How Do Reclamation Conditions Affect the Invasion Success of the Exotic Autumn Olive?
Post-mining landscapes are currently reclaimed using the Forestry Reclamation Approach (FRA) developed at Virginia Tech that seeks to achieve high hardwood tree canopy cover following establishment of “tree-compatible groundcover”. FRA has been successful in advancing development of ecosystem structure (e.g., ground cover, species diversity, stem density). However, as Dr. Burger and colleagues pointed out in 2010, FRA results in more bare ground, which “allows more invasion by plant species from nearby areas.” They point out this is often from adjacent native species from natural dispersal or by animals. However, the gaps left by FRA leave much of the ground open to invasion by exotic plants as well, that may have negative impacts to desirable vegetation. Exotic invasive plants are known to have negative impacts to ecosystem structure and function in a wide range of systems. However, the effect of these exotic plants can be especially problematic on reclaimed mine sites due to the harsh growing environment. One of the most common exotic invaders of the Powell River Project is autumn olive, and is problematic for mine operators during bond release.