PARENT SESSION
Oral Session 5: Disturbance Ecology I: Scaling, Wind, and Ice.
Presiding: D McKenzie
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room B 113.
Bamboo demography and wind disturbance in an alluvial forest.
Gagnon, Paul*,1, Platt, William1, 1 Louisiana State University, Baton Rouge, LA, U.S.A.
ABSTRACT- Multi-species and monodominant plant communities sometimes co-occur within landscapes. Variation in the effects of natural disturbances may control the boundaries between such communities. Vast monodominant bamboo stands called canebrakes, formed by cane (Arundinaria gigantea), were once common adjacent to species-rich bottomland hardwood forests in the southeastern U.S. Canebrakes were widespread when Europeans first explored North America but have now virtually disappeared. We hypothesize that natural disturbances such as windstorms and wildfires were important determinants of canebrake structure and dynamics. We are studying the effects of natural windstorms on remnant canebrakes in the Lower Mississippi Alluvial Valley of northeastern Louisiana. A massive tornado blowdown within the Buckhorn Wildlife Management Area affords the opportunity to investigate demographic responses to a large-scale wind disturbance. We are conducting life table response experiments (LTREs) on cane in both the blowdown and adjacent canopied forest. We are building stage-based models of cane dynamics by monitoring multiple ramets within given cane patches. Initial results indicate different dynamics for cane growing 1) in the blowdown gap compared to under forest canopy (
= 1.50 vs. 1.06), 2) at patch edges compared to patch interiors ( = 1.40 vs. 1.16), and 3) in small discrete patches compared to dense, continuous stands. Ramets growing in the blowdown and at patch edges are younger and less-often damaged than those growing in the forest and in patch interiors. Cane responds to large-scale natural disturbances like blowdowns with rapid and extensive clonal growth that increases clone size and ramet density and produces a stand structure comparable to the canebrakes described by early explorers.
Key words: Arundinaria gigantea, bottomland hardwood forest, bamboo, wind disturbance