PM01 Amphibian Research and Monitoring
Exhibit Hall
8:00 AM - Monday, 10 November 2003
(PM014) Steroidal hormones at cattle grazing sites in eastern Oregon.
Rostad, C1, Anderson , C2, Wente, W3, Pearl, C3, Adams , M3, Noyes , T1, 1 USGS Water Resources Discipline, Branch of Regional Research, Denver, CO, USA2 USGS Water Resources Discipline, Oregon District Office, Portland, OR, USA3 USGS Forest and Rangeland Ecosystem Science Center, Corvallis, OR, USA
ABSTRACT- As part of an on-going project to determine the effects of cattle grazing and related habitat alteration on Columbia spotted frog populations in Oregon, water samples were collected for water quality analysis from several ponds located in the Wallowa-Whitman National Forest and the Vale Bureau of Land Management district. The study areas consist of 5-10 ponds that have been excluded from grazing for >5 years, 5-10 fully grazed ponds, and 5-10 ponds that will be grazed during the first 2 years of the study and then fully excluded for the remaining 4 years. Water samples from the older excluded areas, the fully excluded experimental ponds, and the fully grazed ponds will be analyzed for water quality parameters, including steroidal hormone compounds that are associated with grazing cattle and can negatively affect amphibians, such as 17b-estradiol, 17a-estradiol, trenbolone, and a-zearanol. For the ponds sampled in the first year of the study (2002), detections of steroidal hormones were relatively few, and concentrations of detected steroidal hormones were low (less than 0.1 ug/L). This initial portion of the study provides background water quality data for later comparisons.
Key words: cattle, steroids, amphibians, water quality