PARENT SESSION
Oral Session #88: Wetland Ecology.
Presiding: K. Ewel
Thursday, August 8. 1:00 PM to 3:45 PM. Gila Meeting Room, TCC.
Effect of the 1999-2001 drought on degraded cypress-tupelo swamps in Lake Maurepas wetlands, Louisiana.
HOEPPNER, SUSANNE*,1, SHAFFER, GARY1, 1 Department of Biological Sciences, Hammond, LA
ABSTRACT- The wetlands south of Lake Maurepas have previously been identified as degraded swamp forests in need of restoration. A freshwater diversion has been proposed to bring a greater load of nutrients, sediments and freshwater into the 160 square kilometer study area. Measures of the primary production of trees and the herbaceous undercover, and various soil and water characteristics were taken at twenty characteristic study sites within the Lake Maurepas basin to evaluate the potential effects of the proposed diversion. This presentation focuses on the primary productivity and survival of trees and their associated soil characteristics in the cypress-tupelo swamp ecosystem during drought and non-drought year conditions. Soil characteristics examined included soil bulk density, interstitial salinity, pH, redox potential (Eh), soil nitrogen levels, and soil phosphorus levels. Tree mortality was higher and primary productivity was lower during the drought in 2000 when compared to the subsequent year. Also, despite abundant rainfall in the year following the drought, soil salinity remained elevated in many areas. The most degraded sites chosen for this study exhibited the highest soil water salinities measured and were found to have the lowest rates of primary productivity per study plot among all study sites. The most productive sites of this study were interior swamps with relatively high throughput and those affected by the Amite River Diversion Canal. Lakeside sites exhibited decreased productivity due to salt stress.
KEY WORDS: diversion, swamp, drought, productivity