Genetic Diversity of Stratiotes aloides L. (Hydrocharitaceae) Stands across Europe

Abstract

Intense land use and river regulations have led to the destruction of wetland habitats in the past 150 years. One plant that is affected by the reduction in appropriate habitats is the macrophyte Stratiotes aloides which has become rare in several areas. The preservation of genetic diversity within a species is a prerequisite for survival under changing environmental conditions. To evaluate the level of genetic diversity within and among populations of Stratiotes aloides, we investigated samples from waterbodies across Europe using AFLP. Low genetic diversity among samples from the same population was found, proving that stands consist of few clones which propagate clonally. Nevertheless, most populations showed differences compared to other populations indicating that there is genetic diversity within the species. The analyzed samples formed two groups in STRUCTURE analyses. The two groups can be further subdivided and mainly follow the major river systems. For conserving the genetic diversity of Stratiotes aloides, it would thus be preferable to focus on conserving individuals from many different populations rather than conserving selected populations with a higher number of individuals per population. For reintroductions, samples from the same river system could serve as founder individuals.

Origin and Early Evolution of Hydrocharitaceae and the Ancestral Role of Stratiotes

“…The notable absence of dispersed Stratiotes pollen in the pre-Pleistocene global paleopalynological records to date can be attributed to the entomophilous nature of the plants [13]. Stratiotes produce only a small amount of pollen (even none at all) per fertile stamen [15], and extant Stratiotes also reproduce vegetatively [29]. Also, because of the structure and function of the pollen wall (see before), the grains disintegrate easily.…”

Macrophytes in Inland Waters: From Knowledge to Management

“…Turner et al [ 9 ] focused on Stratiotes aloides L., a vascular macrophyte with a wide distribution (from northern Central Europe in the west to Siberia in the east) but that is becoming rare in some areas; in their article, they show the importance of assessing the genetic structure of a species in order to manage it, both for preserving the diversity of the species as a whole and for possible reintroductions. As in other species, the authors verified that, in European populations of this aquatic plant, there is low genetic diversity within each population but high genetic diversity between populations.…”