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, Figure 5. The marsh at Cardenas Creek (mile 70.9-L) (continued). B. February 26, 1993. Marshes, prime riparian habitat in Grand Canyon and elsewhere, pro.vide habitat to native fishes and wildlife, particularly birds. Young native fish use the backwaters as protection ~rom p~edators, and birds frequently nest in the dense vegetation. The marsh at Cardena~ Creek, for example, IS nestmg . habitat for southwestern willow fly catchers, which is an endangered species. But mar~hes were n.ot p.resent In 1890; they exist solely because of the flood control by Glen Canyon Dam. M~st of the. Increased np~nan vegetation in the view is tamarisk, although willow, arrowweed, and other native species also have Increased (Tom Wise, Stake 1440). , Lava Falls Rapid (mile 179) and Three Springs Canyon (mile 215.7-L) - were observed by Clover and Jotter (1944), who collected plant specimens from these sites. In the 1950s, Reilly observed that the marsh in the mouth of Three Springs Canyon had a patch of cane 100 feet across; it also contained willows, tamarisk, and cattails. Riparian vegetation surrounding the springs at Deer Creek Falls (mile 136.3-R), Vaseys Paradise (mile 31.8-R), and on the right side of Hance Rapid (mile 76.7-R) shows prominently in historic photographs. Rigg and Nichols stopped at Cardenas Creek (mile 70.9-L) before Glen Canyon Dam and agreed that the area now supporting a marsh was sand and rocks. Reilly saw willows at Cardenas Creek but did not specifically mention tamarisk, which he saw elsewhere. Cutter commented that the current large amount of reeds along the river corridor did not resemble anything she saw in 1938. . Desert Vegetation Cutter thought the desert above the river appeared greener in 1995, than in 1938. Both years had relatively wet winters and normal summers. From replication of the Stanton photographs from 1890, we attribute the difference to a large increase in brittlebush (Webb and Bowers, 1993). Jotter stated that she and Clover would certainly have listed now-common species such as snakeweed and tamarisk if they had been present at any of their sampling locations. This allows use of their plant lists (Clover and Jotter, 1944) as a baseline for evaluating invasions or increases of common species. At the site where the type specimen of beavertail cactus (Opuntia basilaris var. longiaureolata) was collected in 1938, we could find nothing that matched the original plant, which has not been recollected. We believe the variety they collected may have been a hybrid. SPECIFIC CHANGES OBSERVED IN GRAND CANYON 21