Daniel Twedt, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 93
Development of management objectives for breeding birds in the Mississippi Alluvial Valley Development of management objectives for breeding birds in the Mississippi Alluvial Valley
We used a six-step process to set habitat objectives and population goals for breeding birds in the Mississippi Alluvial Valley. Specifically, we used existing empirical studies and mathematically derived viable population estimates to define habitat objectives and population goals for bottomland hardwood forest, the most important habitat type in this physiographic area. Although...
Authors
A.J. Mueller, D.J. Twedt, C.R. Loesch
An evaluation strategy for conservation goals of the Mississippi Alluvial Valley An evaluation strategy for conservation goals of the Mississippi Alluvial Valley
The population goals and habitat objectives established by the Mississippi Alluvial Valley Migratory Bird Initiative are based on several unverified assumptions. We have developed an evaluation strategy that identifies research needed to verify these assumptions. We also have outlined a monitoring strategy designed to track progress toward achieving habitat objectives and population...
Authors
D.J. Twedt, P.B. Hamel, R.J. Cooper, M.S. Woodrey
Conservation planning and monitoring avian habitat Conservation planning and monitoring avian habitat
Migratory bird conservation plans should not only develop population goals, they also should establish attainable objectives for optimizing avian habitats. Meeting population goals is of paramount importance, but progress toward established habitat objectives can generally be monitored more easily than can progress toward population goals. Additionally, local or regional habitat...
Authors
D.J. Twedt, C.R. Loesch
Temporal differences in point counts of bottomland forest landbirds Temporal differences in point counts of bottomland forest landbirds
We compared number of avian species and individuals in morning and evening point counts during the breeding season and during winter in a bottomland hardwood forest in west-central Mississippi. USA. In both seasons, more species and individuals were recorded during morning counts than during evening counts. We also compared morning and evening detections for 18 species during the...
Authors
W.P. Smith, D.J. Twedt
Impact of forest type and management strategy on avian densities in the Mississippi Alluvial Valley, USA Impact of forest type and management strategy on avian densities in the Mississippi Alluvial Valley, USA
Avian territory densities were determined from 20 Breeding Bird Censuses in mature (>30 years) bottomland hardwood stand: and 18 Breeding Bird Censuses in young (6-9 years old) cottonwood (Populas deltoides) plantations in the Mississippi Alluvial Valley. Avian species richness, diversity, and territory density were greater (p 0.01) in bottomland hardwood stands than in intensively...
Authors
D.J. Twedt, R.R. Wilson, J. Henne-Kerr, R.B. Hamilton
Waterfowl density on agricultural fields managed to retain water in winter Waterfowl density on agricultural fields managed to retain water in winter
Managed water on private and public land provides habitat for wintering waterfowl in the Mississippi Valley, where flood control projects have reduced the area of natural flooding. We compared waterfowl densities on rice, soybean, and moist-soil fields under cooperative agreements to retain water from 1 November through 28 February in Arkansas and Mississippi and assessed temporal...
Authors
D.J. Twedt, C.O. Nelms
Forest area and distribution in the Mississippi alluvial valley: Implications for breeding bird conservation Forest area and distribution in the Mississippi alluvial valley: Implications for breeding bird conservation
Knowing the current forest distribution and patch size characteristics is integral to the development of geographically defined, habitat-based conservation objectives for breeding birds. Towards this end, we classified 2.6 million ha of forest cover within the Mississippi Alluvial Valley using 1992 thematic mapper satellite imagery. Although historically this area, from southern Illinois...
Authors
D.J. Twedt, C.R. Loesch
Increasing point-count duration increases standard error Increasing point-count duration increases standard error
We examined data from point counts of varying duration in bottomland forests of west Tennessee and the Mississippi Alluvial Valley to determine if counting interval influenced sampling efficiency. Estimates of standard error increased as point count duration increased both for cumulative number of individuals and species in both locations. Although point counts appear to yield data with...
Authors
W.P. Smith, D.J. Twedt, P.B. Hamel, R.P. Ford, D.A. Wiedenfeld, R.J. Cooper
Shorebird use of managed wetlands in the Mississippi Alluvial Valley Shorebird use of managed wetlands in the Mississippi Alluvial Valley
We assessed shorebird densities on managed wetland habitats during fall and winter within the primarily agricultural landscape of the Mississippi Alluvial Valley. From November through March, shorebird densities were greater on soybean fields than on rice or moist-soil fields. Killdeer (Charadrius vociferus) and Common Snipe (Gallinago gallinago) were common throughout winter, whereas...
Authors
Daniel Twedt, Curtis Nelms, Virginia Rettig, S. Aycock
Bottomland hardwood reforestation for neotropical migratory birds: Are we missing the forest for the trees? Bottomland hardwood reforestation for neotropical migratory birds: Are we missing the forest for the trees?
Reforestation of bottomland hardwoods on lands managed for wildlife or timber production has historically emphasized planting heavy-seeded oaks (Quercus spp.). Although techniques have been developed for successful oak establishment, these plantings often require 5 or more years before establishing a 3-dimensional forest structure. We suggest that lands planted to fast-growing early...
Authors
Daniel Twedt, J. Portwood
Evaluation of a mallard HSI model for the Lower Mississippi Valley Evaluation of a mallard HSI model for the Lower Mississippi Valley
We evaluated a habitat suitability (HSI) model developed for mallards (Anas platyrhynchos) wintering in the Lower Mississippi Valley by comparing mallard densities obtained from aerial surveys with habitat suitability indices derived from satellite imagery for 25, 256km2 sampling units. Regression models that related mallard densities to habitat suitability indices accounted for only 29%...
Authors
D.J. Twedt, Michael Brown, James Nassar
Breeding bird census: Bottomland hardwood forest I-IV Breeding bird census: Bottomland hardwood forest I-IV
No abstract available.
Authors
Daniel Twedt
Science and Products
Filter Total Items: 93
Development of management objectives for breeding birds in the Mississippi Alluvial Valley Development of management objectives for breeding birds in the Mississippi Alluvial Valley
We used a six-step process to set habitat objectives and population goals for breeding birds in the Mississippi Alluvial Valley. Specifically, we used existing empirical studies and mathematically derived viable population estimates to define habitat objectives and population goals for bottomland hardwood forest, the most important habitat type in this physiographic area. Although...
Authors
A.J. Mueller, D.J. Twedt, C.R. Loesch
An evaluation strategy for conservation goals of the Mississippi Alluvial Valley An evaluation strategy for conservation goals of the Mississippi Alluvial Valley
The population goals and habitat objectives established by the Mississippi Alluvial Valley Migratory Bird Initiative are based on several unverified assumptions. We have developed an evaluation strategy that identifies research needed to verify these assumptions. We also have outlined a monitoring strategy designed to track progress toward achieving habitat objectives and population...
Authors
D.J. Twedt, P.B. Hamel, R.J. Cooper, M.S. Woodrey
Conservation planning and monitoring avian habitat Conservation planning and monitoring avian habitat
Migratory bird conservation plans should not only develop population goals, they also should establish attainable objectives for optimizing avian habitats. Meeting population goals is of paramount importance, but progress toward established habitat objectives can generally be monitored more easily than can progress toward population goals. Additionally, local or regional habitat...
Authors
D.J. Twedt, C.R. Loesch
Temporal differences in point counts of bottomland forest landbirds Temporal differences in point counts of bottomland forest landbirds
We compared number of avian species and individuals in morning and evening point counts during the breeding season and during winter in a bottomland hardwood forest in west-central Mississippi. USA. In both seasons, more species and individuals were recorded during morning counts than during evening counts. We also compared morning and evening detections for 18 species during the...
Authors
W.P. Smith, D.J. Twedt
Impact of forest type and management strategy on avian densities in the Mississippi Alluvial Valley, USA Impact of forest type and management strategy on avian densities in the Mississippi Alluvial Valley, USA
Avian territory densities were determined from 20 Breeding Bird Censuses in mature (>30 years) bottomland hardwood stand: and 18 Breeding Bird Censuses in young (6-9 years old) cottonwood (Populas deltoides) plantations in the Mississippi Alluvial Valley. Avian species richness, diversity, and territory density were greater (p 0.01) in bottomland hardwood stands than in intensively...
Authors
D.J. Twedt, R.R. Wilson, J. Henne-Kerr, R.B. Hamilton
Waterfowl density on agricultural fields managed to retain water in winter Waterfowl density on agricultural fields managed to retain water in winter
Managed water on private and public land provides habitat for wintering waterfowl in the Mississippi Valley, where flood control projects have reduced the area of natural flooding. We compared waterfowl densities on rice, soybean, and moist-soil fields under cooperative agreements to retain water from 1 November through 28 February in Arkansas and Mississippi and assessed temporal...
Authors
D.J. Twedt, C.O. Nelms
Forest area and distribution in the Mississippi alluvial valley: Implications for breeding bird conservation Forest area and distribution in the Mississippi alluvial valley: Implications for breeding bird conservation
Knowing the current forest distribution and patch size characteristics is integral to the development of geographically defined, habitat-based conservation objectives for breeding birds. Towards this end, we classified 2.6 million ha of forest cover within the Mississippi Alluvial Valley using 1992 thematic mapper satellite imagery. Although historically this area, from southern Illinois...
Authors
D.J. Twedt, C.R. Loesch
Increasing point-count duration increases standard error Increasing point-count duration increases standard error
We examined data from point counts of varying duration in bottomland forests of west Tennessee and the Mississippi Alluvial Valley to determine if counting interval influenced sampling efficiency. Estimates of standard error increased as point count duration increased both for cumulative number of individuals and species in both locations. Although point counts appear to yield data with...
Authors
W.P. Smith, D.J. Twedt, P.B. Hamel, R.P. Ford, D.A. Wiedenfeld, R.J. Cooper
Shorebird use of managed wetlands in the Mississippi Alluvial Valley Shorebird use of managed wetlands in the Mississippi Alluvial Valley
We assessed shorebird densities on managed wetland habitats during fall and winter within the primarily agricultural landscape of the Mississippi Alluvial Valley. From November through March, shorebird densities were greater on soybean fields than on rice or moist-soil fields. Killdeer (Charadrius vociferus) and Common Snipe (Gallinago gallinago) were common throughout winter, whereas...
Authors
Daniel Twedt, Curtis Nelms, Virginia Rettig, S. Aycock
Bottomland hardwood reforestation for neotropical migratory birds: Are we missing the forest for the trees? Bottomland hardwood reforestation for neotropical migratory birds: Are we missing the forest for the trees?
Reforestation of bottomland hardwoods on lands managed for wildlife or timber production has historically emphasized planting heavy-seeded oaks (Quercus spp.). Although techniques have been developed for successful oak establishment, these plantings often require 5 or more years before establishing a 3-dimensional forest structure. We suggest that lands planted to fast-growing early...
Authors
Daniel Twedt, J. Portwood
Evaluation of a mallard HSI model for the Lower Mississippi Valley Evaluation of a mallard HSI model for the Lower Mississippi Valley
We evaluated a habitat suitability (HSI) model developed for mallards (Anas platyrhynchos) wintering in the Lower Mississippi Valley by comparing mallard densities obtained from aerial surveys with habitat suitability indices derived from satellite imagery for 25, 256km2 sampling units. Regression models that related mallard densities to habitat suitability indices accounted for only 29%...
Authors
D.J. Twedt, Michael Brown, James Nassar
Breeding bird census: Bottomland hardwood forest I-IV Breeding bird census: Bottomland hardwood forest I-IV
No abstract available.
Authors
Daniel Twedt