Pollution Squeezing Out Rare Plants

In the upper Midwest, the number of species declined by 50 percent as invasive European grasses took over. Many of those that were lost were low-growing plants that found themselves in the shade of the taller grass, and thus deprived of the sunlight they needed to survive.

In the Kansas prairie, more than half the legumes -- plants that bear pods -- were lost because they couldn't metabolize the added nitrogen, and other plants simply took over. The lost species included members of the pea family.

In California, grasslands flourished and California poppies and other wild flowers diminished.

And in Alaska, birch shrubs on the tundra, which are dinky little things compared to the towering birch trees to the south, grew a whopping fivefold while reducing the number of species to a mere handful.

Although these were controlled experiments, designed to measure the impact of nitrogen fertilization, similar cases have been documented in the wilds, where nitrogen enrichment is an inadvertent result of human activities.

Nitrogen may be wonderful for our gardens, Suding notes, but the research shows "it is possible to have too much of a good thing."

Lee Dye's column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

  • 1
  • |
  • 2
Join the Discussion
You are using an outdated version of Internet Explorer. Please click here to upgrade your browser in order to comment.
blog comments powered by Disqus
You Might Also Like...
See It, Share It
PHOTO: Oscar de la Renta and Oprah Winfrey attend the Costume Institute Gala Benefit to celebrate the opening of the American Woman: Fashioning a National Identity exhibition at The Metropolitan Museum of Art, May 8, 2010, in New York City.
Rabbani and Solimene Photography/WireImage/Getty Images
PHOTO: Up in Ash: Mount Sinabung Erupting
Tibt Nangin/Anadolu Agency/Getty Images
PHOTO: Firefighters rescue a woman who got stuck in a chimney in Thousand Oaks, Calif.
Ventura County Fire Department
PHOTO: Apple Pay is demonstrated at Apple headquarters on Oct. 16, 2014 in Cupertino, Calif.
Marcio Jose Sanchez/AP Photo