Ph.D. Candidate, University of Illinois Urbana-Champaign
When is restoration win-win? Evaluating plant diversity and carbon storage
tradeoffs across restored floodplains
Conference Travel Grant Type 2
“The simultaneous recovery of plant diversity and carbon (C) storage in restored wetlands is uncertain because many interdependent disturbances create tradeoffs among primary productivity, vegetation composition, and soil organic carbon (SOC) accumulation. In this study, we compared these tradeoffs across eight Illinois sites with paired restored and reference floodplain forests. At each site, we established six 10-m × 10-m plots to survey woody vegetation and measure canopy cover; then, we established five nested 1-m × 1-m quadrats to survey herbaceous vegetation and remove soil cores. After analyzing cores for total C (TC) and SOC concentrations, we quantified (1) total, live tree, and herbaceous layer species richness and (2) soil, litter, woody debris, and biomass C stocks. To explain variation in SOC, we also measured two SOC fractions and multiple soil edaphic properties, including moisture, texture, aggregate stability, and nutrient concentrations. Although inorganic and particulate organic C stocks were somewhat lower in restored than reference wetlands, high mineral-associated organic C stocks in restored wetlands led to TC and SOC stocks only marginally below reference levels. Despite nearly recovered soil C storage, all restored wetlands had much lower total ecosystem C storage due to their limited woody material. Conversely, plant species richness was only lower than reference levels at younger restored sites (<20 years), which had less canopy cover and more invasive biomass than older restored sites (>20 years). Thus, beyond hydrology, tree density could be an important secondary factor regulating long-term plant diversity and ecosystem C storage in restored forested floodplains.”