"Clover and Jotter (1938)...were the first scientists to systematically record observations on the flora of the river corridor. The photographs of Franklin Nims and Robert Brewster Stanton well document the conditions seen by Clover and Jotter; showing a stark river corridor largely devoid of trees and riparian plants...most of this zone was deviod of plants because they could not survive the scouring and inudations by periodic floods."
"The river corridor that Stanton saw and photographed was desolate in comparison to the verdant channel banks for today. Operation of Glen Canyon Dam has increased the amount of riparian habitat in Grand Canyon. The channel banks are now biologically productive..." However, since closure of the Glen Canyon Dam this habitat "is now occupied by thickets of tamarisk, coyote willow, Gooding willow, cottonwood, arrowweed and other native shrubs. This new high water zone - where the number of breeding birds is five to ten times greater than before - is a critical resource of the river corridor in Grand Canyon."
"Moreover, the new high-water zone is one of the few major riparian areas in the southwestern United States that has had an increase in vegetation this century. What in 1890 was barren sand is now critical wildlife habitat. The density of nesting birds in some well-developed patches of vegetation in the high-water zone was comparable to the highest densities ever reported for non-colonial birds in North America" (Carothers, 1974).
"The riparian community of the new high-water zone, including everything from plants and birds to reptiles and small mammals, is an unanticipated gift and should be managed as such. The tamarisk-dominated new high-water zone is not displacing native plant communties, because virtually no vegetation existed there before the scouring floods were limited in frequency and size. The unique combination of native and introduced species interacting in a productive manner identifies the new high-water zone as a naturalized community."
"For example, the southwest willow flycatcher is an obligate riparian species that nests exclusively in the new high-water zone, making extensive use of tamarisk. It is legally designated as endangered in the the Southwest, so modifications to its nesting habitat in the river corridor are subject to the terms of the Endangered Species Act."