Herbaceous Understory Response to Prescribed Burning and Oak Wilt in a Degraded Oak Savanna

Abstract

This study was part of a Nature Conservancy oak savanna restoration project in the Quincy Bluff and Wetland Preserve, Adams County, Wisconsin. I examined the response of the herbaceous understory of a degraded oak savanna to prescribed fire and oak wilt, and the response of the seedbank to light, temperature and leaf cover. Three treatment areas were compared in the field. Species percent cover was sampled in each. Treatment area I was burned in spring 1993; treatment area II was not burned and served as a control; and treatment area III was affected by oak wilt Soil samples were taken from treatment area II and placed in a greenhouse under varying light and leaf cover regimes, and in a growth chamber under varying temperature and leaf cover regimes. Total number of germinants and prairie/savanna germinants were found to be significantly different between temperature treatments (p = .001 and < .001) and cover treatments (p = < .001 and < .001). Prairie/savanna species were identified using lists from Bray (1960) and Tester (1989). The total number of germinants was significantly (p = .001) affected by light level, whereas the number of prairie/savanna germinants was not A paired t-test was run on the percent cover data collected in 1993 and 1994 on the burn, control and oak wilt treatments. Total percent cover did not vary significantly for any of the areas between years. The percent cover of prairie/savanna species, however, significantly (p = .014) increased in 1994 on the burn area. These results indicate that fire was an effective tool for increasing some prairie/savanna species. Both the field experiments and controlled environment experiments demonstrate the effects reduced litter cover can have on the germination and percent cover of prairie/savanna species. These results also indicate that prairie and savanna species have not yet disappeared from the seedbank and understory of this degraded savanna.