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R. Bruce Bury

Publications and source records attributed to R. Bruce Bury.

63 records · Page 4Linked to original sources
USGS1987

Evaluation of pitfall trapping in northwestern forests: Trap arrays with drift fences

We operated pitfall arrays with 5-m drift fences at 30 stands in western Oregon and Washington for 180 days. Pitfall arrays had a pronounced removal effect on small mammals (but not on the herpetofauna) during the 1st 60 days of trapping. Conventional short (10-day) trapping periods were only adequate to detect the most common mammals. About 60 days were needed to compile a relatively complete species list (>85% of species captured) at each site. Reptiles were caught almost exclusively in the summer; amphibian captures were correlated with increased precipitation in the fall. Short (2.5-m) drift fences were less effective than the standard length of 5 m. Funnel traps captured few forest vertebrates. Pitfalls captured more insectivorous mammals than did snap traps, but snap traps were more effective for a few cricetid rodents. Pitfall arrays are adaptable to many habitats and can help assess the presence of small vertebrates, such as shrews and amphibians, that are undersampled by other techniques.

Oregon, Washington↗
USGS1986

Habitat use and terrestrial activity by red tree voles ( Arborimus longicaudus ) in Oregon

Several species of vertebrates may find optimal habitat for breeding, nesting, or foraging in old-growth (>200 years old) confierous forests in the Pacific Northwest. Old-growth forests are economically valuable, however, and most unprotected stands will be cut within 40 years (Franklin et al., 1981). Meslow et al. (1981) and Raphael (1984) identified a critical need to document habitat use and establish the relationship of wildlife species in these forests. In 1983, we operated arrays of pitfall traps for six months to investigate habitat use by terrestrial herpetofauna and small mammals in four age classes of Douglas-fir ( Pseudotsuga menziesii ) forest in and near the H. J. Andrews Experimental Forest, Linn and Lane counties, Oregon. Red tree voles, Arborimus longicaudus , were among the mammals captured. This species is considered to find optimum habitat in old-growth forests (Franklin et al., 1981; Meslow et al., 1981), but quantitative data on the local occurrence of the species are lacking. Here we report on habitat use by A. longicaudus and document terrestrial activity for this presumably arboreal species. A pitfall array was located in each of 18 stands dominated by Douglas-fir. Each array consisted of two sets of three 5-m aluminum drift fences each with pitfall traps (No. 10 tin cans; 6.4 l in volume) at the ends of the fences (see Bury and Raphael, 1983). The 18 stands represented four successional stages based on estimated age: 3 pre-canopy (clear cuts 5-9 years old), 3 young (30-69 years), 4 mature (76-150 years), and 8 old-growth (195-450 years). Additionally, old-growth stands were ranked on a general moisture gradient (wet, mesic, or dry) based on aspect, topographic position, and presence of indicator plant species. Pitfall traps were operated continuously for 180 days from late May to late November, 1983.

Oregon↗
USGS1986

Morphological variation and zoogeography of racers ( Coluber constrictor ) in the central Rocky Mountains

We examined 63 specimens of Coluber constrictor from Colorado and Utah using eight external morphological characters that have been used to distinguish C. c. mormon from C. c. flaviventris . We grouped the snakes into three Operational Taxonomic Units (OTU's) in a transect across the Rocky Mountains: the eastern Front Range foothills in Colorado; the inter-mountain region (western slope of Colorado and northeastern Utah); and the western foothills of the Wasatch Mountains in Utah. Statistically significant variation among the OTU's was discovered for ration of tail length to total length, number of central and subcaudal scales, and number of dentary teeth. However, variation is clinal with nearly complete overlap from one end f the transect to the other for each character, suggesting a wide zone of intergradiation in the inter-mountain region. We do not believe reported differences in reproductive parameters between Great Plains and Great Basin racers are sufficient grounds for recognition of species, because clutch size is both geographically variable and dependent on the environment. The distribution of C. constrictor is similar to that of other reptiles with transmontane distributions in the western United States, and we suggest two possible routes of dispersal across the Continental Divide in southwestern Wyoming. Thus, elevation of C. c. mormon to species status is not supported by morphological, reproductive, or zoogeographic evidence.

Colorado;Utah↗
USGS1977

Effects of off-road vehicles on vertebrates in the California desert

Off-road vehicle (ORV) use provides a form of outdoor recreation that is increasingly popular. The purpose of this study was to examine the impact of these machines on creosote shrub habitat and associated wildlife in the western California Desert. Comparisons at eight paired sites (Control and ORV use) demonstrate that ORV-use areas have significantly fewer species of vertebrates, greatly reduced abundance of individuals, and noticeably lower reptile and small mammal biomass. Diversity, density, and biomass of reptiles and small mammals are inversely related to the level of ORV usage. The number of individuals found in heavily used and pit areas was 55% and 20%, respectively, of that present in undisturbed sites. Biomass estimates were even lower (23% and 17%, respectively). Censuses at three localities also showed decreased diversity, density, and biomass estimates of breeding birds in DRV-used areas. Present evidence indicates that off-road vehicles have a negative effect on desert wildlife over large areas. This widespread impact must be recognized to manage and conserve resources in DRV-use areas.

California↗