Fire Management of an Ozark Woodland
A Summary Report on the Response of Amphibians and Reptiles
Kenneth S. Mierzwa and Beth M. Churchwell
In the lower Ozarks of Missouri, relatively frequent fire maintained open oak-hickory-shortleaf pine savannas and woodlands on much of the landscape before the early 1800s. After an interval of even more frequent fire associated with European settlement and subsequent logging, and grazing, fires were almost completely suppressed from about 1930 until very recently. As a result vegetation structure has changed, with an increase in tree canopy cover and shrub density, and a loss of herbaceous cover.
Various studies have demonstrated that many small terrestrial animals are affected by changes in vegetation structure. From 1997 through 1999, we investigated the effects of prescribed fire on amphibians and reptiles at The Nature Conservancy's 6000-acre Chilton Creek Preserve in Shannon and Carter Counties, Missouri. Visual encounter surveys were used to sample amphibians and reptiles on randomly located plots within burn units and in nearby unburned areas. A total of 42 amphibian and reptile species were observed within the preserve boundaries. Overall species richness was non-significantly higher on burned plots than on unburned plots, largely because of the presence of additional reptile species. Plethodon albagula, the most abundant species on the site, did not differ significantly in abundance between burned and unburned plots. Two common salamanders, Eurycea longicauda and Eurycea lucifuga, were less abundant on burned plots, while one frog (Pseudacris crucifer) and one snake (Carphophis vermis) were more common within burn units. After two years of prescribed fire, amphibian and reptile diversity had improved, with small reptiles characteristic of more open conditions accounting for much of the change.
Analysis of once burned and twice burned units is complicated by uneven coverage of the second fire, with only drier ridgetops relatively completely burned. A partial analysis, not yet complete at this time, implies that fewer animals inhabited areas subject to annual fire, and those areas remained largely barren of ground cover through the completion of our study. Eurycea longicauda was markedly less common on twice burned plots than on either once burned or unburned plots.
We conclude that the return of fire management to an historically fire dependent Ozark woodland ecosystem is beneficial to overall amphibian and reptile richness and diversity. Although a few relatively common amphibian species may decrease in abundance, other, less common, amphibians and reptiles are more frequently observed in post-burn woodlands with fewer shrubs and greater herbaceous cover. Longer term studies will be necessary to determine the effects of different fire frequencies, or burning in different seasons.
This study was supported by The Nature Conservancy of Missouri, St. Louis and TAMS Consultants, Inc. -- Chicago. Numerous volunteers, including graduate students from Washington University and the University of Missouri-St. Louis, assisted with field work under often strenuous and difficult conditions. A more detailed final report will be posted at a later date, and will include complete acknowledgements.