Invasive: thoughts and threads

Recent invasive species web log additions have caught my attention. Hybridization and Sexual Reproduction in the Invasive Alien ..., which examines "...how hybridization may influence the sexual reproduction of the complex in Belgium and to determine how it may contribute to the dispersal of the species” and UCR Researchers Examine How Some Invasive Plants Gain a Foothold reports on research into the relationship of population size and relatedness to species spread and the potential implication for control and regulatory measures. The idea submitted would be to regulate the distribution of only one genotype of a particular species.

In the mid 1990’s, while I was still personally propagating and growing perennials for the landscape and home trade, I was introduced to Lythrum spp. and was told through the grapevine that research in Canada had found a sterile cultivar: Lythrum “Morden’s Pink”. In the background of day to day production activities, I heard rumor of the plants’ invasive tendencies. With in a few years, I began to notice, Lythrum seedlings coming up in corners of the production farm, and working with our propagator collected seed from our sterile cultivars. We were astounded at the germination rate. I chose to unilaterally discontinue the sale of the plant, assuming that the self sterile plants has crossed with naturalized invaders, and that, as with Bradford pears and other “sterile cultivars”, the cat had left the barn with the entire chicken coop in paw, so to speak. The two articles, at a basic level, support my non-scientific observations from 15 years ago.

The nursery industry supports research into cultivar sterility and hybridization which would lead to a “minimulization” of invasive traits. Defining and researching invasive traits is an important step in the right direction. The problem would seem to be one of practical control unless we find a way to either subordinate the “invasive traits” or eliminate the species ability to reproduce without human interaction. Further, we should be reasonably certain that an introduced “New-Improved-Less-Invasive” does not quietly help in the reproductive processes of related genotypes already loose in the landscape.

There would seem to be two approaches to the challenges of invasive plants, the first entailing early detection and rapid response, with a modicum of prevention, and the second comprising genetic modifications which would disable invasive traits. The intersection of short term economic goals with long term environmental needs can give rise, of course, to the obverse of these lines of investigations, such as the pursuit of a better Miscanthus for bio-fuel sourcing giving rise to the interesting possibility of intentionally adding more know invasive species to the palette. If we add to this the claim of sterility, we are back to my uninformed observations of 15 years ago.

All of these scientific pursuits are needed, valuable and on-going. Bringing the strands of inquiry together in an environmentally sympathetic manner is a work in progress.