Genetic models reveal historical patterns of sea lamprey population fluctuations within Lake Champlain.

The origin of sea lamprey (Petromyzon marinus) in Lake Champlain has been heavily debated over the past decade. Given the lack of historical documentation, two competing hypotheses have emerged in the literature. First, it has been argued that the relatively recent population size increase and concomitant rise in wounding rates on prey populations are indicative of an invasive population that entered the lake through the Champlain Canal.

Phytogeography of Najas gracillima (Hydrocharitaceae) in North America and its cryptic introduction to California.

Premise Of The Study: The discontinuous North American distribution of Najas gracillima has not been explained satisfactorily. Influences of extirpation, nonindigenous introduction, and postglacial migration on its distribution were evaluated using field, fossil, morphological, and molecular data. Najas is a major waterfowl food, and appropriate conservation measures rely on accurate characterization of populations as indigenous or imperiled.

The Effects of Herbivorous Snails on Submerged Macrophyte Communities in Minnesota Lakes.

The influence of herbivorous snails on freshwater macrophytes was examined both in the laboratory and the field. In the laboratory, 14 macrophyte species grown in the absence of herbivores had growth rates ranging from 1-10%/d. When grown with four densities of herbivorous snails, species that grew fastest in the absence of herbivores were, in general, most negatively influenced by grazing.