PARENT SESSION
Oral Session #52: Plant Ecology: Light and Carbon Allocation.
Presiding: T. Day
Wednesday, August 7. 8:00 AM to 11:30 AM. Gila Meeting Room, TCC.
Leaf regeneration in neotropical understory herbs following experimental defoliation.
Cooley, Arielle*,1,2, Reich, Alexandra1, Rundel, Philip2, 1 La Selva Biological Station, Sarapiqui, Costa Rica2 UCLA, Los Angeles, CA
ABSTRACT- Large tropical understory herbs are frequently damaged by falling canopy debris. Understanding the diversity of strategies for tissue regeneration and plant persistence in the light-limited understory of tropical rainforests is an important, yet understudied, aspect of forest dynamics. Responses to leaf removal were studied in eight species of herbaceous monocots (five from old-growth forest; three from more open, disturbed areas) from the Cyclanthaceae, Araceae, Costaceae, Marantaceae and Heliconiaceae. Forty-five individuals of each species were selected and treated with 0%, 50%, or 100% leaf removal. Production of new leaves was recorded every other week for 12 weeks and related to light environment, clonal versus solitary life form, and root-shoot ratios. Leaf production across all taxa was positively correlated with light availability (multiple R2=0.330, p<0.01). Removal of 100% of leaves was associated with increased production of new leaves in one species, decreased production in two species, and no change in the remaining five. Leaf replacement rates following 100% leaf removal were 357.3% higher in disturbed-site than in old-growth species, and 86.4% higher in nonclonal than in clonal species. Root-shoot ratio was not a predictor of regeneration rate. Many of the regeneration patterns observed in this study differ from those previously described for understory palms, and they illustrate the great diversity of regeneration strategies in the herbaceous component of the tropical rainforest.
KEY WORDS: tropical rainforest, understory herb, regeneration, leaf damage