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We examined bird and bat mortality at a new 89-turbine windfarm constructed in an environmentally sensitive area in north-central Iowa. The windfarm became operational in November 2001. It is located in cropland between three Wildlife Management Areas (WMA's) with historically high bird use. In the past, migrant and resident waterfowl, shorebirds, raptors, and songbirds moved between the WMA's through the area now occupied by the windfarm. Studies of bird collision mortality in California and elsewhere raised concerns about the possibility of mortalities in this area. From April 15, 2003 and December 15, 2003 we searched for dead animals under 26 randomly selected turbines. Six 76.2 m by 3.0 m transects were maintained...
Ecological processes of low-productivity ecosystems have long been considered to be driven by abiotic controls with biotic interactions playing an insignificant role. However, existing studies present conflicting evidence concerning the roles of these factors, in part due to the short temporal extent of most data sets and inability to test indirect effects of environmental variables modulated by biotic interactions. Using structural equation modeling to analyze 65 years of perennial vegetation change in the Sonoran Desert, we found that precipitation had a stronger positive effect on recruitment beneath existing canopies than in open microsites due to reduced evaporation rates. Variation in perennial canopy cover...
We examined bird and bat mortality at a new 89-turbine windfarm constructed in an environmentally sensitive area in north-central Iowa. The windfarm became operational in November 2001. It is located in cropland between three Wildlife Management Areas (WMA's) with historically high bird use. In the past, migrant and resident waterfowl, shorebirds, raptors, and songbirds moved between the WMA's through the area now occupied by the windfarm. Studies of bird collision mortality in California and elsewhere raised concerns about the possibility of mortalities in this area. From April 15, 2003 and December 15, 2003 we searched for dead animals under 26 randomly selected turbines. Six 76.2 m by 3.0 m transects were maintained...
Tall wind turbines, with hub heights at 80 m or above, can extract large amounts of energy from the atmosphere because they are likely to encounter higher wind speeds, but they face challenges given the complex nature of wind flow and turbulence at these heights in the boundary layer. Depending on whether the boundary layer is stable, neutral, or convective, the mean wind speed, direction, and turbulence properties may vary greatly across the tall turbine swept area (40 to 120 m AGL). This variability can cause tall turbines to produce difference amounts of power during time periods with identical hub height wind speeds. Using meteorological and power generation data from a West Coast North American wind farm over...
Very detailed models often hinder the ability to develop a broad, highlevel understanding of system behavior. A system-of-systems perspective combined with a policy analysis approach offers an alternative approach for policy decision-making. This paper specifies the elements of the energy system-of-systems using this new approach and illustrates its use via an example from the Dutch residential sub-sector. The resulting comprehensive problem representation provides meaningful insights into the interdependencies of relevant factors and values among different levels of the system-of-systems covering both the supply and demand side. The paper also shows that despite the high complexity of the energy sector, an energy...
We examined bird and bat mortality at a new 89-turbine windfarm constructed in an environmentally sensitive area in north-central Iowa. The windfarm became operational in November 2001. It is located in cropland between three Wildlife Management Areas (WMA's) with historically high bird use. In the past, migrant and resident waterfowl, shorebirds, raptors, and songbirds moved between the WMA's through the area now occupied by the windfarm. Studies of bird collision mortality in California and elsewhere raised concerns about the possibility of mortalities in this area. From April 15, 2003 and December 15, 2003 we searched for dead animals under 26 randomly selected turbines. Six 76.2 m by 3.0 m transects were maintained...
We examined bird and bat mortality at a new 89-turbine windfarm constructed in an environmentally sensitive area in north-central Iowa. The windfarm became operational in November 2001. It is located in cropland between three Wildlife Management Areas (WMA's) with historically high bird use. In the past, migrant and resident waterfowl, shorebirds, raptors, and songbirds moved between the WMA's through the area now occupied by the windfarm. Studies of bird collision mortality in California and elsewhere raised concerns about the possibility of mortalities in this area. From April 15, 2003 and December 15, 2003 we searched for dead animals under 26 randomly selected turbines. Six 76.2 m by 3.0 m transects were maintained...
Ecological processes of low-productivity ecosystems have long been considered to be driven by abiotic controls with biotic interactions playing an insignificant role. However, existing studies present conflicting evidence concerning the roles of these factors, in part due to the short temporal extent of most data sets and inability to test indirect effects of environmental variables modulated by biotic interactions. Using structural equation modeling to analyze 65 years of perennial vegetation change in the Sonoran Desert, we found that precipitation had a stronger positive effect on recruitment beneath existing canopies than in open microsites due to reduced evaporation rates. Variation in perennial canopy cover...
We examined bird and bat mortality at a new 89-turbine windfarm constructed in an environmentally sensitive area in north-central Iowa. The windfarm became operational in November 2001. It is located in cropland between three Wildlife Management Areas (WMA's) with historically high bird use. In the past, migrant and resident waterfowl, shorebirds, raptors, and songbirds moved between the WMA's through the area now occupied by the windfarm. Studies of bird collision mortality in California and elsewhere raised concerns about the possibility of mortalities in this area. From April 15, 2003 and December 15, 2003 we searched for dead animals under 26 randomly selected turbines. Six 76.2 m by 3.0 m transects were maintained...
We examined bird and bat mortality at a new 89-turbine windfarm constructed in an environmentally sensitive area in north-central Iowa. The windfarm became operational in November 2001. It is located in cropland between three Wildlife Management Areas (WMA's) with historically high bird use. In the past, migrant and resident waterfowl, shorebirds, raptors, and songbirds moved between the WMA's through the area now occupied by the windfarm. Studies of bird collision mortality in California and elsewhere raised concerns about the possibility of mortalities in this area. From April 15, 2003 and December 15, 2003 we searched for dead animals under 26 randomly selected turbines. Six 76.2 m by 3.0 m transects were maintained...
Increasing demands on arid and semiarid ecosystems, which comprise one-third of Earth's terrestrial environment, create an urgent need to understand their biodiversity, function, and mechanisms of change. Sagebrush (Artemisia) steppe, the largest semiarid vegetation type in North America, is endangered because of losses to agriculture, excessive grazing, and invasive species. Establishment in 1950 of what is now designated as the Idaho National Engineering and Environmental Laboratory (southeastern Idaho, USA) created the largest existing reserve of this extensive vegetation type. We used cover, density, and frequency data for vascular plants sampled on 79 permanent plots nine times during 45 years to (1) assess...
Longterm (45 years) temporal data were used to assess the influence of spatial scale on temporal patterns of a semi-arid west Texas grassland. Temporal basal area dynamics of common curlymesquite (Hilaria belangeri (Steud.) Nash) collected from permanent plots within two areas that were released from disturbance (longterm overgrazing and drought), were evaluated at two spatial scales (quadrat, site). Wiens (1989) proposed hypotheses to characterize the influence of scale on variability, predictability, and equilibrium. These hypotheses were tested for this grassland and temporal patterns observed were different for each spatial scale. The large scale (site) was characterized by low variation between units, high...
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In 2004 U.S. Geological Survey biologists recorded vegetation and biological soil crust (BSC) cover by species as well as measured soil stability and compaction data along 85 transects at the Badger Wash study area in western Colorado. Soil samples were collected and processed for chemistry and texture. Using analysis of variance and nonmetric multidimensional scaling (NMDS) we assessed the cover of vegetation and BSC both grouped by plant physiognomy and dynamic soil properties (soil chemistry/nutrients and stability and compaction) as influenced by the effects of grazing history and soil group (which varied by slope, topographic wetness index and soil properties). Vegetation and BSC cover data were also compared...
Tags: Badger Wash, Colorado, Dry Canyon Wash, Ecology, Environmental Health, All tags...
We examined bird and bat mortality at a new 89-turbine windfarm constructed in an environmentally sensitive area in north-central Iowa. The windfarm became operational in November 2001. It is located in cropland between three Wildlife Management Areas (WMA's) with historically high bird use. In the past, migrant and resident waterfowl, shorebirds, raptors, and songbirds moved between the WMA's through the area now occupied by the windfarm. Studies of bird collision mortality in California and elsewhere raised concerns about the possibility of mortalities in this area. From April 15, 2003 and December 15, 2003 we searched for dead animals under 26 randomly selected turbines. Six 76.2 m by 3.0 m transects were maintained...
We examined bird and bat mortality at a new 89-turbine windfarm constructed in an environmentally sensitive area in north-central Iowa. The windfarm became operational in November 2001. It is located in cropland between three Wildlife Management Areas (WMA's) with historically high bird use. In the past, migrant and resident waterfowl, shorebirds, raptors, and songbirds moved between the WMA's through the area now occupied by the windfarm. Studies of bird collision mortality in California and elsewhere raised concerns about the possibility of mortalities in this area. From April 15, 2003 and December 15, 2003 we searched for dead animals under 26 randomly selected turbines. Six 76.2 m by 3.0 m transects were maintained...
Beaver–willow (Castor-Salix) communities are a unique and vital component of healthy wetlands throughout the Holarctic region. Beaver selectively forage willow to provide fresh food, stored winter food, and construction material. The effects of this complex foraging behavior on the structure and function of willow communities is poorly understood. Simulation modeling may help ecologists understand these complex interactions. In this study, a modified version of the SAVANNA ecosystem model was developed to better understand how beaver foraging affects the structure and function of a willow community in a simulated riparian ecosystem in Rocky Mountain National Park, Colorado (RMNP). The model represents willow in...


    map background search result map search result map Vegetation and Soils Data from Grazed and Ungrazed Watersheds in the Badger Wash Study Area, Colorado, USA Vegetation and Soils Data from Grazed and Ungrazed Watersheds in the Badger Wash Study Area, Colorado, USA