PARENT SESSION
Poster Session 11: Disturbance Ecology
Tuesday, August 9, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Herbaceous plant community responses to fire in longleaf pine forests.

Schnurr, Jaclyn^*,1, Collins, Beverly², ¹ Wells College, Aurora, NY, USA² Savannah River Ecology Lab, Aiken, SC, USA

ABSTRACT- Fire is a common management tool used in the forests of the Southeastern United States to maintain the dominance of Pinus palustris (longleaf pine) over deciduous tree species. Fire also affects herbaceous vegetation, and has been shown to increase ground layer diversity in longleaf pine forests of Florida. We compared understory vegetation in longleaf pine forests on the Savannah River Site, near Aiken, SC, that had different fire management histories (B00: recently burned, B90: last burned 10 years prior to the study, and B50: last burned prior to 1950) and in two unmanaged stands (DEC: deciduous and SND: sandhills). We determined species richness, diversity, abundance and composition using line-intercept sampling in summer, 2001. The Shannon-Wiener diversity index was similar in all stands (H^,=2.5), but species richness differed. The B90 sites had the highest richness (N=37), while DEC sites had the lowest (N=22). The B00 sites had significantly more grass cover (P=0.001), and B90 sites had the most tree sapling (P=0.001) and liana (P=0.005) cover. The B50 sites were the only sites to have cover of a reindeer lichen, Cladonia leporina. In contrast to its effects in managed Pinus palustris stands in Florida, fire did not increase species diversity in the SC forests, but did result in different species composition and abundance.

Key words: herbaceous vegetation, fire, Pinus palustris, Savannah River Site