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Geology topics

R.M. DeGraaf

Publications and source records attributed to R.M. DeGraaf.

4 recordsLinked to original sources

Description and evaluation of a remote camera and triggering system to monitor carnivores

Remotely triggered cameras have been used in many ecological studies, but most are relatively inexpensive one-time-only systems or expensive infrared systems. We describe the setup and wiring technique for a moderately priced, multiple-photo camera system. Two study areas, California and Vermont, were used to assess usefulness of the camera system. Although some target carnivore species were photographed regularly, visitation rates of other carnivores were low, due either to low population densities or camera shyness. Cameras generally worked well under all conditions, but the pressure-plate triggering devices sometimes became inoperable during heavy rains. Other camera activation systems may reveal additional uses for this remote camera system.

Wildlife Society Bulletin

Integrating across scales: Effectively applying science for the successful conservation of Atlantic salmon (Salmo salar)

Atlantic salmon (Salmo salar) is an excellent species on which to focus synthetic, integrative investigations because it is an economically important species that captures the public imagination, is heavily impacted by humans, uses several ecosystems over its life, and is the subject of a large body of extant literature. The following 24 papers were solicited to provide the biological basis for effective and innovative approaches that biologists, managers, and social scientists can use to develop policies that sustain Atlantic salmon and related species. Together these papers highlight the need for and benefits of (a) synthesizing within populations, (b) choosing the appropriate scale, (c) comparing across populations using rigorous, focused, question-oriented methods, (d) integrating across disciplines, (e) incorporating the human perspective, (f) linking multiple ecosystems, and (g) applied problem solving. To show how Atlantic salmon can guide research and conservation efforts for other species in other systems, we review the justification for the supplement and summarize the defining concepts that emerge from the volume.

Conference Paper

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