Information on the biology of Gunnera tinctoria
Gunnera tinctoria (Gunneraceae) has a narrow ecological niche as it needs constant water availability. It is a major invader species in Ireland. Habitat mapping of G. tinctoria in Ireland indicates a preference for anthropogenic habitats associated with human settlements and former agricultural land, as well as stream or river banks.
Experiments carried out in Ireland showed that a large number of seeds are produced by individual plants, leading to a large and persistent seed bank. This finding contradicts the initial belief that this species propagated solely asexually from discarded rhizomes or plant fragments. Few seeds germinate in the field. The reason for this low germination rate is probably related to low soil temperatures. Model projections indicate, however, that relatively modest increases in temperature, consistent with climate change projections, would result in increasing numbers of seeds germinating in the field. Seed viability is thought to be up to 70 years.
Sources
Osborne B, Fennell M ; Armstrong C (2001) The riddle of Gunnera tinctoria invasions: a particularly Irish enigma. In: Bohren C, Bertossa M, Schönenberger N, Rossinelli M, Conedera M. (ed) 3rd International Symposium of Environmental Weeds and Invasive Plants. Abstracts. October 2 to 7 2011. Monte Verità, Ascona, Switzerland.
Available from Internet
http://www.wsl.ch/epub/ewrs/sessions/detail_EN?id=288;session=3;type=oralpresentations Birmensdorf, Swiss Federal Institute for Forest, Snow and Landscape Research WSL.