Trojan Horse attack on native lupine

(Washington University in St. Louis) At Point Reyes National Seashore in Marin County, Calif., a fierce battle is taking place under the oblivious, peeling noses of beachgoers. It’s a battle between an invasive plant and a native plant, but with a new twist. The two plants, European beachgrass and Tidestrom’s lupine, are not in direct competition, and yet the beachgrass is helping to drive the lupine over the cliff. European beachgrass provides cover that allows a timid deer mouse to get close enough to the lupine to snip off stalks of lupine fruits without being nabbed by overflying birds. In the August issue of Ecology, biologists at Washington University in St. Louis report on the interplay between these species in three lupine populations over a period of four years. Emily Dangremond, Eleanor Pardini and Tiffany Knight used field data to construct a mathematical model of lupine populations. The model predicts that if things go along as they have been so far, all three populations of lupines will be driven to extinction. But it also predicts that if the mice eat just a few less seeds, the largest population of lupines, which is under the greatest pressure from seed consumption, will remain stable. … Tiffany Knight, PhD, associate professor of biology in Arts & Sciences, chose Tidestrom’s lupine as a research project because “it is endangered and yet has close relatives that are doing just fine. There’s even a lupine in the northern California, the yellow bush lupine, that is really common and, in fact, is expanding its range. It’s all the way up into Canada and it’s been introduced to New Zealand and is doing well enough to be considered invasive there. “So you have these lupines that are performing very differently and the basic ecological question is why? What makes some species vulnerable and others not?” … According to the World Conservation Union, one out of every four plant species on the planet is currently under the threat of extinction.