Biogeography of copepods in lakes and ponds of subarctic Quebec, Canada

We aimed to determine whether the copepod assemblages in lakes and ponds of northern Quebec, Canada, were closer in composition to those found in sout hern Quebec, or to those reported from the subarctic and arctic. Six calano id and five cyclopoid species were identified from 37 ponds and lakes locat ed in the region between 55 degrees N and 59 degrees N. Species diversity w as generally low, ranging from 0 to 4 species per lake. Dominant species we re Leptodiaptomus minutus and Acanthocyclops vernalis. The species assembla ges showed high affinity with those found in forested regions of southern Q uebec. Exceptions were Leptodiaptomus tyrrelli, previously only recorded we st of Hudson Bay, and Hesperodiaptomus arcticus, hitherto recorded north of 58 degrees N. Relationships between the lakes, species, and environmental variables were explored using multivariate analysis. Lakes situated along t he coast and on two offshore islands clustered together and were characteri sed by higher conductivity and pH than those lakes located further inland. Leptodiaptomus tyrrelli was common in these coastal lakes. Canonical corres pondence analysis revealed statistically significant relationships between copepod distributions and conductivity, dissolved organic carbon and pH. Th ese three variables accounted for 70% of the variation in the species' dist ribution.