Ecological Changes in Lake Tahoe: The Influence of Introduced Species

Prior to large changes in community structure and water column nutrient concentrations, Lake Tahoe’s community assemblage was relatively simple with 12 orders of zoobenthic taxa, 6 zooplankton species, and 8 fish taxa (Juday 1906, Miller 1951, Frantz and Cordone 1996, Chandra 2003, and Vander Zanden et al. 2003). The benthic invertebrate community consisted of one endemic, a wingless form of stonefly, while the fish community was comprised of 7 species and 2 subspecies. A series of species introductions combined with landscape disturbances (i.e., deforestation) in the mid to late 1800’s, initiated the alteration of the lake’s biology, and many of these changes exist today. The purpose of this article is to describe the ecology of the lake prior to the introduction and establishment of the nonnative species, and provide insights into the changes that have occurred as a result of the introduction of particular nonnative species in the last 140 years (Figure 1).