Publications
Filter Total Items: 1994
Biotic soil crusts in relation to topography, cheatgrass, and fire in the Columbia Basin, Washington
We studied lichen and bryophyte soil crust communities in a large public grazing allotment within a sagebrush steppe ecosystem in which the biotic soil crusts are largely intact. The allotment had been rested from grazing for 12 years, but experienced an extensive series of wildfires. In the 350, 4 x 0.5 m plots, stratified by topographic position, we found 60 species or species groups that can be
Authors
Jeanne Ponzetti, B. McCune, David A. Pyke
Dachtal Isomers and Acidic Herbicides and Pesticides in Eggs of Osprey (Pandion haliaetus) from the Seattle and Everett Areas, Washington, U.S.A
Current-use chlorophenoxy herbicides including 2,4-dichlorophenoxyacetic acid, dicamba, triclopyr, dicamba, dimethyl tetrachloroterephthalate (DCPA or dacthal), and the metabolite of pyrethroids, 3-phenoxybenzoic acid (3-PBA), and the fungicide, chlorothalonil, were investigated in the eggs of osprey (Pandion haliaetus) that were collected from 15 sites from five study areas Puget Sound/Seattle ar
Authors
S. Chu, Charles J. Henny, James L. Kaiser, K.G. Drouillard, G.D. Haffner, R.J. Letcher
Arthropod prey of Wilson's Warblers in the understory of Douglas-fir forests
Availability of food resources is an important factor in avian habitat selection. Food resources for terrestrial birds often are closely related to vegetation structure and composition. Identification of plant species important in supporting food resources may facilitate vegetation management to achieve objectives for providing bird habitat. We used fecal analysis to describe the diet of adult Wil
Authors
Joan C. Hagar, Kate Dugger, Edward E. Starkey
The state of the art in raptor electrocution research: A global review
We systematically reviewed the raptor electrocution literature to evaluate study designs and methods used in raptor electrocution research, mitigation, and monitoring, emphasizing original research published in English. Specifically, we wondered if three decades of effort to reduce raptor electrocutions has had positive effects. The majority of literature examined came from North America, western
Authors
Robert N. Lehman, P.L. Kennedy, J. A. Savidge
Thermal, chemical, and optical properties of Crater Lake, Oregon
Crater Lake covers the floor of the Mount Mazama caldera that formed 7700 years ago. The lake has a surface area of 53 km2 and a maximum depth of 594 m. There is no outlet stream and surface inflow is limited to small streams and springs. Owing to its great volume and heat, the lake is not covered by snow and ice in winter unlike other lakes in the Cascade Range. The lake is isothermal in winter e
Authors
Gary L. Larson, Robert L. Hoffman, D. C. McIntire, M. W. Buktenica, Scott Girdner
Fix success and accuracy of GPS radio collars in old-growth temperate coniferous forests
Global Positioning System (GPS) telemetry is used extensively to study animal distribution and resource selection patterns but is susceptible to biases resulting from data omission and spatial inaccuracies. These data errors may cause misinterpretation of wildlife habitat selection or spatial use patterns. We used both stationary test collars and collared free-ranging American black bears (Ursus a
Authors
Kimberly A. Sager-Fradkin, Kurt J. Jenkins, Robert L. Hoffman, P. Happe, J. Beecham, R. G. Wright
Oregon Spotted Frog (Rana pretiosa) movement and demography at Dilman Meadow: Implications for future monitoring
From 2001 to 2005, we studied the demography and seasonal movement of Oregon spotted frogs (Rana pretiosa) translocated into created ponds in Dilman Meadow in central Oregon. Our objectives were to inform future monitoring and management at the site, and to elucidate poorly known aspects of the species’ population ecology. Movement rates revealed complementary use of sites seasonally, with one sma
Authors
Nathan D. Chelgren, Christopher A. Pearl, Jay Bowerman, M. J. Adams
Territoriality, prospecting, and dispersal in cooperatively breeding Micronesian Kingfishers (Todiramphus cinnamominus reichenbachii)
We investigated territoriality, prospecting, and dispersal behavior in cooperatively breeding Pohnpei Micronesian Kingfishers (Todiramphus cinnamominus reichenbachii) throughout the annual cycle using radiotelemetry and color-band resights. Mean home-range size was 6.3 ha and territories were 8.1 ha. Within territories, Micronesian Kingfishers shared 63% of their home-range space with coterritoria
Authors
D.C. Kesler, S. M. Haig
Impacts of a gape limited Brook Trout, Salvelinus fontinalis, on larval Northwestern salamander, Ambystoma gracile, growth: A field enclosure experiment
The formation of amphibian population structure is directly affected by predation. Although aquatic predators have been shown to have direct negative effects on larval salamanders in laboratory and field experiments, the potential impacts of gape-limited fish on larval salamander growth has been largely underexplored. We designed an enclosure experiment conducted in situ to quantify the effects of
Authors
C.R. Currens, W.J. Liss, R.L. Hoffman
Invasion by nonnative brook trout in Panther Creek, Idaho: Roles of local habitat quality, biotic resistance, and connectivity to source habitats
Theoretical models and empirical evidence suggest that the invasion of nonnative species in freshwaters is facilitated through the interaction of three factors: habitat quality, biotic resistance, and connectivity. We measured variables that represented each factor to determine which were associated with the occurrence of nonnative brook trout Salvelinus fontinalis in Panther Creek, a tributary to
Authors
Joseph R. Benjamin, Jason B. Dunham, M.R. Dare
Microsatellite loci for distinguishing spotted owls (Strix occidentalis), barred owls (Strix varia), and their hybrids
We identified four diagnostic microsatellite loci that distinguish spotted owls (Strix occidentalis), barred owls (Strix varia), F1 hybrids and backcrosses. Thirty-four out of 52 loci tested (65.4%) successfully amplified, and four of these loci (11.8%) had allele sizes that did not overlap between spotted and barred owls. The probability of correctly identifying a backcross with these four loci i
Authors
W. Chris Funk, Thomas D. Mullins, Eric D. Forsman, Susan M. Haig
Seasonal and interannual variability in the taxonomic composition and production dynamics of phytoplankton assemblages in Crater Lake, Oregon
Taxonomic composition and production dynamics of phytoplankton assemblages in Crater Lake, Oregon, were examined during time periods between 1984 and 2000. The objectives of the study were (1) to investigate spatial and temporal patterns in species composition, chlorophyll concentration, and primary productivity relative to seasonal patterns of water circulation; (2) to explore relationships betwe
Authors
McIntire C. David, Gary L. Larson, Robert E. Truitt