We studied the habitat selection of pronghorn (Antilocapra americana) during seasonal migration; an important period in an animal’s annual cycle associated with broad-scale movements. We further decompose our understanding of migration habitat itself as the product of both broad- and fine-scale behavioral decisions and take a multi-scale approach to assess pronghorn spring and fall migration across the transboundary Northern Sagebrush Steppe region. We used a hierarchical habitat selection framework to assess a suite of natural and anthropogenic features that have been shown to influence selection patterns of pronghorn at both broad (migratory neighborhood) and fine (migratory pathway) scales. We then combined single-scale predictions into a scale-integrated step selection function (ISSF) map to assess its effectiveness in predicting migration route habitat. During spring, pronghorn selected for native grasslands, areas of high forage productivity (NDVI), and avoided human activity (i.e., roads and oil and natural gas wells). During fall, pronghorn selected for native grasslands, larger streams and rivers, and avoided roads. We detected avoidance of paved roads, unpaved roads, and wells at broad spatial scales, but no response to these features at fine scales. In other words, migratory pronghorn responded more strongly to anthropogenic features when selecting a broad neighborhood through which to migrate than when selecting individual steps along their migratory pathway. Our results demonstrate that scales of migratory route selection are hierarchically nested within each other from broader (second-order) to finer scales (third-order). In addition, we found other variables during particular migratory periods (i.e., native grasslands in spring) were selected for across scales indicating their importance for pronghorn. The mapping of ungulate migration habitat is a topic of high conservation relevance. In some applications, corridors are mapped according to telemetry location data from a sample of animals, with the assumption that the sample adequately represents habitat for the entire population. Our use of multi-scale modelling to predict resource selection during migration shows promise and may offer another relevant alternative for use in future conservation planning and land management decisions where telemetry-based sampling is unavailable or incomplete.
Black‐tailed prairie dog (Cynomys ludovicianus) is an influential species in prairie ecosystems. Accurate estimates of active prairie dog colony area are needed to assess the status of the species and evaluate the effects of management actions. In 2008, Montana Fish, Wildlife and Parks conducted a survey of potential black‐tailed prairie dog habitat. Using fixed‐wing aircraft and an aerial line‐intercept method, we surveyed 771 transects totaling 56,530 km in 32 counties in central and eastern Montana, USA, excluding tribal lands. We recorded 667 black‐tailed prairie dog colony intercepts totaling 336,636 m in 21 counties. Ground intercepts were 1.091 (95% credible intervals = 1.087–1.094) times longer than air intercepts. The estimated percent of colonies classified as active from the air that were active on the ground was 86.8% (95% credible intervals = 77.9–93.5%). Corrected estimates resulted in 77,430 ha (95% credible intervals = 69,480–83,380) of active and 12,990 ha (95% credible intervals = 7,039–20,970) of inactive black‐tailed prairie dog colonies. We conducted a sensitivity analysis of the estimated area of active prairie dog colonies by reducing a percentage of long intercepts assumed to be entirely active. More than 30% of active intercepts >750 m in length would need to, in fact, be inactive in order for our active colony area estimates to differ >10,000 ha (13%; i.e., outside of our margin of error) from our estimates. Aerial line‐intercept methods provide a reliable and repeatable method for obtaining estimates of active and inactive prairie dog colony area over large areas. Our estimates provide the basis for long‐term monitoring of prairie dogs on a landscape scale. © 2013 The Wildlife Society.
Executive SummaryIn Montana, very little information exists on the status and distribution of a diverse assemblage of nonavian vertebrates, including small mammals, amphibians, terrestrial reptiles and bats. The Montana Inventory and Monitoring Project (Diversity Monitoring) was initiated to: (1) simultaneously provide information on a diverse suite of faunal groups;(2) provide baseline information on species' distributions, site occupancy rates, and detection probabilities that can be used to inform current species conservation status ranking and management efforts; (3) evaluate methodologies and preliminary estimates of site occupancy and detection rates in order to refine survey protocols for future monitoring efforts; (4) establish a baseline of information that can eventually be used to assess changes in distribution and status over time related to changes in habitat and/or management efforts; (5) identify immediate or future research needs for individual species, species assemblages, or habitats; and (6) identify gaps in species' ranges across the state and potentially create maps identifying patterns in individual or collective occupancy rates of species across the state.During the period 2008 -2010, 3,863 individual surveys were conducted during 213 days at 3,048 unique locations within 282 quarter-quadrangle sampling areas in Montana. A majority of sampling occurred on private property (51%), with additional sampling occurring on US Forest Service (16%), Bureau of Land Management (13%), State (12%), and other lands (9%).During structured surveys, 5,806 species detections were recorded, and of those detections, 84 unique species were identified. In addition to structured survey observations, 5,912 species observations were recorded incidentally at 2,634 different locations. We detected 21 Species of Concern in Montana during structured surveys, but failed to detect several others identified as Species of Greatest Conservation Need in Montana's 2005 Comprehensive Fish and Wildlife Conservation Strategy. These included, Great Basin Pocket Mouse, Northern Bog Lemming, Meadow Jumping Mouse, Coeur d'Alene Salamander, Milksnake, Smooth Greensnake, and Western Hog-nosed Snake; all of which may require species specific survey efforts in the future.The data collected through this work expanded the known range for the following seven species: Dusky or Montane Shrew, Pygmy Shrew, Fringed Myotis, Eastern Red Bat, Pallid Bat, Southern Red-backed Vole, and Montane Vole.The number of detections and number of different species detected for each survey method varied considerably by geographic location. In general, the number of bat species detected was highest along the length of the Missouri River and lowest in the northern quarter of the State. The number of amphibian and aquatic reptile species detected at lentic sites was highest in east-central Montana. For small mammals, the number of species detected at survey sites was highest in eastern Montana and lowest in southwestern Montana. The greatest number of terrestria...
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