Importance of Site Preparation and Prescribed Fire on Tallgrass Prairie Reconstructions

Abstract

Prairie ecosystems have experienced dramatic declines in species diversity due to habitat loss, the introduction of invasive species, and the suppression of fire. Historically, fire was a key ecological process in shaping the tallgrass prairie, promoting the dominance of native grasses and forbs while preventing the spread of woody vegetation. Without fire, many prairies shift toward lower biodiversity, with invasive plants such as smooth brome (Bromus inermis) and Kentucky bluegrass (Poa pratensis) outcompeting native species like big bluestem (Andropogon gerardii) and Indian grass (Sorghastrum nutans). My study addresses the importance of site preparation in prairie reconstructions, and how fire can be used to maintain these ecosystems and reduce non-native species abundance. I analyzed field data from prairie reconstructions on the Shakopee Mdewakanton Sioux Community land. Vegetation surveys were conducted on prairies where prescribed fire was used as a management tool. Total number of species and their abundance were recorded before and after the burn to compare native species regeneration andchanges in diversity. These data were compared against prairies where no management took place between vegetation surveys. Species richness and alpha diversity were stable or slightly declined in the unburned prairies and increased in the burned prairies. Contrary to expectations, the percentage of native species decreased moderately in both the burned and unburned prairies. This pattern suggests that something beyond the fire treatment is shaping community composition, possibly drought stress, pressure from disturbance-tolerant species, or larger landscape-level shifts that neither treatment could fully counteract. A similar trend appears in the changes in overall plant height, reinforcing the idea that broader environmental factors were likely driving vegetation responses during this period.