Geology ReportsSearch

Geology topics

A. D. Geis

Publications and source records attributed to A. D. Geis.

At least 19 recordsLinked to original sources

Bird population and habitat surveys in urban areas

Breeding bird populations in six habitats in Columbia. MD, were studied to develop procedures suitable for measuring bird use of residential areas and to identify habitat characteristics that define the distribution of various common bird species. A procedure to measure bird use based on 4-min transect counts on plots measuring 91 m ? 91 m proved better than point counts. Transect counts reduced many of the problems associated with counting birds in urban areas, such as varying noise and visibility. Eighty percent of observations were recorded in the first 4 min. Habitat measurement procedures were examined also. It was found that a subsample of woody tree and shrub crown volumes made on 0.2 ha was highly correlated with similar measures made on 0.8-ha plots.

Landscape and Urban Planning

Effects of roads on small mammals

(1) The study was designed to determine the effects of roads on the diversity, spatial distribution, and density of small mammals. (2) Forty species of small mammal (5859 individuals) were snap-trapped in the study. Data resulted from 144 360 trap-nights of effort for an average of 4.06 captures per 100 trap-nights. (3) Small mammal community structure and density were both influenced by roads. Community structure in right-of-way (ROW) habitat was different from that in adjacent habitat. Five species did not prefer ROW habitat: the golden mouse, dusky-footed woodrat, brush mouse, pinon mouse, and California red-backed vole. However, there were more species present in ROW habitat than in adjacent habitat. Grassland species generally preferred ROW habitat and many less habitat-specific species were distributed in ROW and adjacent habitat. (4) Small mammal density (all species combined) was greater in interstate ROW habitat than in adjacent habitat. This was also true individually for the eastern harvest mouse, white-footed mouse, meadow vole, prairie vole, vagrant shrew. Townsend's vole, and California vole. Small mammal density was less in county road ROWs than in adjacent habitat, probably because of the small size of these areas. The data indicate that ROW habitat and its accompanying edge are attractive no: only to grassland species but also to many less habitat-specific species that make use of the ROW-edge-adjacent habitat complex. (5) Mortality on interstate highways was greatest for those species with highest densities in ROW habitat, and did not appear to be detrimental to populations of these species.

Journal of Applied Ecology

Feeding Wild Birds

Explore the source record for details and available documents.

Virginia Cooperative Extension Service, Publicatio

Looking ahead!

Explore the source record for details and available documents.

Naturopa