Eliza Stein | Search USGS

USGS2026

Integrating targeted surveys during community-wide occupancy assessments improves detection rates for a pollinator species of concern

Conservation practitioners can often struggle to achieve multiple goals—such as monitoring community diversity, tracking species of concern, and evaluating community and species' responses to on-the-ground activities—within limited time and budgets. This study aimed to identify the most efficient field and analytical methods for achieving monitoring goals simultaneously in pollinator surveys. We evaluated whether integrating targeted visual surveys with standard community netting surveys could improve detection efficiency for Bombus occidentalis (western bumble bee), a declining species of concern, while still capturing broader community data. In 2023, we conducted netting surveys for bumble bees ( Bombus spp.) at 22 sites in Glacier National Park and added visual surveys specifically for western bumble bees if not detected during netting. We estimated western bumble bee occupancy and detection using two site-occupancy models: (1) traditional detection/non-detection (DND) models and (2) time-to-detection (TTD) models. We also assessed model performance with reduced (subsampled) survey effort. Models that integrated net and visual surveys produced similar occupancy estimates but higher cumulative detection probability than net-only surveys, with visual surveys requiring less effort than additional net surveys. Notably, 17% of visits (11 of 66) yielded western bumble bee detections during visual surveys only. Although full datasets yielded comparable results between TTD and DND models, subsampling introduced large bias and decreased precision, particularly for net-only and single-survey TTD models. For conservation practitioners with limited time and budgets for monitoring, incorporating targeted visual surveys into community-level surveys can increase detection of species of concern without increasing the number of visits.

Montana↗

USGS2025

Evaluating mountain goat population structure in Glacier National Park and Waterton Lakes National Park

Mountain goats are an iconic, climate-sensitive species across their North American alpine range. Among its nearly complete complement of native wildlife, no single species embodies Glacier National Park (GNP) more than the mountain goat. They play an important role as an alpine food source for many of the park’s carnivores including wolverines, mountain lions, and grizzly bears. Mountain goats face many increasing threats, particularly at the southern extent of their range. These include changes in precipitation and temperature, shifts in forage and fire frequency and intensity, and rapidly increasing visitation and recreation. Although the high latitude and elevations of GNP offer refugia, the mountain goat population likely declined between 2008 and 2019 and may also have a smaller distribution. In Montana, many other native mountain goat populations are also declining or have disappeared entirely. Using a combination of staff and citizen scientists, we collected fecal pellets across GNP in Montana, USA, and adjoining Waterton Lakes National Park (WLNP) in Alberta, Canada, between 2019 and 2023. We used genotypes of 6 to 19 loci microsatellites to identify individuals and assess isolation by distance, genetic structure, and genetic diversity. We found no evidence of genetic structure and only limited isolation by distance. This suggests that mountain goats in GNP and WLNP can be considered a single population, so samples can be combined across the area to estimate a single population size. Genetic diversity was similar to recent mountain goat studies conducted in other regions; allelic richness was 3.54 and inbreeding coefficients ( F IS ) ranged from 0.01–0.19, with values >0.11 only in the Livingston Range in the northwest of the study area. The high F IS in the Livingston Range suggests several closely related groups with little interchange, and perhaps a recent decrease in gene flow, both of which are consistent with a recent population decline in that area. We detected a high number of closely related individuals throughout our study area, consistent with the high adult survival, low reproductive success life history of goats, but also suggesting that we sampled much of the overall population.

Alberta, Montana↗