Connections among strains differing in reproduction system

The loss of genetic diversity is considered a key element in entering the extinction vortex. Shrinking population size reduces the number of genetic variants available to cope with changes in habitat conditions. Together with other factors such as genetic drift, the species in question increasingly loses its fitness. This is especially true for asexually reproducing species, where recombination of traits is limited to the genetic variability of a single parent. The conservation of genetic diversity is thus a central element of conservation concepts. In this project, Chara canescens, a stonewort alga, is studied. This species has mostly asexually reproducing populations, but also a few sexually reproducing populations. The asexual populations are widespread and found throughout Europe, with populations also known from North America, Australia and Central Asia. The sexual populations are very rare, with only 5 sites currently known in Europe. Previous projects have shown that the asexual populations of Chara canescens have a higher genetic diversity than assumed. These results have led to the establishment of the following hypothesis: Species consisting of linked sexual and asexual populations can overcome the risk of loss of genetic diversity as long as efficient transfer of genotypes between populations is ensured. So far, little is known about the connections between sexual and asexual lineages of a species. All this together is the basis for the present project, which aims to clarify the extent to which populations from different regions and with different reproductive mechanisms are connected or whether genetic exchange takes place. In order for an exchange and thus a coherent network of populations to be possible, stepping stone biotopes between the populations are necessary. In these biotopes, the charophyte populations must be kept fit and lost stepping stone biotopes as well as former sites of sexually reproducing populations might still contain diaspora banks that can be revitalised to increase stability under climate change conditions. In addition to field work to study recent populations, herbarium material will also be included. Genetic analyses to clarify the links within and between individuals (field collections and herbarium material) from the different populations will be based on a GBS method. In addition to clarifying the connections/relationships between the populations, the creation or maintenance of a functional biotope network for exchange between the populations is also the aim of this project.