John B Taft

 

Affiliate
Adjunct, Natural Resources &

Environmental Sciences
Senior Research Scientist,

Illinois Natural History Survey
399 Natural Resources Building MC-652
1816 S. Oak Street
(217) 244-5046

Research

Vegetational ecology and fire effects in oak woodland communities including flatwoods and barrens, development and analysis of a method for assessing floristic integrity for the Illinois flora, vegetation ecology of grasslands including prairies of Illinois and steppes of Kyrgyzstan in central Asia, and floristic surveys of unique habitats in Illinois.

 

Barrens burn study
Barrens, savanna-like openings in wooded landscapes, are gradually vanishing due to woody encroachment. This long-term study compares changes in the ground cover, shrub, and tree strata at a Pope County site treated with prescribed fire with a nearby fire-free control site. As predicted, ground-cover species richness and cover increase with fire and gradually decline at the control site. These changes are correlated to changes in density of woody plants. An emerging ground cover in closed barrens is a minor floristic subset of the open barrens, suggesting that species survival in the seed bank is selective. Unexpectedly, warm-season prairie grasses continue to decline at both study sites.

 

Flatwoods burn study
During periods of prolonged fire absence, many flatwoods undergo changes in composition and structure that result in lower vegetational diversity. High-quality remnants are rare. Many areas of degraded flatwoods remain but their restoration potential is uncertain. This long-term study measures the response of vegetative strata to the introduction of fire in a degraded remnant. Results following three burns indicate that considerable herbaceous species diversity native to the habitat resides in soil seed banks until stimulated by fire effects. Improved available light conditions with the reduction of sapling and shrub density appear to meet reproductive requirements for the emergent ground cover, ensuring population establishment and growth.

 

Floristic quality assessment for Illinois
Floristic quality assessment is a method for evaluating the integrity of native plant communities. Coefficients of conservatism were assigned to each taxon in the Illinois flora. A mean value and site index indicative of relative floristic quality are derived from compiled species lists. These values are useful in the identification of both natural areas and the damaged remnant habitats that have potential for ecological recovery. Floristic quality assessment can be combined with quantitative data to provide a useful measure of vegetational changes over time. Such trends are valuable for assessing management effects and goals.


Publications

Taft, J. B., C. Hauser, and K. R. Robertson. 2006. Estimating floristic integrity in tallgrass prairie. Biological Conservation 131:42-51.

 

Taft, J. B. 2005. Fire effects on structure, composition, and diversity in a flatwoods remnant in south-central Illinois. Castanea 70:298-313.

 

Taft, J. B. 2003. Fire effects on community structure, composition, and diversity in a dry sandstone barrens. Journal of the Torrey Botanical Society 130:170-192.

 

Taft, J. B. 2003. Composition and structure of an old-growth floodplain forest of the lower Kaskaskia River, Illinois. Pages 146-158 in: Van Sambeek, J. W.; Dawson, J. O.; Ponder, F., Jr.; Loewenstein, E. F.; Fralish, J. S., eds. Proceedings of the 13th Central Hardwoods Conference. USDA Forest Service General Technical Report from the USDA Forest Service North Central Forest Experiment Station (146-158).