Photo of the Week – April 24, 2015

The aesthetic values of prairie are more subtle than those in many other ecosystems.  There is much beauty to be found, but you sometimes have to look for it – it doesn’t often rise up and slap you in the face.  That’s especially true in the early spring as the first wildflowers are just starting to bloom.

If you had driven past the Platte River Prairies this week, you would have likely dismissed them as a lot of brown grass with a little green grass here and there.  Blah.  But if you’d gotten out of the car and taken a walk – and if you had been especially observant – you might (MIGHT) have spotted one of my favorite wildflowers.

Viola rafinesquii, a tiny and easy to miss wildflower.  The Nature Conservancy's Platte River Prairies, Nebraska.

Viola rafinesquii is a tiny, beautiful, and easy to miss wildflower. The Nature Conservancy’s Platte River Prairies, Nebraska.

Known variously as field pansy, Johnny Jump-up, and other names, Viola rafinesquii is an annual violet species that makes its appearance in the early spring, just before most better recognized flowers begin to bloom.  One a short hike yesterday, the Fellows and I spotted several hundred of these plants, but if we hadn’t been specifically looking for them, we probably would have missed them altogether.  The plants stand only a few inches tall, and the diameter of the flowers is about that of a dime.

It’s a gorgeous little plant, but you’ve got to get on your hands and knees to really appreciate it.  In that way, it’s a pretty good metaphor for prairies in general – if you don’t look closely, you’ll probably miss the beauty altogether.

…and that would be a shame.

 

Posted in Prairie Natural History, Prairie Photography, Prairie Plants | Tagged , , , , , , , , , , | 6 Comments

What’s the Best Time to Burn?

As I mentioned last week, prescribed fire can help meet many prairie management objectives.  It’s important, however, to match the timing of the burn to those objectives in order to avoid conducting a fire that is either unproductive or counterproductive.  For example, if you’re burning to set back trees or invasive plants, you’ll want to be sure to burn when the fire will suppress those species and encourage growth of competing plants.  Too many times, people burn to control smooth brome or another invasive cool-season grass but burn so early in the season that they end up helping the plants they’re trying to hurt.  Here are some examples of various management objectives for prescribed fire, along with examples of how to time those burns to meet those objectives successfully.

dormant

This early March burn (dormant season) will stimulate the growth of cool-season invasive grasses such as smooth brome or Kentucky bluegrass.  However, we brought in cattle to knock back the strong growth of those species.

In the Platte River Prairies, our biggest invasive species threat comes from smooth brome, Kentucky bluegrass, and other invasive grasses that grow early in the season.  They can monopolize space and moisture, reduce plant diversity and wreak havoc on habitat conditions.  When we target those species with fire, we try to burn when the targeted species is just about to bloom.  By doing so, we can knock the brome or bluegrass back after it has invested energy in growth but before it invests in reproduction.  At the same time, we create excellent conditions (lots of light and warm soil) for competing warm-season native species which are just getting ready to start their growing season.  Bluegrass blooms significantly earlier than brome, so we can’t get maximum impact on both species with one burn.  Instead, we have to decide which is the more dominant grass at the time.  Regardless, the timing of our burn is aimed at the growth stage of the plant, not a particular date, since plant growth rates vary by year.

One issue we’ve seen with using fire to control brome or bluegrass is that while we can suppress those cool-season grasses and facilitate growth of warm-season native grasses, we often just trade one dominant grass for another without encouraging overall plant diversity.  As a result, we often combine cattle grazing with fire to add a more selective defoliator (cattle) to the mix.  When we’re using grazing, the timing of the fire can be more flexible.  We can conduct a burn in the fall or early spring, and while that will stimulate strong growth of brome and bluegrass, we can use intensive spring cattle grazing to counter that strong growth and suppress those invasives.  Later in the summer, a fairly light stocking rate of cattle can help suppress major warm-season grasses and keep them from simply taking all the space left open by weakened invasive grasses.  This creates opportunities for wildflowers to flourish.  Since cattle prefer big bluestem and indiangrass over all other plant species in our summer prairies, that kind of grazing usually works pretty well.  There are too many potential combinations of fire and grazing to cover here, but suffice it to say we can burn at many times of the year when using cattle to complement the effects of those fires.

bluegrass

This fire was conducted at about the time Kentucky bluegrass was starting to bloom, so it should knock the vigor of that species back for a year or two.

If cattle aren’t an option but you find that fire alone just encourages dominant grasses of one kind or another (a more common result in the Great Plains than in the Midwest), one option could be a summer fire.  If you’ve never seen a summer prescribed fire, you might find it hard to believe that green prairie can burn, but as long as there is sufficient old growth from previous seasons that dead vegetation will carry a fire, regardless of how green this year’s vegetation is.  (That green vegetation does make summer fires extra smoky, however.)  If big bluestem is the dominant species you want to suppress, the best time to burn is when it’s just ready to bloom.  Remember that there are many other factors to consider with summer fires, including the various animals that are active in the prairie at that time of year.  It’s usually best to burn only a small portion of a prairie in the summer to avoid excess impacts on wildlife and invertebrates.  However, summer fires can be very good for encouraging wildflower growth, and the habitat benefits from added plant diversity help counteract short-term impacts of the fire on animals.  Another caution with summer fires is that if cool-season invasive grasses are a problem at a site, they will likely benefit from a summer fire, and could thrive during the following fall and spring without some other treatment.

Controlling trees with fire is a common objective for prairie managers, but timing is also important for that objective – and appropriate timing varies by the species of tree being targeted.  We’ve had some very good late spring burns that suppressed brome wonderfully but failed to kill small eastern red cedar trees.  I think the trees failed to die because there was insufficient heat created to make up for the increased moisture in the stems at that time of year.  The trees turned yellow-orange after the fire but then greened up again.  We’ve found dormant season fires to be far more successful when we’re targeting cedars.  On the flip side, it seems like we’ve had the best luck suppressing (but not killing) dogwoods and other deciduous trees and shrubs when we burn as those species are just leafing out later in the spring.  However, our success with deciduous plants has been inconsistent enough that I hate to make recommendations – and deciduous tree control with fire is usually temporary at best.  Dirac Twidwell, range ecologist at the University of Nebraska-Lincoln, has experimented with intense summer fires during drought conditions in the southern plains and has found that the combination of high temperatures and drought stress can be deadly on trees not ordinarily considered to be susceptible to fire.  Unfortunately, burning under those conditions takes much more training and preparation (and more trusting fire chiefs) than most of us can muster.

cedar

This cedar will probably survive this growing season burn.  It turned yellow but will likely turn green again and continue its growth.

Dormant season burns include any fires conducted after the prairie turns brown in the fall and before it greens again in the spring.  Impacts from late fall and early spring burns are pretty similar to each other, with the caveat that fall burned prairies have bare ground all winter long, which can dry out the soil somewhat and – obviously – provide very different winter habitat than prairies with standing vegetation for species that need that.  Drier soil and bare ground are not necessarily bad things, especially if there is other prairie habitat nearby.  In fact, some managers in northern parts of the United States have found that bare soil over the winter can help winter kill Kentucky bluegrass during particularly cold winters.  Fall or winter burning can also help extend the window needed to find the right weather to conduct a dormant season burn.  Depending upon your objectives, those fall burns could be just as effective as an early spring burn and you can relax all winter, knowing that your burn is already done.  One additional consideration with fall burns is that the day length (at least in North America) is considerably shorter in November than in March, giving you less time to conduct a fire during daylight hours.

There are many other possible objectives for prescribed fire, and examples of how to achieve them.  Those of us who harvest seed for restoration work, for example, use fire to stimulate seed production in some species (especially big bluestem).  In addition, because time since the last fire is linked to the amount of thatch and litter present in a prairie, burning can help manipulate habitat conditions for many wildlife species.  Speaking of wildlife, it’s critically important to remember how vulnerable some invertebrates and animals are to fire and to keep that in mind when setting burn objectives.  Burning an entire prairie (especially one that is isolated from others by roads or other obstacles) can completely eliminate some species of invertebrates that are aboveground during the fire – including many that overwinter in standing dead vegetation.  Depending upon your other objectives, you might consider not going into a burn unit to light all the patches of vegetation that didn’t burn initially – leaving those unburned areas can provide important refuges for vulnerable insects and other critters.  In addition to invertebrates, nesting birds, recently emerged reptiles in the spring, and other less mobile animals are all species to consider as you plan growing season burns.  There will always be negative impacts of any fire, but they should not be reasons to avoid burning.  Instead, they are examples of why it’s so important to have clear objectives so that you make sure you get the desired benefits from the fire and minimize the undesirable outcomes.

refuges

This growing season burn left behind numerous unburned patches, providing refuges for invertebrates and other small animals.

Fire is a powerful but dangerous tool for prairie management.  While it can be very useful for a wide range of objectives, there are too many risks (to people, property, and wildlife) to use it in a cavalier manner.  Setting specific goals for a fire and being thoughtful about the timing and tactics for that fire will help ensure that it is as productive as possible.

Be safe out there.

Posted in Prairie Management, Prairie Photography | Tagged , , , , , , , , , , , , , , | 5 Comments

Photo of the Week – April 17, 2015

We are behind on our burn schedule this year.  The weather hasn’t been great for carrying out safe and effective burns, so we’ve only gotten a few done.  Our prescribed fires are always part of broader management plans, often including cattle grazing, so we have specific objectives for when and how we want a site to burn.  Some plans call for a dormant season fire, other call for a growing season fire.  This spring, we’re already transitioning into the growing season and still have some dormant season fires that we didn’t get done between November and March.  That means we’ll have to adjust our management plans for those properties (as we often do).

During periods of wild weather variability such as those over the last several months, completing a burn is even more satisfying than normal.  Here are a couple photos from a recent fire we used to set up patch-burn grazing and facilitate over-seeding of a degraded prairie.

Mardell Jasnowski lights a "flanking head fire" at a recent burn in our Platte River Prairies.

The Nature Conservancy’s Mardell Jasnowski lights a “flanking head fire” at a recent burn in our Platte River Prairies.

h

Here, Mardell is waiting for the rest of the crew to catch up to her.  The ATV driver is pulling a trailer of water and spraying the fire to keep it from creeping into the mowed firebreak.

After the fire is over, the crew relaxes and discusses what went well and what didn't.

After the fire is over, the crew relaxes and discusses what went well and what didn’t.  We share crews with several partners along the river.  In this case, we had help from the Central Platte Natural Resources District.

Posted in Prairie Management | Tagged , , , | 7 Comments

Introducing: The Prairie Word of the Day

I’m sure many of you are as tired of this blog as I am.  The same old nature photos, natural history, prairie management/restoration information…  It just drones on and on.  Honestly, I don’t know how you manage to drag your eyes through most of my posts.  How much prairie stuff can one person read about, after all?

(…Yes, I’m kidding – there is no limit to how much prairie information one person can read about.  And I am not at all tired of this blog… though you certainly might be, I don’t know.)

Well, the blog isn’t going away anytime soon (why, what have you heard??)  But in an effort to keep it from growing stale, I’m introducing a new feature called “The Prairie Word of the Day.”  …Yes, I know –  a titillating title, isn’t it?  It ought to be, it took me about three months to refine it.  It’s pithy, catchy, and descriptive all at once.  Or at least descriptive.

As with any field, prairie ecology is full of jargon; words that make sense to those of us who spend most of our waking hours thinking about prairies but make no sense to anyone else.  I try hard not to use to much prairie jargon in my posts, but I slip up now and then.  Sorry about that.  There are a lot of fun, but confusing, prairie jargon words out there, so I thought I’d highlight one now and then and try to explain what it means.  I would love to hear nominations from you as well – what undecipherable words do I or others use when talking or writing about prairies?

Ok, without further ado, the inaugural Prairie Ecologist Blog Prairie Word of the Day is:

Tiller

Sure, everyone knows what a tiller is, right?  You use it to prepare your garden for planting.  Or, if you are a pirate, you might use it to steer your ship.  (If you are a pirate and read this blog, PLEASE let me know.  Prairie-loving pirates is a demographic I would love to reach out to.)

However, if you are REALLY into prairies or botany, you might be familiar with a third definition; one that is related to grasses.

Tiller

Although it is used somewhat inconsistently, a tiller usually refers to the aboveground shoot of a grass.  In other words, if you were to look closely at a grass plant you’d see that most of them have multiple stems at their base.  Each of those stems is a tiller.  Usually, the term tiller only applies to shoots that emerge from buds at the base of other tillers, not from seeds.  Thus, when a grass seed germinates and starts to grow, the first shoot that pops out of the ground is not a tiller.  It’s just a shoot.  I guess.  But after that, every new shoot that comes out of the ground from that plant is a tiller.

Tillers are primarily important, as far as I can tell, because professors like to make graduate students count them.  As in, “Hey Sara, take this 1 x 1 meter plot frame out to that prairie, lay it down and count the number of grass tillers inside it. (snicker)  Then do that 99 more times. (guffaw!)  Then we’ll move on to the next prairie.”

Grass greening up in the Derr Sandhills about a week after a prescribed fire.

The tillers of this bunchgrass are all bunched together.

 

A related botanical prairie word is “sward” which basically means a bunch of grass.  Well, not really a “bunch” because that’s its own term (grasses like little bluestem are called bunch grasses because they grow their tillers tightly together and look neat and tidy, as opposed to grasses such as prairie sand reed that across the prairie like they own the place).  A better way to describe a sward, then, is that it’s an area of grass.  However, I don’t think there’s any restriction on how big that area of grass has to be, which makes the term less useful.  That’s probably why you don’t hear it used very often.  Except by grassland poets trying to rhyme something with “charred”.  As in, “Lo, the land was black and charred.  No trees remained throughout the sward.”

There are an awful lot of tillers in this sward.  Too many to count - even for a graduate student.

There are numerous tillers in this sward. Too many to count – even for a graduate student.

If botanists were funny, they might say something like, “Arrr, Matey!  Take over the tiller smartly while I decide whether to shoot this lubber or run him through with my sward.”

(I’m kidding, of course.  Botanists can be very funny.  Sometimes on purpose.  Also, many are quite hirsute.  Except on top, where some are pretty glabrous.)

Well anyway, that concludes the first ever installment of The Prairie Word of the Day.  I hope it was instructive.  Please nominate terms (in the comments section below) you’d like to see included in future Word of the Day posts and I’ll try to use as many as I can.

Posted in Prairie Natural History, Prairie Plants | Tagged , , , , , , , , , | 35 Comments

Pretty but Powerful

Because they can’t run away, plants may seem helpless against the many large and small herbivores that like to eat them.  Nothing could be further from the truth.

This caterpillar may appear to be chewing on a helpless plant, but most plants are not as helpless as they seem.

The plant this caterpillar is chewing on may not be as helpless as it appears.

Many plants have physical defenses such as thorns or stiff hairs to deter animals from eating them.  Grasses contain varying levels of silica, which can increase the abrasiveness of their leaves and help make them more difficult to eat and digest.  In addition, the chemical makeup of many plants helps make unpalatable or toxic to potential herbivores.  While herbivory is certainly a major threat, plants also have a variety of defenses against pathogens (diseases).  If you’re interested in more background on this topic, here is a really nice overview of plant defenses against both diseases and herbivores.

A the stiff hairs on plants such as black-eyed susan (Rudbeckia hirta) can make them more difficult for some herbivores to eat.

A the stiff hairs on plants such as black-eyed susan (Rudbeckia hirta) can make them more difficult for some herbivores to eat.

Within the last couple of years, there have been a couple of published studies that highlight some fantastic strategies plants use to defend themselves.   In the first of those, German scientists studied a wild tobacco plant and found that when it is attacked by a caterpillar the plant releases a chemical that, in turn, attracts a predatory bug to eat the caterpillar.  The production of the bug-attractant is triggered by the caterpillar’s saliva.  Essentially, then, the caterpillar sets off an alarm that calls in predators to eat it.  How cool is that?

A second study, done at the University of Missouri-Columbia, found that a species of mustard plant could detect the vibration signature of a caterpillar chewing on one of its leaves.  When the plant identified that signal, it increased production of chemicals that make its leaves taste bad to herbivores.  Researchers were able to replicate and reproduce the vibrations and trigger the response in the lab.  They also showed that other kinds of vibrations did not cause the plants to defend themselves, so the chemical production appeared to be a direct response to herbivory.

Cattle and other large herbivores have to deal with a number of plant defenses, from silica and other compounds that make plants difficult to eat and digest to chemicals that make them bad tasting or toxic.

Cattle and other large herbivores have to deal with a number of plant defenses, from silica and other compounds that make plants difficult to eat and/or digest to chemicals that make them bad tasting or toxic.

These and other research projects help show that plants are not at all defenseless.  Not only do they have strategies to make themselves more difficult to eat (toxins, spines, etc.), they can also respond when they are attacked.  In prairies, there are numerous examples of plants defending themselves in interesting ways, including sunflowers that produce sweet stuff to attract predatory ants and grasses that increase their silica content under intensive grazing pressure.

Of course, herbivores have evolved their own tricks to counter all those plant defenses. Several insect species, for example, have developed ways to deal with the toxins produced by milkweed plants and happily munch away on leaves that would kill other insects.  Now its the milkweed’s turn to (through natural selection and over many years) come up with a response to that response.  The world is pretty fascinating, isn’t it?

So, the next time you’re walking through peaceful-looking prairie on a pleasant morning, remember that those little plants you’re crushing beneath your feet may not be as helpless as they appear.  Sure, those plants are mostly fighting back against animals trying to eat them, but you may still find yourself an accidental victim of their defense strategies.  Experienced hikers are well acquainted with the abrasive edges of grass leaves and the sharp spines on species such as roses and cacti.  At one time or another, most of us have blundered into a patch of nettles or poison ivy.

No, plants are certainly not helpless.  Let’s just be thankful they haven’t (yet) figured out how to chase us down.

Posted in Prairie Animals, Prairie Insects, Prairie Natural History, Prairie Plants | Tagged , , , , , | 5 Comments

Photo of the Week – April 3, 2015

A month ago, we apparently had a large number of white winged visitors hanging around our Derr Wetland Restoration.  I only know this because our timelapse cameras picked them up.

Snow geese.  March 3, 2015.  3pm.

Snow geese. March 3, 2015. 3pm.

Snow geese are common along the Platte River in the late winter and early spring.  Flocks of tens or even hundreds of thousands of birds are frequently seen, resembling huge white clouds of feathered chaos.  Except, of course, that chaos is not the right word since the geese seem incredibly adept at avoiding collisions as they swirl up and down between earth and sky.

Although it was somewhat less impressive visually, another photo from the same cameras showed two bigger white birds in our wetland a few weeks earlier.  Trumpeter swans are rarely seen in our neighborhood, so it was a real treat to know they’d recognized our restored wetland as a good place to hang out.

Trumpeter swans on the restored Derr Wetland.  February 13, 2015

Trumpeter swans on the restored Derr Wetland. February 13, 2015

We can’t (unfortunately) be out at the wetland every minute of the day, so we miss a lot of action. Even though our timelapse cameras only fire once an hour, it’s amazing how much we can learn from them.

(Thanks, as always, to Moonshell Media for their help with our timelapse project.)

Posted in Prairie Animals, Prairie Natural History, Prairie Photography | Tagged , , , , , , | 4 Comments

Media Coverage of Our Restoration Work

Our friends at Platte Basin Timelapse (PBT) created a very nice radio piece about our restoration work that aired on NET Radio (Nebraska Educational Telecommunications) today.   The link below includes that audio, along with a transcript and short video of our staff harvesting, mixing, and planting seed.  You can also see video of me describing what we’re doing and why.

It’s always difficult to distill the complexities of land management and restoration into sound bites and video clips, but this was a very good description of our work.  I really appreciate the time and consideration that Ariana Brocious, Peter Stegen, and others at PBT put into this project.

If you’re interested, you can see and hear the story HERE.

Ariana Brocious (with headphones) and Pete Stegen (green coat) collect audio and video footage as we prepare to overseed a degraded prairie back in January of this year.

Ariana Brocious (with headphones) and Pete Stegen (green coat) collect audio and video footage as we prepare to overseed a degraded prairie in January of this year.

 

 

Posted in Prairie Restoration/Reconstruction | Tagged , , , , , , , , , , , , , | 1 Comment

Tuning Out and Tuning In

It had been way too long since I’d taken the kids camping.  Earlier this month, however, I managed to get two out of three of them to come with me and we had a great overnight trip to our family prairie.  We go out to our prairie – and other natural areas – pretty frequently, but there’s something extra special about camping.  Maybe it’s the collaborative work needed to set up housekeeping, and tend to basic needs such as food, fuel and shelter.  Maybe it’s the opportunity to slow down and spend time with family away from all the distractions at home.  Maybe it’s the chance to see the stars, listen to wildlife calls, and experience other nature-at-night phenomena that we usually miss by being at home in our beds.  Maybe it’s all those things and more.

(Ok, who am I kidding?  It’s mostly the chance to play with a campfire – at least from my boys’ perspective!)

Against my better judgement, the boys talked me into setting up camp at the bottom of a draw (there was zero chance of rain, fortunately).  One advantage of that location was that we had enough trees to support our hammock.

Against my better judgement, the boys talked me into setting up camp at the bottom of a draw (there was zero chance of rain, so I gave in). One advantage of the location was that we had enough trees to support our hammock.

Anyone who has been camping knows that food always tastes better when cooked on a campfire.

Everyone knows food always tastes better when cooked over a campfire.  We had to have two fires so the boys could “work” with one while I cooked on the other.

We filled our time with simple but profound activities.  We practiced a little archery.  The boys took turns lying in the hammock.  We poked around down by the pond.  Supper was cooked on sticks held over a fire.  When the sun went down, we walked into the prairie, laid down beneath the stars and let ourselves be swallowed up by the universe.  We identified a few constellations and saw either a satellite or the space station, but nobody really cared about identification.  After playing some cards in the tent, we listened to coyotes, owls, turkeys, frogs, and some passing cranes as we went to sleep and woke up the next morning.  I figured the boys would enjoy a chance to sleep in, but well before sunrise they woke me and pushed me out into the cold morning to get a fire started.  (Did I mention the boys like campfires?)  Breakfast was unhurried and delicious.

We weren't remote enough to escape lights from nearby towns, but we still had a pretty great night sky show to admire.

We weren’t remote enough to completely escape lights from nearby towns but we still had a pretty amazing night sky to admire.

I brought along some loppers and saws for cutting small cedar trees out of the prairie, figuring that if the boys got bored we could at least be productive.  As it turned out, they didn’t get bored and we didn’t accomplish anything productive.

Except that we did.  We really did.

Posted in Prairie Natural History, Prairie Photography | Tagged , , | 15 Comments

Photo of the Week – March 26, 2015

Despite snide comments from certain friends, I do – now and then – take photos of subjects other than insects and plants…

As I write this, the annual sandhill crane migration phenomenon is taking place on Nebraska’s Platte River.  The river valley abounds with tall gray birds feeding in crop fields and meadows and the sound of calling cranes fills the air.  I haven’t had a lot of time for crane photography this year, but have managed to pull the camera out of its bag a few times.  A couple weeks ago, for example, I was in a riverbank viewing blind with a group of birdwatchers, watching cranes coming in to their river roost against a rose-colored post-sunset sky.  The muted light made photography difficult, but I managed a few photos, including the one below.

Sandhill cranes landing on the Platte River, where they will roost overnight.  Because of low light levels, this photo was taken with an ISO of 2000, making it relatively grainy.

Sandhill cranes landing on the Platte River, where they will roost overnight. Because of low light levels, this photo was taken with an ISO of 2000, making it relatively grainy.

After the light and color faded a little more that evening, I decided to try a short video.  If you have never been to the Platte River during this time of year, this will give you a tiny glimpse of what it’s like to watch cranes coming to the river in the evening.

Watching cranes drop into the river at sunset is fun, but I prefer to visit them in the early morning as the roosting birds start to wake up and get ready for the day.  We have to sneak into the blind well before daylight and it’s often difficult to tell how many birds are on the river until the growing light slowly reveals their shadowy outlines.  On a good morning, we may have 10-20,000 birds or more within view as the sun comes up.  The sight and sound of those birds is astounding.  As the sun rises and the air warms up, the activity level of the birds increases, and we get to see a great deal of social behavior – preening, pair-bonding and courtship “dancing”, and aggressive posturing.  The short video below documents that kind of increasing activity through one morning this spring.

I am grateful to have a front row seat to an annual ecological phenomenon that draws birdwatchers and nature lovers from around the globe.  The sound of sandhill crane calls is a pretty great soundtrack to my spring.  The only regret I have is that the majority of crane-watchers never get to see the Platte River Prairies during the summer when – though we have no cranes around – our grasslands are teeming with the sights and sound of birds, insects, flowers, and generally spectacular prairie life.  Please come visit!

Flying cranes silhouetted against the dusk.  The Nature Conservancy's Platte River Prairies, Nebraska.

Flying cranes silhouetted against the dusk. The Nature Conservancy’s Platte River Prairies, Nebraska.  March 2015.

 

Posted in Prairie Animals, Prairie Photography | Tagged , , , , , , , , | 10 Comments

From the Ashes

Last Friday, I wandered through the small prairie we burned back on March 10.  Even though it is still very early spring, there were already a number of prairie plants popping out of the ground.  I posted photos of this site right after the fire was completed.  Today, I’m posting some photos taken 10 days later at the same site, along with some discussion of the impacts and effectiveness of prescribed prairie fires.

Purple poppy mallow (Calliroe involucrata)

Purple poppy mallow (Callirhoe involucrata) begins its new year of growth.

Most prairie plants grow from belowground buds, making them much less vulnerable to fire than trees and shrubs, which start their new growth above ground – from buds at the tips of branches.  When fire burns woody plants, those aerial buds and living tissue are destroyed, stressing the plants and forcing them to start over from ground level.  However, fire (at least during the dormant season) simply burns up the old stems and leaves of non-woody prairie plants, causing no injury.  Instead removing those dead stems helps stimulate growth in the coming season, especially via increased sunlight, which warms the ground and is available to new shoots as they first emerge.

Scribner's panicum (Panicum oligosanthes), a native cool-season grass.

Scribner’s panicum (Panicum oligosanthes), a native cool-season grass.  In this photo, you can see that the tips of the grass leaves had just started to grow when the fire came through ten days earlier.  Since the leaves grow from the base, those burned tips don’t impede plant growth.

Increased sunlight hitting the ground has helped the small area we burned on March 10 green up much faster than unburned prairie nearby.  Our main objective for the fire was to remove thatch in order to improve the effectiveness of planned herbicide treatment/re-seeding of some smooth brome patches within the small prairie.  The brome is responding very strongly to the fire, and its rapid growth (and the absence of thatch to intercept spray droplets) will make the grass more susceptible to our herbicide treatment.  However, since many other plants are also popping up, we’ll carefully spray only the thickest patches of brome where no other species are growing.

Green sage (Artemisia campestre)

Green sage (Artemisia campestre) growing next to its old stem from last year.

Prescribed fire can be a useful tool when trying to temporarily flip the balance of power from cool-season invasive grasses (smooth brome, Kentucky bluegrass, etc.) to native warm-season grasses (big bluestem, indiangrass, etc.).  However, timing is critically important.  A dormant season or early spring fire is actually counterproductive unless it is followed by herbicide treatment, mowing or grazing.  Those early fires stimulate the growth of cool-season plants – including smooth brome and Kentucky bluegrass – giving them a big advantage over later-season plants which won’t start growth until late April or early May.  By the time those warm-season plants start growing, the early plants will have had a month or more to extract soil moisture and nutrients, and will be big enough to dominate competition for light and root space.

If we’d wanted to suppress smooth brome solely with fire (and not follow up with herbicide), we would have waited until late April or early May to burn.  That late season burn would have stressed the actively-growing brome and bluegrass and provided direct sunlight to freshly emerging shoots of big bluestem and other warm-season grasses.  More often, we combine periodic fire and grazing to suppress brome and bluegrass and facilitate greater plant diversity.

Here's one of the grasses we would like not to see coming back after a fire - Kentucky bluegrass (Poa pratensis).

Along with smooth brome (Bromus inermis), Kentucky bluegrass (Poa pratensis) also responded well to the fire.  This particular plant will likely have a very good year, but the brome and bluegrass in the thicker patches of this prairie will be sprayed with glyphosate herbicide and re-seeded.

The regrowth of prairie plants after fire can seem almost magical.  Fire is absolutely an important natural process and a very useful tool for prairie managers.  However, prescribed fire is not magic, and doesn’t automatically lead to better prairies.  As with any tool, fire has to be applied thoughtfully (and carefully!) in order to meet objectives.

The timing of fire dramatically impacts the way prairie plant communities respond.  Early spring, late spring, summer, and fall fires each have different effects on plants, and those effects are also influenced by soil moisture, the presence/absence of grazers, and many other factors.  Prescribed fire can also have serious impacts on some animals, even during the dormant season.  Many invertebrates, for example, overwinter in the aboveground plant stems or thatch, making them very vulnerable to fire. It’s important not to burn an entire prairie at once – especially if that prairie is isolated from other grasslands.

I'm not sure what species of wildflower this is.

I’m not sure what species of wildflower this is but I’m looking forward to finding out as it gets bigger!

Fire plays many critical roles in prairie ecology – suppressing woody plants, removing thatch, stimulating microbial activity, aiding in nutrient cycling, and more.  However, while fire is important and its effects are both useful and aesthetically pleasing, it is not automatically positive.  Safe use of prescribed fire requires training, experience, and caution.  The effective use of fire requires clear objectives and careful planning that ensures those objectives will be met.

As I’ve discussed before, the actual process of conducting a fire can be very stressful.  However, once the smoke clears and I can relax, its easy to appreciate both the beauty and ecological benefits of prairie fires.  The emergence of bright green prairie plants through black ash is one of my favorite sights, and I love watching plant and animal communities respond and adapt to changing habitat conditions.

In prairies, rising from the ashes is more than a metaphor – it’s a way of life.

 

Posted in Prairie Management, Prairie Natural History, Prairie Photography, Prairie Plants, Uncategorized | Tagged , , , , , , , , , | 14 Comments