be converted to agricultural use or other human development. In addition, grassland birds respond well to livestock grazing systems that increase habitat heterogeneity by mimicking historic grassland disturbance, such as fire and bison grazing. Montana Department of Fish, Wildlife, and Parks (FWP) implements a rest-rotation grazing system within conservation easements to increase structural heterogeneity of grassland vegetation on the landscape. However, the rest-rotation grazing system administered by Montana FWP was developed for more arid, bunchgrass-dominated rangelands and has not been evaluated as a management tool for creating structurally diverse wildlife habitat in the northern mixed-grass prairie. This study examines the effect of a rest-rotation grazing system on breeding season habitat selection and abundance of four native grassland songbird species, Baird’s sparrow (Ammodramus bairdii), grasshopper sparrow (Ammodramus savannarum), vesper sparrow (Pooecetes gramineus), and western meadowlark (Sturnella neglecta), relative to traditional season-long or rotational grazing systems on a Montana FWP conservation easement in eastern Montana. Our objectives for the study are: 1) evaluate how abundance and spaceuse of four focal grassland bird species are affected by grazing treatment; 2) estimate the importance of habitat and vegetation characteristics for focal species within pasture treatments; 3) offer management recommendations to agencies and private landowners for improving grassland bird abundance and habitat quality

Use of Snares to Live-Capture Beavers

Wildlife managers, researchers, and nuisance-control operators often require a nonlethal means of capturing beavers (Castor canadensis). Historically, live-capture has relied on enclosure-type traps such as Bailey or Hancock traps. We describe the live-capture of 231 beavers using snares in southern Illinois from 2002 to 2005. Capture success averaged 5.4 beavers/100 trap-nights. Capture success did not differ between sexes (P = 0.57) or age-classes (P = 0.68). We captured most beavers in haul-out slide sets, surface run sets, or channel sets. Recaptures accounted for 28% (n = 65) of all captures. Mortality rate using snares was 10% and decreased annually during the study period. Snares are advantageous over enclosure-type traps because they have a high capture:cost ratio and are less heavy and cumbersome than traps. However, mortality rates are relatively high, limiting the utility of this technique for some research

Impacts of alternative grassland management regimes on the population ecology of grassland birds

We investigated the impacts of rangeland management practices on the diversity, density, and nest survival of grassland songbirds and on the demography, habitat selection, and population viability of Greater Prairie-Chickens (Tympanuchus cupido). Our study site was located in eastcentral Kansas and included portions of Chase, Greenwood, Lyon, and Morris Counties. We had access to ~1,100 km2 of private and public lands. Over 95% of the land was privately owned (~1040 km2), and the remaining ~5% was the Tallgrass Prairie National Preserve. Our final project report is based on data collected during a 3-year period from Feb. 2011 through Feb. 2014. Our study focused on grassland songbirds and Greater Prairie-Chickens as indicators of ecosystem response. Our analyses are based on direct comparisons between monitoring efforts in pastures managed with patch-burn grazing (PBG) and pastures managed with traditional intensive early stocking and annual burning (IESB).Citation: Sandercock, B.K., V.L. Winder, A.E. Erickson, and L.B. McNew. 2014. Impacts of alternative grassland management regimes on the population ecology of grassland birds. Kansas Department of Wildlife, Parks and Tourism, Final Project Report for Award No. KDWP-W-67-R. (technical report)

Effects of Supplementation Strategy and Dormant Season Grazing on Cattle Use of Mixed-Grass Prairie Habitats

Dormant season grazing reduces reliance on harvested feeds, but typically requires protein supplementation to be successful. However, information relating supplementation strategies to individual resource utilization on dormant forage is lacking.  Thus, the intent of this research is to examine cattle resource utilization, residual cover of vegetation and utilization on rangelands grazed during the dormant season under two supplementation strategies. Thirty transects were randomly located within each pasture for measuring vegetation composition, production, canopy cover and visual obstruction readings (VOR) pre and post grazing.  Grazing locations were monitored for seven individuals within each treatment with Lotek GPS collars containing head position sensors that record daily space use. Resource utilization effect size was variable by treatment and time period. Vegetation response to treatment was similar for both cake and protein treatments across time periods (44.2 ± 4.8% vs 41.7 ± 4.5%, 36.7 ± 4.8% vs 30.7 ± 4.3%, 10.4 ± 3.1% vs 16.5 ± 3.5%). VOR was affected by supplementation treatment during time period 1, such that protein treatment significantly decreased VOR in comparison to the Cake treatment (36.6 ± 5.6% vs 15.7 ± 3.6%). Herbaceous and ground cover effects were similar across both supplementation treatments during time periods 1 and 3, while time period 2, cake supplementation had greater percent decrease of litter cover than the protein treatment (28.2 ± 4.4% vs 10.4 ± 2.9%). This research addresses comprehensive agro-ecosystem responses of dormant season grazing while providing multidimensional insight to stakeholders concerning grazing behavior and the ecological impacts on Montana rangelands