Douglas Johnson (Former Employee)
Science and Products
Filter Total Items: 318
Nesting biology of three grassland passerines in the northern tallgrass prairie Nesting biology of three grassland passerines in the northern tallgrass prairie
Basic nesting information on grassland passerines is needed for improving grassland bird management. Among the information needs are (1) the suitability of nesting habitat, (2) periods during the breeding season in which birds are most vulnerable to disturbances, and (3) how to fit grasslands into a prioritization scheme for conservation. Comparisons of nesting parameters among grassland...
Authors
Maiken Winter, Douglas H. Johnson, Jill A. Shaffer, W. Daniel Svedarsky
Effects of distance from cattle water developments on grassland birds Effects of distance from cattle water developments on grassland birds
Many North American grassland bird populations appear to be declining, which may be due to changes in grazing regimes on their breeding areas. Establishment of water developments and confining cattle (Bos taurus L.) to small pastures often minimizes spatial heterogeneity of cattle forage consumption, which may lead to uniformity in vegetative structure. This increased uniformity may...
Authors
A.L. Fontaine, P.L. Kennedy, Douglas H. Johnson
Calibration of remotely sensed, coarse resolution NDVI to CO2 fluxes in a sagebrush–steppe ecosystem Calibration of remotely sensed, coarse resolution NDVI to CO2 fluxes in a sagebrush–steppe ecosystem
The net ecosystem exchange (NEE) of carbon flux can be partitioned into gross primary productivity (GPP) and respiration (R). The contribution of remote sensing and modeling holds the potential to predict these components and map them spatially and temporally. This has obvious utility to quantify carbon sink and source relationships and to identify improved land management strategies for
Authors
Bruce K. Wylie, Douglas A. Johnson, Emilio Laca, Nicanor Z. Saliendra, Tagir G. Gilmanov, Bradley C. Reed, Larry L. Tieszen, Bruce B. Worstell
Guidelines for finding nests of passerine birds in tallgrass prairie Guidelines for finding nests of passerine birds in tallgrass prairie
The productivity of birds is one of the most critical components of their natural history affected by habitat quality. Birds might occur at high densities in a given habitat patch but have low nesting success. Such "population sinks" would not be detected if observers relied solely on estimates of bird density. Therefore, it is essential to monitor nests and determine their outcomes...
Authors
Maiken Winter, Shawn E. Hawks, Jill A. Shaffer, Douglas H. Johnson
Effects of leafy spurge infestation on grassland birds Effects of leafy spurge infestation on grassland birds
Grassland bird populations are declining. Invasive plant species may be contributing to these declines by altering habitat quality. However, the effects of invasive plants on grassland birds are largely unknown. Leafy spurge (Euphorbia esula) is an exotic, invasive weed in the northern Great Plains. We examined the effects of leafy spurge infestation on densities of breeding birds, nest...
Authors
D.M. Scheiman, E.K. Bollinger, Douglas H. Johnson
Sampling designs for carnivore scent-station surveys Sampling designs for carnivore scent-station surveys
Scent stations usually are deployed in clusters to expedite data collection and increase the number of stations that can be operated for a given cost. Presumed benefits of cluster sampling may not be realized, however, unless cluster sizes are chosen with respect to sampling variation within and among clusters. To encourage and facilitate the use of efficient designs and reporting...
Authors
G.A. Sargeant, Douglas H. Johnson, W. E. Berg
Science and Products
Filter Total Items: 318
Nesting biology of three grassland passerines in the northern tallgrass prairie Nesting biology of three grassland passerines in the northern tallgrass prairie
Basic nesting information on grassland passerines is needed for improving grassland bird management. Among the information needs are (1) the suitability of nesting habitat, (2) periods during the breeding season in which birds are most vulnerable to disturbances, and (3) how to fit grasslands into a prioritization scheme for conservation. Comparisons of nesting parameters among grassland...
Authors
Maiken Winter, Douglas H. Johnson, Jill A. Shaffer, W. Daniel Svedarsky
Effects of distance from cattle water developments on grassland birds Effects of distance from cattle water developments on grassland birds
Many North American grassland bird populations appear to be declining, which may be due to changes in grazing regimes on their breeding areas. Establishment of water developments and confining cattle (Bos taurus L.) to small pastures often minimizes spatial heterogeneity of cattle forage consumption, which may lead to uniformity in vegetative structure. This increased uniformity may...
Authors
A.L. Fontaine, P.L. Kennedy, Douglas H. Johnson
Calibration of remotely sensed, coarse resolution NDVI to CO2 fluxes in a sagebrush–steppe ecosystem Calibration of remotely sensed, coarse resolution NDVI to CO2 fluxes in a sagebrush–steppe ecosystem
The net ecosystem exchange (NEE) of carbon flux can be partitioned into gross primary productivity (GPP) and respiration (R). The contribution of remote sensing and modeling holds the potential to predict these components and map them spatially and temporally. This has obvious utility to quantify carbon sink and source relationships and to identify improved land management strategies for
Authors
Bruce K. Wylie, Douglas A. Johnson, Emilio Laca, Nicanor Z. Saliendra, Tagir G. Gilmanov, Bradley C. Reed, Larry L. Tieszen, Bruce B. Worstell
Guidelines for finding nests of passerine birds in tallgrass prairie Guidelines for finding nests of passerine birds in tallgrass prairie
The productivity of birds is one of the most critical components of their natural history affected by habitat quality. Birds might occur at high densities in a given habitat patch but have low nesting success. Such "population sinks" would not be detected if observers relied solely on estimates of bird density. Therefore, it is essential to monitor nests and determine their outcomes...
Authors
Maiken Winter, Shawn E. Hawks, Jill A. Shaffer, Douglas H. Johnson
Effects of leafy spurge infestation on grassland birds Effects of leafy spurge infestation on grassland birds
Grassland bird populations are declining. Invasive plant species may be contributing to these declines by altering habitat quality. However, the effects of invasive plants on grassland birds are largely unknown. Leafy spurge (Euphorbia esula) is an exotic, invasive weed in the northern Great Plains. We examined the effects of leafy spurge infestation on densities of breeding birds, nest...
Authors
D.M. Scheiman, E.K. Bollinger, Douglas H. Johnson
Sampling designs for carnivore scent-station surveys Sampling designs for carnivore scent-station surveys
Scent stations usually are deployed in clusters to expedite data collection and increase the number of stations that can be operated for a given cost. Presumed benefits of cluster sampling may not be realized, however, unless cluster sizes are chosen with respect to sampling variation within and among clusters. To encourage and facilitate the use of efficient designs and reporting...
Authors
G.A. Sargeant, Douglas H. Johnson, W. E. Berg