Long-Term Changes in Chicago Region Prairie Vegetation in Relation to Fire Management
Digitization StatusBorn digital
AbstractTo understand long-term change in Chicago region prairies, in 2001 we re-investigated 62 prairie stands that were originally sampled in 1976 by the Illinois Natural Areas Inventory. For those sites with fire-management records, we correlated changes in species richness, composition and structure with the frequency at which the sites were burned over time. About 77% of all prairies remained intact, and, with the exception of many railroad prairies, most of the surviving sites are now protected. The majority of stands with fire records had been burned less than 40% of the time. With respect to change in species richness, higher quality prairies tended to be stable, while lower quality prairies increased in richness, presumably in response to fire management. We also found that alien species and woody vegetation increased across all sites, and that native species richness tended to decline as woody vegetation increased. Fire frequencies of about 50 %, i.e. biennial burning, appear necessary to maintain composition and structure of mesic and wet-mesic prairies, and few sites were burned at this rate. This appears to be causing long-term deterioration of many sites, and we propose that increased fire management will be needed to maintain these important natural areas.
Volume, Issue, Page Number2, 2, 7-16