DISPERSAL PATTERNS OF LONICERA-PERICLYMENUM DETERMINED BY GENETIC-ANALYSIS

Colonization of Lonicera periclymenum L. (honeysuckle) was studied by RAPD analysis of young ramets in two woodlots planted 20 years ago, an d in all ramets in older woodlots within a range of 1 km. Mature ramet s that climbed in a particular tree always belonged to one individual. Twenty-five percent of the mature individuals had reproduced vegetati vely to other trees or patches nearby, which indicates that the larger part of reproduction is sexual. Some young plants that were growing a t close distances from each other were genetically highly similar and shared high similarities to the same mature plants. They may be the pr oduct of one dispersal event. Detection of parents of young individual s by exclusion was not successful, because of the dominant nature of t he bands. Average distances from young plants to genetically most simi lar mature plants were variable, due to the small number of colonizati on events. However, four ways of analysis of genetic similarity among all individuals indicated that exchange of genetic material by seed an d pollen occurs to a large extent over small distances and within wood lots: (i) using the Mantel test, pairs of individuals with highest sim ilarity were found significantly more often in the same woodlot than i n different woodlots; (ii) genetic similarities between individuals de creased significantly with geographical distance, but only for distanc es up to 300 m; (iii) individuals of woodlots in the Western part of t he study area were hardly related to individuals in the Eastern part o f the study area, a distance of 2-3 km; (iv) phi(ST) in the study area was 0.186, indicating a limited gene flow between woodlots. These res ults are consistent with the dispersal distance as estimated from the average distance between colonized woodlots and the nearest occupied o ld woodlot in earlier research.