Estimating parasitic sea lamprey abundance in Lake Huron from heterogenous data sources
Robert J. Young, Michael L. Jones, James R. Bence, Rodney B. McDonald, Katherine M. Mullett, Roger A. Bergstedt
2003, Journal of Great Lakes Research (29) 214-225
The Great Lakes Fishery Commission uses time series of transformer, parasitic, and spawning population estimates to evaluate the effectiveness of its sea lamprey (Petromyzon marinus) control program. This study used an inverse variance weighting method to integrate Lake Huron sea lamprey population estimates derived from two estimation procedures: 1) prediction...
Zebra mussels (Dreissena polymorpha) limit food for larval fish (Pimephales promelas) in turbulent systems: a bioenergetics analysis
L.A. Bartsch, W. B. Richardson, M.B. Sandheinrich
2003, Hydrobiologia (495) 59-72
We conducted a factorial experiment, in outdoor mesocosms, on the effects of zebra mussels and water column mixing (i.e., turbulence) on the diet, growth, and survival of larval fathead minnows (Pimephales promelas). Significant (P < 0.05) larval mortality occurred by the end of the experiment with the highest mortality (90%)...
Species area relationships in mediterranean-climate plant communities
Jon E. Keeley, C. J. Fotheringham
2003, Journal of Biogeography (30) 1629-1657
Aim To determine the best-fit model of species–area relationships for Mediterranean-type plant communities and evaluate how community structure affects these species–area models.Location Data were collected from California shrublands and woodlands and compared with literature reports for other Mediterranean-climate regions.Methods The number of species was recorded from 1, 100 and 1000 m2...
Measurements of thermal updraft intensity over complex terrain using American white pelicans and a simple boundary-layer forecast model
H.D. Shannon, G.S. Young, M. Yates, Mark R. Fuller, W. Seegar
2003, Boundary-Layer Meteorology (104) 167-199
An examination of boundary-layer meteorological and avian aerodynamic theories suggests that soaring birds can be used to measure the magnitude of vertical air motions within the boundary layer. These theories are applied to obtain mixed-layer normalized thermal updraft intensity over both flat and complex terrain from the climb rates of...
How should environmental stress affect the population dynamics of disease?
Kevin D. Lafferty, Robert D. Holt
2003, Ecology Letters (6) 654-664
We modelled how stress affects the population dynamics of infectious disease. We were specifically concerned with stress that increased susceptibility of uninfected hosts when exposed to infection. If such stresses also reduced resources, fecundity and/or survivorship, there was a reduction in the host carrying capacity. This lowered the contact between...
The use of sea ice habitat by female polar bears in the Beaufort Sea
George M. Durner, Steven C. Amstrup, Ryan M. Nielson, Trent McDonald
2003, Conference Paper, Ninth information transfer meeting and Barrow information update meeting: Final proceedings (MMS 2003-042)
Polar bears (Ursus maritimus) depend on ice-covered seas to satisfy life history requirements. Modern threats to polar bears include oil spills in the marine environment and changes in ice composition resulting from climate change. Managers need practical models that explain the distribution of bears in order to assess the impacts...
Size and performance of anoxic limestone drains to neutralize acidic mine drainage
C.A. Cravotta III
2003, Journal of Environmental Quality (32) 1277-1289
Acidic mine drainage (AMD) can be neutralized effectively in underground, anoxic limestone drains (ALDs). Owing to reaction between the AMD and limestone (CaCO3), the pH and concentrations of alkalinity and calcium increase asymptotically with detention time in the ALD, while concentrations of sulfate, ferrous iron, and manganese...
Do ungulates accelerate or decelerate nitrogen cycling?
F. J. Singer, K.A. Schoenecker
2003, Forest Ecology and Management (181) 189-204
Nitrogen (N) is an essential nutrient for plants and animals, and N may be limiting in many western US grassland and shrubland ungulate winter ranges. Ungulates may influence N pools and they may alter N inputs and outputs (losses) to the ecosystem in a number of ways. In this paper...
A nested-intensity design for surveying plant diversity
D.T. Barnett, T.J. Stohlgren
2003, Biodiversity and Conservation (12) 255-278
Managers of natural landscapes need cost-efficient, accurate, and precise systems to inventory plant diversity. We investigated a nested-intensity sampling design to assess local and landscape-scale heterogeneity of plant species richness in aspen stands in southern Colorado, USA. The nested-intensity design used three vegetation sampling techniques: the Modified-Whittaker, a 1000-m2 multiple-scale...
The human footprint in the west: a large-scale analysis of human impacts
Matthias Leu
2003, Fact Sheet 127-03
Background Humans have dramatically altered wildlands in the western United States over the past 100 years by using these lands and the resources they provide. Anthropogenic changes to the landscape, such as urban expansion and development of rural areas, influence the number and kinds of plants and wildlife that remain. In...
The rich get richer: Patterns of plant invasions in the United States
T.J. Stohlgren, D.T. Barnett, J.T. Kartesz
2003, Frontiers in Ecology and the Environment (1) 11-14
Observations from islands, small-scale experiments, and mathematical models have generally supported the paradigm that habitats of low plant diversity are more vulnerable to plant invasions than areas of high plant diversity. We summarize two independent data sets to show exactly the opposite pattern at multiple spatial scales. More significant, and...
Multiple pathways for woody plant establishment on floodplains at local to regional scales
D.J. Cooper, D.C. Andersen, Rodney A. Chimner
2003, Journal of Ecology (91) 182-196
1. The structure and functioning of riverine ecosystems is dependent upon regional setting and the interplay of hydrologic regime and geomorphologic processes. We used a retrospective analysis to study recruitment along broad, alluvial valley segments (parks) and canyon segments of the unregulated Yampa River and the regulated Green River in...
Habitat selection of two gobies (Microgobius gulosus, Gobiosoma robustum): influence of structural complexity, competitive interactions and presence of a predator
P. J. Schofield
2003, Journal of Experimental Marine Biology and Ecology (288) 125-137
Herein I compare the relative importance of preference for structurally complex habitat against avoidance of competitors and predators in two benthic fishes common in the Gulf of Mexico. The code goby Gobiosoma robustum Ginsburg and clown goby Microgobius gulosus (Girard) are common, ecologically similar fishes found throughout the Gulf of Mexico and in the...
Quantile regression models of animal habitat relationships
Brian S. Cade
2003, Thesis
Typically, all factors that limit an organism are not measured and included in statistical models used to investigate relationships with their environment. If important unmeasured variables interact multiplicatively with the measured variables, the statistical models often will have heterogeneous response distributions with unequal variances. Quantile regression is an approach for...
Estimating lake-wide abundance of spawning-phase sea lampreys (Petromyzon marinus) in the Great Lakes: extrapolating from sampled streams using regression models
Katherine M. Mullett, John W. Heinrich, Jean V. Adams, Robert J. Young, Mary P. Henson, Rodney B. McDonald, Michael F. Fodale
2003, Journal of Great Lakes Research (29) 240-252
Lake-wide abundance of spawning-phase sea lampreys (Petromyzon marinus) can be used as one means to evaluate sea lamprey control efforts in the Great Lakes. Lake-wide abundance in each Great Lake was the sum of estimates for all streams thought to contribute substantial numbers of sea lampreys. A subset of these...
Compensatory mechanisms in Great Lakes sea lamprey populations: implications for alternative control strategies
Michael L. Jones, R.A. Bergstedt, Michael B. Twohey, Michael F. Fodale, Douglas W. Cuddy, Jeffrey W. Slade
2003, Journal of Great Lakes Research (29) 113-129
Compensatory mechanisms are demographic processes that tend to increase population growth rates at lower population density. These processes will tend to reduce the effectiveness of actions that use controls on reproductive success to suppress sea lamprey (Petromyzon marinus), an economically important pest in the Great Lakes. Historical evidence for compensatory...
Crustal structure of the Peninsular Ranges batholith from magnetic data: Implications for Gulf of California rifting
V.E. Langenheim, R.C. Jachens
2003, Geophysical Research Letters (30) 51-1
A 70-km-wide belt of magnetic highs extends ???1200 km northwest from the southern tip of the Baja California peninsula into southern California. The anomalies are caused by the mafic western belt of the Peninsular Ranges batholith, which is exposed extensively along the northern 800 km length of the magnetic belt....
Formation and evolution of valley-bottom and channel features, Lower Deschutes River, Oregon
Janet H. Curran, Jim E. O’Conner
Jim E. O’Conner, Gordon E. Grant, editor(s)
2003, AGU Water Science and Application Series 7-5
Primary geologic and geomorphic processes that formed valley-bottom and channel features downstream from the Pelton-Round Butte dam complex are inferred from a canyon-long analysis of feature morphology, composition, location, and spatial distribution. Major controls on valley-bottom morphology are regional tectonics, large landslides, and outsized floods (floods with return periods greater...
The wilderness use simulation model: an historical perspective
J. W. van Wagtendonk
2003, International Journal of Wilderness (9) 9-13
Clinical disease and laboratory abnormalities in free-ranging desert tortoises in California (1990-1995)
Mary M. Christopher, Kristin H. Berry, Brian T. Henen, Kenneth A. Nagy
2003, Journal of Wildlife Diseases (39) 35-56
Desert tortoise (Gopherus agassizii) populations have experienced precipitous declines resulting from the cumulative impact of habitat loss and human and disease-related mortality. Diagnosis of disease in live, free-ranging tortoises is facilitated by evaluation of clinical signs and laboratory test results but may be complicated by seasonal and environmental effects. The...
Improving size estimates of open animal populations by incorporating information on age
Bryan F.J. Manly, Trent L. McDonald, Steven C. Amstrup, Eric V. Regehr
2003, BioScience (53) 666-669
Around the world, a great deal of effort is expended each year to estimate the sizes of wild animal populations. Unfortunately, population size has proven to be one of the most intractable parameters to estimate. The capture-recapture estimation models most commonly used (of the Jolly-Seber type) are complicated and require...
Introduction to fire danger rating and remote sensing - Will remote sensing enhance wildland fire danger prediction?
Britta Allgower, J.D. Carlson, Jan W. Van Wagtendonk
Emilio Chuvieco, editor(s)
2003, Series in Remote Sensing 4-1
While ‘Fire Danger’ per se cannot be measured, the physical properties of the biotic and abiotic world that relate to fire occurrence and fire behavior can. Today, increasingly sophisticated Remote Sensing methods are being developed to more accurately detect fuel properties such as species composition (fuel...
High-resolution climatic evolution of coastal northern California during the past 16,000 years
J.A. Barron, L. Heusser, T. Herbert, M. Lyle
2003, Paleoceanography (18) 20-1-20-19
Holocene and latest Pleistocene oceanographic conditions and the coastal climate of northern California have varied greatly, based upon high-resolution studies (ca. every 100 years) of diatoms, alkenones, pollen, CaCO3%, and total organic carbon at Ocean Drilling Program (ODP) Site 1019 (41.682°N, 124.930°W, 980 m water depth). Marine climate proxies (alkenone...
Effects of channel modification on fish habitat in the upper Yellowstone River: Final report to the USACE, Omaha
Zachary H. Bowen, Ken D. Bovee, Terry J. Waddle
2003, Open-File Report 2003-476
A two-dimensional hydrodynamic simulation model was coupled with a geographic information system (GIS) to produce a variety of habitat classification maps for three study reaches in the upper Yellowstone River basin in Montana. Data from these maps were used to examine potential effects of channel modification on shallow, slow current...
Soil characteristics and plant exotic species invasions in the Grand Staircase-Escalante National Monument, Utah, USA
Michael A. Bashkin, Thomas J. Stohlgren, Yuka Otsuki, Michelle Lee, Paul H. Evangelista, Jayne Belnap
2003, Applied Soil Ecology (22) 67-77
The Grand Staircase - Escalante National Monument (GSENM) contains a rich diversity of native plant communities. However, many exotic plant species have become established, potentially threatening native plant diversity. We sought to quantify patterns of native and exotic plant species and cryptobiotic crusts (mats of lichens, algae, and mosses on...
