Douglas Johnson (Former Employee)
Science and Products
Filter Total Items: 318
Factors associated with duck nest success in the prairie pothole region of Canada Factors associated with duck nest success in the prairie pothole region of Canada
Populations of some dabbling ducks have declined sharply in recent decades and information is needed to understand reasons for this. During 1982-85, we studied duck nesting for 1-4 years in 17 1.6 by 16.0-km, high-density duck areas in the Prairie Pothole Region (PPR) of Canada, 9 in parkland and 8 in prairie. We estimated nest-initiation dates, habitat preferences, nest success, and...
Authors
Raymond J. Greenwood, Alan B. Sargeant, Douglas H. Johnson, Lewis M. Cowardin, Terry L. Shaffer
[Book review] Railroad Postcards in the Age of Steam, by H. Roger Grant [Book review] Railroad Postcards in the Age of Steam, by H. Roger Grant
Book review: Railroad Postcards in the Age of Steam. H. Roger Grant. University Of Iowa Press. 1994. 217 pages. ISBN: 0877454655.
Authors
Douglas H. Johnson
Statistical sirens: The allure of nonparametrics Statistical sirens: The allure of nonparametrics
Although nonparametric statistical methods have a role to play in the analysis of data, often their virtues are overstated and their deficiencies overlooked. A recent Special Feature in Ecology advocated nonparametric methods because of an erroneously stated advantage that they require no assumptions regarding the distribution underlying the observations. The present paper points out...
Authors
Douglas H. Johnson
Conservation Reserve Program and migratory birds in the northern Great Plains Conservation Reserve Program and migratory birds in the northern Great Plains
U.S. Department of Agriculture programs have mediated supply and demand of commodities and maintained the agricultural industry, but several programs have also offered various kinds of conservation benefits. The 1985 Food Security Act (Farm Bill) featured the Conservation Reserve Program (CRP), which paid farmers to plant perennial cover on highly erodible lands and to leave this land...
Authors
Douglas H. Johnson, Rolf R. Koford
Contributions of the Conservation Reserve Program to populations of breeding birds in North Dakota Contributions of the Conservation Reserve Program to populations of breeding birds in North Dakota
Previous studies have shown that habitat provided by the Conservation Reserve Program (CRP), a feature of the 1985 farm bill, is used by many birds. The present study quantitatively assesses the importance of the CRP by estimating changes in breeding-bird populations of North Dakota projected if CRP land would revert to cultivation. Of 18 species that were common in CRP or crop fields or...
Authors
Douglas H. Johnson, L.D. Igl
Using known populations of pronghorn to evaluate sampling plans and estimators Using known populations of pronghorn to evaluate sampling plans and estimators
Although sampling plans and estimators of abundance have good theoretical properties, their performance in real situations is rarely assessed because true population sizes are unknown. We evaluated widely used sampling plans and estimators of population size on 3 known clustered distributions of pronghorn (Antilocapra americana). Our criteria were accuracy of the estimate, coverage of 95...
Authors
Kathy M. Kraft, Douglas H. Johnson, Jack M. Samuelson, Stephen H. Allen
Science and Products
Filter Total Items: 318
Factors associated with duck nest success in the prairie pothole region of Canada Factors associated with duck nest success in the prairie pothole region of Canada
Populations of some dabbling ducks have declined sharply in recent decades and information is needed to understand reasons for this. During 1982-85, we studied duck nesting for 1-4 years in 17 1.6 by 16.0-km, high-density duck areas in the Prairie Pothole Region (PPR) of Canada, 9 in parkland and 8 in prairie. We estimated nest-initiation dates, habitat preferences, nest success, and...
Authors
Raymond J. Greenwood, Alan B. Sargeant, Douglas H. Johnson, Lewis M. Cowardin, Terry L. Shaffer
[Book review] Railroad Postcards in the Age of Steam, by H. Roger Grant [Book review] Railroad Postcards in the Age of Steam, by H. Roger Grant
Book review: Railroad Postcards in the Age of Steam. H. Roger Grant. University Of Iowa Press. 1994. 217 pages. ISBN: 0877454655.
Authors
Douglas H. Johnson
Statistical sirens: The allure of nonparametrics Statistical sirens: The allure of nonparametrics
Although nonparametric statistical methods have a role to play in the analysis of data, often their virtues are overstated and their deficiencies overlooked. A recent Special Feature in Ecology advocated nonparametric methods because of an erroneously stated advantage that they require no assumptions regarding the distribution underlying the observations. The present paper points out...
Authors
Douglas H. Johnson
Conservation Reserve Program and migratory birds in the northern Great Plains Conservation Reserve Program and migratory birds in the northern Great Plains
U.S. Department of Agriculture programs have mediated supply and demand of commodities and maintained the agricultural industry, but several programs have also offered various kinds of conservation benefits. The 1985 Food Security Act (Farm Bill) featured the Conservation Reserve Program (CRP), which paid farmers to plant perennial cover on highly erodible lands and to leave this land...
Authors
Douglas H. Johnson, Rolf R. Koford
Contributions of the Conservation Reserve Program to populations of breeding birds in North Dakota Contributions of the Conservation Reserve Program to populations of breeding birds in North Dakota
Previous studies have shown that habitat provided by the Conservation Reserve Program (CRP), a feature of the 1985 farm bill, is used by many birds. The present study quantitatively assesses the importance of the CRP by estimating changes in breeding-bird populations of North Dakota projected if CRP land would revert to cultivation. Of 18 species that were common in CRP or crop fields or...
Authors
Douglas H. Johnson, L.D. Igl
Using known populations of pronghorn to evaluate sampling plans and estimators Using known populations of pronghorn to evaluate sampling plans and estimators
Although sampling plans and estimators of abundance have good theoretical properties, their performance in real situations is rarely assessed because true population sizes are unknown. We evaluated widely used sampling plans and estimators of population size on 3 known clustered distributions of pronghorn (Antilocapra americana). Our criteria were accuracy of the estimate, coverage of 95...
Authors
Kathy M. Kraft, Douglas H. Johnson, Jack M. Samuelson, Stephen H. Allen