Wednesday, April 7, 2010

GMO’s and Invasive Species, Is There a Connection?

Are genetically modified organisms likely to become invasive species? It’s a valid question and one that leads to some other interesting points to ponder. Have any genetically modified plants or animals developed so far become invasive? Are traits now being added to likely to make them invasive? Does genetic modification, either through traditional breeding or modern gene transfer techniques, ever increase fitness? Could you make an invasive species if you wanted to? Here are my thoughts on the subject.

First it is worth noting that none of the species on Oregon’s noxious weed list or 100 worst invaders list is a GMO or a species altered by man through traditional breeding. Ditto for the federal noxious weed list. In fact I’m not aware of any GMO crops, or traditionally bred crops for that matter, that have become invasive. If you know of examples, please share them.

The closest example I know of is canola; a crop created by traditional breeding from rapeseed. In recent years, bioengineering has been used to produce varieties resistant to several different herbicides. Volunteer canola is an agricultural and roadside weed in areas where canola is a crop. These volunteers include GMO varieties. A triple-resistant variety was discovered in Alberta a few years back demonstrating that genes in GMO canola can combine in volunteers and persist at least for a while in agricultural systems. This could be a problem in agricultural system reliant on herbicides, but it doesn’t mean that these plants will spread into natural environments and compete with native plants.

Herbicide resistance in volunteer canola plants wouldn’t give them any advantage in the wild. The modified plants will only have an advantage in agricultural systems where herbicides are a selective force, but that’s different. Absent that force, genes that result in production of proteins not useful to the plant would be a liability, wouldn’t they? This is one of the questions USDA regulators are grappling with in the debate over whether to deregulate Roundup Ready bentgrass.

A quick check of the database on GMO crops shows that as of April 7, 2010, 77 GMO varieties have completed safety testing. Crops on the list include: corn, cotton, soybean, rice, beet, rapeseed, tobacco, potato, flax, chicory, tomato, papaya, and squash. That doesn’t read like a list of invasive species to me. Nor do the traits that have been added sound like ones likely to produce invasiveness: glyphosate tolerance, European corn borer resistance, nicotine levels reduced, etc.

So could a mad scientist create an invasive species? I’m not so sure. Genetic engineering and breeding are great for improving crop yields, but that is a far cry from improving on fitness developed through eons of natural selection. What do you think?

Submitted by Dan Hilburn

1 comment:

  1. I am less concerned about Roundup resistant genes in pure agricultural crops than I am in species that are already known to spread and invade - like bentgrass. I don't think the point is that the genetic modifications may make a species more invasive, but rather for a species that can and does spread, our management options then become severely hampered. I have seen what I believe was bentgrass invade and fill-in the slow moving margins of an intermittent stream that was critical breeding habitat for an endangered one-inch fish (unarmored threespine stickleback) in Southern California. I tried removing this mechanically - ha! If that grass becomes resistant to glyphosate, what options do we have in our riparian areas? We have very limited options for invasive grasses in riparian areas. The concern becomes even greater if the glyphosate-resistant genes can flow to hybrid species that do occur widely in natural areas.

    I'm obviously no expert in this area, but as a land manager responsible for weed management on 25 million acres, glyphosate-resistant genes make me very nervous. On a related note, another lawsuit was filed against the FWS wildlife refuge system in Delaware for growing GMO crops on the refuge. They lost a similar lawsuit in 2009.

    Shawna Bautista