Monday, August 4, 2008

Invasive Species: Shall We Dance?

From the latest Ecological Application, "The adaptive value of remnant native plants in invaded communities: An example from the Great Basin" by Leger, EA.

"...Plants collected from invaded sites responded more quickly to watering, growing more leaves in the. rst 10 days after transplanting. In addition, big squirreltail plants collected from invaded areas experienced a smaller decrease in plant size when grown with competition than did plants collected from uninvaded areas. Accordingly, while there were fewer big squirreltail individuals in the invaded sites, they were more competitive with cheatgrass than were the more abundant conspeci. cs in nearby uninvaded areas. It is possible that annual grasses were the selective force that caused these population differences, which may contribute to the long- term persistence of the native populations.

While it is tempting to restore degraded areas to higher densities of natives ( usually done by bringing in outside seed material), such actions may impede long- term adaptation to new conditions by arresting or reversing the direction of ongoing natural selection in the resident population. If hot spots of rapid evolutionary change can be identified within invaded systems, these areas should be managed to promote desirable change and could serve as possible sources of restoration material or reveal traits that should be prioritized during the development of restoration seed material."

No comments: