Publications
Filter Total Items: 1990
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 hymenoides).
Authors
K.L. Cole, N. Henderson, D.S. Shafer
Shorebird diet and size selection of nereid polychaetes in South Carolina coastal diked wetlands
Coastal wetlands that are diked and managed may supplement declining natural habitat for migrating shorebirds (Charadriiformes). However, data on shorebird diet in these diked wetlands are scarce. We examined shorebird diet and prey size selection in brackish diked wetlands at the Yawkey Center on South Island, South Carolina, USA. Gut contents of seven Lesser Yellowlegs (Tringa flavipes) and seve
Authors
Louise M. Weber, Susan M. Haig
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 roughness he
Authors
Beatrice Marticorena, G. Bergametti, Jayne Belnap
DDE still high in white-faced ibis eggs from Carson Lake, Nevada
White-faced Ibis (Plegadis chihi) eggs collected in 1996 at Carson Lake, Nevada, showed no decrease in p,p′-DDE (DDE) concentrations from levels in 1985 and 1986 which is contrary to DDE patterns shown for most avian species. An estimated 40-45% of the population was adversely affected by DDE in 1985, 1986, and 1996 with a probable net loss of about 20% of the expected productivity. One segment of
Authors
Charles J. Henny
Photosynthesis of green algal soil crust lichens from arid lands in southern Utah, USA: Role of water content on light and temperature responses of CO2 exchange
Biotic soil crusts are a worldwide phenomenon in arid and semi-arid landscapes. Metabolic activity of the poikilohydric organisms found in these crusts is dominated by quick and drastic changes in moisture availability and long periods of drought. Under controlled conditions, we studied the role of water content on photosynthetic and respiratory CO2 exchange of three green algal soil crust lichens
Authors
Otto L. Lange, Jayne Belnap, Angelika Meyer
Population dynamics of the deer mouse (Peromyscus maniculatus) and Sin Nombre Virus, California Channel Islands
Hantavirus pulmonary syndrome, first documented in 1993, is caused by Sin Nombre virus (SNV), which is carried by the Peromyscus species. In 1994, high SNV antibody prevalence was identified in deer mice from two California Channel Islands. We sampled two locations on three islands to estimate mouse population density and SNV prevalence. Population flux and SNV prevalence appear to vary independen
Authors
T. B. Graham, B.B. Chomel
Long-term limnological data from the larger lakes of Yellowstone National Park, Wyoming, USA
Long-term limnological data from the four largest lakes in Yellowstone National Park (Yellowstone, Lewis, Shoshone, Heart) are used to characterize their limnology and patterns of temporal and spatial variability. Heart Lake has distinctively high concentrations of dissolved materials, apparently reflecting high thermal inputs. Shoshone and Lewis lakes have the highest total SiO2 concentrations (a
Authors
E.C. Theriot, S.C. Fritz, Robert E. Gresswell
Using mark-recapture methods to estimate fish abundance in small mountain lakes
The majority of lacustrine fish populations in the western USA are located far from the nearest
road. Although mark-recapture techniques are widely accepted for estimating population
abundance, these techniques have been broadly ignored for fisheries surveys in remote mountain
lakes because of restricted access and associated logistical constraints. In this study, mark recapture experiments wer
Authors
Robert E. Gresswell, W.J. Liss, G.A. Lomnicky, E. Deimling, Robert L. Hoffman, T. Tyler
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 energy require
Authors
D.J. Mattson
Sustainable grizzly bear mortality calculated from counts of females with cubs-of-the-year: An evaluation
Unduplicated counts of female grizzly bears Ursus arctos horribilis with cubs-of-the-year are currently used to estimate minimum population sizes used, in turn, to calculate allowable (assumed to equal sustainable) mortality for grizzly bear populations in the contiguous United States of America. This calculation assumes that unduplicated counts are an unbiased and accurate indicator of population
Authors
David J. Mattson
Influence of basin-scale physical variables on life history characteristics of cutthroat trout in Yellowstone Lake
Individual spawning populations of Yellowstone cutthroat trout Oncorhynchus clarki bouvieri differ in life history characteristics associated with broad spatial and temporal environmental patterns, but relationships between specific life history characteristics of Yellowstone cutthroat trout and physical aspects of the environment are poorly understood. We examined basin-scale physical characteris
Authors
Robert E. Gresswell, W.J. Liss, Gary L. Larson, P. J. Bartlein
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 carnivores to hu
Authors
David J. Mattson