NOTES FROM PRAIRIE INVERTEBRATE SESSION OF FRIDAY MORNING.

NOTES FROM THE INVERTEBATE SESSION OF FRIDAY MORNING

David Zahrt convenes. Andrew Williams takes notes. Eighteen people participated.

David starts by asking how we can save prairie plants so prairie bugs may continue to be present?

Is fire essential in prairie management?

1 Yes, it is, also grazing. The model of grazing as a tool is not what we see generally around us. Overgrazing is typical.

2 Yes, but we try to limit our burning.

3 Fragments are not the same as a landscape so fire needs to be used cautiously, also grazing.

4 Grazing affects fire behavior by increasing patchiness of burns.

David talked of his land in the Loess Hills and the terrible red cedar invasion problem there. He thinks grazing leads to red cedar invasion, even where he has been limited the grazing. How can one use many animals for a short period and then get them off the prairie?

Pauline sayes at the NWR that there is some effort under way to survey and monitor several types of invertebrates: beetles, spiders, moths and butterflies, leaf hoppers and ants. Five species of native earthworms have been found there. Pitfall traps, lighting at night for moths, transect surveys in daylight for butterflies, baiting of ants with tuna are methods used.

Andrew spoke of the tremendous diversity of invertebrates, that those who study plants or vertebrates must come at invertebrates differently. There are many more species involved, still some undescribed species right here, and few workers who have the training and time to help with specimen determinations. So our management strategies must take into account that we are and that we will remain ignorant of the majority of the species present (both their identity and their life histories) for decades to come.

We know fire benefits prairie plants, helps exclude trees and brush, but there are groups of fauna that are adversely affected by fire: How do you maintain these in the landscape?

Susanne said that a decade ago, she conceived of a "good burn" as complete coverage of the entire area under management. Today, she thinks a "good burn" is one covering partially only part of the area under management, that patchiness is good. But she voiced frustration at the daunting challenge of controlling the red cedars without broadscale fire and the corollary loss of these refugia.

Prairie burns well, but brush and cedars and cool season grass patches do not, alas.

Pauline raised 3 issues:

1 We are in an emergency situation, trying to save the few remaining sites before they’re lost to woody plant invasion

2 size: small vs. large. Her big circular fires may not be good for small remnant in the burn unit.

3 patchiness.

How much of a site to burn at once?

1 Susanne suggests burning about 25%.

2 Mike burns tiny patches in remnants, using plywood as a firebreak.

3 The % to burn has been declining in our minds over time.

4 Chad says that, on his 800 acre site, he thinks it is important to diversify the tools, the timing, and even the boundaries of burn units. He introduced the word MOSAIC into our discussion and this word continued to crop up.

John said burning large numbers of very small burn units was impractical for DNR land managers who were each responsible for several sites scattered widely about the state.

Time of the burn is important.

No right time as whatever we do affects different species in different ways: some for the better, some for the worse. And we don’t know for the majority of taxa present whether they’ve been affected for the better or the worse.

OUR STAFFS, BUDGETS, AND TIME LIMITS ARE ALL TOO SMALL.

Brush cutting is an activity in which volunteers can be used. Herbiciding done in conjunction with this work is best done by licensed workers.

One way to introduce the mosaic idea is to consciously and persistently manage different sites in different ways.

We should document our activities so we can better learn through trial and error, and so that managers who follow in our footsteps can know the management history of these sites so they can better adjust then current management practices.

Cindy said when she sees prairie violets, she feels she is doing the right thing in managing her land. But where is the feedback in the context of invertebrates?

Andrew said there is and can be no such feedback, the ignorance problem again, but some researchers disagree and are trying to develop a list of management-sensitive prairie insects.

Pauline quoted Ron Panzer, :"The only thing worse than fire for prairie invertebrates is the suppression of fire".

This is again the statement that fire is essential in managing the vegetation that supports these specialized fauna, but itself poses a threat to the fauna. In Panzer’s view the lack of fire and subsequent loss of the prairie is the greater hazard. Andrew said that if the prairie flora can be saved only at the loss of the prairie fauna, then we’re paying too great a price in prairie biodiversity.

Herbicide drift and fertilizer runoff are also issues we need to consider.

Rod said it all hinges on our specific purpose. Each agency has a different mandate. At Effigy Mounds, he is charged with restoring a landscape of several habitats to appear as they were about 1000 years ago. Exotics are a bad problem. Smooth brome is one example. Now he is using a lot of fire to try to control brome, but he anticipates moderating his use of fire, and varying the timing of its application, after brome is under some control.

Andrew said fire can more safely be used in new prairie plantings to help plants get established, in managing roadside plantings of limited diversity, and in managing the weedier, more degraded parts of larger reserves. The bulk of the prairie biodiversity is in the remnant prairies, and these are the sites where fire should be used most conservatively.

Diversify management on sites.

1 Timing of burns, summer burns promote leafy spurge.

2 grazing leads to increased patchiness of burns, which is good, but how can one get big numbers of animals into a unit for a short time and then get them OUT?

3 Fall burning may alienate hunters in the local and/or conservationist communities