PARENT SESSION
Oral Session # 55: Resource Management II: Terrestrial Systems.
Presiding: E Latty
Wednesday, August 6. 1:30 PM to 5:00 PM, SITCC Meeting Room 106.
Predictability of within-site invasion dynamics for native and exotic plant species.
Meiners, Scott*,1, Cadenasso, Mary2, Pickett, Steward2, 1 Eastern Illinois University, Charleston, IL2 Institute of Ecosystem Studies, Millbrook, NY
ABSTRACT- The rate of within-site spread is a key diagnostic for setting management priorities as slower invaders tend to be lower management priorities than faster invaders. However invasion dynamics are rarely quantified. Here we present data from the Buell-Small Succession Study, a long-term study of post-agricultural vegetation dynamics, to evaluate the dynamics of plant species invasions over a 44-year period. The analyses focus on a range of species of varying successional status, life history and form. We have determined the rates of invasion for the 20 most abundant native and exotic invaders at the site (40 species in total). Based of rates of increase in frequency of occurrence in the sites, native and exotic species do not differ in invasion rate. However, plant life forms vary predictably in rate of invasion. Short lived and herbaceous plants invade at much greater rates than more long-lived woody species. These life forms follow the following ranking from fastest to slowest invaders: annuals > biennials > perennials > woody spp. The length of population lag times (the time between when an invader first appears in a site and when it's population begins to grow) follows the same ranking, with annuals having the shortest lag times. These results suggest that short-lived invaders may pose more immediate management concerns than longer-lived species. This information provides land managers with a simple way to assess management priorities without extensive population monitoring. Furthermore, exotic and native plant invasions appear not to have fundamentally different dynamics.
Key words: exotic species, invasion rate, succession, long-term studies