Ranking the components of ecological resistance to biological invaders : an experimental manipulation in a southern Appalachian riparian forest.

The theory that communities can withStand introductions of non-natives is called “ecological resistance,” which was hypothesized to consist of three interdependent elements: (1) environmental resistance, which may be mediated through natural disturbances; (2) biotic resistance, which is a consequence of plant adaptive strategies; and (3) demographic resistance, which may be expressed as differential dispersal and establishment. I separated the influences of natural disturbance, biotic resistance, and demographic resistance and ranked their contributions to ecological resistance with a field experiment. This research was conducted at Big Stony Creek, a naturally flooded system within the Jefferson National Forest in southwestern Virginia. I manipulated resident diversities and functional group representation along a disturbance gradient and planted differing quantities of invaders into these manipulated plots. Success of an invasion was measured by survivorship and growth of the invader.