Clonal diversity in differently-aged populations of the pseudo-annual clonal plant Circaea lutetiana L.

In many clonal plant species seedling recruitment is restricted to short co lonization episodes early in the development of the population, and clonal diversity (i.e., genet diversity) in the population is expected to decrease with increasing population age. In established populations of the pseudo-a nnual Circaea lutetiana seedling recruitment has previously not been observ ed. Therefore, we expected established populations to have low clonal diver sities. We analysed number and frequency of genets and spatial distribution of genets in six differently-aged C. lutetiana populations with the use of four informative RAPD primers. We found relatively low clonal diversities in young populations but very high clonal diversities in established popula tions. Therefore, the hypothesis was rejected that seedling recruitment doe s not occur in established populations. Moreover, we did not find large gen et size asymmetries in established populations. Genet size differences can be caused by stochastic processes or by fitness related traits, such as dif ferences in vegetative reproduction. Because vegetative propagation of rame ts is dependent on ramet size, and the number of ramets and the size of eac h ramet determine genet size, we expected that large genets produced, on av erage, large ramets. However, this was not the case, suggesting that stocha stic processes caused genet size differences. Genet size may also be bounde d if spatial distribution of genets is affected by micro-habitat difference s. For this we expected to find a dumped spatial distribution of ramets of the same genet. However, ramets of large genets were always found interming led with ramets belonging to other genets.