Difficult Decisions – Growing Season Fires and Other Prairie Management Choices

Would you purposefully destroy the nest of a wild turkey or grasshopper sparrow?  Of course not.  But what if that destruction was a consequence of a land management action that benefits the larger prairie community?  That was the situation we were faced with last week as we mulled over whether or not to conduct a late spring (early summer?) prescribed burn.

Michelle Biodrowski ignites a prescribed fire last week (June 6) at a wet-mesic prairie.  The Nature Conservancy's Platte River Prairies.

Michelle Biodrowski ignites a prescribed fire last week (June 6) at a wet-mesic prairie. The Nature Conservancy’s Platte River Prairies.

In the aftermath of any prescribed fire, there are winners and losers.  Fire rapidly and dramatically alters habitat and growing conditions in ways that favor some plant and animal species and put others at a disadvantage.  Fires also kill some insects and other animals outright.  For example, dormant season (late fall through early spring) fires burn up a lot of invertebrates that overwinter in prairie thatch.  Growing season fires, of course, can kill numerous small animals – especially slow-moving non-flying ones.  We usually don’t see the evidence of those impacts, but when we do, it’s no fun.  Over the years, I’ve seen way too many fried snakes and scorched nests, in addition to animals who suffered injuries from our fires.  It can be tough to deal with the knowledge that I made the decision to light the fires that killed or maimed those animals.

Regal

I’m sure we burned up a number of regal fritillaries in our fire last week because the females are within a few weeks of emerging as adults, and the kind of thatchy prairie we burned is prime habitat for overwintering larvae.  However, we would have done the same damage to those caterpillars if we’d burned the prairie any time between October and July.  Fortunately, regal fritillaries are very common in our prairies, so I know the overall population will be fine.

.

garter

Snakes are common victims of growing season fires.  It’s likely we killed some snakes last week, though I didn’t see any corpses as I walked around the next day.  I did, however, find a live red-sided garter in one of the small unburned patches in the middle of the burn unit – so at least one survived…

While it can certainly be deadly to insects and animals, fire is also an important part of our strategies to maintain diverse and healthy prairie communities.  Fire can help suppress invasive species, remove thatch and stimulate vigorous plant growth, and attract grazing activity – among many other things.   Prairies that aren’t burned fairly frequently often suffer from tree/shrub encroachment, excessive build-up of litter, and/or dominance by a few native grass species.  Other tools, including grazing and haying, can be used instead of fire (or in addition to it) but those can also have negative impacts, and can’t replicate everything fire can do.  Knowing that fire can cause problems for some species, we try to minimize those impacts as much as we can.  For example, we usually only burn a portion of a larger prairie so that any impacts are not likely to affect the entire population of a species.

A smooth brome

Smooth brome was mostly done blooming when we burned, and starting to make seed.  I’m not sure how much we sapped the vigor out of the brome (a week or two earlier might have been better) but I guess we at least prevented it from making seed this year.

The main objective for our burn last week was to create an attractive patch of nutritious grass to concentrate cattle grazing in that portion of the prairie - part of our patch-burn grazing system.  We are using a light stocking rate of cattle this year, so we expect the grazing in the burned patch to be selective (the cattle should eat mostly grass) and to favor wildflower diversity by suppressing dominant grasses.  Meanwhile, unburned areas won’t be grazed much at all, allowing them to rest from previous years’ grazing and last year’s drought.  The result should be a messy mixture of habitat types and growing conditions across the prairie that will allow just about every species to thrive somewhere.

We’d hoped to burn the site earlier in the spring, but never got the right weather window to do it.  In other sites where we didn’t get our planned burns done this year, we’re using electric fence to temporarily enclose the cattle in what were supposed to be the burned patches.  The idea is to get the cattle to graze the areas down sufficiently that when we take the fence down in early July the cattle will continue to graze the regrowth (which will then be the best quality forage in the prairie) in those patches for the remainder of the season – similar to what we’d see in burned patches.  It’s far from a perfect subsitute for burning, but it does at least concentrate grazing pretty well in one portion of the prairie and allow other areas to rest.  The biggest disadvantage of the temporary grazing enclosure method is that cattle aren’t very selective in their grazing within that enclosure, so we lose some of the benefits we in burned patches when cattle graze mainly grasses.

patches of green

It was a pretty complete (though pretty slow and smoky) burn last week, but there were a few patches that didn’t burn – mostly in low, wet areas where the thatch was moist enough it didn’t carry fire.  The green strip shown here is at the bottom of a wetland swale and is also where I found the surviving red-sided garter snake mentioned earlier.

After weighing the pros and cons of burning in early June, we decided to go ahead with last week’s fire.  We certainly burned up nests of meadowlarks, grasshopper sparrows, and at least one turkey (a forlorn-looking female was wandering around after the fire).  I expect most of those will have time to re-nest, but that only makes me feel marginally better about it.  I’m sure we also killed lots of insects and some wildlife species.  On the other hand, the burn allows us to move ahead with our management strategy to improve the wildflower diversity of the entire prairie.  That increase in wildflower diversity will benefit a wide range of insect and wildlife species in coming years, as will the habitat structure created in both the burned and unburned patches.  We burned about 65 acres, but left more than 300 acres of the prairie unburned.  Actually, there is much more unburned prairie than that, since there are more than 1,000 acres of unburned grassland on adjacent land as well.  That unburned prairie should be a great refuge for fire-sensitive species and give them opportunities to recolonize last week’s burn over the next several years.

eastern red cedar

This eastern red cedar burned brown after the fire, but it’s unlikely to die.  Experience has shown us that growing season fires rarely “cook” cedar trees enough to kill them.  Even when they turn brown, they tend to green up again.  However, this prairie has had numerous dormant season fires, so cedar control was not an objective for last week’s fire.  We’ll get this one next time.

The kind of difficult decision we made last week is a regular part of land management.  Every management treatment leads to the improvement of conditions for some species but hurts others – often literally.  Just letting “nature take its course” by not managing at all isn’t any better.  An idled prairie eventually becomes dominated by trees and shrubs, along with just a few grass and wildflower species.  That degradation of habitat kills or evicts more animals and plants than active management, which maintains diverse plant and animal communities.

Right or wrong, I guess I’ve trained myself to focus on the long-term positive outcomes of our management and not to dwell on the short-term negative impacts.  I’m not sure if that makes me insensitive or just sensible.  One thing that helps me justify our actions to myself is that we’re collecting as much data as we can about the overall impacts of our management.  If we’re going to make tough decisions that have negative consequences for other living creatures, I want to KNOW that those decisions are leading to the long-term benefits we think they are.  We can never collect enough data to know everything we want to, but we collect enough that I’m convinced most of our management strategies are working as planned, and we constantly tweak those strategies as we learn more.

Ants

The ants in these mounds appeared to survive the fire just fine.  I assume they’ll be able to find plenty of food, and satisfy their other needs, as the prairie greens up around them over the next few weeks.

Regardless of the tough decisions we have to make, I love my job.  I feel good that we’re improving the condition of our prairies, and that we’re sharing successes and failures with other prairie managers so they can do the same.  It’s difficult for me to imagine a more fulfilling career.  I always try to focus on the big picture instead of dwelling on the immediate negative impacts of some of our actions.  At the same time, I try to be ethical about what we do, and not cause harm when it’s not necessary.

It’s a messy world and a messy job, but I wouldn’t have it any other way.

About these ads

About Chris Helzer

Chris Helzer is an ecologist and Eastern Nebraska Program Director for The Nature Conservancy. He supervises the management and restoration of approximately 4,000 acres of land in central and eastern Nebraska - primarily along the central Platte River. Chris is also the author of "The Ecology and Management of Prairies in the Central United States", published by the University of Iowa Press.
This entry was posted in Prairie Animals, Prairie Insects, Prairie Management, Prairie Natural History, Prairie Photography, Prairie Plants and tagged , , , , , , , , , , , , , , , . Bookmark the permalink.

20 Responses to Difficult Decisions – Growing Season Fires and Other Prairie Management Choices

  1. Rex says:

    Chris,
    I was a at a meeting last fall where there was great concern that the migratory bird act or treaty makes spring burning of invasive cedar trees to reestablish grasslands illegal.. Do you know anything about that?

    • Chris Helzer says:

      Rex,
      My understanding is that projects or sites that receive federal funding can be restricted in the activities they do during bird nesting season. Tree clearing, burning, and other management treatments that might interfere with nesting birds can be restricted between May and July. It’s one of those well-intended rules that doesn’t always end up working out to be logical.

  2. Bob Brewer says:

    Chris,
    Very thoughtful description of the respect for so many diverse members of the biosphere and the consequences of simulating natural burns. I feel like I am walking on the prarie seeing the things you see. thanks for sharing.

  3. Brian Miller says:

    This was one of your best yet Chris. As the manager at Prairie State Park in Missouri… Making these decisions are never easy and answering the questions later is almost as hard… Thanks for your continued hard work and passion for Prairies.

  4. Trent says:

    Have you considered altering your firing to give the somewhat mobile critters at least a shot at getting out of the unit. A ring-head fire is almost designed to trap animals.

    • Chris Helzer says:

      Trent – it’s a great point. We have used a variety of ignition patterns, but also have to include safety and ability to reach objectives in our consideration. I agree that ring fires are not the best pattern for preventing injury to animals, but sometimes they are the quickest and safest option (quickest is often the safest since the longer fire is on the ground, the more time there is for something to go wrong). Last week’s fire was ignited with a strip head fire technique because the burn was pretty slow, and required multiple ignition lines to get the interior of the unit to burn in a timely fashion. I’m not sure if that was better or worse for animals… I will say, the slow speed of the headfire should have given some critters a chance to find shelter underground or even to find their way out of the unit altogether.

  5. chad says:

    hey Chris,

    Do you think doing a spring/summer burn like this is beneficial in the mists of a drought. i know you guys have gotten more rain in recent weeks, but how do you think the prairie will respond if Mother Nature turns up the thermostat and turns off the water for the rest of the summer? Do you think there is a possibility of actually hurting the prairie more than benefiting it by burning during a drought?

    • Chris Helzer says:

      Chad – it’s a fair question. I don’t think the fire will hurt the prairie long-term, regardless of weather conditions. The sites we burned last year’s drought are coming through really nicely. That said, a dry summer would certainly add stress to the prairie. I’m actually planning for that to happen, because I think it’s the most likely scenario. Our objectives are to stress the dominant grasses and release forbs. The drought, piled on top of the intensive grazing we’re planning anyway, will fit right into our objectives. We’re stocked down from last year, so a dry year will be just fine with our current stocking rate. The site we burned has had very little grazing for a couple years, so even with last year’s dry weather, it has a very strong root reserve to draw on. You have to remember that we’re TRYING to stress these sites, and while we’re going to really hurt this year’s burned area, there will be other portions of the same prairie that will get very little stress and will be recovering and gaining vigor in preparation for their turn to be stressed next year. Rather than moderately using all parts of the prairie each year, we “overutilize” some parts and “underutilize” others but shift that use around so that everything gets nice long recovery periods. The result is a vibrant and diverse plant community and also a nice range of habitat conditions at each prairie.

      Come take a look sometime – I’d be happy to show you around!

    • Blayr says:

      Chad, patch burning is a great management system during drought due to the stock pile of forage in the older patches. We have seen this with cow calf and ranchers have also seen this with stocker cattle.

  6. Blayr says:

    In a patch-burn system, cattle aren’t selective on grasses in the recently burned patch, they are selective to the patch itself. They are going to take advantage of the high crude protein forbs while they are young and very palatable. They select grasses over forbs when an area isn’t burned, because the forbs are not palatable. That’s just one of many benefits to the patch-burn grazing system.

    Sometimes you have to sacrifice small loss for the greater good. Research has shown that most of the species declining, especially bird species, are declining due to habitat loss, not because they are being killed by fire. And many species will re-nest.

    • Chris Helzer says:

      Blayr, what you say is true when using higher stocking rates than we use. At our lower stocking rates (0.5 to 0.75 AUMs/ac) cattle are not only selecting for patch, but also selecting grasses over forbs – even those which are very young and palatable. I published an article in Ecological Restoration on the results of one season of this early on, but we’ve seen the same pattern year after year. When we increase stocking rate, that forage plant selectivity decreases. The same happens later in the season when grass palatability decreases – we see cattle switching over to forbs more at that point and/or grazing more outside the burn patch…unless we provide a new burned patch for that season. The most interesting aspect of this is that at lower stocking rates in PBG systems, cattle actually have the same kind of forage selection tendencies as bison. You can talk to Bob H or Sam F about this – they’ve both visited our sites here and have heard me ramble on about it at PBG meetings…

      • Blayr says:

        I know about patch burning, I live on the OSU Research Ranch where most of our land is under a patch burn grazing system, where Sam Fuhlendorf has done a lot of his research and I work with him as well along with Bob, I see it every day. We have a low stocking rate as well, year-round… Don’t see those kinds of selections, especially cattle switching to forbs late in the season.

  7. Excellent post, Chris. I often make the points, sometimes even to those who’ve heard me say them before, that no management action is worse than some management, and that any management has winners and losers in the short term, and these often switch their winning or losing status in the period between burns.
    By the way, ants just love being on the CICC (cooked insect clean-up crew) after any burn followed by good foraging conditions.

    • James McGee says:

      The ants can have all the cooked ticks. I prefer visiting a recently burned prairie because there are less blood suckers trying to crawl up my leg.

  8. James McGee says:

    Chris, Sometimes I wonder if you all are just reverse engineering the knowledge possessed by the native inhabitants long before settlement by Europeans.

  9. matt says:

    As someone that manages sites with Mead’s Milkweed and borders Kansas City, summer regional air quality and allowing the Mead’s to bloom would never allow for me to burn in May/June but I totally understand your goals. Hard choices!

  10. Jeff says:

    Chris, I sympathize with your thoughts, due to a switch in wind we had to ring a fire quickly and found a nest of young rabbits burned up. It made me sick. But the other thing I almost always see is a quick arrival of hawks to the scene, usually as soon as the headfire is done burning. I wonder if its learned behavior or instinct. In my area I doubt many of them see enough fire for it be learned, but regardless the animals that are burned don’t go to waste. Its good to know that every dark cloud can have a silver lining for some critter in nature.

  11. I’m faced with a similar situation regarding management of native warm-season grassland in a preserve in the northern Piedmont on the East Coast. We can’t burn (burning is prohibited by municipal ordinances and air quality regulations), so we manage by patch-haying during the winter and very early spring. However, we have a severe problem with Canada thistle, which would overwhelm our grassland if we didn’t manage it. So, we use herbicides, and we have to apply them during the growing season, much to the consternation of our birders (and me). It’s much the same quandary that you’ve had to resolve, Chris.

    • Chris Helzer says:

      I feel your pain… Conflicts are often unavoidable. It can be especially hard when the conflict involves species that people are strongly attached to. Even if the treatment for Canada thistle is clearly in the best long-term interest of the birds and many other species of the site, it can be hard for people to understand the need for doing something that could negatively impact their favorite species.

PLEASE COMMENT ON THIS POST!

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s