Publications
Filter Total Items: 1990
Feeding behavior and aquatic habitat use by Oregon spotted frogs (Rana pretiosa) in central Oregon
No abstract available.
Authors
Christopher A. Pearl, Jay Bowerman, Donnie Knight
The role of fire in shaping avian communities in sagebrush ecosystems
Four experiments were conducted to examine the riboflavin, niacin, pantothenic acid and choline requirements of young Bobwhite quail. Quail fed purified diets deficient in either riboflavin, niacin, pantothenic acid or choline grew poorly and high mortality occurred by 5 weeks of age. Under the conditions of these experiments, it was found that: (1) young quail require approximately 3.8 mg. ribo
Authors
Aaron Holmes, Steven T. Knick, R.F. Miller
Microclimate and nest-site selection in Micronesian Kingfishers
We studied the relationship between microclimate and nest-site selection in the Pohnpei Micronesian Kingfisher (Todiramphus cinnamominus reichenbachii) which excavates nest cavities from the mudlike nest structures of arboreal termites (Nasutitermes sp.) or termitaria. Mean daily high temperatures at termitaria were cooler and daily low temperatures were warmer than at random sites in the forest.
Authors
Dylan C. Kesler, Susan M. Haig
Estimated ultraviolet radiation doses in wetlands in six national parks
Ultraviolet-B radiation (UV-B, 280–320-nm wavelengths) doses were estimated for 1024 wetlands in six national parks: Acadia (Acadia), Glacier (Glacier), Great Smoky Mountains (Smoky), Olympic (Olympic), Rocky Mountain (Rocky), and Sequoia/Kings Canyon (Sequoia). Estimates were made using ground-based UV-B data (Brewer spectrophotometers), solar radiation models, GIS tools, field characterization o
Authors
S. A. Diamond, P.C. Trenham, M. J. Adams, B. R. Hossack, R.A. Knapp, L. Stark, D. Bradford, P. S. Corn, K. Czarnowski, P. D. Brooks, D.B. Fagre, B. Breen, N.E. Dentenbeck, K. Tonnessen
Distribution patterns of lentic-breeding amphibians in relation to ultraviolet radiation exposure in western North America
An increase in ultraviolet-B (UV-B) radiation has been posited to be a potential factor in the decline of some amphibian population. This hypothesis has received support from laboratory and field experiments showing that current levels of UV-B can cause embryo mortality in some species, but little research has addressed whether UV-B is influencing the distribution of amphibian populations. We comp
Authors
M. J. Adams, B. R. Hossack, R.A. Knapp, P. S. Corn, S. A. Diamond, P.C. Trenham, D.B. Fagre
Assessing mercury exposure and effects to American dippers in headwater streams near mining sites
To evaluate mercury (Hg) exposure and possible adverse effects of Hg on American dipper (Cinclus mexicanus) reproduction, we collected eggs and nestling feathers and the larval/nymph form of three Orders of aquatic macroinvertebrates (Ephemeroptera, Plecoptera and Trichoptera = EPT) important in their diet from three major headwater tributaries of the upper Willamette River, Oregon in 2002. The Co
Authors
Charles J. Henny, James L. Kaiser, Heidi A. Packard, Robert A. Grove, Mike R. Taft
Spacing and physical habitat selection patterns by peregrine falcons in central West Greenland
We examined nest-site spacing and selection of nesting cliffs by Peregrine Falcons (Falco peregrinus) in central West Greenland. Our sample included 67 nesting cliffs that were occupied at least once between 1972 and 1999 and 38 cliffs with no known history of Peregrine Falcon occupancy. We measured 29 eyrie, cliff, and topographical features at each occupied nesting cliff and unused cliff in 1998
Authors
Catherine S Wightman, Mark R. Fuller
The influence of forest management on headwater stream amphibians at multiple spatial scales
Understanding how habitat structure at multiple spatial scales influences vertebrates can facilitate development of effective conservation strategies, but until recently most studies have focused on habitat relationships only at fine or intermediate scales. In particular, patterns of amphibian occurrence across broad spatial scales are not well studied, despite recent concerns over regional and gl
Authors
M. Stoddard, J. P. Hayes
A hierarchical perspective of plant diversity
Predictive models of plant diversity have typically focused on either a landscapea??s capacity for richness (equilibrium models), or on the processes that regulate competitive exclusion, and thus allow species to coexist (nonequilibrium models). Here, we review the concepts and purposes of a hierarchical, multiscale model of the controls of plant diversity that incorporates the equilibrium model o
Authors
Daniel Sarr, D.E. Hibbs, M. Huston
Riparian communities associated with Pacific Northwest headwater streams: Assemblages, processes, and uniqueness
Riparian areas of large streams provide important habitat to many species and control many instream processes — but is the same true for the margins of small streams? This review considers riparian areas alongside small streams in forested, mountainous areas of the Pacific Northwest and asks if there are fundamental ecological differences from larger streams and from other regions and if there are
Authors
John S. Richardson, Robert J. Naiman, Frederick J. Swanson, David E. Hibbs
Tree species and size structure of old-growth Douglas-fir forests in central western Oregon, USA
We characterized the structure of 91 old-growth forests dominated by Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), using inventory data from recent (1985–1991) old-growth timber sales in western Oregon. The data were complete counts (i.e., censuses) of all live trees >20 cm diameter at breast height (dbh, measured at 1.4 m above the ground) over a mean area of 17.1 ha at each site. Across al
Authors
Nathan Poage, J. C. Tappeiner
Assessing uncertainty in ecological systems using global sensitivity analyses: A case example of simulated wolf reintroduction effects on elk
Often landmark conservation decisions are made despite an incomplete knowledge of system behavior and inexact predictions of how complex ecosystems will respond to management actions. For example, predicting the feasibility and likely effects of restoring top-level carnivores such as the gray wolf (Canis lupus) to North American wilderness areas is hampered by incomplete knowledge of the predator-
Authors
J. Fieberg, Kurt J. Jenkins