Heracleum mantegazzianum

BIOLOGY/ECOLOGY Dispersal mechanisms The species reproduces entirely by seeds; fruits are oval-elliptical broadly winged mericarps (6-18 × 4-10 mm), which are dispersed by wind, water and humans. Reproduction The species is monocarpic, that is, it reproduces only once in its lifetime. Plants are able to self-fertilize. A single plant produces about 20,000 seeds which have to be stratified in the soil in cold and wet conditions during winter and then are highly germinable. Known predators/herbivores Insect or pathogens have little effect. Grazing by livestock can significantly decrease the reproductive output but also prolong the lifespan before flowering. Resistant stages (seeds, spores etc.) Seeds form a short-term persistent seed-bank; the majority of them germinate the following year after release and only about 1% of seeds are able to survive more than 3 years in the soil.