PARENT SESSION
Poster Session # 7: Restoration, Resource Management, and Conservation.
Monday, August 4 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Integrated monitoring of terrestrial riparian resources along the Colorado River in Grand Canyon.
Kearsley, Michael*,1, Yard, Helen2, Cobb, Neil1, 3, Lightfoot, David4, Brantley, Sandra4, Frey, Jennifer5, Carpenter, Geoff4, 1 Department of Biological Sciences, Flagstaff, AZ2 Helen Yard Consulting, Flagstaff, AZ3 Merriam - Powell Center for Ecological Research, Flagstaff, AZ4 Biology Department, Albuquerque, NM5 Department of Fishery and Wildlife Sciences, Las Cruces, NM
ABSTRACT- Monitoring of diverse resource types in large and complex systems is often done in piecemeal fashion, with tasks divided among unconnected groups along taxonomic or methodological lines. Here we present the framework for monitoring the effects of discharges from Glen Canyon Dam in Grand Canyon National Park which recognizes the connectedness of many terrestrial elements in the Colorado River corridor. Joint sampling trips simultaneously collect data on habitat productivity (vegetation structure) and the abundance and composition of breeding birds, waterfowl, small mammals, herpetofauna and terrestrial invertebrates at a series of sites over the entire year. Sites are revisited at one to three year intervals in an augmented serially rotating panel design in order to balance change detection power against observer impacts and canyon-wide representation. Sites are divided into three zones based on hydrology: a pre-dam xeroriparian zone, a shoreline zone below the current range of non-emergency flows, and a post-dam riparian zone between the two. Data collected in the first two years shows several interesting patterns. First, vegetation density is more stable than we would expect based on large differences in precipitation in 2001 and 2002. Second, breeding bird densities within sites differ between years, but shift among zones depending on the where invertebrates and other food sources are greatest. Third, vegetation density sets an upper bound on breeding bird density rather than predicting it outright. Fourth, mammal diversity and density is highest in the pre-dam zone where productivity is lower. Fifth, herpetofaunal densities and diversity are highest in the interfaces between hydrologic zones, especially between the lower two. These patterns have important implications for efficiencies and insight gained by monitoring many resources in an integrated fashion.
Key words: adaptive management, river regulation, monitoring, riparian