PARENT SESSION
Wednesday, August 9, 5:00-6:30 pm
Poster Session 18 - Forest ecology and management
Exhibit Hall, Ballroom Level, Cook Convention Center
The impacts of liana removal on aboveground biomass recovery in treefall gaps in a tropical moist forest.
Mascaro, Joseph*,1, Schnitzer, Stefan1, Carson, Walter2, 1 University of Wisconsin - Milwaukee, Milwaukee, WI2 University of Pittsburgh, Pittsburgh, PN
ABSTRACT- Lianas (woody vines) are an integral component of tropical forest community and ecosystem dynamics. Although poorly studied, lianas may account for as much as 10% of aboveground biomass and 15% of canopy leaf area in mature tropical forests, and can further impact aboveground carbon dynamics by arresting tree regeneration, altering treefall patterns, and competing directly with trees for water and soil nutrients. To assess the impact of lianas on gap-phase regeneration of forest biomass, we measured tree and liana diameters in 18 canopy gaps in a tropical moist forest on Gigante Peninsula, near Barro Colorado Island, Panama. Gaps were identified shortly after a treefall, and all trees and lianas (> 3 mm dbh) in both gap interiors (footprint of open canopy directly overhead) and exteriors (5-m-radius-donuts surrounding the interiors) were followed annually from 1998 to 2001, and measured again in 2003 and 2006. Using published allometric regression equations to estimate the aboveground biomass of lianas and trees, we found that interior control plots accumulated 0.6 ± 0.4 Kg/m2 of biomass over the duration of the study, compared to 1.0 ± 0.4 Kg/m2 in interior plots with lianas removed. Year-to-year dynamics also differed between treatments. In control interior plots, liana biomass accumulation was positive only in the first year of gap closure, and net liana biomass accumulation over eight years of measurements was 0.0 ± 0.5 Kg/m2. Thus, lianas appeared to be much more opportunistic than trees in the first year. Lianas also may have limited gap-level biomass accumulation thereafter: In control plots, total biomass accumulation in the first year of interior gap closure averaged 0.44 ± 0.21 Kg/m2/yr, of which 86% was attributable to lianas, compared to -0.13 ± 0.21 Kg/m2/yr for removal plots with only trees present. Following the first year, removal interior plots accumulated biomass more rapidly than control interior plots during all four remaining measurement intervals. Lianas may be increasing in abundance in large areas of tropical forests, and our findings support the notion that such an increase may limit the rate at which regenerating forests accumulate carbon.
Key words: aboveground biomass, tropical moist forest, gap regeneration