Clonal diversity and structure within a population of the pondweed Potamogeton pectinatus foraged by Bewick's swans

Abstract

Clonal diversity within plant populations is affected by factors that influence genet (clone) survival and seed recruitment, such as resource availability, disturbance, seed dispersal mechanism, propagule predation and the age of the population. Here we studied a population of Potamogeton pectinatus, a pseudo-annual aquatic macrophyte. Within populations reproduction appears to be mainly asexually through subterranean propagules (tubers), while recruitment via seeds is believed to be relatively unimportant. RAPD markers were used to analyse clonal diversity and genetic variation within the population. Ninety-seven genets were identified among 128 samples taken from eight plots. The proportion of distinguishable genets (0.76) and Simpson's diversity index (0.99) exhibited high levels of clonal diversity compared to other clonal plants. According to an analysis of molecular variance (amova) most genetic variation occurred between individuals within plots (93-97%) rather than between plots (8-3%). These results imply that sexual reproduction plays an unexpectedly important role within the population. Nevertheless, autocorrelation statistics revealed a spatial genetic structure resulting from clonal growth. In contrast to genetic variation, clonal diversity was affected by several ecological factors. Water depth and silt content had direct negative effects on clonal diversity. Tuber predation by Bewick's swans had an unexpected indirect negative effect on clonal diversity through reducing the tuber-bank biomass in spring, which on its turn was positively correlated to clonal diversity. The disturbance by swans, therefore, did not enhance seed recruitment and thus clonal diversity; on the contrary, heavily foraged areas are probably more prone to stochastic loss of genets leading to reduced clonal diversity.

Genetic diversity of Potamogeton pectinatus L. in Iran as revealed by ISSR markers

“…Such a situation is also observed in southern (KF) accessions, those that grouped together in dendrogram and PCoA 2D plot. Hangelbroek et al (2002) indicated that seeds rather than vegetative structures are responsible for gene flow within populations of P. pectinatus. This species is an important food source for many herbivorous waterfowls and water birds (Triest et al 2010).…”

“…In most cases there was a geographic pattern of diversity and also a correlation between genetic diversity and migration pathways of water birds (Mader et al 1998, Hangelbroek et al 2002. Triest and Fenart (2013) indicated a correlation between genetic structure of clones and habitat type in this species.…”

“…Accessions of P. pectinatus have been analysed using isozyme (Hettiarachchi and Triest 1991), RAPD (Mader et al 1998, Hangelbroek et al 2002, ISSR (King et al 2002) and AFLP (Han et al 2014) markers. In most cases there was a geographic pattern of diversity and also a correlation between genetic diversity and migration pathways of water birds (Mader et al 1998, Hangelbroek et al 2002.…”

The aquatic leaf beetle Macroplea mutica (Coleoptera: Chrysomelidae) in Europe: Population structure, postglacial colonization and the signature of passive dispersal

“…The host plants of M. mutica, namely pondweed Potamogeton (pectinatus) and widgeon grass Ruppia sp., are preferred food of waterfowl (Clausen et al, 2002;Green et al, 2002;Marklund & Sandsten, 2002). Dispersal by waterfowl is likely and is known to influence the genetic structure of plant populations (Mader et al, 1998;Hangelbroek et al, 2002;King et al, 2002). Thus it is likely that Macroplea (especially cocoons and eggs) are eaten by birds and survive the passage through their digestive tract.…”

Genetic structure and gene flow in an endangered perennial grass, Arctophila fulva var. pendulina

“…Jonsson et al 1996;Auge et al 2001;Lundqvist and Andersson 2001;Persson and Gustavsson 2001;Hangelbroek et al 2002). For example, in Carex bigelowii no seed-derived plantlets have been observed in natural stands, even though the species is genotypically highly variable (Jonsson et al 1996).…”