ABSTRACT
Impatiens glandulifera was first thought to be a highly desirable addition to English gardens. In general, the early recognition of an undesirable/potentially invasive species is rare and often takes decades (Williamson, 1996) and this was most certainly the case with I. glandulifera. This may be due to a lag phase associated with the invasive nature of some plants, where initially the population expansion is slow while the species adapts to the new environment; subsequently, this is followed by the exponential phase that sees a
rapid explosion in the spread and occurrence of the species. The rate at which a species spreads is likely to be as much related to human activity (Perrings et al, 2002) and landscape factors, as it is to the biology and ecology of the species (Williamson et al, 2005). I. glandulifera has found its ideal conditions predominantly along the rivers of Europe and elsewhere, aided by the explosive release of its seeds coupled with hydrochorous dispersal. There is also evidence that
I. glandulifera is capable of invading disturbed deciduous woodland and ungrazed tall herb/ruderal/ grassland habitats (e.g. Maskell et al, 2006; Andrews et al, 2009) as a result of human-assisted transportation of seed material in soil, by beekeepers and accidental release in garden waste and on vehicles (Kowarik, 2003).
