Author : Frederick C. Hall
Publisher : Unknown
Page : 44 pages
File Size : 45,8 Mb
Release : 2005
Category : Beavers
ISBN : MINN:31951D02977035O
Emigrant Creek Cattle Allotment by Frederick C. Hall Pdf
Emigrant Creek cattle allotment is located 48 km northwest of Burns, Oregon. It was photo sampled at nine original sites, starting in 1975. Photos were taken three times per year: June 15 prior to cattle grazing, August 1 at pasture rotation, and October 1 at the end of grazing. An additional four photopoints were established following disturbance from flooding and beavers. Results reported here cover 30 years, 1975 to 2005. Cattle did not significantly impact the riparian area. Beavers (Castor canadensis) arrived in 1984 and departed in 1994. They seriously reduced aboveground willow biomass by harvesting stems for food and dam construction. Dams raised the water table causing a dry meadow to become moist, and increased water in a wet meadow that inhibited willow growth. Beaver departure in 1994 left dams unmaintained. A 50-year flood event in February 1996 eroded dams and created a new channel. The water table was reduced below that of the 1984 levels, causing a dry meadow to revert to pre-1984 conditions and permitting willows to vigorously expand in a wet meadow. Dynamic riverine riparian environmental conditions seriously challenge the typical range management concepts of S2condition and trend. S3 There is no S2climax good condition. S3 Instead a S2state-and-transitionS3 concept seems a more apt range management concept to describe range conditions resulting from beaver dams and flooding over a 30-year period on Emigrant Creek cattle allotment.