PARENT SESSION
Poster Session #61: Soil Ecology II.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Soil biota effects on decomposition in burned and unburned tallgrass prairie.

Reed, Heather^*,1, Seastedt, Timothy¹, ¹ University of Colorado, Boulder, CO

ABSTRACT- At Konza Prairie Long Term Ecological Research site, annually burned prairie is associated with lower plant diversity, greater belowground plant inputs, and significantly less surface litter accumulation compared to unburned prairie. Based on these differences in plant inputs to the soil, we hypothesized that decomposition of surface and buried materials would differ between these communities. Decomposition resistance and resilience in burned and unburned prairie could differ because of different microclimates or soil faunal assemblages. We minimized differences in microclimate to isolate the effects of the associated soil communities on decomposition. To test the resistance of decomposition to an environmental stress, we imposed a drought in each community type and measured decomposition rates. Two substrates, roots and wood dowels were placed belowground, while litter was placed aboveground. Wood dowels decomposed significantly faster in the burned prairie sites. We also found trends of greater decomposition of surface litter in unburned prairie and buried roots in burned prairie. These results were consistent across two years and support the general hypothesis that buried material decomposes faster in burned communities while surface litter decomposes faster in unburned communities. The imposed drought caused significant reductions in decomposition for litter and roots but not wood dowels; however, community type did not affect resistance. While these communities are thought to differ substantially in numbers and types of detritus feeders, the communities' responses to an applied stress appear similar.

KEY WORDS: decomposition , resistance, tallgrass prairie, soil community