PARENT SESSION
Poster Session # 16: Invasive Species.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Dispersal of Ailanthus altissima seeds into varying environments: Is any area safe from invasion?
Kota, Nathan*,1, Landenberger, Rick1, McGraw, James 1, 1 Department of Biology, Morgantown, WV, USA
ABSTRACT- Ailanthus altissima (Tree of Heaven) is an invasive tree species from central China. Initially confined to highly disturbed urban areas, Ailanthus has recently been found in relatively natural, undisturbed habitats. Female trees can produce up to 300,000 wind-dispersed samaras, which may travel long distances from focus populations. We examined seed dispersal by trapping seeds in open fields, intact forests, and a recently harvested forest to characterize the dispersal kernel in these common, rural environments. Seeds were found out to 100 m from isolated focus populations at all sites, and seed densities showed strong declines with increasing distance; one intact forest site, however, showed no relationship over distance and had the same average density across the entire 100 m sampling interval. Examining seed weight as a function of site and distance from focus populations, we found that mean weight varied among all sites (F=69.12, p<0.0001) but showed no consistent statistical relationship with dispersal distance (F=0.5365, p=0.46). Heavy seeds traveled just as far, on average, as light seeds; however, the effect of distance depended on site (F=6.71, p<0.0001), with one intact forest site showing an increase in mean seed weight at greater distances (R2=0.12 p=0.01), and a harvested forest site showing the opposite effect (R2=0.05, p=0.02). Ailanthus focus populations vary in their dispersal properties in significant ways, but our results show clearly that long-distance dispersal is frequent in both open and forested environments. This pattern makes control of this noxious invasive plant challenging. Nevertheless, control may become increasingly important with expected increases in timbering over the next several decades.
Key words: seed dispersal, Ailanthus altissima