PARENT SESSION
Contributed Oral Session 135: Invasive Species: Plant - Soil Feedbacks; Invasion Success
Thursday, August 11, 1:30 PM - 5:00 PM, Meeting Room 518 A, Level 5, Palais des congrès de Montréal
Decomposition dynamics of native and invasive litter in single and two-species mixes.
Hickman, Jonathan*,1, Howe, Kate2, Gurevitch, Jessica1, Lerdau, Manuel1, 1 The State University of New York at Stony Brook, Stony Brook, NY, US2 The Nature Conservancy, Indianapolis, IN, US
ABSTRACT- Because chemical and structural differences in leaf litter from exotic invasive and native plants can cause them to decompose differently, the deposition of invasive litter may have important impacts on ecosystem properties such as nutrient availability and cycling. The deposition of invasive litter may also alter ecosystem properties by affecting the decomposition dynamics of native litter. When litter from different species is placed in mixtures, patterns of mass-loss, nutrient transfer, and decomposer activity and abundance are frequently non-additive (that is, these patterns cannot be predicted by the dynamics of each species decaying singly). To study these decomposition dynamics, we made litterbags using litter from two congeneric and one confamilial pair of native and invasive species found in forests of the northeastern U.S., using a full factorial design in which each litterbag consisted of either a single or two-species mix. We destructively harvested litterbags at six time points over the course of the year and measured mass loss and C and N content. Additional litterbags were harvested at three time points for assays of enzyme activity to examine differences in associated microbial communities. Our data indicate that both direct and non-additive ("mixed-species") effects act on decomposition and nutrient dynamics in these forests. These results suggest that future calculations of invasive species impacts on ecosystems must consider both types of effects.
Key words: Invasion, decomposition, Acer, Rubus