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Our analysis of 156 lakes and 5 nonnative aquatic macrophyte species suggest that 4 water chemistry variables can be used to assess the risk associated with species invasion in Connecticut lakes. Our analysis showed that water chemistry and longitude explained a significant amount of the total data variance (33%). Additionally, individual species logistic regressions suggest that these species’ distributions were determined by the specific conductance and pH of the water body. Lakes were then placed into one of the following groups: (1)Cabomba caroliniana/Myriophyllum heterophyllum(CM), (2)Myriophyllum spicatum/Najas minor/Potamogeton crispus(MNP), (3) Mixed (Mixed), or (4) No Invasive (NI). Multivariate analysis of variance suggests that water chemistry of the groups CM and MNP differed significantly (p < 0.001), and the variables that contributed to this difference were specific conductance (F = 22.16), alkalinity (F = 19.40), and pH (F = 18.61). The Mixed and No Invasive groups were not significantly different. Discriminant function analysis was used as a final analytical tool to determine the risk of NI group lakes developing populations of our nonnative species. The results suggest that the 4 abiotic variables could predict the identity of the CM and MNP groups with a high degree of certainty (i.e., 79 and 71% correct, respectively). When the NI group was included in the discriminant analysis, 34% of these lakes were grouped with CM and 14% with MNP. The remaining 52% of NI lakes had water chemistry parameters capable of supporting all species examined in this study. From these findings, water chemistry risk assessment ranges were developed for these common nonnative species in Connecticut. [ABSTRACT FROM AUTHOR]

The aquarium trade has been shown to be a source for introductions of nonnative aquatic macrophyte species. Improvements are needed in identification, labeling, and retailer awareness of banned aquatic plants. In the state of Connecticut, United States, 20 nonnative macrophytes are banned from sale by state statute. At least 13 of these species are already established in the state's lakes, while the remainder are either present in near-shore wetlands or absent but thought to be capable of naturalizing. We documented the sale of banned plants in the Connecticut aquarium trade by visiting 23 retailers in 2008 and 47 retailers in 2010. Plants that resembled Connecticut's banned species were purchased and identified using standard morphological techniques. In 2010, we also employed DNA sequencing to aid in plant identification. We found that nearly 30% of stores sold banned aquatic plants includingCabomba caroliniana,Egeria densa,Myriophyllum aquaticum, andMyriophyllum heterophyllum.Cabomba carolinianarepresented more than half of the banned species being sold; it was found in 17% of the stores in 2008 and 19% of the stores in 2010.Egeria densawas mislabeled 50% of the time asEgeria najasorAnacharis najas; it was sold in 11% of the stores in 2008 and 17% of the stores in 2010. In 2010,Myriophyllumspecimens from 6 stores were unidentifiable using morphological characteristics. Using these techniques, one of the specimens was identified asMyriophyllum heterophyllum. Of the 29 chain stores surveyed, 7% sold banned species compared to 56% of the 27 independent stores. [ABSTRACT FROM PUBLISHER]