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The scientific bases for preservation of the Mariana crow The scientific bases for preservation of the Mariana crow

The Panel recently released the report and recommendations resulting from its work over the last six months. Although primarily focused on the Mariana Crow, the report highlights that this is a matter potentially far more serious than the preservation of the crow on Guam and Rota. The report includes major sections dealing with the need to intensify research and control activities on the...
Authors
Committee on the Scientific Bases for the Preservation of the Mariana Crow National Research Council, W.D. Duckworth, S. R. Beissinger, S.R. Derrickson, T. H. Fritts, S. M. Haig, F.C. James, J.M. Marsluff, B.A. Rideout

Factors controlling threshold friction velocity in semiarid and arid areas of the United States Factors controlling threshold friction velocity in semiarid and arid areas of the United States

A physical model was developed to explain threshold friction velocities u*t for particles of the size 60a??120 I?m lying on a rough surface in loose soils for semiarid and arid parts of the United States. The model corrected for the effect of momentum absorption by the nonerodible roughness. For loose or disturbed soils the most important parameter that controls u*t is the aerodynamic...
Authors
Beatrice Marticorena, G. Bergametti, Jayne Belnap

Holocene vegetation and historic grazing impacts at Capitol Reef National Park reconstructed using packrat middens Holocene vegetation and historic grazing impacts at Capitol Reef National Park reconstructed using packrat middens

Mid- to late-Holocene vegetation change from a remote high-desert site was reconstructed using plant macrofossils and pollen from 9 packrat middens ranging from 0 to 5400 yr in age. Presettlement middens consistently contained abundant macrofossils of plant species palatable to large herbivores that are now absent or reduced, such as winterfat (Ceratoides lanatd) and ricegrass (Stipa...
Authors
K.L. Cole, N. Henderson, D.S. Shafer

Supervised classification of Landsat thematic mapper imagery in a semi-arid rangeland by nonparametric discriminant analysis Supervised classification of Landsat thematic mapper imagery in a semi-arid rangeland by nonparametric discriminant analysis

In this article the authors used a nonparametric discriminant function in a supervised classification of Landsat Thematic Mapper satellite imagery of a ~240,000-ha semi-arid region in the Snake River Plains, southwestern Idaho. First, agriculture pixels were classified by distance from the soil baseline and water pixels by the thermal band value. Next, successive nonparametric...
Authors
Steven T. Knick, J.T. Rotenberry, T.J. Zarriello

Population identification of western hemisphere shorebirds throughout the annual cycle Population identification of western hemisphere shorebirds throughout the annual cycle

Identification of relationships among geographically distinct populations of migratory species can provide an understanding of breeding and natal philopatry, migration pathways, and population mixing during winter. We used random amplified polymorphic DNA (RAPD) analyses to search for markers specific to difficult‐to‐differentiate shorebird species (e.g. long‐billed dowitcher Limnodromus
Authors
Susan M. Haig, C. L. Gratto-Trevor, Thomas D. Mullins, M. A. Colwell

Spatial use and habitat selection of golden eagles in southwestern Idaho Spatial use and habitat selection of golden eagles in southwestern Idaho

We measured spatial use and habitat selection of radio-tagged Golden Eagles (Aquila chrysaetos) at eight to nine territories each year from 1992 to 1994 in the Snake River Birds of Prey National Conservation Area. Use of space did not vary between years or sexes, but did vary among seasons (home ranges and travel distances were larger during the nonbreeding than during the breeding...
Authors
J.M. Marzluff, Steven T. Knick, M.S. Vekasy, Linda S. Schueck, T.J. Zarriello

Productivity of golden eagles wearing backpack radiotransmitters Productivity of golden eagles wearing backpack radiotransmitters

We examined the association between the presence of backpack radiotransmitters and Golden Eagle (Aquila chrysaetos) reproduction (percentage of occupied territories producing young, and number of nestlings produced) over three years. The association between radio-tagging and nesting success and the number of nestlings produced varied significantly among years. A negative association with...
Authors
J.M. Marzluff, M.S. Vekasy, Michael N. Kochert, Karen Steenhof

Use of ungulates by Yellowstone grizzly bears Ursus arctos Use of ungulates by Yellowstone grizzly bears Ursus arctos

Previous results of fecal analysis from the Yellowstone area and the known abilities of grizzly bears Ursus arctos to acquire and digest tissue from vertebrates suggested that grizzlies in this ecosystem obtained substantial energy from ungulates. This issue was addressed using observations from radio-marked grizzly bears, 1977–1992. Ungulates potentially contributed the majority of...
Authors
D.J. Mattson

Wilderness-dependent wildlife: The large and carnivorous Wilderness-dependent wildlife: The large and carnivorous

Wilderness is vital to the conservation of wildlife species that are prone to conflict with humans and vulnerable to human-caused mortality. These species tend to be large and are often carnivorous. Such animals are typically problematic for humans because they kill livestock and, occasionally, humans, and cause inordinate damage to crops. The vulnerability of large herbivores and...
Authors
David J. Mattson

Clonal foraging in perennial wheatgrasses: A strategy for exploiting patchy soil nutrients Clonal foraging in perennial wheatgrasses: A strategy for exploiting patchy soil nutrients

1. Foraging by means of plasticity in placement of tillers in response to low- and high-nutrient patches was examined in the rhizomatous wheatgrass Elymus lanceolatus ssp. lanceolatus. Its ability to exploit soil nutrient patches was compared to that of the closely related but caespitose E. lanceolatus ssp. wawawaiensis. 2. Clones of 14 genets of each taxon were planted in boxes...
Authors
L. David Humphrey, David A. Pyke
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