Daniel Twedt, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 93
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 J. Twedt, Curtis O. Nelms, Virginia Rettig, S. Ray 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 J. 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 W. Brown, James R. Nassar
Breeding bird census: Bottomland hardwood forest I-IV Breeding bird census: Bottomland hardwood forest I-IV
No abstract available.
Authors
Daniel J. Twedt
Science and Products
Filter Total Items: 93
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 J. Twedt, Curtis O. Nelms, Virginia Rettig, S. Ray 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 J. 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 W. Brown, James R. Nassar
Breeding bird census: Bottomland hardwood forest I-IV Breeding bird census: Bottomland hardwood forest I-IV
No abstract available.
Authors
Daniel J. Twedt