Benthic macroinvertebrate communities in southwestern Lake Ontario following invasion of Dreissena and Echinogammarus: 1983 to 2000

Abstract

AbstractBenthic macroinvertebrate communities were quantified at natural cobble and artificial reef sites in Lake Ontario in 1983 (7 y pre-Dreissena invasion) and in 1991 to 1992 and 1999 to 2000 (1–2 and 9–10 y post-Dreissena invasion, respectively). Overall, the cobble community had higher diversity and abundance than the reef community. In both communities, diversity and abundance of non-Dreissena taxa rose sharply between 1983 and 1991 to 1992 and declined to 1983 levels by 1999 to 2000. However, taxonomic composition (excluding Dreissena and the recent invader Echinogammarus ischnus) was consistent across study years. Between 1983 and 1999 to 2000, Stagnicola catascopium and Physella spp. increased in abundance, several taxa (Musculium partumeium, Bithynia tentaculata, Elimia livescens, Trichoptera, and Chironomidae) decreased in abundance, and changes in the abundance of many taxa were correlated with Dreissena abundance. Dreissena continued to make up >40% of total macroinvertebrate abundance at th...