PARENT SESSION
Poster Session 32: Biogeochemistry
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Decomposition at multiple spatial scales in oak savanna.

DeForest, Jared^*,1, Noormets, Asko¹, Tenney, Gwen¹, Chen, Jiquan¹, ¹ Earth, Ecological, and Environmental Sciences, Toledo, OH

ABSTRACT- Accurate measurements of decomposition rates are important to estimate ecosystem C cycling. However, we poorly understand if leaf (cm²) mass loss can be scaled-up to the forest floor (m²), and landscape (km²) scale. Because mass loss can correspond with soil respiration (R_soil), which is closely linked with ecosystem respiration (R_E), we reason mass loss can be estimated at the landscape-scale. We tested our hypothesis in an oak savanna in northwest Ohio from November to February (90 days) to minimize respiration from plants. R_soil was estimated using a temperature-dependent model and R_E was measured by eddy-covariance. Leaf mass loss was measured using litter bags, whereas forest floor mass loss was determined by sequential harvesting. Landscape mass loss was estimated from R_E using the relationship between forest floor mass loss and R_soil. Mass loss (%) from litter bags strongly (r² = 0.97) correlated with forest floor % mass loss. Moreover, forest floor leaf mass loss (%) was correlated (r² = 0.88) with R_soil. Estimates of leaf litter mass loss for 90 days was 14% from litter bags, 40% for forest floor, and 37% at the landscape-scale. Results suggest that short-term decomposition from leaf litter bags may underestimates decomposition by 35% when compared to decomposition in the forest floor. Identifying and understanding the behavior of the respiration sources at different spatial scales will allow the use small-scale measurements for scaling landscape-level C fluxes.

Key words: carbon cycling, decomposition, landscape ecology, winter ecology