From evidence of lingering DDT damage, to questions about artificial wetlands as habitat, to the uses of a dynamic ecosystem evaluation and monitoring tool, USGS scientists will present a variety of wildlife research findings at the annual meeting of The Wildlife Society at the Buffalo Convention Center, Buffalo, N.Y., Sept. 22-26, 1998.
Native Animals Snub Exotic Vegetation and Grazed Areas -- Tues. Sept., 22, session 3
Mammals, reptiles and amphibians, and other animals are signficantly more common in areas covered primarily by native vegetation than in areas covered primarily by exotic vegetation that have also experienced various levels of grazing.
In 1990, researchers began monitoring 450 sample plots to determine the diversity of land animals at the 75,000-acre Golden Gate National Recreation Area near San Franciso. The monitored habitats consisted of coastal grassland, scrub and evergreen woodlands, some of which were under active grazing or had experienced grazing historically.
The prevalence of native animals in previously grazed native vegetation is significant. For example, in one ten-day trapping period, researchers trapped only two species in the previously grazed-exotic vegetation habitat, but they trapped 17 native species on nearby sites dominated by native grasses and shrubs. ("Grazing Succession Plots of the Golden Gate National Parks, California," by Judd A. Howell and Marcia Semenoff-Irving, USGS, Sausalito, Calif. )
DDT May Still be Having an Impact on Cormorants -- Thurs., Sept., 24, session 7b
Although DDT was banned in the U.S. in the 1970s, results of a 1994-1995 study
suggest DDT may still be adversely affecting reproduction of the double-crested
cormorant. The study examined the effects of organochlorines, including DDE (a
degradation product of DDT) and PCBs (polychlorinated biphenyls), on the
Contact: Bob Reynolds
United States Geological Survey