Conservation of desert tortoises: genetics and protection of isolated populations
No abstract available.
Book↗
Geology topics
R. Bruce Bury
Publications and source records attributed to R. Bruce Bury.
Sampling methods for amphibians in streams in the Pacific Northwest
Methods describing how to sample aquatic and semiaquatic amphibians in small streams and headwater habitats in the Pacific Northwest are presented. We developed a technique that samples 10-meter stretches of selected streams, which was adequate to detect presence or absence of amphibian species and provided sample sizes statistically sufficient to compare abundance of individual species among streams. Physical and biological parameters of stream are described as well as ways to collect amphibians effectively. The system can be modified for use in a variety of waterways and for different study objectives. We provide recommendations for improvements on future studies.
Report↗
Logging in western Oregon: responses of headwater habitats and stream amphibians
We compared occurrence and abundance of four species of aquatic amphibians in 23 streams flowing through uncut forests to 20 streams flowing through forests logged between 14 and 40 years prior to the study. Species richness was highest in streams in uncut forests. Eleven streams in uncut forests contained all four species, and only two of these streams had fewer than three species present. Eleven streams in logged stands had one or no species present, and only one contained all four species. Density and biomass of all four species were significantly greater (2–7 X) in streams in uncut forests. Physical comparisons between types of streams were similar, except that streams in logged stands had generally smaller substrata, resulting from increased sedimentation. Densities of Pacific giant salamanders ( Dicamptodon ensatus ) and Olympic salamanders ( Rhyacotriton olymoicus ) were positively correlated with stream gradient in logged stands, but not in uncut forests, suggesting that the disruptive effects of increased sedimentation are greatest in low-gradient streams. Tailed frogs ( Ascaphus truei ) and Dunn's salamanders ( Plethodon dunni ) occurred more often in streams in logged stands when uncut timber was present upstream, but neither density nor biomass of any species were related to either presence of uncut timber upstream or years since logging. Logging upstream from uncut forests also had no effect on the presence, density or biomass of any species. Tailed frogs and Olympic salamanders may be extirpated from headwaters traversing clearcuts; these streams should be afforded some protection in plans for managed forests.
Oregon↗
Acid precipitation studies in Colorado and Wyoming: interim report of surveys of montane amphibians and water chemistry
Acid deposition may be detrimental or stressful to native populations of wildlife. Because many species of amphibians breed in shallow ponds created by spring rains or melting snow, they may be particularly vulnerable to the effects of acidification. From 1986 to 1988, we surveyed 105 locations in the central Rocky Mountains where amphibians had been recorded previously, and we found that two species of amphibians had experiences major losses. We found the northern leopard frog ( Rana pipiens ) at only 4 of 33 (12%) historically known localities, and the boreal toad ( Bufo boreas ) was present at 10 of 59 (17%) known localities. Three other species have not suffered region-wide declines. Tiger salamanders ( Ambystoma tigrinum ) and wood frogs ( Rana sylvatica ) were present at 45% and 69% of known localities respectively, and were observed at several localities were they had not been recorded previously. Chorus frogs ( Pseudacris triseriata ) suffered a catastrophic decline in population size in one population monitored since 1961, but regionally, this species was observed in 36 of 56 (64%) known localities and in another 19 localities where there were no previous records. Complete water chemistry was recorded for 41 localities, and pH was measured at 110 sites in total. Acid neutralizing capacity, pH, specific conductivity, and cation concentrations were negatively correlated with elevation. However, in mountain ponds and lakes, pH was rarely less than 6.0 during the amphibian breeding season. We tested the tolerance of embryos of the four species of frogs to low pH. The LC 50 pH was 4.8 for chorus frogs, 4.4-4.7 for leopard frogs, 4.4-4.5 for boreal toads, and 4.2-4.3 for wood frogs. Survival of wood frog embryos declined when exposed to aluminum concentrations of 100 µg/L or greater, but boreal toad embryos survived exposure to aluminum concentrations of 400 µg/L. Acid deposition does not appear to be a major factor in the decline of leopard frogs and boreal toads. However, we have not yet investigated effects of sublethal pH on growth and development of tadpoles. Pollution remains suspect, but other factors, including natural fluctuations in population size, may account for the observed declines.
Colorado;Wyoming↗
Distribution of the voles Arborimus longicaudus and Phenacomys intermedius in the central Oregon Cascades
No abstract available.
Oregon↗
Responses of aquatic and streamside amphibians to timber harvest: a review
Stream-dwelling amphibians, which can be the dominant vertebrates of small streams in forests of the Pacific Northwest, are prototypic riparian or ganisms. Larvae of several species are totally aquatic, while adults use the terrestrial streamside (riparian) habitat to varying degrees. Impacts of timber harvest vary among species, physical habitats, and regions of the Pacific Northwest. Populations of giant salamanders (Dicamptodon) increased fol lowing clear-cutting in the Oregon Cascades, while in the Oregon Coast Range, the long-term effects of logging were negative and severe for all species. Timber harvest is less disruptive in high-gradient streams and in streams where there is uncut timber remaining upstream. Buffer strips ad jacent to headwater and small streams can provide shade and reduce sedimentation from logging activities. Critical needs exist to define the ecological requirements of amphibians in headwaters, assess the effects of logging on amphibians in different regions and under varying climatic regimes, and determine what sizes of buffer strips or uncut patches are most effective and cost-efficient for protecting stream amphibians.
Book chapter↗
Douglas-fir forests in the Oregon and Washington Cascades: relation of the herpetofauna to stand age and moisture
Pitfall traps effectively sampled amphibians but not reptiles in Douglas-fir (Pseudotsuga menziesii) forests. The abundance of only one amphibian species varied across an age gradient or a moisture gradient. Salamanders and frogs that breed in ponds or streams were captured in large numbers in some stands, likely due to the presence of nearby breeding habitat rather than forest conditions. Lizards occurred mostly in dry stands and clearcuts. Time-constrained searches showed different use of downed woody debris among terrestrial salamanders. The occurrence and abundance of species in naturally regenerated forests markedly differed from clearcut stands.
Oregon;Washington↗
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↗
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↗
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↗
Review of the ecology and conservation of the bog turtle, Clemmys muhlenbergii
Explore the source record for details and available documents.
Special Scientific Report - Wildlife↗
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↗