Gregory Crutsinger has shed light on a level of biodiversity that could influence the way farmers and gardeners grow plants and sow seeds.
Research has shown for some time that when different species of plants are grown together, the overall productivity of their ecosystem increases. This effect leads to a more diverse community associated with the plants.
Crutsinger is a graduate student in UT’s Department of Ecology and Evolutionary Biology. His research, published in the Aug. 14 issue of the journal “Science,” looked at the same qualities on a different scale.
Crutsinger examined the effect of using plants -- specifically goldenrod -- of the same species, but with different genetic types. Using an apple orchard that grew Fuji, Granny Smith and Red Delicious side-by-side would be an equivalent agricultural model of this.
“Greg was able to show, with a novel experiment, that many ecologists have overlooked the diversity within species,” said Nathan Sanders, the UT professor who oversees Crutsinger’s work. “That could be key to understanding how ecosystems work, and just as importantly, how to put them back together again after disturbance.”
Crutsinger’s results showed that mixing the genetic types of a species can have just as much influence, if not more, than species diversity of both plants and insects in the area. This finding could have implications in a number of fields, from conservation to agriculture.
Crutsinger’s analysis demonstrated that when multiple genotypes were grown in a plot together, they produced more biomass and maintained more insects than the sum of their individual genotypes grown separately. Biomass describes the weight of the part of the plant above the ground.
“This adds to the idea that diversity begets diversity,” Crutsinger said. “When you mix these different genetic types, a patch of plants can be more than the sum of its parts.”
He chose goldenrod because it is a dominant plant in old-field ecosystems, growing from Florida up to Canada. It also features significant genetic diversity and is a food source for a wide variety of herbivores.
Crutsinger made his first plantings in April 2005, measuring their growth and insect abundance through October of the same year.
“It was a lot of physical labor,” said Crutsinger, who built a rain collection and irrigation system on the land to ensure that the plants received the proper amount of water.
Oak Ridge National Laboratory and the U.S. Department of Energy provided the land for the research, which is located on the Freels Bend area of the Laboratory’s reservation.