Appendix C. A figure showing the sensitivity analysis performed to evaluate the effects of remnant prairie age on the estimated rate of soil carbon accrual following restoration.
FIG. C1. Sensitivity analysis to evaluate the effects of remnant prairie age on the rate of soil C accrual following prairie restoration. We used a range of remnant prairie ages starting at 163 and ending at 2000 years-old. Prairie remnant ages included 163, 188, 215, 263, 315, 363, 415, 515, 615, 715, 815, 915, 1015, 2000 years of age. The first age, 163 yr-old, was determined by the earliest description of the site in 1839 U.S. Public Land Survey. The original General Land Office survey of the Fermilab area was conducted from November 1839 through June 1840. The Survey states that nearly 80% of the landscape was prairie and 20% was timber along the Fox River Valley near the west side of the site (Bowles et al. 1998). The remnant prairie is located along the Burlington Northern Railroad near the northern boundary of the site, and it includes an area that would have been considered in the right-of-way of the railroad tracks. We conclude that the prairie was present during the Public Land Survey 163 years before our sampling and the site was preserved by its proximity to the railroad tracks. We used SAS nonlinear fitting procedures to calculate the C sequestration rate after 26 yr of prairie restoration using equation (ii) for each of the range of potential ages for the remnant prairie.
Bowles, M. L., J. McBride, and L. Bell. 1998. Landscape vegetation patterns, composition and structure of DuPage County, Illinois, as recorded by the U.S. Public Land Survey (1821-1840). The Morton Arboretum, Lisle, IL. Ecological Services, Urbana, Illinois, USA.