Evolutionary Ecology of Japanese Knotweed Research goals: we plan to study japanese knotweed from two Perspectives: 1) map the current locations in Broome Co. with respect to road and river networks. If it doesn’t make seed, it should not be able to disperse upstream, and therefore some areas that would otherwise be vulnerable may currently be safe – so long as care is taken to prevent dispersal via the road network. 2) Evolutionary studies to determine genetic diversity present, whether hybridization is occurring, and to what extent seed production may be occurring (visual evidence suggests that a very small number of individuals are now producing seed). Introduction Japanese knotweed (Polygonum cuspidatum) may be the worst invasive plant species in the northeastern US, though because it is relatively recent it is less well-recognized than some alien species that have been here longer, such as purple loosestrife and giant reed. Japanese knotweed can dominate floodplains, to the near exclusion of other plants. Currently, it almost never produces seeds, dispersing instead by root pieces that are moved by bulldozers or floods. In Europe, where it also is a serious invading species, it hybridizes with Siberian knotweed, producing fertile offspring that can produce seeds. Siberian knotweed also is now reported in upstate NY, and it is to be expected that fertile hybrids will begin to appear in our county. Successful seed production by this species (or species complex) would greatly increase its invasiveness, turning into a truly monstrous problem. The Hybrid Soup Hypothesis Spencer Barrett pointed out that alien species often have very low genetic diversity, and therefore are poorly suited to the overseas environments into which they have been introduced. He argued that those aliens that are able to hybridize with closely related species pick up new diversity forming a hybrid soup - which can greatly increase their adaptation to those new environments. This appears to be happening in Europe for Japanese knotweed, and may be about to happen here. Japanese knotweed (background) in Johnson City The results should be of both theoretical interest – hybridization as an evolutionary mechanism is a hot topic at the moment – and of practical benefit in guiding mitigation efforts for dealing with this most problematic of invading , alien species.