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Re: Burning of prairies

    I'd like to make a few additional comments in regard to Christopher
Linclon's comments on burning prairies. I manage the University of
Illinois' biological research areas, which include two re-established
prairie plots. I know enough about prairie burns to know that I am by no
means an expert.
    Here are some general thoughts. Prairie communities are not a set group
of plants. There is a tremendous variation of species geographically. The
native species I would be working with in Illinois will be a much different
set than what someone in Texas or South Dakota would be working with. The
only underlying common factor is that each community developed by the
selective pressure of fire. In essence, prairie communities were composed
of the only plants left that could withstand fire. Managing a prairie with
fire is beneficial in a number of ways. Three of the most important effects
are: rids competing "weeds and non-native plants" by killing the plants
outright and/or by destroying seeds, releases nutrients, and removes the
accumulated duff layer which changes the surface temperature and moisture
levels, and allows sunlight to reach the soil (major effect on seed bank
and young shoots).
     Use of fire eleminates the more aggressive non-naitve praire species,
allowing for a more level playing field for true prairie plants to compete
in. However, the timing of fire affects different species differently.
Early spring burns vs. late spring vs. summer vs. fall burns all will favor
different species. Depending upon where you are in the country, and what
you're working with or trying to re-establish, different fire regimes will
aid or delay your goals. I can't summarize what specific plants will do
best under different burn timings. The information is out there, however.
If you don't mind wading through some of the scientific literature, the
single best source to begin with is:
    Henderson, R. A. and S. H. Statz. 1995. Bibliography of fire effects
and related literature: Applicable to the ecosystems and species of
Wisconsin. Technical Bulletin No. 87, Department of Natural Resources, P.O.
Box 7921, Madison, Wisconsin 53707.
    It's a hefty bulletin. They give good general information on burning
then list 841 literature citations. You can find titles that deal with
anything you could ever want to know about, and that might deal with your
specific site.
    In general, spring is the easiest time of the year to burn from a
management standpoint. Everything is dormant and dry and it won't directly
impact any species negatively. But it will give the earlier growing and
flowering species an overall advantage. If you burn in summer, to simulate
lightning strikes, you'll give the edge to earlier flowering and growing
species and set back the large warm season (C4) grasses and later flowering
species (Good article: Howe, H. F. 1995. Succession and fire season in
experimental prairie plantings. Ecology pp. 1917-1925). Summer burns are
also very destructive to bird/animal nesting and rearing. Fall burns will
also have a different effect on species composition but I can't find a good
summary offhand. The drawbacks to fall burns are potential increased soil
erosion and lost winter cover for animals, birds, etc.
     Couple specific points about burning.
    The positive effects of fire on the large grasses such as little
bluestem and Indian grass is short lived. Hadley, E. B. and B. J.
Kieckhefer (Productivity of two prairie grasses in relation to fire
frequency. 1963. Ecology 44:389-395) found that the first growing season
after fire, both species showed greatly increased above ground growth and
flowering. But by the second growing season, growth was reduced back to
unburned levels.
    Insects are an important part of any plant community, prairie remnants
in particular (providing there is enough prairie to host a unique insect
community). In general 50% of grassland/prairie insects species get
hammered by fire. But providing contiguous prairie/grassland is left
unburned as an insect resevoir, about 85% of the affected insect species
will rebound within one year. Insects should be considered a major factor,
and they are in part why managers are strongly encouraged not to burn all
of any given prairie tract in a single year.
    In our 18 acre restored prairie (50 years old!) I've divided it into
four quadrants. Two quadrants are in a fall burn regime and two are in a
spring burn regime. Similar burns are kitty cornered to each other and only
two quadrants are burned in any single year. The goals are to increase
plant diversity, safeguard insect populations, and provide continous cover
for the bird and animal communitites that use the areas year around.
    For those I bored, I apologize. For those who might consider anything
I've said as gospel, keep in mind I'm still a self-confessed idiot when it
comes to prairie communitites. For those more learned, you're welcome to
"have at" anything I've said.
    Hope something here was helpful.

Steve Buck
University of Illinois
Committee on Natural Areas
116 Vivarium
606 E. Healey
Champaign IL 61820
(217)-333-6458


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