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
Razing cane: The effect of fire on a native North American bamboo.
Gagnon, Paul*,1, Platt, William1, 1 Louisiana State University, Baton Rouge, LA, USA
ABSTRACT- Natural disturbances that vary across landscapes may influence the boundary between very different community types. A monodominant bamboo community called the canebrake was once very common in the southeastern United States alongside species-diverse bottomland hardwood forests. Today these tall, dense bamboo stands have virtually disappeared. Nonetheless, the bamboo that formed canebrakes (Arundinaria gigantea) can still be found throughout much of its former range, where it grows in small, sparse patches. What happened to the vast, dense canebrakes of 200 years ago? We hypothesize that interacting natural disturbances like wildfire and windthrow were important determinants of canebrake structure and dynamics. We are studying the effects of fire and windstorm on Arundinaria gigantea (commonly called cane). Our fieldsite is located in the Buckhorn Wildlife Management Area, within the Lower Mississippi Alluvial Valley of Louisiana. Here a massive tornado blowdown in bottomland hardwood forest affords the opportunity to investigate cane response to large-scale disturbances. We are conducting a variety of life table response experiments (LTREs) on burned and unburned cane growing in both blowdown gap conditions and under adjacent forest canopy. We are building stage-based models of cane dynamics by monitoring multiple ramets within given cane patches. Results from prescribed-fire treatments suggest that burning increases ramet growth rates (
) for several years following a fire. In unburned plots, a substantial fraction of senescing culms are not replaced when they die. In contrast, in the majority of burned study plots virtually every bamboo culm that died in fires was replaced by a brand-new culm. These young culms should live longer from the time of the fire than the older culms they replaced. Compared to unburned plots, we expect burned plots will attain substantially higher culm densities during the several years following fire. These results suggest vigorous post-fire regeneration as a mechanism by which A. gigantea attained dense canebrake stand structure.
Key words: canebrakes, bottomland hardwood forest, Arundinaria gigantea, multiple disturbances