摘要：The exotic cladoceran, Daphnia tumholtzi, was collected at several sites in Elephant Butte Reservoir, New Mexico, from spring through fall of 2003. Densities were always relatively low, suggesting that D. lumholtzi is in the early stages of invasion. There were two seasonal peaks in abundance of D. lumholtzi. One peak occurred in August and coincided with highest surface water temperature and declines in the densities of native Daphnia species; the second peak was in November.
