Fifty years of prairie fire – a case study from Iowa

Small, isolated prairie remnants often show a decline in native species over time, and their sustainability is questioned. Given the rarity of tallgrass prairie in the upper Midwest, it is important to monitor changes over time to determine the long term impacts of land management.

This case study sought to document changes in the vegetation at Kalsow Prairie, one of the largest virgin prairies remaining in Iowa. Management at Kalsow, prior to 1950, was predominantly annual summer mowing, after 1950 management was gradually shifted to spring burning.

Implications for managers:

• Managing the same way over time (e.g., burning in the spring every 2 years) may not maximize biodiversity of the plant community due to the strong selection pressure.
• Larger isolated prairie sites may be less prone to establishment of non-native species when managed with fire
• Prescribed fire may stabilize prairie communities, and keep non-native species from establishing

For further summary of the study's results and implications for management, view or download a PDF version of the research brief: "Fifty years of prairie fire – a case study from Iowa."

The original paper is:

Reference:

Dornbush, Mathew E. 2004 Plant community changes following fifty-years of management at Kalsow Prairie Preserve, Iowa, U.S.A. American Midland Naturalist 151:241-250.

Evaluating sixteen years of restoration in prairie

Long-term studies can track changes over time, and provide examples of expected community trajectory under similar restoration activities. In this study, authors focused on tallgrass prairie remnant at the University of Michigan Nichols Arboretum in Ann Arbor. 

After 16 years of research comparing prescribed fire treatments (annual fires and fires every three years), the authors did not observe changes in dominance or richness related to differences in fire frequency. 

For a summary of the study's results and implications for management, you can view or download a PDF version of "Evaluating sixteen years of restoration in prairie."

This research brief for research managers summarizes the following peer-reviewed publication:

Heslinga, Justin L., Robert E. Grese. 2010. Assessing plant community changes over sixteen years of restoration in a remnant Michigan tallgrass prairie. American Midland Naturalist 164:322-336.

Can burning benefit insects in isolated prairies?

The lack of long term data looking at how invertebrates respond to prescribed fire led Ron Panzer to conduct a six year study spanning three states. Invertebrates were grouped by their dependence on remnant prairie sites and populations tracked through multiple burns to determine rates of recovery. 

Implications for Management:

• Annual fires may not allow a long enough recovery time for a minority subset of prairie insects
• Burning every 2-3 years may balance concerns over insect recovery with other conservation goals (e.g., plants, birds)
• Remnant dependent insects recover at the same rate as remnant independent insects

For a summary of the study's results and implications for management, you can view or download a PDF version of "Can burning benefit insects in isolated prairies?" 

This research brief for research managers summarizes the following peer-reviewed publication:

Ron Panzer. 2002. Compatibility of prescribed burning with the conservation of insects in small, isolated, prairie reserves. Conservation Biology 16:1296-1307.

Prairie Burn Management and Native Species Diversity

The varying effects of fire frequency on native prairies continues to be the subject of study and interest among restorationists and ecologists in the Upper Midwest. This study, in prairie remnants in the eastern tallgrass prairie region, took a close look at species composition changes over five decades.

Among several crucial findings, the authors cautioned against site monitoring protocols based on plant species diversity, which in this resurvey remained stable--despite the clear shift toward common species and away from conservative specialist species.

Management Implications

• Continue to burn remnants. A burn regime of 4-17 fires in 20 years had the greatest influence on keeping species composition similar to 1950.
• Put monitoring emphasis on rare species rather than species diversity, as diversity does not always indicate a decrease in rare species.
• Managers may not need to go to great effort to remove all woody species. The most stable prairies had less than 50% canopy cover.

For a summary of the study's results and implications for management, you can view or download a PDF version of "Prairie Burn Management and Native Species Diversity."

This research brief for research managers summarizes the following peer-reviewed publication:

Milbauer, M. L., and M. K. Leach. 2007. Influence of species pool, fire history, and woody canopy on plant species density and composition in tallgrass prairie. J. Torrey Bot. Soc. 134: 53–62. 2007.

Response of tallgrass prairie to fire frequency

This brief summarizes results from a study that was focused on eastern tallgrass prairie sites and examines how fire frequency influences the plant community. To investigate how fire frequency affects eastern tallgrass prairie, sites surveyed in 1976 were revisited in 2001 (25 years later). Sites ranged from those rarely (or never) burned to some which had been burned almost annually.

For a summary of the study's results and implications for management, you can download a PDF version of the research brief here.

The original paper is:

Marlin L. Bowles and Michael D. Jones. 2013. Repeated burning of eastern tallgrass prairie increases richness and diversity, stabilizing successional vegetation. Ecological Applications 23:464-478.