Molecular diversity of Phalaris arundinaceapopulations in relation to river regulation (Merkys case study)

Abstract

Within Baltic States it is unknown about genetic diversity of populations of Phalaris arundinacea and how they might be affected by anthropogenic activities such as river regulation. Within 50s-60s of the former century Merkys river basin underwent severe anthropogenic regulations. It is the largest protected area of Lithuania. The objectives of the study were to compare SSR loci based molecular parameters of populations from natural river fragments with populations from regulated river parts. The index of Nei’s gene diversity was not very high. Selected for the study populations have bigger part of the genetic diversity within, rather than among populations. Upstream part of the Merkys basin populations had lower gene diversity compared to downstream part. The mean number of polymorphic SSR loci was lower for populations from regulated parts of the river basin compared to natural ones. Main principle coordinate analysis revealed populations of regulated rivers at marginal positions. Bayesian clustering suggested that current populations are admixtures of at least three formerly distinct genetic groups. Structure analysis allowed geographical subdivision of populations into upper part of the river basin and lower part also separation of populations belonging to natural parts of the river basin and two out of four populations from regulated parts. Pilot study suggests that river regulation might be impaired in changes of genetic diversity of P. arundinacea populations.