PARENT SESSION
Session #9: Ecological forecasting - Ecosystem management based on predictive science. Organized by: J. E. Fauth and D. Scavia.
Tuesday, August 7, 2001. Madison Ballroom B

Predicting the potential distribution of a plant invader: integrating field studies and climate matching approaches.

Pattison, Robert¹, Mack, Richard¹, Black, Robert¹, ¹

ABSTRACT- Accurate prediction of the potential distribution of invasive species is important to their control. Field studies and a computer model (CLIMEX) were used to predict the potential distribution of the invasive Chinese tallow tree, Sapium sebiferum. Seedlings of S. sebiferum were planted in 4 microhabitats in a factorial design of open and closed canopy and upland and lowland microhabitats at 7 sites along a coastal (1,300 km) transect and an inland (400 km) transect in the southeastern U.S. These transects, which are orthogonal to each other, extend beyond the current geographic range of S. sebiferum. Seedling survival and growth rates were measured 1 year after planting. In predicting the potential U.S. distribution of this invasive tree, model parameters for CLIMEX were based on greenhouse studies of seedling tolerances to key environmental conditions and on climate matching of the known global distribution of S. sebiferum with U.S. climatic records. Average seedling survival ranged from 20 to 100% and was 100% in at least one microhabitat at all sites. Average seedling basal diameter ranged from 3.3 to 7.5 mm with the largest seedlings occurring in open microhabitats and in sites beyond the present southeastern distribution of S. sebiferum. Computer predictions match field results and suggest that S. sebiferum has yet to occupy its entire new range in the U.S.

KEY WORDS: sapium sebiferum, climate matching, climex