Douglas Johnson
Douglas Johnson is a Research Statistician (Emeritus) for the USGS Northern Prairie Wildlife Research Center in Jamestown, North Dakota.
Science and Products
Filter Total Items: 310
Statistics for wildlifers: how much and what kind?
Quantitative methods are playing increasingly important roles in wildlife ecology and, ultimately, management. This change poses a challenge for wildlife practitioners and students who are not well-educated in mathematics and statistics. Here we give our opinions on what wildlife biologists should know about statistics, while recognizing that not everyone is inclined mathematically. For those who
Authors
D. H. Johnson, T.L. Shaffer, W.E. Newton
Habitat fragmentation effects on birds in grasslands and wetlands: A critique of our knowledge
Habitat fragmentation exacerbates the problem of habitat loss for grassland and wetland birds. Remaining patches of grasslands and wetlands may be too small, too isolated, and too influenced by edge effects to maintain viable populations of some breeding birds. Knowledge of the effects of fragmentation on bird populations is critically important for decisions about reserve design, grassland and we
Authors
D. H. Johnson
Surveys of calling amphibians in North Dakota
Amphibians have received increased attention in recent years from the scientific community and general public alike. Many populations throughout the world have declined, or have been extirpated, often without an apparent cause. Concern about the status of amphibians has translated into a growing interest in systematic and statistically sound monitoring programs. Several extensive efforts to monito
Authors
D. H. Johnson, R.D. Batie
Mitochondrial phylogeography, subspecific taxonomy, and conservation genetics of sandhill cranes (Grus canadensis; Aves: Gruidae)
Six subspecies of sandhill cranes (Grus canadensis) have been denoted based on perceived morphological and/or breeding locality differences among them. Three subspecies are migratory, breeding from the high arctic in North America and Siberia (lesser sandhill, G. c. canadensis),south through central Canada (Canadian sandhill, G. c. rowani) and into the northern United States (greater sandhill, G.
Authors
J.M. Rhymer, M.G. Fain, J. E. Austin, D. H. Johnson, C. Krajewski
Mitochondrial phylogeography, subspecific taxonomy, and conservation genetics of sandhill cranes (Grus canadensis; Aves: Gruidae)
Six subspecies of sandhill cranes (Grus canadensis) have been denoted based on perceived morphological and/or breeding locality differences among them. Three subspecies are migratory, breeding from the high arctic in North America and Siberia (lesser sandhill, G. c. canadensis), south through central Canada (Canadian sandhill, G. c. rowani) and into the northern United States (greater sandhill, G.
Authors
J.M. Rhymer, M.G. Fain, J. E. Austin, D. H. Johnson, C. Krajewski
Book review: Research techniques in animal ecology: Controversies and consequences, by Luigi Boitani and Todd K. Fuller
Review of: Research Techniques in Animal Ecology: Controversies and Consequences. Edited by Luigi Boitani and Todd K. Fuller. Columbia University Press, New York, USA. 2000. xxxii + 442 pp., index. $75.00, ISBN 0231113404 (cloth); $32.00, ISBN 0231113412 (paper).
Authors
D. H. Johnson
Area requirements of grassland birds: A regional perspective
Area requirements of grassland birds have not been studied except in tallgrass prairie. We studied the relation between both species-occurrence and density and patch size by conducting 699 fixed-radius point counts of 15 bird species on 303 restored grassland areas in nine counties in four northern Great Plains states. Northern Harrier (Circus cyaneus), Sedge Wren (Cistothorus platensis), Clay-col
Authors
Douglas H. Johnson, Lawrence D. Igl
Estimated areal extent of colonies of black-tailed prairie dogs in the northern Great Plains
During 1997–1998, we undertook an aerial survey, with an aerial line-intercept technique, to estimate the extent of colonies of black-tailed prairie dogs (Cynomys ludovicianus) in the northern Great Plains states of Nebraska, North Dakota, South Dakota, and Wyoming. We stratified the survey based on knowledge of colony locations, computed 2 types of estimates for each stratum, and combined ratio e
Authors
John G. Sidle, Douglas H. Johnson, Betty R. Euliss
Use of macroinvertebrates to identify cultivated wetlands in the Prairie Pothole Region
We evaluated the use of macroinvertebrates as a potential tool to identify dry and intensively farmed temporary and seasonal wetlands in the Prairie Pothole Region. The techniques we designed and evaluated used the dried remains of invertebrates or their egg banks in soils as indicators of wetlands. For both the dried remains of invertebrates and their egg banks, we weighted each taxon according t
Authors
Ned H. Euliss, David M. Mushet, Douglas H. Johnson
Habitat fragmentation effects on birds in grasslands: A critique of our knowledge
Habitat fragmentation exacerbates problems due to habitat loss for grassland and wetland birds. Remaining patches of grassland and wetland may be too small, too isolated, and too influenced by edge effects to maintain viable populations of some breeding birds. Knowledge of the effects of fragmentation on bird populations is critically important for decisions about reserve design, grassland and wet
Authors
Douglas H. Johnson
Evidence for edge effects on multiple levels in tallgrass prairie
We tested how edges affect nest survival and predator distribution in a native tallgrass prairie system in southwestern Missouri using artificial nests, natural nests of Dickcissels (Spiza americana) and Henslow's Sparrows (Ammodramus henslowii), and mammal track stations. Survival of artificial nests was lower within 30 m of forest edge. Nesting success of Dickcissels and Henslow's Sparrows was l
Authors
Maiken Winter, Douglas H. Johnson, John Faaborg
Science and Products
Filter Total Items: 310
Statistics for wildlifers: how much and what kind?
Quantitative methods are playing increasingly important roles in wildlife ecology and, ultimately, management. This change poses a challenge for wildlife practitioners and students who are not well-educated in mathematics and statistics. Here we give our opinions on what wildlife biologists should know about statistics, while recognizing that not everyone is inclined mathematically. For those who
Authors
D. H. Johnson, T.L. Shaffer, W.E. Newton
Habitat fragmentation effects on birds in grasslands and wetlands: A critique of our knowledge
Habitat fragmentation exacerbates the problem of habitat loss for grassland and wetland birds. Remaining patches of grasslands and wetlands may be too small, too isolated, and too influenced by edge effects to maintain viable populations of some breeding birds. Knowledge of the effects of fragmentation on bird populations is critically important for decisions about reserve design, grassland and we
Authors
D. H. Johnson
Surveys of calling amphibians in North Dakota
Amphibians have received increased attention in recent years from the scientific community and general public alike. Many populations throughout the world have declined, or have been extirpated, often without an apparent cause. Concern about the status of amphibians has translated into a growing interest in systematic and statistically sound monitoring programs. Several extensive efforts to monito
Authors
D. H. Johnson, R.D. Batie
Mitochondrial phylogeography, subspecific taxonomy, and conservation genetics of sandhill cranes (Grus canadensis; Aves: Gruidae)
Six subspecies of sandhill cranes (Grus canadensis) have been denoted based on perceived morphological and/or breeding locality differences among them. Three subspecies are migratory, breeding from the high arctic in North America and Siberia (lesser sandhill, G. c. canadensis),south through central Canada (Canadian sandhill, G. c. rowani) and into the northern United States (greater sandhill, G.
Authors
J.M. Rhymer, M.G. Fain, J. E. Austin, D. H. Johnson, C. Krajewski
Mitochondrial phylogeography, subspecific taxonomy, and conservation genetics of sandhill cranes (Grus canadensis; Aves: Gruidae)
Six subspecies of sandhill cranes (Grus canadensis) have been denoted based on perceived morphological and/or breeding locality differences among them. Three subspecies are migratory, breeding from the high arctic in North America and Siberia (lesser sandhill, G. c. canadensis), south through central Canada (Canadian sandhill, G. c. rowani) and into the northern United States (greater sandhill, G.
Authors
J.M. Rhymer, M.G. Fain, J. E. Austin, D. H. Johnson, C. Krajewski
Book review: Research techniques in animal ecology: Controversies and consequences, by Luigi Boitani and Todd K. Fuller
Review of: Research Techniques in Animal Ecology: Controversies and Consequences. Edited by Luigi Boitani and Todd K. Fuller. Columbia University Press, New York, USA. 2000. xxxii + 442 pp., index. $75.00, ISBN 0231113404 (cloth); $32.00, ISBN 0231113412 (paper).
Authors
D. H. Johnson
Area requirements of grassland birds: A regional perspective
Area requirements of grassland birds have not been studied except in tallgrass prairie. We studied the relation between both species-occurrence and density and patch size by conducting 699 fixed-radius point counts of 15 bird species on 303 restored grassland areas in nine counties in four northern Great Plains states. Northern Harrier (Circus cyaneus), Sedge Wren (Cistothorus platensis), Clay-col
Authors
Douglas H. Johnson, Lawrence D. Igl
Estimated areal extent of colonies of black-tailed prairie dogs in the northern Great Plains
During 1997–1998, we undertook an aerial survey, with an aerial line-intercept technique, to estimate the extent of colonies of black-tailed prairie dogs (Cynomys ludovicianus) in the northern Great Plains states of Nebraska, North Dakota, South Dakota, and Wyoming. We stratified the survey based on knowledge of colony locations, computed 2 types of estimates for each stratum, and combined ratio e
Authors
John G. Sidle, Douglas H. Johnson, Betty R. Euliss
Use of macroinvertebrates to identify cultivated wetlands in the Prairie Pothole Region
We evaluated the use of macroinvertebrates as a potential tool to identify dry and intensively farmed temporary and seasonal wetlands in the Prairie Pothole Region. The techniques we designed and evaluated used the dried remains of invertebrates or their egg banks in soils as indicators of wetlands. For both the dried remains of invertebrates and their egg banks, we weighted each taxon according t
Authors
Ned H. Euliss, David M. Mushet, Douglas H. Johnson
Habitat fragmentation effects on birds in grasslands: A critique of our knowledge
Habitat fragmentation exacerbates problems due to habitat loss for grassland and wetland birds. Remaining patches of grassland and wetland may be too small, too isolated, and too influenced by edge effects to maintain viable populations of some breeding birds. Knowledge of the effects of fragmentation on bird populations is critically important for decisions about reserve design, grassland and wet
Authors
Douglas H. Johnson
Evidence for edge effects on multiple levels in tallgrass prairie
We tested how edges affect nest survival and predator distribution in a native tallgrass prairie system in southwestern Missouri using artificial nests, natural nests of Dickcissels (Spiza americana) and Henslow's Sparrows (Ammodramus henslowii), and mammal track stations. Survival of artificial nests was lower within 30 m of forest edge. Nesting success of Dickcissels and Henslow's Sparrows was l
Authors
Maiken Winter, Douglas H. Johnson, John Faaborg