Why some plants become aggressive

Why some plants become aggressive



Feb 2007 - A new study of 
reed canarygrass has led to the discovery of a novel mechanism 
that explains why some plant species become aggressive when 
introduced in new territory. 
In its native European range, reed canarygrass does not push 
out other species or expanding its terrain. But, first 
introduced into the United States in the mid-19th century, it 
has run rampant, choking out native plants in wetlands. The 
grass is now considered an invasive pest in about ten states 
and its range is growing. 
According to research published in the Feb. 27 edition of the 
Proceedings of the National Academy of Sciences," the invasive 
power of this grass, comes not from any one individual plant, 
but from this history of multiple introductions from different 
regions of Europe. 
Over decades, U.S. farmers and others have planted the grass 
as livestock feed, for erosion control, and for wastewater 
treatment, taking plants from places as far apart as France, 
the Czech Republic and Finland. 
These multiple introductions, and subsequent interbreeding, 
create a kind of biological stacked deck, the researchers 
said. By drawing on genetic variety from across the European 
continent, new strains have emerged in the United States with 
higher genetic diversity and more potentially advantageous 
qualities than their species brethren across the Atlantic. 
"It's not that you're taking the ones in France and moving 
them to the US and they're suddenly invasive," said study 
coauthor Jane Molofsky, associate professor of plant biology 
at the University of Vermont. "It's that you move some plants, 
and then you move some from somewhere else and they recombine 
here to form something better, genetic superstars." 
This has significance far beyond the headache of reed 
canarygras, the researchers concluded, showing that invasive 
species can evolve extremely rapidly.

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