Eric J. von Wettberg
Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island
Invasive Escaped Ornamental Impatiens: Prospects for new varieties and better control
Distribution of Impatiens
Environmental Issue Scientific Approach glandulifera in New England.
Because the seeds float, the
potential for future invasion
•Invasive species cause over $137 Billlion in down the coast of Maine, and
•Hypothesis: Population differentiation is an important
damages and losses in the US factor allowing escape out of gardens into harsher uncultivated down the Housatonic
-Invasive species, or environmental weeds, are exotic species areas. If it is, it can be used as a factor to make control more watershed in Ma and Ct is a
that spread after introduction to a new area. efficient and as a way to develop safer new varieties. concern. But, because the
-Invasive species are also a threat to ecosystems and native invasion has just begun in the
species. Nearly 50% of the 100 rarest plants in New England •Research Plan: Northeast -- early action can
are threatened by invasive species. stop it.
Measure population differentiation
•Many invasive plants are escaped -I have developed molecular finger-printing markers (AFLPs) to
Impact on Conservation and
measure gene flow and population differentiation.
-Garden environments are forgiving to plants, with abundant
-I will grow plants in the greenhouse to measure morphological
differentiation and plasticity to varying shade conditions.
resources, and can be sources for seeds or propagules that
•Conservation in New England
disperse into native ecosystems and conservation land. Examine seed dispersal potential -Raising awareness of this invasion with land managers
-The horticultural industry produces and disperses enormous -Impatiens glandulifera seeds float, and this may be an
numbers of plants. The hundred million dollar Impatiens increases the prospects of early detection and control of new
important factor in developing regional control strategies. infestations. I have begun discussions with the Berkshire, MA
industry distributes millions of plants. Most ornamental -All populations in proximity of a watershed must be removed
Impatiens are not weeds, but some individuals of all varieties TNC and Vindalhaven, ME Landtrust to begin wider sampling.
because seeds from one population can recolonize areas
have escaped, and policeman’s helmet (Impatiens glandulifera) where control efforts are attempted.
is highly invasive in temperate regions of Europe and North An infestation of Impatiens
America. glandulifera, Policeman’s -Studies I have begun this fall on the ability of seeds to float
Helmet or Himalayan may find natural variants unable to float or disperse well.
•More information is needed to develop Balsam. This is the most These would be safer ornamentals than the currently
invasive of the ornamental commercially available policeman’s helmet.
viable control strategies and safer
Impatiens, and has caused
ornamental varieties considerable damage in
-Information is lacking on dispersal distances and degree of Europe where it is also -Understanding this invasion will increase our ability to predict
population differentiation in escaped ornamental populations. invasive. These and control other invasions
-The horticulture industry requires good information to develop monspecific stands reduce -Understanding what makes Impatiens glandulifera a good
new varieties with less invasive potential than many popular native biodiversity. invader may help explain why most Impatiens are not common
current varieties. invaders
For more information visit http://www.brown.edu/Departments/EEB/graduate/evw.htm or contact Eric_von_Wettberg@brown.edu; Thanks to NSF DDIG, SICB, and Brown University for additional funding; and Johanna Schmitt; Novem Auyeung, Lisa Mandle, and Nava Tabak for assistance