Choosing Your Destination Before You Choose Your Mode of Transport

Last week, I attended a science and stewardship conference of The Nature Conservancy in Madison, Wisconsin.  It was an inspiring and thought-provoking week.  There were a lot of topics that will provide fodder for future blog posts, but I wanted to start with an issue that came up in several sessions.  The topic had to do with setting appropriate objectives for conservation strategies, and for land management in particular.  In short, it’s really important to make sure we’re not setting objectives that are focused on strategies rather than outcomes.

This mixed-grass prairie is managed with both prescribed fire and grazing.  However,  neither fire nor grazing is the objective, they are tools that are strategically employed to create desired outcomes.  Gjerloff Prairie – Prairie Plains Resource Institute

Here’s an illustration of what I mean.  If I was planning a vacation for next summer, I probably wouldn’t start with the following question: “What mode of transportation should I take on my vacation next year?”

Clearly, it’s tough to answer that question without knowing more about the ultimate objectives of the vacation.  Where do I want to go?  What time of year am I going?  How many people are going with me?  If I’m planning to travel from Nebraska to Ireland, I probably won’t be able to do that by bus.  I could conceivably travel by motorcycle (if I had one) to the Rocky Mountains, but probably not if I was going during the winter or planning to take little kids with me.

It seems silly to start by thinking about how to get somewhere before deciding where to go, but as land managers, it’s easy to fall into exactly that mindset.  We sometimes set objectives about using fire or grazing, for example, instead of first defining the outcome we want and then thinking about what tools and strategies might get us there (which may or may not include fire or grazing).  In this post, I’ve provided examples of how this trap can present itself, both to managers of conservation land and private landowners, and some thoughts about how to avoid the trap.

Significant research has helped us understand the kinds of fire and grazing patterns under which North American prairies developed.  For example, in many places, we have a pretty good idea how often a particular site burned, on average, before European settlement.  We also have reasonably good information on the presence, abundance, and behavior of historic grazers.  Based on that information, a land manager could decide that the best management for their prairie would be to reinstate, as closely as possible, the timing and intensity of historic fire and grazing that site likely evolved under. 

Historically, prairies in this region probably burned on an average of every 4-5 years.  However, within that average range, there would have been wide variation.  More importantly, this prairie sits within a very different landscape today, with challenges not faced by those historic prairies.

Patch-burn grazing is often described, for example, as “mimicking historic fire and grazing patterns.”  Mob grazing advocates trumpet (though I’m skeptical) that their system replicates the way bison moved across a landscape.  Some in the Upper Midwest region of North America point to research showing high populations of indigenous people and scarce evidence of abundant bison and argue that their prairies should be managed only with fire.  We can argue about all three of those examples – and many more – but the bigger point is that none of those arguments should determine our management strategies.  Again, we shouldn’t be setting objectives about the strategy we want to use without first identifying the outcome we want.

To make a clunky return to my vacation travel analogy, it would be silly of me to choose horseback as my preferred mode of transportation across the Great Plains to the Rocky Mountains just because it’s what worked several hundred years ago.  Today’s landscape is broken up into countless fenced off private land parcels, which would make cross-country horse travel difficult, to say the least.  In addition, there is a pretty nice set of modern opportunities (roads and vehicles) I can take advantage of nowadays.

Likewise, our prairies exist within a different world today, with a new set of challenges and opportunities.  Mimicking historic disturbance regimes won’t necessarily keep prairies in good shape in a world with habitat fragmentation, massive invasive species pressure, climate change, nitrogen deposition, and other factors.  And speaking of good shape, our first and primary concern should really be to define what “good shape” is, right?  Are we managing for plant diversity or a few rare plants?  Are we trying to sustain diverse bird populations?  Habitat heterogeneity? Is ecological resilience the goal?  If so, what are the factors driving resilience, and how to we sustain those?  There are countless reasonable goals for land managers to choose from, many dependent upon scale, but those goals should be based on the outcome we want.

This annually-hayed prairie maintains high plant diversity but provides only one type of habitat structure for nesting birds and other wildlife species.  Depending upon the objectives for the site, that could be fine, but it very much depends upon what the manager wants to accomplish.

I feel it’s important to say this here:  I am a big proponent of both fire and grazing as management tools – you can find myriad examples of that by searching through my previous blog posts.  However, while I think combining fire and grazing can create some fantastic results, those strategies/results don’t fit all objectives.  More importantly, your particular site may or may not respond well to those kinds of fire and grazing combinations.

Let’s say your primary objective is to provide habitat for as many species of grassland birds as possible.  First, you’ll need a pretty big swath of land – many bird species have minimum habitat size requirements.  Assuming you’ve got sufficient land, the major factor grassland nesting birds respond to is habitat structure.  Some birds prefer tall thatchy structure, others like short/sparse vegetation, and others want something in-between.  A reasonable outcome-based objective might be that you want to provide all three of those habitat types across your prairie each year (and you’ll want to make sure the habitat are being successfully used by a diverse bird community).  Perfect.  Now, how will you create those habitat types?

 Grasshopper sparrows tend to nest in prairies with relatively short structure, but with some thatch (which they use to build nests) along the ground.  Some of the highest abundances of grasshopper sparrows around here are found in relatively heavily-grazed prairie.

Fall or spring fires can create short habitat structure that some birds really like to nest in.  However, some bird species (e.g., grasshopper sparrows) usually like short habitat with a little more thatch in the ground layer than is usually found in recently burned prairies.  Also, while burned areas are short and unburned areas are tall, it’s difficult to create in-between height/density habitats using only fire.  This is where other tools such as mowing and grazing might be helpful.  Mowing can reduce the height of tall vegetation and create short or mid-height structure that grasshopper sparrows, meadowlarks, and other species prefer.  Grazing can do the same and can have the advantage that cattle or bison are selective grazers, eating some plants and leaving others.  This can create structure with both tall and short vegetation mixed together and can also help suppress grasses and allow for greater expression of forbs (broadleaf plants) – something birds such as dickcissels often prefer.

Upland sandpipers prefer to nest where vegetation structure is short, but often move to sites with strong forb cover and a little patchier structure when their chicks become active.

If we’re trying to create optimal bird habitat, then, fire, mowing and grazing might all be useful tools to consider.  It’s important to understand how each tool can be used to affect habitat structure, as well as the potential risks of using each (fire can sometimes kill aboveground animals and stimulate invasive plants, grazers can sometimes target vulnerable plants and create issues via trampling).  With all of that information, you can start putting together strategies that employ the right tools, and then test those strategies against the OUTCOMES you desire.  Notice that the process I’ve just described is independent of the kinds of historic fire returns for your area or whether or not you think grazing was a significant factor in the evolution of regional plant communities.  Define your objective by the outcomes you want and test/adapt strategies based on that objective.

Other examples: At my family prairie, we aren’t using prescribed fire because we’ve been able to use grazing to meet our objectives of habitat heterogeneity and increasing plant diversity, and we use loppers/herbicide to successfully control woody invasion.  In small prairies where preserving particular plant species is the objective, a strategy using only fire or mowing could be most appropriate.  If that small prairie has rare insects or reptiles that are especially vulnerable to fire, maybe mowing is the best tool.  Regardless, the right tools and strategies depend upon the outcome-based objective.

This photo was taken in the burned patch of a patch-burn grazed prairie at Konza prairie, near Manhattan, Kansas.  The grazing created varied habitat structure because of the selective grazing by cattle.  Leadplant and other ungrazed forbs contrast with surrounding short grasses.

For ranchers and farmers who manage prairies, this same objective setting process should apply, but of course those prairies also have to help provide sufficient income to keep a family or business thriving.  Even in those cases, however, it’s still important to start with outcome-based objectives.  Those objectives can include a certain amount of needed income but should also include specific habitat or other ecological objectives.  Once you’ve decided, for example, that you really want to manage in a way that provides a certain amount of quail habitat or provides consistent pollinator resources through the season, you can look for ways to accomplish that while still providing the needed income.  When a conflict between income and habitat objectives arises, you can make the decisions that make sense to you, but at least you’re making those decisions with all the information needed to fully consider the options.

Prescribed fire can be a great tool for accomplishing some objectives, but it can also be difficult to implement for some managers.  While it is an important ecological process in prairies, employing prescribed fire should still be seen as a tool/strategy, rather than as an objective in and of itself.

There are plenty of reasonable prairie management objectives to choose from, but they should be based on outcomes rather than on tools and strategies.  Employing more frequent prescribed fire is not a good objective.  However, using more frequent prescribed fire might be a great strategy to reach a particular outcome.  (It could also be a terrible strategy, depending upon your objective.)  Don’t fall into the trap of choosing your transportation method before you know where you want to go. 

P.S. I’m sure some of you are thinking it, so let me address what might appear to be a weakness of my vacation transportation analogy.  Yes, it’s perfectly fine to start vacation planning by deciding that you want to take a cruise ship or motorcycle if the OUTCOME you really want is to ride on a ship or motorcycle.  If you don’t care where you go, the destination isn’t the outcome, it’s just a by-product of your mode of travel.  Fine.  But I think you understand what I was trying to say, right?  Sure, you could argue that conducting prescribed fires could be your objective if all you want is a legal way to light things on fire and watch them burn.  If that’s your objective, though, you’re not managing prairies, you’re lighting things on fire – and there’s a big difference.  Ok?  Ok.

Prairie Word of the Day – Habitat Heterogeneity

Do you know what time it is?  It’s time for another PRAIRIE WORD OF THE DAY!

Today’s Prairie Word of the Day (fine, it’s actually two words) is:

Habitat Heterogeneity

Heterogeneity is really just a longer word for Diversity, which is another way of saying “lots of different things”.  So why use the word “heterogeneity” instead of just saying “lots of different things”?  Well, for one thing, using big words makes a person sound smart, and when you’re a prairie ecologist and no one really understands what it is you do for a living, it’s good to at least sound smart.

More importantly, there’s a nice alliterative (another big word!) feel to the phrase Habitat Heterogeneity, which happens to be one of the most important phrases in prairie ecology.  In fact, I would argue that the foremost objective of any prairie manager should be to create habitat heterogeneity within the prairie(s) they manage.

Habitat heterogeneity simply means diversity or variety in habitat types.  Habitat homogeneity is the opposite – a lot of habitat that is all the same.

Every organism in a prairie has its own unique habitat requirements, so the number of different habitat types in a particular prairie is correlated with number of species that can live there.   Let’s use prairie birds as an example.  Birds such as upland sandpipers like to nest in large patches of relatively short-stature grassland.  Around here, a big hay meadow is great habitat for them, especially if it was cut fairly late in the previous year and is still short in stature when the subsequent breeding season starts.  On the other hand, Henslow’s sparrows want to nest in prairie habitats with relatively tall and dense vegetation.  It would be highly unusual to find Henslow’s sparrows and upland sandpipers nesting in the same patch of prairie because their habitat preferences are very different.  So, if you want both species in your prairie, you have to provide both short and tall/dense habitat.  Other birds have their own unique habitat requirements, including nearly bare ground (e.g., horned lark), relatively short, but with abundant thatch (grasshopper sparrow), tall with lots of tall/weedy wildflowers (dickcissels), tall and nearly impenetrably dense vegetation (sedge wrens), and many others.  Only if your prairie provides all those different habitat conditions will you attract all those different bird species.

Dickcissels prefer
Dickcissels prefer habitat with lots of tall wildflowers or weeds.  They often weave their nest into the stems of a tall clump of vegetation.

The same diversity of habitat preferences exists in other groups of prairie species as well.  Among small mammals, for example, voles tend to prefer habitats with abundant thatch, while pocket mice are more often found where bare ground is abundant – and there are many others.  Insects and other invertebrates have the same kind of diversity in habitat preferences

Scale is important.  While a bird, mammal, or insect might have a broad preference for a certain kind of habitat structure, it is likely to need some heterogeneity within that habitat too.  A mouse, for example, might prefer patches of prairie with fairly sparse vegetation, but it is likely to need a few clumps of vegetation dense enough to hide in when predators are near.  Insects and reptiles are ectothermic (cold blooded) and need to regulate temperature, so while a snake might like to hide in tall dense so it can bite your ankle as you walk by (I’M KIDDING!), it also needs some places to bask in the sun.  All of this means that habitat heterogeneity is important any many different scales.  Heterogeneity at a fairly large scale (acres) helps provide places for many different animals to live in a prairie, but heterogeneity within the home range or territory of each animal (square meters, or even centimeters) can be important too.

Some habitat heterogeneity occurs simply because soil texture, nutrients, and moisture, along with topography all vary across a landscape.  A prairie is likely to have areas of more productive soils where vegetation grows tall and thick, and less productive soils where vegetation is more sparse, for example.  In addition, water will pool in some areas of a prairie more than others because of topography, altering the habitat for both plants and animals.  However, despite this “naturally occurring” heterogeneity, it’s still important for prairie managers to look for ways to provide more.

This landscape at The Nature Conservancy's Broken Kettle Grasslands in northwest Iowa shows the kind of natural heterogeneity that occurs in many landscapes.
This landscape at The Nature Conservancy’s Broken Kettle Grasslands in northwest Iowa shows the kind of natural heterogeneity that occurs in many landscapes.  Topography, soil variability, and other factors create a diverse set of conditions for plant growth and habitat structure.  Land management can add to that heterogeneity and improve it even more.

Prescribed fire and haying/mowing do a great job of altering habitat structure at a fairly large scale (acres).  By applying those treatments in different parts of a large prairie each year (and varying the timing of each from year to year), a manager can create a shifting mosaic of habitat patches that supports a wide diversity of animals.  However, both fire and mowing are pretty non-selective – most or all of the vegetation within a burned or mowed area gets the same treatment.  Leaving unmowed patches of grass here and there and varying the height of the mower as it moves across the site can help leave more heterogeneity behind.  Designing prescribed fires so that not all vegetation burns (e.g., mowing around some patches ahead of time, burning on days with lower temperatures or higher humidity, etc.) can also help with habitat heterogeneity – though those kinds of fire might also be less effective at killing trees or accomplishing other objectives.

In prairies where livestock grazing (cattle or bison, for example) is feasible, it is much easier to create small scale heterogeneity because grazers pick and choose which plants, and how much of each plant, to eat at any one time.  By controlling grazing intensity, and varying it across both time and space, managers can create prairie patches that are ungrazed, almost completely grazed, and in various stages of partial grazing – with a mixture of tall vegetation and nearly bare ground.  The uneven application of “fertilizer” from the rear ends of grazers contributes even more to habitat heterogeneity by temporarily altering soil productivity in lots of little spots across the prairie.

These cattle at Konza Prairie in Kansas
These cattle at Konza Prairie in Kansas have created a nice example of small scale habitat heterogeneity by grazing many of the grasses short while leaving leadplant, purple prairie clover, and other wildflowers ungrazed.

Whether it’s fire, mowing, grazing, herbicides or various combinations of those, creating habitat heterogeneity may the most important job of a prairie manager.  We still have a lot to learn about how the scale and configuration of habitat patches affect wildlife and insect populations.  What we do know, however, is that the prairies thrive when they have a lot of different types of habitat.  …When they have habitat heterogeneity.

And that, folks, is your Prairie Word of the Day.

Photo of the Week – May 28, 2015

One difference between using cattle grazing and other grassland management options like fire or mowing is that cattle have brains.  They can decide where they want to go (within our fences) and what they want to eat, and their behavior isn’t always completely predictable.   For example, while we know that cattle will spend more time grazing in the burned patch of a prairie than in unburned areas, it’s always interesting to see what plants they decide to graze on or avoid, and how that changes day to day and season to season.  Overall, their unpredictability is a positive for our management because we build it into our plans.

Cattle joining the photographer for lunch  Platte River Prairies.
Curious cattle.  The Nature Conservancy’s Platte River Prairies.

Another interesting facet of cattle behavior is their interaction with us when we’re out in the field.  Cattle are often curious and come to investigate what we’re up to – probably because they’re hoping we have something fun to eat with us.  I did some plant community monitoring this week and the cattle in that prairie tagged along for a while.

Hey, what's for lunch?
“Hey, what’s for lunch?  Also, what’s that white thing?  Does it taste good?  Can I lick it?”

They ignored me all morning, but when I stopped to eat my peanut butter sandwich, the cattle happened to be coming to get water nearby, so they checked up on me.  When I finished my lunch and started walking transects again, they followed along just to make sure I wasn’t doing anything that concerned them.  (I wasn’t.)

Vegetation monitoring
Vegetation monitoring with an audience.  Counting species within a plot frame has a different vibe when you’re being watched.

Eventually, they apparently got bored (or hungry) and wandered off, leaving me to work alone.  By myself.

Sigh.

Why There Is No Cookbook for Restoring and Managing Prairies

From Anne Stine, Hubbard Fellow:

My big goal for this fellowship is to learn how to make a prairie from scratch.  I also want to know enough about prairie restoration/management that I can evaluate a prairie’s condition and then prescribe treatments to fix it.  For these first few months with The Nature Conservancy, and especially at the Grassland Restoration Network workshop (July 16-18, 2013 in Columbia, MO), I’ve been asking questions about the problems and solutions common to prairie restorations.  My naïve desire is to develop some sort of prairie restoration cookbook.  When I asked Chris why this didn’t exist, he laughed and said “If that were possible my book would’ve been a lot shorter.”  I built my flowchart anyway.

This blog post will be a bit different- I’m going to share the “Patch-Burn Grazing Flowchart” I developed.  Then Chris will respond and explain why the cookbook method doesn’t work.

(Click on the flowchart to see it as a larger image)

PBGbigfcResponse from Chris:

I give Anne credit – it’s clear she’s paying attention and learning a lot during the first couple months of her Fellowship experience.  Her flow chart includes very appropriate treatments for issues that pop up in prairies, and it’s a nice guide to some of those options.  However, prairie restoration and management is a more complex and dynamic process than can be easily captured in a flowchart (or even in a book).  That complexity can seem daunting to some, but is really what makes prairies fun and interesting to work with.  The trick is to accept the complexity and roll with it.

I've been working to rejuvenate our family's prairie south of Aurora, Nebraska for well over a decade.  It's getting there, but it's been anything but a straightforward process.  Every year brings new challenges and surprises.
I’ve been working to rejuvenate our family’s prairie south of Aurora, Nebraska for well over a decade. It’s getting there, but it’s been anything but a straightforward process. Every year brings new challenges and surprises, and we continue to tweak our management strategies.

When I wrote my book on managing prairies, I purposefully stayed away from prescribing any particular management regime (or recipe), and instead tried to provide some background on how prairies work and some guiding principles for managing them.  You can find a partial compilation of those ideas by going to PrairieNebraska.org and clicking on the “Prairie Management” or “Prairie Restoration” tabs at the top of the page.  There are lots of reasons I didn’t prescribe particular management recipes.  Here are a few of them:

1. Every prairie has its own unique species composition (plants, insects, animals, fungi) and that composition drives the way it responds to weather and management.  In some ways, prairie management is like parenting – each prairie (and child) has its own personality and needs to be treated in ways that match that personality.  The best parenting books are the ones that suggest general philosophies and offer tips to try in various situations.  Anyone who has been a parent knows that there is no cookbook for how to do it well.

2. Every year is different.  Last year was the driest on record for our Platte River Prairies.  This spring was very cool and wet, followed by a hot dry July, followed by a cool and wet August (so far).  Prairies respond very differently to fire, grazing, seeding, herbicide treatments, and other techniques due to weather conditions.  Countless times, we’ve applied a treatment to part of a prairie and were excited to see how it worked.  The next year, we applied the treatment in exactly the same way and things would turn out very differently.  We try to tailor our management and restoration to the weather, but we know we’ll be surprised by how things turn out.  Those surprises are what I look forward to most each year.

During the drought of 2012 this sandhill prairie was burned and grazed pretty intensively.  By late summer, it was looking pretty tough.
During the drought of 2012 this sandhill prairie was burned and grazed pretty intensively. By late summer, it was looking pretty tough.  The same burn timing and grazing stocking rate in a wet year would have resulted in a very different impact.
After adjusting our management plans to account for last year's drought, the prairie was grazed briefly this spring and - thanks to some good spring rains - looked lush and green by early June.
After adjusting our management plans to account for last year’s drought and grazing, the same sandhill prairie shown above was grazed briefly this spring and – thanks to some good spring rains – looked lush and green by early June.

3. Prairie restoration is not very predictable either.  We have developed and tested seeding rates, seeding methods, site preparation, and other techniques that seem to work well at our particular sites, but those same techniques wouldn’t necessarily work somewhere else.  One of the big pieces of advice shared each year at Grassland Restoration Network workshops is that when starting a large restoration project, the best plan is to spend several years experimenting with various techniques on small portions of the overall restoration site to figure out what works best at that particular location.  Once you figure out what seems to work best, start planting larger and larger areas each year.

However, even when the exact same techniques are applied, results can still vary from year to year.  Jeb Barzen and Richard Beilfuss did a great experiment at the International Crane Foundation in the early 1990’s in which they seeded 1 acre a year for five years, using the same seed mix and the same techniques.  Even though all the seedings were in the same crop field, each turned out very differently from each other.  The same thing happens everywhere.  Differences are partially tied to the rainfall and other weather that occurs in the early stages of the seeding, but there are many more factors that are difficult to understand or control.  This isn’t a bad thing, it just means that you have to relax your expectations a bit, and embrace the idea of variability.  Why would you want to create multiple prairie plantings that look exactly the same as each other anyway?

4. Invasive species are always a major challenge, and (you’ll not be surprised at this) have to be handled in unique ways depending upon the species and the site.  Every invasive species has its own growth and reproductive strategies, so an approach to controlling one won’t work well on others.  There are general approaches to controlling each species that have been tested and can be useful, but those approaches will work differently from year to year and from site to site.  One of most important aspects of invasive species control is prioritization, something Anne’s flowchart covers pretty well, and more information on that can be found here.

5. Finally, one of my guiding principles for prairie management is that diverse prairies require diverse management.  Doing the same thing every year means always favoring the same group of species – and, by default, managing against another group.  Eventually, that kind of repetitive management can reduce overall species diversity by eliminating plants or animals that can’t thrive under that management.  It’s good to mix things up to allow all the species in a prairie to have a good productive year now and then.

If a prairie is large enough, splitting it into multiple management units each year can help ensure that animals and insects can always find what they need for habitat (it’s more difficult to do that in very small prairies).  However, it’s also important to avoid simply splitting a prairie into the same three or four pieces and rotating management between them in a repetitive pattern – even those patterns can restrict species diversity over time.

Many prairie insects and animals have fairly specific habitat needs.  Grasshoppers, for example, tend to thrive best in prairies with patchy vegetation structure that allows them to move easily back and forth between shade and sun.  Splitting prairie into multiple management units each year can help provide the kind of habitat variety needed to maintain high species diversity.
Many prairie insects and animals have fairly specific habitat needs. Grasshoppers, for example, tend to thrive best in areas with patchy vegetation structure that allows them to move easily back and forth between shade and sun. Splitting prairie into multiple management units each year can help provide a variety of habitat conditions and maintain high species diversity.

During the next couple of months, Anne and Eliza will be part of our annual management planning process here in the Platte River Prairies.  Each fall, we go around to each of our prairies and go through a basic evaluation process.  How does the prairie look this year?  What were the impacts of weather and management this year?  What challenges, including invasive species, are we facing?  What kinds of management have occurred over the last several years?  What does the monitoring data from the last couple of years tell us about how past management has been working (sometimes we have hard data, but we always have field notes and other observations to consider).

We walk around, look at maps, and talk about ideas.  Then we sketch out a plan for the next season based on all of those factors.  We try to make sure it’s different from what we’ve done over the last year or two, but that it addresses the challenges the prairie is facing.  Most importantly, we make sure that we’re learning from and adapting to what we’ve tried in the past and the ways the prairie has responded.

I suppose I could capture that process in a flowchart.  It would look something like this:

Helzer Flowchart

That’s probably not exactly what Anne was hoping for, is it?

Hubbard Fellowship Blog – Weed Whacking with Konstantin

Guest Post by Anne Stine, one of our 2013-14 Hubbard Fellows:

When one considers that the weed-whacker is the modern incarnation of the scythe, Konstantin Levin’s ecstatic enlightenment while cutting wheat with his peasant tenants in Anna Karenina comes across as a little ridiculous.  It is easy to imagine him, a ruddy-faced and awkward aristocrat, smiling beatifically in the center of a line of serious men going about the business of mowing.

Instead of a wheat field in Russia, this is my work site.
Instead of a wheat field in Russia, this is my work site.  The Nature Conservancy’s Platte River Prairies, Nebraska.

Scythes and weed-whackers use the same efficient, swaying pivot through the body. Back and forth, back and forth, the returning stroke hitting the grass missed in the initial swing.  Such work does provide the opportunity for quiet thoughts.  Unlike Levin, however, I did not achieve enlightenment while weed whacking the grass beneath the 14-gauge wire of an electric fence.  Drifting into the repeating beat of the movement, my mind rippled towards the remarkably competent field technicians I have known.

I have been continuously impressed by the manual aptitude of the technicians I have worked with in my academic career.  If something broke, rather than sitting completely stumped, they had the know-how to wire it together and make it work. I hope to gain a measure of this generalized comfort with mechanical workings during my tenure as a Hubbard Fellow.  I’ve already learned to drive an ATV, a tractor, and a riding mower; and to operate weed-wackers and backpack sprayers.  I’ve set electric fence and helped cut free a calf tangled in wire.  I want to write all of my physically competent colleagues and say “See! I’m learning.”

Similar to on a farm, the summer season in our pastures is the busiest time of year.  We’ve spent most of our hours so far as plant executioners- mowing, spraying, and spading invasives, aggressive natives, and other plants growing where we don’t want them to.  The major difference is that our primary product is a restored and healthy prairie rather than cattle or corn.

Thistle chasing has been our primary objective.  The musk thistle is classified as a noxious weed—this means that we are legally obliged to assist in its eradication.  The musk thistle can grow to be well over a meter high, with multiple fuchsia flower heads.  Their leaves are edged in sharp thorns but no hair, and the undersides of their leaves are green rather than white like the native thistles.  Originating in Europe, it gets its name from the supposedly odiferous roots and vegetation.  We attack them with herbicides and spades.  They are prolific seeders.  Sometimes killing musk thistles can feel like a Quixotic quest, like we are fighting the tide with a bucket.

The enemy (with a grasshopper sparrow sitting on it).
The enemy (with a grasshopper sparrow sitting on it).

.

My weapon of choice.
My weapon of choice.

Killing plants and fixing fences is a full time job in the summer growing season.   I have already gained an appreciation for the broad-based knowledge necessary to maintain a working pasture.  I hope to continue to develop my applied skill-set, and I will keep saying to the world: “See! I’m learning.”

Lessons From a Project to Improve Prairie Quality – Part 1: Patch-Burn Grazing, Plant Diversity, and Butterflies

We recently completed a large multi-year restoration and management project at our Platte River Prairies.  Our specific objectives were to improve habitat quality for various at-risk prairie species and evaluate the impacts of our management on at-risk butterflies – particularly regal fritillaries.  The project was supported by the Nebraska Game and Parks Commission, who funded our work with two State Wildlife Grants (U.S. Fish and Wildlife Service money).  Over five years, we conducted fire/grazing management in our prairies and enhanced plant diversity through overseeding and seedling plugs.  We measured the results of that work by measuring changes in prairie plant communities and by looking at the use of our prairies by regal fritillaries and other butterflies.

Plant diversity and buttterfly habitat were the objectives of our 5-year project.
We’ve worked hard to get plant diversity in our restored prairies, including this one.  We wanted to know whether or not our management was maintaining that diversity, and also how it was affecting butterflies.  The prairie shown here was being grazed at the time of the photo – July 2009.  The Nature Conservancy’s Platte River Prairies, Nebraska.

The following is a brief summary of the major lessons we’ve gleaned from the fire/grazing component of the project, including implications for future management and restoration work.  I will summarize the overseeding/seedling work in a separate upcoming post.  If you want more details, you can see our entire final report to the funding agencies here.  As a warning, the report is 14 pages long, with an additional 21 pages of Appendices, full of tables and graphs.

What We Did
Between 2008 and 2012, we treated over 1,500 acres of prairie with varying applications of patch-burn grazing management.  During that time, we altered the timing of burning and the intensity of grazing from year to year, and included years of complete rest from grazing in some prairies.  For the purposes of this project, we evaluated the results of our work in two main ways:

–          We measured changes in plant diversity and mean floristic quality.

–          We conducted three years of butterfly surveys to evaluate how regal fritillaries and other butterfly species responded to our restoration and management work.

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Using Defoliation of Dominant Grasses to Increase Prairie Plant Diversity

 In many prairies, the primary suppressors of plant diversity are dominant grasses – both native and non-native.  These grasses, left unchecked, can monopolize light, moisture, and nutrients to the point that few other plant species can coexist with them.  I’m not sure why some prairies suffer from this more than others.  There is some evidence that hemi-parasitic and allelopathic plants such as pussy toes, false toadflax, and wood betony can play a role in suppressing grasses and facilitating forb diversity, but I don’t think that’s the whole answer because I’ve seen very diverse prairie plant communities without those species – or with only a few scattered populations of them.  Regardless of the reasons, we are left with many prairies that have lost – or are losing – plant diversity through domination by grasses, and we have to decide what to do with them.  Some of those prairies are restored (reconstructed) prairies that started out with high plant diversity but have since lost much of that diversity.  Others are remnant prairies that have been degraded by overgrazing and/or broadcast herbicide application.  Still others are relatively diverse remnant prairies that are slowly losing diversity as individual forbs die without reproducing.

Big bluestem. A good native grass, but sometimes so dominant that overall plant diversity suffers.

I think one of the best tools we have for combating grass domination in prairies is defoliation – the removal of above-ground portions of plants.  Defoliation has always been a major component of prairie ecosystems through fire and herbivory, and mowing and (non-lethal “burn back”) herbicide applications are additional options at our disposal today.  Plants respond to defoliation in various ways, depending upon the severity of defoliation, the frequency and/or duration of the defoliating event, the stage of the plant’s growth at the time of defoliation, and each species’ genetic programming.  The way each plant, and its neighbors, respond to a defoliation event determines which plants will gain or lose territory.  In other words, defoliation influences the competition between plants – and manipulating competition between plants is really what most prairie management is all about. 

Some of the earliest research I’m aware of on the effects of prairie plant defoliation can be found in range management research from the 1950’s and 1960’s.  The earliest paper that is often cited from that era is by F.J. Crider, who documented the effects of defoliation on the root growth of grasses.  He (and others since) found that a severe defoliation of a grass plant resulted in an immediate cessation of root growth as plants reallocated resources from root growth to regrow leaves and stems.  More importantly, those grass plants actually abandoned sections of living roots as well – shrinking the total root mass of the plant fairly dramatically.  This makes sense, since the plant has to support those roots through photosynthesis, and a severe defoliation takes away most of the plant’s ability to photosynthesize. 

A simplified look at how dominant grasses can affect plant diversity. In the top example (A) grasses have monopolized both aboveground (light) and belowground resources (moisture and nutrients). After defoliation (B), both the above and belowground parts of the grasses have shrunk, freeing up resources and allowing other plants to establish within that lost territory. As the grasses recover from the stress of defoliation, their vigor and size increase, but the new plants have a fighting chance - at least for a while - to hold the new ground they've taken.

Those early range science research data provide some useful context for today’s prairie management, but those researchers were primarily trying to figure out the intensity of grazing they could employ while still maintaining a dominant stand of grass.  As prairie managers, by contrast, we want to reduce the dominance of grass to increase the diversity of other plants.  We can still learn from what those range scientists discovered; we just want to employ it in a different way.  Since plants primarily compete for light, moisture, and nutrients, we want to find ways to make those three kinds of resources more available to plants other than dominant grasses.  Defoliation can reduce shading aboveground (removal of leaves and stems), while simultaneously freeing up the availability of moisture and nutrients belowground (reduction of root masses).

In prairies where dominant grass species are suppressing plant diversity, we want to defoliate those grasses in a way that forces them to cede territory to other species.  In order for that to work, the first important factor is that the defoliation has to happen during the growing season.  Defoliating a dormant plant (e.g. with an early spring burn) doesn’t have any impact on its root system, which is a critically-important part of its competitive ability.  In order to force a plant to reallocate resources away from its roots, defoliation needs to take place after the plant has already invested significant resources in above-ground growth.  This is why a late-spring burn can have a significant (if temporary) impact on cool-season exotic grasses such as smooth brome.  Burning, grazing, or mowing grasses when they are just starting to flower has the biggest impact on most species because they have invested the maximum amount in their above-ground growth by that point.  Alternatively, repetitive mowing or grazing of grasses can also have a strong – and perhaps longer lasting – impact on their root systems because every time the grasses start to regrow, they get nipped off again, forcing them to regroup and reallocate resources time after time.

The immediate result of that kind of severe and/or repeated defoliation of dominant grasses is a release of opportunistic plants that thrive under low levels of competition.  This includes many annual and biennial plants, but also perennial plants that are built to move quickly into open space.  The quick flush of these plants often turns people off of defoliation because of a widely-held misperception that those “weedy” plants are outcompeting “good” plants.  In truth, the weedy plants are only able to grow because the competition that normally holds them in check has been suppressed.  When the defoliation event is over, the dominant grasses and other perennial plants will slowly recover their vigor – at which point the weedy plants will retreat and wait for another opportunity.  Rather than indicating a problem, I use the presence of weedy plants to tell me that my defoliation treatment has succeeded in weakening dominant grasses and has opened up space for other plants to take advantage of. 

As common as the overly-dominant grass problem is in prairie conservation, there is a frustrating scarcity of research that addresses it.  However, a recently-published research project by Kat McCain and others at Kansas State University provides some very nice insight into what can happen when dominant grass species are suppressed in a restored (reconstructed) prairie.  Kat and her colleagues studied plots of seeded prairie that had become heavily dominated by big bluestem and switchgrass over time.  They found that removing half or all of the big bluestem tillers (stems) – by clipping and herbicide application – from a plot significantly increased plant diversity.  Interestingly, removing switchgrass tillers in the same way had much less impact.  Following the removal of big bluestem tillers, the researchers saw increases in the vegetative cover of some forb species, including roundheaded bushclover (Lespedeza capitata),  pitcher sage (Salvia azurea), and blue wild indigo (Baptisia australis) within those plots, as well as new establishment of forb species including whorled milkweed (Asclepias verticillata), green antelopehorn milkweed (Asclepias viridis), leadplant (Amorpha canescens), roundheaded bushclover, and heath aster (Symphyotrichum ericoides).  In other words, suppression of big bluestem competition led to increased vigor among existing forbs and also allowed new plants to establish in the territory previously held by the dominant grass.  The study bolsters the theory that grass competition is suppressing forb diversity in many prairies, but also provides information on how plant communities might respond if that grass competition is reduced.

Of course there is a difference between simple defoliation and the kind of clipping/herbicide combination used by McCain and her colleagues.  In addition, most defoliation treatments (especially prescribed fire and haying) in prairie management are non-selective, meaning that all plants are simultaneously defoliated – not just the ones we want to suppress.  Uniform defoliation likely decreases some of the benefits of suppressing grass vigor because the vigor of the plants we hope will respond is suppressed as well.  However, there will be still be plants that can take advantage of the newly available light and soil resources following a uniform defoliation treatment, and by altering the timing of defoliations from year to year, we can ensure that a variety of species get the opportunity to respond.

Haying is a good example of uniform defoliation. Every plant gets cut at the same height and at the same time.

 

Ideally, though, we would like the ability to defoliate only those species that are suppressing plant diversity.  One way to do that is by using a selective herbicide such as Poast, which affects only grasses (not forbs, sedges, or other plants).  Poast is labeled for control of annual grasses, but at light rates can also provide short-term burn-back (defoliation) of perennial grasses as well, and some prairie managers have seen plant diversity increase following treatments.  Because it can kill annual grasses, and calibrating the appropriate application rate with the desired result can be tricky, it’s probably best to use this treatment on restored prairie rather than on remnant prairies for now – and to test it on small patches first. 

Another way to get selective defoliation is by the use of grazing.  In an earlier post, I described our use of patch-burn grazing in our Platte River Prairies as a way to increase and maintain plant diversity.  Patch-burn grazing is essentially a technique that uses patches of burned prairie within a larger prairie to attract grazing animals, concentrating grazing activity in those burned areas while allowing other areas to recover.  Under a light stocking rate, we find that cattle – even in the burned patches – are very selective about the plants they choose to eat.  Their top choice of grasses in the spring is smooth brome, and their summer favorite is big bluestem.  These happen to be two of the top three grasses that appear to stifle plant diversity in our prairies (the third is Kentucky bluegrass, which cattle like less well).  In our application of patch-burn grazing, a burned patch of prairie is normally grazed intensively for an entire season before the next patch is burned and cattle shift their attention to that.  That length of intense defoliation has significant impacts on the plants that are grazed – and again, under light stocking rates, the primary plants that are defoliated are smooth brome and big bluestem.  Interestingly, switchgrass is much less attractive to cattle and is often left ungrazed – or lightly grazed – in our prairies.  I found it intriguing (and encouraging!) that McCain and her colleagues found that switchgrass appeared to have much less impact on plant diversity than big bluestem did.

The effects of selective grazing in a restored prairie. This photo shows the burned patch with a patch-burn grazing system where a light stocking rate allows cattle to be selective about their eating preferences. Big bluestem is cropped very short, while other grasses and forbs are ungrazed or lightly grazed. Species such as hoary vervain aren't typically grazed even under high stocking rates, but many species such as purple prairie clover (front left), illinois bundleflower (middle left) and stiff sunflower (blooming) are commonly considered to be favorites of cattle - but only at higher stocking rates.

It would stand to reason that selective grazing of big bluestem and smooth brome would favor the expansion of the ungrazed plant species growing with those grasses.  While I’ve not had the time or resources to conduct much full-scale research (help wanted!), I do have data that supports that idea.  Through annual data collection of plant species frequency, I’ve found that the density of species (the number of plant species per 1m2 plot) increases by 20 to 30 percent in the year following the burn/graze treatment in a patch of prairie – in both restored and remnant prairies. 

Data from two prairies under patch-burn grazing. In both cases, the graphs show the number of plant species per square meter over time from the year of fire and intense grazing through the two subsequent years. The East Dahms site is a degraded remnant prairie and the Dahms 95 site is a restored prairie that was seeded in 1995 with over 150 plant species. The error bars represent 95% confidence intervals.

Of course, the increase I see in species density following grazing includes many plants such as ragweed and other opportunistic species, but I also see species like purple prairie clover (Dalea purpurea), Illinois bundleflower (Desmanthus illinoiensis), and stiff sunflower (Helianthus laetiflorus) respond as well.   In addition to seeing this in my plot data, I can walk out into the prairies and see seedlings of these species around the adult ungrazed plants.  Not all of those young plants survive their first year or two, but some permanent plot data I’ve looked at shows that at least some of them do.  By the way, I see similar post-grazing increases in plant species density and establishment of species like prairie clover under patch-burn grazing with higher stocking rates (less selective grazing) as well. 

As I said in my previous post on grazing, I’m not advocating that all prairies need to be grazed.  I’m not even advocating grazing as the solution to all prairies that suffer from overly-dominant grasses.  However, as we search for answers to address grass suppression of plant diversity, grazing certainly appears to be one viable alternative that is worth more investigation.  I’m continuing to experiment with variations in the way we employ fire and grazing treatments, and will keep learning as I go.  I’m also combining seed additions with those grazing treatments to see if I can take advantage of the open space created by defoliation to help establish new plants from seed – something that appears to happen rarely without some kind of suppression of surrounding vegetation.  I’m seeing some positive results, but it’s too early to know how well it will work long-term, and I’m still tweaking seeding rates and other factors.

Whether it’s grazing, prescribed fire, haying, or herbicide application, defoliation may be the most powerful tool available to help us suppress dominant grasses and increase plant diversity in prairies – where that is an issue.  The biggest obstacle to its application is probably the fear of causing damage to prairie by burning, cutting, or grazing plants during the growing season, but I think that fear ignores the resilience of prairie communities.  We still have a lot to learn about the most effective ways to apply defoliation to achieve our objectives, but the only way we’ll learn is by experimentation.  I hope you’ll join me in testing these methods and tracking the results.  If you do, please share what you learn with the rest of us so we can all work to figure this out.

The Problem with “Calendar Prairies”

I think I first heard the term “calendar prairie” from my friend Bill Whitney of Prairie Plains Resource Institute.  He was talking about the mental image many people have of prairies that comes from seeing photographs of grasslands full of big showy flowers in books, posters, and calendars.  The term, and its implications for prairie management, has stuck with me over the years. 

 
 
 
An example of a "Calendar Prairie" photo. The Henry C. Greene Prairie at the University of Wisconsin-Madison Arboretum.

 

Unrealistic Expectations

There are a couple of dangers associated with people holding a mental image of what a prairie is supposed to look like.  The first is that it’s easy for people to have unrealistic expectations for prairies.  I’m a photographer, so I know firsthand that flowery photos don’t always represent an accurate picture of the prairie in which the photos were taken.  Photographers are often drawn to the biggest patches of showy flowers, and by creative use of perspective they can make those patches look even showier than they look in real life.  The result is usually a beautiful photograph that someone familiar with the prairie might not recognize.  To be clear, I’m not saying this kind of photography is a bad; on the contrary, attractive photographs have been extremely important for building the public’s interest in prairies. 

However, photos dominated by big showy flowers have the potential to be counterproductive as well.  For example, I worry that someone whose only vision a prairie comes from a “calendar prairie” image will be disappointed when they first see a prairie in person.  Regardless of how wonderful that real-life prairie is, it’s unlikely to live up to the photograph(s) that person has seen.  If that happens, it’s possible that a possible prairie enthusiast might instead feel duped and decide that prairies aren’t their thing after all.

For people that are already prairie enthusiasts, or perhaps prairie owners/managers, calendar prairies can become an unfair standard by which they measure the prairies they’re familiar with.  I’ve been in some astonishingly showy tallgrass prairies, where photos full of big flowers are easy to take just by pulling out a camera and shooting randomly.  However, not all prairies look like that – nor should they – and the ones that do don’t usually look like that all season long.  There are numerous conditions (including topography, soil moisture, soil texture, management history, etc.) that determine the appearance of a prairie’s plant community.  Using a calendar prairie image as the standard by which all prairies is judged is obviously naïve – much like a young woman using a movie star as the standard by which she judges her own identity.  The value of a prairie can be judged in many ways, including by its habitat value for a wide range of animal and insect species, many of which do not rely on big showy flowers.  In fact, the biggest value of an individual prairie is its very individuality – its unique combination of species composition and habitat attributes makes a unique contribution to the larger prairie conservation mission.  (Read my earlier post on this topic.)

This is not to say that all prairies are perfect the way they are.  Most (all?) prairies can be improved, but goals for improvement should be based on increasing the value of those prairies for biological diversity – not on making them look more like a photograph.

Effects on Management

The second danger of a calendar prairie image is that it can affect the way a prairie is managed.  Prairie managers sometimes form a mental picture of what they want their prairie to look like.  Sometimes that picture is based on an unrealistic idea of what prairies should look like.  Other times, it’s based on a fond memory of what their prairie looked in a previous season.  Either way, the problem occurs when that manager tries to make the prairie look like that mental picture all the time.  Rather than managing the prairie in response to threats such as invasive species, or in ways that allow different plant and animal species to gain an advantage each year, the prairie gets the exact same management treatments every year.

A summer fire on The Nature Conservancy's Platte River Prairies. We've seen very interesting and positive responses from summer fires, with and without grazing. For example, I've been managing this prairie for more than 10 years and have only seen wind flower (Anemone caroliniana) twice - both times it was growing in the portion of the prairie that had been burned the previous summer.

 

When a prairie gets the same management each year (e.g. early spring fire or summer haying) some plants, animals, and insects that are favored by that management and others are not – year after year.  Eventually, those species that are put at a disadvantage each year can disappear from the prairie.  Sometimes the strategy seems successful to the manager because the plant community appears the same each year; they always see the same big showy flowers blooming, for example.  However, other plant species may be slowly fading away.  More importantly, many animals and insects that have specific requirements for habitat structure will have a difficult time surviving in a prairie that provides only a single habitat structure type across the entire prairie each year.  Even those animals and insects that thrive may become more at risk from predation because the number of predators and their focus on particular prey species can both grow when their food source is consistently available in the same place and abundance each year.

 In a large contiguous grassland landscape, individual parcels of land that are managed the same way every year may not be a big deal – as long as there is variety among parcels.  If the Brown prairie is managed with annual late-spring fire, the adjacent Smith prairie is managed with annual summer haying, and nearby prairies are managed with other strategies, the conglomeration may retain good biological diversity, even if each individual tract of land contains a relatively narrow set of species.  However, when neighbors manage in similar ways, or when isolated prairies are managed in ways that decrease the number of resident species over time, the entire landscape can lose diversity.  If that happens, it’s unlikely that the diversity will recover because there are no places for the lost species to recolonize from.

 Ideally, every prairie would have multiple management treatments applied to various parts of it each year.  For example, a portion might be burned, a portion idled, and a portion grazed, with those treatments shifting from place to place each year – not necessarily in a predictable manner.  In a prairie managed that way, most or all plant species are likely to find favorable conditions in which to grow and bloom every few years – something that is critical to their long-term survival.  Animals and insects in a prairie that has multiple management treatments across it have a good chance to find suitable habitat each year by moving to the portion of the prairie that is most favorable in that year.

Light grazing on a restored Platte River Prairie - cattle are grazing the grass but leaving most wildflowers ungrazed. Periodic grazing can certainly change the appearance of a prairie, but plants that are grazed recover quickly. In the meantime, the grazing can provide different habitat structure and opportunities for plant species that are normally suppressed by dominant grasses.

 Some prairies are small enough that splitting them into multiple management units is not feasible.  In those cases, just shaking up the management so that it’s not exactly the same each year can be important.  Idling a different portion of the prairie each year – even if those portions are small – can provide a refuge for some of the plant and animal species that might not do well under the management applied to the majority of the prairie.  However, when prairies are both very small AND isolated from other prairies, some insect and animal species will simply be unlikely to survive long-term, even with good non-repetitive management.  In those cases, the management objectives may need to be altered – those sites could be treated more like museum pieces than prairies.

 Regardless of a prairie’s size, repetitive management over time can limit its biological diversity.  Prairies evolved under chaotic conditions; fires, grazing, outbreaks of herbivores, and drought came and went, and prairie animals and plants developed strategies to adapt.  Not only can prairie species survive management that changes year to year, they can thrive on it.

 Conclusion

Relying on idealistic visions of what prairies should look like (Calendar Prairies) creates an unrealistic image of what prairies really are.  Prairies evolved as dynamic natural communities that changed in appearance from day to day and year to year.  Rather than selling the public and ourselves on the idea that prairies should consistently look like showy flower gardens, we should celebrate and facilitate their changeable nature.  Real prairies are much more interesting (and valuable) than flower gardens anyway.

Measuring Success in Prairie Conservation – Species Composition vs. Structure and Process

Stick with me – this isn’t as complicated as the title might lead you to believe…

I was involved in an interesting discussion a couple weeks ago among some fellow prairie ecologists about what makes a “good prairie”.  The discussion brought into sharper focus something I had thought a lot about but only in general terms.  Here is the discussion – with some over-simplification of the respective positions:

Position A – Species Composition:

A high quality prairie (tallgrass prairie, in this case) can be judged largely by its plant species composition.  A “good” prairie might have 20 or 30 plant species per square meter, for example, and more than 100 species per acre – including a mixture of both common and rare species.   Besides the value for the direct conservation of species, that kind of plant diversity provides multiple ecological benefits.  More plant species means more choices for animal species that rely on them as food and/or habitat resources, as well as a more consistent supply of those resources through the season – because some plants will always be emerging/blooming as others go dormant.  Because of that, prairies with lots of plant species tend to have lots of insect and other small animal species as well.  In addition, prairies gain resilience from plant species diversity, because if multiple species fill similar ecological roles the prairie community can better withstand the temporary decline of some species due to drought or pest outbreak.   A prairie that is missing many of its species, or that is dominated by a few species with only scattered small populations of others, can’t be considered to be of high quality or to be “conserved.”

A diverse prairie at the Madison Arboretum – Madison, Wisconsin.

Position B – Structure and Process:

What really defines successful grassland conservation is the presence of large-scale and intense disturbances (e.g. fire and grazing).  The combination of fire and grazing shaped historic prairies and that combination is needed today to maintain them.  Without fire, prairies lose integrity in several ways – the most obvious being the encroachment of trees that fire otherwise suppresses.   Fire also helps drive the cycling of nutrients and regulates the amount of standing dead vegetation and thatch in prairies.  Furthermore, the high-quality of the fresh vegetative regrowth following a fire attracts intense grazing by herbivores large and small.  Historically, there would have been few cases where a prairie would burn and not be intensively grazed right afterwards.  That intense grazing suppresses dominant prairie grasses, opening up space for the abundant growth of weedy vegetation once the grazers move on.  As the prairie recovers, the dominant grasses reassert themselves and the vegetation becomes tall and dense enough to carry fire once more.  A landscape consisting of a heterogeneous mixture of recently burned patches and patches that haven’t burned for several years provides the full range of habitat structure – from very short to very tall – and thus supports the full range of prairie wildlife species.  Perhaps most valuable in that range of habitat structure is the post-fire/grazing recovery phase that provides simultaneously provides a wealth of stemmy vegetation cover and abundant seeds for wildlife food.

An expansive prairie landscape in the Nebraska sandhills.

So is Position A or Position  B correct?  Well, yes.  It’s like owning a sports car.  You need to keep all the sparkplugs, tires, and other parts – and keep them in good condition.  On the other hand, a sports car is no good if you can’t drive a standard transmission and/or don’t have good roads to drive on.  Aldo Leopold said, “To keep every cog and wheel is the first rule of intelligent tinkering” – but those important components include both species and the processes that maintain them.

Interestingly, the two positions seem to be strongly correlated with geography.  People who work with the fragmented tallgrass prairies in Midwestern States like Illinois, Wisconsin, and Indiana tend to fall more heavily in the first camp – emphasizing species composition.  In contrast, people who work in the large expanses of grassland in Oklahoma, Kansas, western Nebraska, and the Dakotas, tend to hold Position B – emphasizing process and structure.  In both cases, the positions are reasonable based on the local situation.  In the eastern tallgrass prairie, most of the prairie is gone, so any remaining grassland is precious and there is great concern about the loss of prairie plant and insect species.  Further west, where grasslands still dominate the landscape, there is much less concern about the loss of plant and insect species and more focus on larger wildlife like prairie chickens that require a range of habitat conditions not always found in those ranching-dominated landscapes.

As usually happens in a discussion among reasonable people, a partial consensus emerged in ours, and there was general agreement that neither Position A or B was sufficient by itself.  Proponents of species composition as the measure of prairie conservation success would surely not be fully satisfied with a flowery prairie that was missing species like prairie chickens, upland sandpipers, and bison.  They just don’t often have the opportunity to work with grasslands large enough to support all of those species.  Likewise, proponents of structure and process wouldn’t be happy with 20,000 acres of switchgrass just because it had a heterogeneous mix of fire and bison grazing and lots of prairie chickens.

The point here is not that we need to subscribe fully to either Position A or Position B, but that we can’t afford to ignore either one.  Those working in the fragmented eastern tallgrass prairie need to be sure to emphasize strategies like prairie restoration that can strategically convert crop fields back to prairie vegetation and enlarge remnant prairies to the point where they have a chance of supporting prairie chickens and upland sandpipers, if not bison.  And even at smaller scales, finding creative ways to reintroduce the combination of fire and grazing, where possible, may help provide better wildlife habitat – and might even pay dividends for plant species conservation (more discussion on this in posts to come.)

Meanwhile, ecologists with the luxury of large unplowed expanses of native grassland need not to forget the importance of restoring and/or maintaining both large-scale and small-scale plant diversity.  While adequate habitat structure for species like prairie chickens can be created in a landscape dominated by grasses and weedy forbs, pollinators and many other insects may have a much more difficult time surviving there.  In addition, whether the intervening landscape is dominated by grass or corn, small isolated populations of prairie forbs (and the insects that rely on them) aren’t likely to survive forever if they’re not able to cross pollinate or otherwise interact with each other.  Native bees that have to find consistent sources of nectar within a small radius from their nest rely on small-scale plant diversity to provide abundant blooms every day of the growing season – and pollination by those bees is critically important for the survival of many plant species.  Finally, proponents of process should recognize and appreciate the potential (but understudied) values associated with a diverse plant community – including a diverse and vigorous soil fauna, and the overall resilience offered by a mix of species that provides redundancy of ecological function.

The danger for all of us is that we tend to look at prairie conservation through a cultural lens – and we sometimes don’t see what our prairies, and our strategies, are missing.  It would be great if we could facilitate some cultural exchanges, in which we sent Texas cowboys to the Illinois black soil prairies and Wisconsin prairie restoration experts to the flint hills of Kansas.  Imagine the discussions that would ensue – not to mention the neighborhood coffee shop gossip.

Participants in the Grassland Restoration Network discussing prairie conservation at The Nature Conservancy’s Nachusa Grasslands, Illinois.

I feel fortunate to be involved in two groups that do a great job of stimulating interaction and discussion – the Grassland Restoration Network and the Patch-Burn Grazing Working Group.  The former is a loose affiliation of ecologists working to use prairie restoration as a tool for grassland conservation in fragmented landscapes.  The latter is a network of scientists, land managers, and ranchers trying to find better ways to combine fire and grazing and create heterogenous prairie landscapes.  (I’ll provide more information on both of those groups in future blog posts.)  Now if I can just figure out how to convince the two groups to hold a joint meeting…