Original paper

Genetic diversity of Monoporeia affinis in relationship to environmental and spatial factors in Sweden's largest lakes

Demandt, Marnie H.; Angeler, David G.; Goedkoop, Willem

Abstract

The glacial relict species Monoporeia affinis undergoes pronounced population fluctuations in Sweden's three largest lakes, which may be due to multiple forms of environmental stress, including eutrophication and subsequent hypoxia. In this study, we use cytochrome c oxidase subunit I (COI) and 16srRNA (16 S) sequence data to assess the genetic diversity of this freshwater amphipod, and study their spatial and environmental correlates. The populations in the three lakes were genetically differentiated with haplotype diversity of the 16 S gene being lower in populations from Lake Mälaren compared to those in Lake Vättern and Lake Vänern; however, a broadscale spatial analysis did not detect significant spatial patterns in genetic diversity across the lakes. Within lakes, however, subtle spatial effects were detected in the form of a significant distance decay of genetic diversity in some lakes, highlighting the importance of considering different spatial scales for studying genetic diversity. From the environmental variables studied, a biologically relevant impact of both oxygen and total phosphorus levels on haplotype diversity levels was found, indicating the negative consequences of eutrophication on genetic diversity of M. affinis. Despite significant decreases and fluctuations in population sizes, the demographic history of M. affinis populations is best described by a model of constant population size over time, suggesting a sufficiently large effective population size.

Keywords

genetic diversitycoi16 s rrnamonoporeia affinisamphipodenvironmental factors