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M.L. Morrison

Publications and source records attributed to M.L. Morrison.

8 recordsLinked to original sources
USGS2001

Wildlife Study Design

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Springer series on environmental management.↗
USGS1999

Introduction

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Book chapter↗
USGS1984

Effects of the herbicide glyphosate on avian community structure in the Oregon coast range

A study was conducted on vegetative changes induced by the herbicide glyphosate, and the resultant habitat use of birds nesting on two clearcuts in western Oregon. About 23 percent of total plant cover was initially damaged by aerial application of glyphosate. Most measures of vegetation on the treated site decreased relative to the untreated site 1 year after glyphosate application. By 2 years post-spray, vegetation on the treated site had recovered to near pre-spray status. No difference in density of the bird community was evident between treated and untreated sites during all years of study although individual species densities were modified. Several bird species decreased their use of shrub cover, and increased their use of deciduous trees 1 year after treatment. By 2 years post-spray, many species had returned to pre-spray use of most measured habitat components. Results indicated that application of glyphosate can modify the density and habitat use of birds.

Forest Science↗
USGS1983

Eggshell thickness and DDE residue levels in vlulture eggs

Post-DDT (post-1947) eggshell thickness was examined in samples of Turkey Vulture, Black Vulture, and Crested Caracara eggs from several parts of the United States. Highly significant post-DDT decreases in eggshell thickness indices of at least 10 percent were found in Turkey Vulture eggs from California, Florida, and Texas and in Black Vulture eggs from Texas and Florida. Over one-third of the Black VUlture eggs and about 30 percent of the Turkey Vulture eggs from Texas showed thinning exceeding 20 percent, a level associated with reproductive failure and population decline in other species. A strong negative correlation was found between eggshell thickness indices and DDE residues extracted from eggshell membranes in California and Texas samples of Turkey Vulture eggs and in Texas Black Vulture eggs. Crested Caracara eggs from Texas and Florida showed mean changes in eggshell thickness indices of only -5.6 and -8.2 percent, respectively, although thinning in a few eggs from both states exceeded 20 percent. Most of the post-DDT Old World vulture eggs examined appeared to be of normal thickness, with low DDE residue levels in eggshell membranes; but single eggs of Egyptian Vulture from India, Cinereous Vulture from Spain, and White-headed Vulture from Zambia showed apparent thinning. Further monitoring of vulture populations in tropical regions, where DDT use is still increasing, is recommended.

Book chapter↗
USGS1983

Impacts of forest herbicides on wildlife: Toxicity and habitat alteration

This paper begins with a review of both laboratory and field studies on tbe possible direct toxic effects of herbicides on terrestrial vertebrates, primarily birds and mammals. Alteration of the palatability of forage and changes in reproductive success are also discussed. Emphasis is placed on the use of herbicides in forestry; studies dealing with agricultural systems are referenced where appropriate. The indirect effects of herbicides on wildlife-habitat are then conceptualized and quantified using data from a 3-year study on effects of phenoxy and glyphosate herbicides on bird and small mammal communities in western Oregon. Data on density and habitat use are presented and compared with data available from other geographic regions.

Transactions of the North American Wildlife and Na↗