Spatial patterns of maternal lineages and clones of Galium odoratum in a large ancient woodland: inferences about seedling recruitment

Abstract

Summary We investigated spatial genetic patterns in the clonal herbaceous plant species Galium odoratum L., which has previously been shown to be significantly associated with ancient woodlands. A maternally inherited chloroplast DNA marker was developed for G. odoratum. Seven chloroplast haplotypes were detected in the study area and mapped at different spatial scales. Their spatial patterns suggest that both local and non‐local gene flow occurs via seeds. Fingerprints from DIG‐labelled AFLP technology were validated as markers for G. odoratum clone identification. A single primer–enzyme combination was sufficient to distinguish between clones. A typical patch of G. odoratum is composed of numerous genets, mainly occurring in separate clusters of ramets, which may be several meters in diameter. Pairwise similarities, calculated from the AFLP banding patterns, were used for spatial autocorrelation analysis. The distinct spatial genetic structure at the patch level may be due to the genetic similarity of neighbouring genets or to clonal growth. The spatial patterns obtained using the two DNA markers, suggest that a mixture of local and non‐local gene flow via both seeds and pollen is occurring. Repeated seedling recruitment (RSR) would be consistent with the life history of G. odoratum in ancient woodlands with long‐term spatial continuity.