Document: ANG-3-63-25
Water diversion alters net primary productivity of a riparian ecosystem in the eastern Sierra Nevada mountains, Inyo County, California.
DISALVO, A.* 1 and S.C.HART 1
Northern Arizona University, Flagstaff, AZ 86011 USA 1
University of California, Bishop, CA USA 2
Abstract:
Riparian areas represent one of the most heavily disturbed, yet most valuable, ecosystems in the western United States. The most common disturbance to these areas is stream flow alteration, such as damming and diversion. Stream flow diversion causes reduced water availability to riparian plants, however, ecosystem-level effects are not well documented. Net primary productivity (NPP) is an important indicator of ecosystem integrity and may provide a useful tool for increasing our understanding of the impacts of water regime alteration. Total (above- and below- ground) net primary productivity was determined for riparian areas under a high flow and low flow water regime along Bishop Creek, Inyo County, California. This eastern Sierra Nevada stream has been diverted for over 80 years to provide water and hydroelectric power to surrounding areas. Aboveground NPP was determined by harvesting and weighing shrub and herbaceous growth, and woody components were measured indirectly through the use of allometric equations and litterfall collection. Belowground NPP was determined from constructing a carbon balance by measuring soil respiration and litterfall inputs. For the 1999 season, high-flow sites exhibited higher herbaceous and shrub production. High-flow sites also exhibited higher rates of soil respiration, which suggests higher rates of belowground production. High- and low-flow sites also differed in woody species composition. To our knowledge, this is the first study of how water diversion alters total NPP in a western riparian ecosystem, and this information will contribute to improving the management of these important ecosystems.
Keywords: net primary productivity, soil respiration, carbon balance, riparian system, stream flow diversion
This abstract is being presented at: 10:30 AM in session:
RIPARIAN ECOLOGY