Effects of the Post-Glen Canyon Dam Flow Regime on the Old High Water Line Plant Community Along the Colorado River in Grand Canyon

摘要

Growth and reproduction of native riparian trees were studied along the Colorado River in Grand Canyon. Populations of mesquite and acacia in the old high water zone were found to be growing and reproducing successfully. Shoot growth in adults is not significantly related to river flow levels. Adult mortality was highest near the river's edge and may reflect damage from the greater than 90,000 cfs flows in 1983. Under the post-dam river flow regime the frequency and height of the highest river flows continue to be the factors controlling the distribution of acacia and mesquite, as they were in the pre-dam era. Establishment of seedlings and survivorship of younger age classes now occurs in the new high water zone.