Seeds of Promise

It’s hard to describe the varied emotions involved in cleaning and mixing big piles of prairie seed.  There is incredible optimism embedded in those tiny packages.  After all, each seed has the potential to become a plant; maybe even the first of an entire colony of plants.  On the other hand, most of them will fail to produce anything other than a little food for some animal or microbe.

Alex mixes up a big pile of seed with a grain scoop.  Amber is helping too, but hidden behind a cloud of dust.

Yesterday was seed mixing day at our Platte River Prairies.  We dumped bags and buckets of harvested seed into piles to be mixed and taken out to planting sites.  In recent years, we’ve shifted our seed harvest focus; instead of aiming for the highest possible diversity of prairie species (150-200) to convert crop fields into prairie habitat, we’re now focusing on 30-40 wildflower species that are largely missing from some of our more degraded native prairies.  Those degraded prairies had years of of chronic overgrazing and/or broadcast herbicide use before we obtained them, and haven’t really increased much in plant diversity, despite over 20 years of the best management we could give them.  By increasing the number of plant species in those prairies via overseeding, we hope to increase the quality of pollinator and wildlife habitat, as well as the overall ecological resilience of the prairie community.

We process many of our seeds by running them through a heavy steel fan blade that used to be part of a riding lawn mower.  It’s a quick and effective way of breaking seeds out of pods and off of stems.

To be clear, when I say “we”, I’m mostly talking about the Platte River Prairies staff and volunteers who are actually doing the work these days.  For many happy years harvesting seed, but that torch has now been largely passed to others.  I still harvest a modest amount of seed on my own time, mostly during evenings and weekends, for use at our family prairie, but I’m just an advisor for the bulk of the restoration work going on at the Platte River Prairies.  Regardless, it was immensely gratifying to help out yesterday.  It felt great to run those seeds through my fingers and inhale a little seed dust into my lungs (though we wear masks to minimize the dust inhalation).

Alex dumps a bag of seed onto the pile.

While I like thinking about each seed as a potential plant, I also recognize how few of them will actually make it that far.  Even in cropfield restoration work, when we’re broadcasting seeds onto bare soil with no preestablished competition from other plants, only a small percentage of seeds really end up as plants.  Some are eaten by animals before they get a chance to germinate.  Others don’t land in a place where they get the light and moisture they need.  Still others germinate, but are then outcompeted by neighboring plants, eaten by something, or don’t get rain at the right time to sustain them.

When we’re overseeding an existing prairie, the number of planted seeds that turn into plants is far lower still.  We burn ahead of time to create bare soil, and graze to reduce competition, but there are still very few spots where a seed can land and have a good chance to thrive.  That means that the vast majority of those wonderful little seeds of promise just die.  Though, as we discussed yesterday while we worked, even the ones that die are feeding something – birds, mammals, insects, fungi, etc. – so it’s not that they’re really wasted.  It’s just that we didn’t really spend all that time harvesting seeds just to feed fungi.

Instead of focusing on how many of those seeds will become fungus fodder, though, I’d prefer to think about the good that will come from those that survive.  By harvesting and broadcasting those seeds, we’re transforming prairies with very few summer wildflowers into prairies with enough floristic diversity that they will support a more robust pollinator population and provide better habitat structure to a number of wildlife species.  Even if one tenth of one percent of the seeds we plant germinate, we’ll be making a big difference.

This overseeded prairie is not yet where we’d like it to be in terms of plant diversity, but it’s far better off than before it had even the number of flowers shown here.  Hopefully, now that some of these wildflowers are established, they’ll be able to spread on their own as we provide helpful management.

Soon, we’ll be releasing those seeds into the wild to take their chances in the world.  Most of our planting these days is done by machine, which helps us cover a lot of ground quickly, with fairly even distribution of seeds.  That’s all well and good, but I sure get a lot of joy from hand-tossing seeds at our family prairie.  Not only can I aim the seeds for areas I think (though I’m totally guessing) they might survive best, I can also give them a little good luck wish as they leave my hand.  Later in the season, when I return to look for seedlings, I can congratulate both the seed and myself on our success whenever I find a new plant.  With enough of those successes, we’ll slowly rebuild the diversity and resilience that will carry these prairies well into the future.

Alex, Amber, and a big ol’ pile of potential prairie plants.

A Plot-Sized Biodiversity and Photography Project

Today, I’m beginning a new photography project aimed at exploring and celebrating the small scale diversity and complexity of prairies.   I’ve picked out a 1 x 1 meter plot in a small patch of restored prairie here in Aurora, Nebraska, and I will be photographing everything I can within that tiny area over the next year or so.  My objectives are to find and document as much beauty and diversity as I can and to show the dynamic nature of prairie life, even at a very small scale.

Lincoln Creek Prairie, with the yellow flags marking my square meter plot.

The plot sits in a narrow strip of land restored in the 1980’s by Bill Whitney and Prairie Plains Resource Institute.  I picked Lincoln Creek Prairie because it’s right across town from me, and therefore easy for me to get to frequently.  It’s also a great restored site that was planted with a diverse mixture of prairie species (over 100 species) and is well-established.  However, the prairie is small enough that it doesn’t host any grassland-nesting birds or other animal species that need relatively large and open prairie habitats, and suffers from all the other issues that come along with tiny prairies.  I anticipate that most or all of the organisms I photograph during the coming year will be plants and invertebrates, but I’m confident that I won’t find a shortage of subject matter.

A view of the 1 x 1 plot from above

I didn’t pick the small plot randomly, but I also didn’t try to find a spot with more diversity than any other nearby.  Instead, I looked for a place that would catch the light well during most of the year but was out of the way enough to not be disturbed by people hiking the nearby trail.  I freely admit that I chose the exact location of the 1 x 1 plot because it has a butterfly milkweed plant in it – it’s a nicely photogenic species.  This isn’t research, after all, and I don’t have to select my plot in a completely unbiased way!  However, I’m confident that the 1 x 1 plot I chose is representative of the rest of the prairie around it.

Switchgrass (Panicum virgatum) with a flower that never completely came out of its sheath last summer.

I began my photography journey within the plot yesterday, and took the photos you see here in this post.  I’ve already discovered one big challenge regarding my plans – it’s going to be difficult to avoid crushing or breaking the vegetation within the plot during my frequent visits.  I don’t see any way to avoid matting down the vegetation around the edge of the plot, but I’ll try not to do any more of that than necessary, and hopefully that won’t excessively impact what I see inside the plot.

The curled and dried leaf of stiff sunflower (Helianthus pauciflorus)

Right now, the plot is fairly uniformly brown, and perhaps drab looking from a distance.  However, I didn’t have much trouble finding interesting shapes and textures to photograph during the 10 minutes or so I spent there yesterday.  Even without green vegetation or crawling invertebrates, there was plenty to look at.  That bodes well for the coming year, I think!  Stay tuned…

Maximilian sunflower (Helianthus maximiliani) seed head, minus the seeds.  Birds, mammals, and/or other creatures likely picked it clean last fall.
A butterfly milkweed (Asclepias tuberosa) seed pod on a curled stem.

The Joy, Angst, Excitement and Dread of Walking Through a Young Restored Prairie

Anyone who has watched a prairie seeding go through its first several years of establishment will appreciate and identify with this post.  For those of you who haven’t, the best analogy I can come up with is that the experience is a little like watching your son or daughter go off into the world on their own.  You can spend tremendous energy planning ahead, preparing a site, and harvesting and planting seed, but at some point, you have to just stand back and let the new prairie stand or fall on its own.  Sure, you can jump in and knock back the weeds a little now and then, but eventual success or failure depends upon many factors beyond your control, and it can be hard to predict the result during the first few years.

In February and March of 2016, we planted about 60 acres of land with a seed mixture of around 140 prairie and wetland plant species.  The site had been cropland for many years, and then was converted to a mixture of native grasses and used as pasture.  Eventually, the site became heavily invaded with tall fescue, smooth brome, and Kentucky bluegrass.  A few years ago, we decided to kill off the existing vegetation and try to establish a much more diverse plant community.  Although it had been farmed, the site still had some remnant wetland swales that had been farmed through and partially filled, but still had some wetland hydrology.  Restoring this 60 acres feeds into our larger restoration objectives of enlarging and reconnecting remnant (unplowed) prairies in the area.

Volunteers hand broadcast wetland seed on frozen wetlands during February 2016.
This “drop spreader” was used to plant the majority of the site.

We used a combination of herbicide application and tillage to get rid of the grasses and prepare a seed bed.  In addition, (under the appropriate permits) we had a contractor with a big scraper come in and deepen/widen the degraded wetland swales.  Using seed we harvested from nearby prairies and wetlands, a couple different groups of volunteers hand-planted the wetland swales and low sandy ridges created by excavation spoil, and we used a broadcast seeder behind a UTV to plant the remainder of the site.  (Thank you to the U.S. Fish and Wildlife Service, Nebraska Natural Legacy Project, and Nebraska Environmental Trust for funding this project.)

During the 2016 growing season, I visited the site very rarely, and didn’t spend much time there when I did.  Early in the season, there wasn’t much germinating and growing except the kinds of “weeds” you’d see in an abandoned crop field (foxtails, pigweeds, ragweeds, annual sunflowers, etc.).  Later in the season, those weedy plants had grown so tall and thick, it was physically difficult to walk through them.

This photo shows the kind of weed cover that grew during the first growing season. Lots of tall ragweed and annual sunflowers were joined by some perennial sunflowers and other plant species we had seeded.  This is pretty typical of what we see during the first year of our restored prairies.

I walked around this site on Monday of this week and tried to capture what I saw with my camera.  As I explored, I experienced a roller coaster of emotions.  Some areas are looking way ahead of schedule, with a nice diversity of prairie and wetland plants coming in, while others don’t look like they’ve even started, or have problematic plants that we might eventually have to deal with.  On the whole, I feel good about the progress of the restoration, though we do have some trees to control, but my overall confidence comes mainly because I’ve been through this process many times.  We’ve had restored prairies look like junk for 4 or 5 years before finally kicking into gear, and others that look like a prairie after two years.  Very rarely have we seen plantings fail.  Regardless, it’s way too early to guess how this planting will turn out.

For what it’s worth, here is what I saw and thought about during my walk around this prairie at the beginning of its second field season.

The first thing I saw as I walked into the new prairie was a pretty good sized patch of 3-4 foot tall cottonwood trees (Populus deltoides).  The parent trees can be seen in the background.  We’ve been getting smarter about removing those kinds of seed  sources before starting projects, but these trees are growing along a public road and we didn’t have the authority to remove them.  We’ll have to evaluate our options for controlling the young cottonwoods in our new prairie.
A skeleton of an annual sunflower from the initial season shows how big some of those pioneering species were last year. Many of the sunflowers were over 12 feet tall.
Biennial wildflowers, like this prairie ragwort (Packera plattensis) germinated last year and are blooming this year. Hopefully, this one will start a colony that will help support spring-flying bees and other pollinators in future years.  A pair of crane flies are mating on top of this one.
I was excited to see quite a few sedges blooming in only their second year. We don’t always get quick establishment of sedges from seeds. This one (Carex craweii) was in a patch of maybe 10 plants along the edge of a wetland, and I found at least three other species growing elsewhere in the site.
To balance out the excitement of seeing lots of sedges, I also found quite a few areas where there wasn’t much yet growing from our seed. This big patch of marestail (Conyza canadensis) was representative of maybe 30% of the planting. I think this is a soil issue – in our alluvial soils, prairie plant communities can vary dramatically from place to place, based on the soil deposits beneath them. Restored prairies establish with great variation for the same reasons.
Canada milkvetch (Astragalus canadensis), hoary vervain (Verbena stricta), goldenrod (Solidago gigantea), and Canada wild rye (Elymus canadensis) make up a very nice patch of new prairie plants.
The wetland swales are filling in quickly with wetland plants, including lots of spikerushes, grasses, rushes, and a few forbs and sedges. Much of that vegetation came from our seed, but I think some also came from the seedbank.
We purposefully designed the wetlands to vary in their depth to groundwater so that we’d have some areas of standing water most of the time, but also many other areas that go dry each summer.
Some of the wetland pools had tadpoles in them, likely from the Woodhouse’s toads that have already colonized the area. I also saw leopard frogs hopping around.  In addition, numerous snails, and aquatic insects were moving around in the water, and dragonflies and damselflies were buzzing around above it.
This section of wetland had standing water a few weeks ago, but has now gone dry, leaving great habitat for shorebirds (but also for young cottonwoods).  The vegetation along the margin of this wetland is mostly native colonizing plant species such as fleabane (Erigeron annuus), yarrow (Achillea millefolium), and Canada wildrye.
Sweetclover (Melilotus sp) is abundant across much of the new site. Experience shows that sweet clover (though I don’t like it) doesn’t seem to actually affect plant diversity much in our restored prairies, so we’ll just let it go until the site is established well enough to support fire and cattle grazing. At that point, the cattle will keep the sweet clover suppressed because it’s one of their favorite plants to eat.
In addition to areas of strong native plant growth and others dominated still by non-native or “weedy” plants, there were also areas where bare ground was still plentiful. Again, alluvial soils make all of this really interesting because the soils vary greatly from place to place and strongly regulate plant growth.
Last year’s seed pods of Illinois bundleflower (Desmanthus illinoensis) show that this native perennial legume established and bloomed in its first year at the site.
Duck and raccoon tracks joined the tracks of many shorebirds along the edges of the restored wetlands. It’s really encouraging to see how quickly wildlife and insect species colonize these sites, even while the plant community is still young.

I’ll probably return to walk through this site numerous times this season because I can’t help myself.  Apart from working on cottonwood trees and a few musk thistles, however, it’s unlikely that we’ll actually do anything else here, so my visits will be mostly out of curiosity rather than to stimulate management.  As with this trip, I’ll see things on future walks that will encourage me and others that will make me wonder if the planting will end up as a disaster, even though I know it’s too soon to know anything.

Within the next few years, we’ll try to burn the new prairie whenever we can, and when the major grasses start to assert their dominance, we’ll begin grazing the site in ways that support a diversity of plants and animals.  Typically, that grazing begins when the site is between 5 and 8 years old.  In the meantime, there’s really nothing to do but wait.  (But I’ll still peek in now and then anyway.)

I was really glad to see coyote tracks along the edge of the site. The presence of these (relatively) large predators will be key to the long-term success of the ecological community in this restored prairie.

For those of you with technical questions about our restoration methods, we didn’t test our seed for viability, but based on previous experience, our seeding rate for this planting was probably about 2-4 lbs PLS/acre, about 2/3 of which was grasses and 1/3 was forbs, sedges, etc.  We typically broadcast our seed into recently harvested soybean fields, so this planting was a little different, but not that different.  We don’t mow weeds during the first season based on trials that have shown no difference in long-term establishment (sandy soils help keep weed densities low enough to still allow sufficient light to hit the ground, despite what it looks like in the 2016 photo in this post).  We don’t cultipack or harrow seeds in either.  We’re fortunate not to have much trouble with aggressive perennial invasive plants in our early plantings, which makes our weed control pretty easy.  Deciduous trees are the main exception to that, especially cottonwoods (as shown above) and Siberian elms (not too bad at this site).  Later, we see invasion by perennial cool-season invasive grasses, but we suppress those with fire and grazing.

How Small Is Too Small?

What’s the minimum effective size of a prairie?

For example, can a prairie be the size of a kitchen table?  Let’s say someone converted a landscape full of prairie to an immense gravel parking lot, leaving only a round kitchen table-sized parcel of vegetation in the middle.  Is that tiny isolated parcel a prairie?

The question might seem silly, but the question became a useful little thought experiment for me.

That little parcel certainly wouldn’t be big enough to meet the needs of most prairie animals.  Birds, small mammals, snakes, and even smaller creatures like grasshoppers and bees would be unable to find enough food to survive within that small area.  The loss of those animals would affect many of the ecological services and functions that make prairies work.  Those services include pollination, nutrient cycling, herbivory and more.

Even small creatures like grasshoppers would have a hard time surviving in a patch of plants the size of a kitchen table.

Some tiny herbivorous invertebrates might be able to survive in that little parcel of vegetation, but probably not enough of them to support most predators that feed on them.  The lack of predation would allow those invertebrate populations to grow much larger than they otherwise would, leading to significant damage, or even mortality, to the plants they feed on.  Once their food is gone, the invertebrates would starve and die as well.

Plants that manage to survive invertebrate attacks and an absence of pollinators in our little parcel would still face major challenges.  In the long-term, they would probably suffer from a huge genetic bottleneck because they don’t have other individuals of their species to cross breed with.  In the meantime, it would take a lot of intensive and thoughtful management to keep them alive.

Smooth brome and other invaders can quickly dominate small prairie patches without constant vigilance and suppression.

Invasive species management would be a huge problem because it wouldn’t take long for an aggressive invader to quickly dominate that small area.  Quick action would be needed to remove invasive plants as they arrive.  Fire or mowing would also be needed to prevent a smothering thatch from accumulating as plants grow and die back each year.  Unfortunately, every fire would kill most invertebrates aboveground at the time and destroy their food sources.  We could try to burn only a portion of the parcel and save some of the insects, but with such small populations, we’d still probably lose most species eventually.  Mowing and raking might be an alternative, but we’d still end up removing either the invertebrates or their food sources.

Ok, so we’d just have to live without most prairie animals, but we’d still have plants.  Or at least a few of them.  Some of those plants would be more competitive than others, especially in an animal-less environment, so it would take a lot of effort to keep them from pushing the less competitive plants out.  And, of course, we’re assuming the mysterious belowground processes that allow plants to survive would still function in our tiny parcel – microbial relationships that allow plants to access and process water and nutrients, for example.  If those are sufficiently intact, we’d have some plants.

Would that be a prairie?

I’m pretty sure no one would argue that a kitchen table-sized area containing few plants is a prairie.  Even in the first moments after the parking lot was created, I would argue the remaining patch of vegetation had ceased to be a prairie, even though it still contained a reasonable diversity of plants and animals. It wasn’t really a prairie anymore, just a doomed fragment of its former self.

If we can agree that a kitchen tabled-size patch of land is too small, how big would we have to make that patch before we’d be willing to call it a prairie?  What species and/or ecological processes should we use as criteria?

Can we agree a prairie needs to be big enough to support a healthy pollinator community?  Does it need to be able to sustain viable populations of small mammals, snakes, leafhoppers, spiders, and other little creatures?  Is it a prairie if it doesn’t have a full complement of grassland bird species?  Does that requisite bird community include larger birds such prairie chickens or other grouse species?  What about at least moderately-sized predators such as badgers and coyotes (or even bigger ones) or large ruminants like bison or elk?  Which of those components are we willing to live without, and more importantly, which can a prairie live without and still sustain itself as an ecological system?  A prairie without badgers, coyotes or bison is functionally different than one with those animals, but is it a non-prairie or just a different kind of prairie?

Bison herds need very large prairies, but we don’t know as much about the amount of land needed to sustain populations of bees, leafhoppers, jumping mice, or even genetically viable plant populations.

Even if we reach consensus on the key components of a prairie, we’re still hamstrung by our lack of information about how big a prairie needs to be to support each of them.  We have decent data on the prairie size requirements for many grassland bird species, but beyond birds, we’re mostly just guessing.  If we want the full complement of species, including bison and other large ruminants, we’re going to need thousands of acres, but how many thousands?

More importantly, what does this mean for the many remaining patches of prairie vegetation too small to support whatever we decide are the key components of a prairie?  It certainly doesn’t make them worthless, but it might be important to make sure we’re viewing them realistically.  What are the likely ramifications of the missing components?  The absence of prairie chickens or upland sandpipers might be disappointing, but might not have the ripple effect that the absence of pollinators or coyotes might have.  Can we identify and compensate for the absence of key prairie components by managing differently or more intensively?  If not, how do we adjust our vision of the future for that prairie parcel, and how does that adjusted vision affect how much management effort we invest?  (You can read more about the challenges of managing small prairies here.)

For many of today’s small prairie patches, the only chance of preserving their species and ecological functions is to make those small patches larger and/or more connected to others.  Restoring adjacent land back to high-diversity prairie vegetation allows formerly landlocked populations to expand and interact with others, and creates enough habitat for larger animals to survive.  Identifying potential restoration opportunities might be the highest priority conservation strategy for those of us working with small prairies.

Reasonable plant diversity and the presence of larval host plants like this prairie violet have so far allowed our family prairie to support a population of regal fritillary butterflies, but the small size and isolated nature of our prairie means if the butterflies have a bad year, they could easily disappear and never return.

Our family prairie is a little over 100 acres in size, is managed with large ruminants (cattle), and has regal fritillary butterflies, coyotes, badgers, upland sandpipers, and even an occasional prairie chicken.  However, I’m certainly not comfortable that our 100 acre island within a sea of cropland will to sustain a prairie ecosystem indefinitely.  This thought experiment has forced me to think more seriously about prospects for increasing the size of our prairie and building connectivity to other grasslands.  I hope it’s useful to others as well.

Photo of the Week – March 24, 2017

Below are two photos of a creek and associated wetlands taken by a timelapse camera.  The first photo was taken in early June, 2015 and the second photo was taken about a month later.  Looking just at those two photos, you’d think nothing much was happening.

Derr Wetland in early June 2015.
Derr Wetland in early July 2015.

However, now look at the next photo, which was taken in mid-June.  After some rains in early June, the stream swelled and filled much of its floodplain, and that high water lasted a couple weeks before it came back down again.  The photos show how dynamic a stream and its floodplain can (and should) be.

Mid-June 2015.

The area in these photos is a restoration site that was formerly a sand pit lake left behind after gravel mining.  A stream flowed into the narrow lake on one end and out the other, and the lake was surrounded by spoil piles and trees.  After restoration, the site now has a couple stream channels, some adjacent wetlands, and provides wide and open habitat for a diverse number of aquatic and terrestrial animals.  In addition to providing great wildlife habitat and a diverse plant community, though, the restored site also improves the floodplain functionality of this stream.

Flooding is a natural and important process, and floodplains play an essential role in that process.  After big rain events, streams quickly gain water that has to go somewhere.  Ideally, that water spreads out into a floodplain where it slows down and sits until it either drains into the soil or gradually is allowed to proceed downstream.  When we restrict or block access of streams to their floodplains, floodwater is forced downstream in a torrent and sometimes breaks out from its restraints, causing unexpected and often catastrophic damage to property.

The 10 second timelapse video below shows (on a small scale) the kind of gentle rise and fall of water levels a functioning floodplain can facilitate.  The images in the video were taken between June 3 and July 1, 2015.  The water level came up fairly quickly between June 4 and 5, remained high for a couple weeks, and then dropped slowly back to where it had started.  Just like it was supposed to.

(If the above video doesn’t work, try clicking on the title of this blog post to open it in a web browser and then try again.  If that doesn’t work, try just following this link.)

Should We Manage for Rare Species or Species Diversity?

Land managers constantly make difficult decisions without really knowing the long-term consequences of their choices.

Balancing the sometimes conflicting needs of rare plants like Canada milkvetch (Astragalus canadensis), pollinators, and many other components of prairie communities can be a major challenge. 

For those of you who aren’t ecologists, here are some important vocabulary terms you’ll need to know for this post. 

 1. Conservative species – plants or animals primarily restricted to “intact” or “high-quality” natural areas, as opposed to species that commonly occur in degraded habitats.

2. Species richness – the number of species found in a certain area. High species richness means there are lots of different kinds of plants and/or animals present

3. Species diversity – a kind of modified species richness that also takes into account the evenness, or relative abundance, of each species. When one site has a few dominant species and lots of uncommon ones, it is less diverse than another site with the same total number of species but with more evenly distributed numbers of individuals.


Imagine this situation:  You’re put in charge of managing a tallgrass prairie with thriving populations of several rare plant species.  The prairie is located in a highly fragmented landscape dominated by rowcrop agriculture.  The prairie has been managed with frequent spring burning for many years, and the populations of those rare plants has been pretty stable for at least the last couple of decades.  As you take over, the previous manager tells you she’d recently been considering management changes that might increase overall plant and animal diversity but would likely reduce the population sizes of some rare plant species.  You have to decide whether to stick with the existing management regime or try something different.  What would you do?

Culver’s root (Veronicastrum virginicum) is a conservative plant species found in a small subset of today’s tallgrass prairies.

It would be perfectly rational and defensible to stick with the strategy that has sustained healthy populations of rare plants for a long time.  Because those plants aren’t found at many other sites, prioritizing them in this prairie makes good sense.  However, before you lock in that choice, let’s consider some other information.

First, there is often an assumption that an abundance of rare plants is an indication that the rest of the prairie community is also intact and healthy. While that assumption seems logical, it’s not always the case.  A good example of this comes from an Illinois study by Ron Panzer and Mark Schwartz.  Their research in the Chicago region showed that neither the number of conservative plant species or rare plant species predicted the number of conservative or rare insect species at a site.  Instead, Panzer and Schwartz concluded that overall plant species richness was more important for insect conservation.

Plant diversity also helps support healthy populations of pollinators and herbivores (invertebrate and vertebrate) by ensuring a consistent supply of food throughout the year.  A wide variety of plant species allows pollinators and herbivores to find high quality food at all times, even though each plant provides those resources at different times of the season.  For this and other reasons, increasing plant species richness can increase both the abundance and diversity of animals, especially invertebrates.  In addition, managing for a variety of vegetation structure types (including a wide range of both plant stature and density) can also help support more animal diversity, including birds, mammals, reptiles, and insects.

Grazing can decrease the size of rare plant populations, especially in comparison to sites under repetitive haying or burning management. However, carefully planned grazing can also increase plant diversity and provide more varied habitat structure for wildlife and invertebrates.

Every species of plant and animal plays a certain role within the prairie community.  High species richness provides redundancy of function and helps ensure that if one species disappears or can’t fill its role, others can cover for it.  That contributes to ecological resilience – the ability of an ecological community to respond to stress without losing its integrity.  Ecological resilience may be the most important attribute for any natural system, especially in the face of rapid climate change, continuing loss and degradation of habitat, encroaching invasive species and other threats.

Aside from the benefits of managing for species richness, a strict management focus on the needs of a few species can put others at risk.  The use of prescribed fire, for example, provides a competitive edge to some plant species, but has negative impacts on other plants, as well as on some animals.  There have been vigorous arguments between advocates for frequent burning and people concerned about rare butterflies and other insects, as well as reptiles and other animals that can be extremely vulnerable to prairie fires.  Repeated intensive grazing by cattle or bison is another management strategy that favors some plant and animal species, but can negatively impact many others, especially without adequate rest periods between grazing bouts. Management that consistently provides favorable conditions for a few species at the expense of others may eventually eliminate some species from a prairie altogether, or at least reduce their ability to effectively contribute to ecosystem functioning.  If those losses lead to decreased ecological resilience, the resulting impacts may end up negatively affecting the same species a site manager is trying to promote.

Regal fritillary butterflies are very sensitive to fire, and can be eliminated from isolated prairies if the entire site is burned at an inopportune time. However, populations can also thrive in large prairies managed with a combination of fire and grazing, as long as sufficient unburned areas are available, and many of their favorite nectar plants (like this Verbena stricta) are common, or even weedy.

So, what’s the right path?  Should we prioritize management for rare or conservative species, assuming that other species don’t need as much help?  Or should we focus on species diversity and ecological resilience because we need the strongest possible natural communities in today’s challenging environment?  How should scale (size of prairie) influence decisions?

There are plenty of potential benefits and risks associated with each path, and I’m not here to tell anyone which they should choose.  In most cases, my own tendency is to focus on diversity and resilience, but I completely understand why managers would go the other way, and I think every situation needs to be evaluated independently.  For example, if a species is teetering on the brink of extinction and we need to keep it alive while we create more habitat elsewhere, I’m perfectly fine with prioritizing management to favor that species.

In other cases, I worry that we’re too sometimes unwilling to manage prairies in ways that promote changes in plant composition.  Years of repetitive management (especially frequent haying or burning) create conditions under which plant communities seem very stable.  However, that stability may be a response to consistent management rather than an intrinsic quality.  Allowing plant populations, even of rare species, to fluctuate in size, or even persist at a lower abundance than we’re used to is not the same as driving those species to extinction.  If rare species survive in smaller populations but the surrounding community is more resilient, that may be a win.  Having said that, reducing the size of rare species’ populations can make them more vulnerable to local extinction, and I don’t take that kind of risk lightly.  These are challenging issues.

This bottle gentian plant (Gentiana andrewsii) is an extremely conservative plant, and was growing in a hayed meadow in the Nebraska Sandhills where management conditions are very stable from year to year.

The hard truth is that we don’t yet understand enough about ecological systems to make these kinds of decisions confidently.  I understand the impulse to manage conservatively, sticking with what seems to have been working for a long time – especially in small and isolated prairies.  At the same time, I also think we need to build as much diversity and resilience in our prairies as we can – focusing on both plants and animals – especially in landscapes where we don’t have many left.  I’m glad managers are experimenting lots of different strategies, but we should all take responsibility for collecting data that help us evaluate our management, and keep open minds as we share what we learn with each other.  None of this is easy, but it is certainly important.

A Milestone for Prairie Restoration

Because conservation work can sometimes seem like blowing into the wind, it’s important to pause periodically to celebrate progress.  For example, I am really excited about what has been accomplished in the field of prairie restoration.  We’ve known for a while that we can convert cropland to prairie vegetation with a high diversity of plant species (150 or more species per planting), and that we can do that on a scale of thousands of acres.  The Nature Conservancy has large projects in states like Indiana, Illinois, and Minnesota where restored prairie landscapes now range from about 5,000 to 20,000 acres in size.  The U.S. Forest Service is transforming an old U.S. Army Arsenal into 20,000 acres of prairie in Illinois.  Prairie Plains Resource Institute, the organization that pioneered restoration techniques in Nebraska, is planting up to 1000 acres a year now and has established well over 10,000 acres total across the state.

Our staff celebrates a successful year of seed harvest back in 2015.
Our staff celebrates a successful year of seed harvest back in 2015.

Here in our Platte River Prairies, we’ve restored more than 1,500 acres of cropland to prairie.  That’s not insignificant, but more importantly, we’ve been testing the idea that those restored prairies can help defragment the ecological landscape around them.  Habitat fragmentation is one of the largest threats to today’s prairies because it shrinks and isolates populations of species, making them vulnerable to becoming locally extinct without the chance of recolonization from nearby sites.  The real promise of prairie restoration is that it can enlarge and reconnect scattered remnants of native prairie, providing populations of animals and plants a much better opportunity to survive and thrive.  It’s not feasible or desirable to convert the majority of cropland in the central North America back to prairie, but there are particular sites where strategic restoration work could make a huge difference in the potential survival of prairie species and ecological services.

In order for prairie restoration to help defragment landscapes, restored prairies have to provide suitable habitat for the species living in small isolated prairies.  Many bees and other insects specialize on certain plant species, for example, and other animals rely upon an abundance of prey, a diversity of seeds, or other particular food or habitat conditions.  Satisfying the individual needs of all those prairie animals is a critical measure of success if prairie restoration is going to successfully stitch isolated prairies back together.

Over the last several years, we’ve been collecting data to see whether the species of bees, small mammals, grasshoppers, and ants in our unplowed prairie remnants have moved into adjacent restored habitat.  The results have been very positive.  While not every species of animal living in our remnant prairies has been found in nearby restored habitat, we’ve found the vast majority of those we’ve looked for.  We suspect that most of the remaining species are also present but that our limited sampling effort just hasn’t yet picked them up.  We’ll keep trying.

Dillon Blankenship, a Hubbard Fellow, compared grasshopper, katydid, and tree cricket communities on three pairs of remnant/restored prairies back in 2014. Almost all species were present in both restored and remnant habitats. In the three species that weren't, only one or a very few individuals were found, so it's likely just a sample size issue.
Dillon Blankenship, a Hubbard Fellow, sampled grasshopper, katydid, and tree cricket communities on three pairs of remnant/restored prairies back in 2014. Almost all species were present in both restored and remnant habitats. In the three species that weren’t, only one or a very few individuals were found, so it’s likely just a sample size issue.
Data from James Trager and Kristine Nemec has helped us compare ant species composition in restored versus restored prairies along the Platte River. So far, we've documented 30 species and only one has been found exclusively in remnant prairie (and, again, it's likely to be a sample size issue).
Data from James Trager and Kristine Nemec has helped us compare ant species composition in restored versus restored prairies along the Platte River. So far, we’ve documented 30 species and only one has been found exclusively in remnant prairie (and, again, it’s likely to be a sample size issue).
Master Naturalist Mike Schrad and Hubbard Fellow Jasmine Cutter have both helped us compare small mammal populations between restored and remnant prairies. This table shows some of Jasmine's data from one site. In general, we're finding that the same species are in both restored and remnant prairies, but the relative abundance of those species is often different - with some apparently favoring remnant habitat and others favoring restored areas.
Master Naturalist Mike Schrad and Hubbard Fellow Jasmine Cutter have both helped us compare small mammal populations between restored and remnant prairies. This table is from Jasmine’s data from one site, showing the number of trapsites in which each mammal species was caught back in 2014. In general, we’re finding that the same species are in both restored and remnant prairies, but the relative abundance of those species is often different – with some apparently favoring remnant habitat and others favoring restored areas.  We’re now looking at how our management affects presence and abundance of each species through time.
We've had several research projects look at native bees in our prairies. Mike Arduser, Anne Stine (Hubbard Fellow), Bethany Teeter, and Shelly Wiggam Rickets have all helped us compare restored and remnant prairies. So far, we've found over 72 species and the vast majority have been in both remnant and restored prairie.
We’ve had several research projects look at native bees in our prairies. Mike Arduser, Anne Stine (Hubbard Fellow), Bethany Teeters, and Shelly Wiggam Rickets have all helped us compare restored and remnant prairies. So far, we’ve found over 72 species and the vast majority have been in both remnant and restored prairie.
I've collected more than 15 years of data showing that plant diversity and the frequency of occurrence of prairie plant species has remained stable through time. These four graphs show four species in one restored prairie where we're comparing fire/grazing management to fire only management.
I’ve collected more than 15 years of data showing that plant diversity and the frequency of occurrence of prairie plant species has remained stable through time. These four graphs show four species in one restored prairie where we’re comparing fire/grazing management to fire only management.  The long-term persistence of prairie plants and diverse plant communities is critically important for plant communities, but also for the success of efforts to defragment habitat for animals.

These results mean that where prairie landscapes have been largely converted to row crops, we don’t have to just watch while insect or small mammal populations careen toward local extinction in tiny isolated prairies.  We’ve shown that we can make those prairies larger and more connected, and that animal populations can grow and use new restored habitat and diverse plant communities.  We’ve also shown that restored prairies can sustain their biological diversity for decades, even through periods of intensive grazing and drought.  While there are still plenty of questions and potential improvements we can make, we’re now at the point where society needs to decide whether and where to do this kind of restoration.

I don’t know about you, but I think that’s pretty exciting!

Nebraska and other states in central North America have large swaths of productive and important cropland.  As I said earlier, I’m not advocating that we convert most of that back to prairie.  However, there are specific sites where row crop agriculture is marginally productive/profitable and the long-term interests of both society and local landowners might be best served by putting land back into diverse and productive grassland.  Agricultural policies and subsidy programs will obviously play a huge role in this kind of strategic large-scale restoration, and getting the policies in place to facilitate this kind of common sense restoration will be plenty difficult.  That’s nothing new, however.  What’s new is our confidence that if we can implement targeted restoration work, it can make a real difference to prairie conservation.

Restoring the viability of prairies in fragmented landscapes is critically important to prairie conservation success.  The challenges of conserving species in small isolated prairies are immense, and many of those prairies will continue to see declines in biological diversity and ecological function over time unless we can make them bigger and more connected with other prairies.  Helping to document our ability to do that – at least for many prairie species – has been one of the most satisfying things I’ve done during my career.

 

Important footnote:  Restored prairies are not the same as remnant unplowed prairies.  Soil organic matter levels, for example, can take many decades to recover from tillage, and relationships between plant and microbial communities may take just as long to become reestablished.  Our success in prairie restoration should definitely not be used as justification for plowing up remnant prairie!  However, it’s equally true that prairie restoration efforts aren’t failures just because they can’t create an exact replica of prairie as it existed before it was converted to farmland.  If defragmenting prairie landscapes is the primary goal of restoration, we just need to create restored prairies that complement – not copy – remnant prairies. 

 

Hubbard Fellowship Post – Community-Based Stewardship and Long-Term Management

This post is by Eric Chien, one of our 2016-17 Hubbard Fellows.  Eric hails from Minnesota, with an undergraduate education from Bowdoin College in Maine.  He has a strong background in prairie management, and hopefully a bright future in that field as well. 

The most compelling experience of the North American Prairie Conference was on a sweltering Tuesday afternoon on a winding path through the Nature Conservancy’s Nachusa Grasslands. While I was beaded with sweat from just walking in the Eastern Tallgrass humidity, I saw three people, laden down with seed bags, hand harvesting seed and ripping problem plants from the ground. Jeff Walk, Illinois TNC Science Director and our guide for the walk assured us that these volunteers were not planted. Furthermore, he noted that this was a fairly regular sight at Nachusa.

Three people. Tuesday morning. Maybe I come from a different community context, but for me, seeing three, independently working, non-professional, unpaid, human beings engaged in land management is akin to seeing a prairie chicken drum on a buffalo’s back under a wildfire sunset. Okay, maybe not quite that, but my point is that intensive, regular community engagement and participation in land management is a rare phenomenon. It was a sight that made me wonder how we plan to achieve our restoration goals for individual sites beyond the immediate future. My predecessor, Evan Barrientos, had begun the work of pulling on this loose thread, and I encourage you to read his post on volunteer stewardship if you have not, but I think it begs further unpacking.

These volunteers helped plant prairies and wetlands on our Platte River Prairies.  It can be more difficult to recruit long-term volunteers to help manage restored (and other) sites.
These volunteers helped plant prairies and wetlands on our Platte River Prairies. It can be more difficult to recruit long-term volunteers to help manage restored (and other) sites.

It is a great feeling to stand in a big tract of prairie knowing that it was once cropland. It is a crushing feeling to stand in a big tract of prairie overrun and choked by invasive plants. And it is unfortunately not an uncommon feeling to have both experiences on the same prairie, just a couple years apart. Many prairie restoration sites have found out what happens when management capacity does not match the scope of their restorations: a seemingly endless game of catch-up with invasive plants ever threatening to swallow a new prairie. Addressing the pitfalls of that disjunct approach was one of the Grassland Restoration Network’s primary prescriptions for restoration success (here is the link to that report). However, I want to think beyond even the 5-15 year timeline to the idea of management in perpetuity. In the reality of a fragmented landscape, it appears likely that even the best restorations (well planned and executed) will require regular management for those lands to continue to achieve our respective management goals for them.

It leads us to important questions: As the acreage of restored prairie grows, have we invested in the organizational groundwork to ensure the continuity of our achievements? Is there a need for innovation in stewardship structures as we seek to move to an increased scale of work? Or should we aim to increase funding for professional management staff augmented with whatever traditional volunteer programs that we have?

Invasive species control is a critically important part of land management, both on restored and remnant sites.
Invasive species control is a critically important part of land management, both on restored and remnant sites.

As someone who is seeking a professional stewardship career, more money aimed at increasing the capacity of professional resource management sounds awesome. As someone who has seen the scope of need for stewardship, I have a hard time envisioning that approach rising to the challenge on its own. So then the big question- what does effective community-based stewardship look like?

I think it sort of looks like Nachusa Grasslands. In a talk at the conference, Bill Kleiman, the Nachusa Grasslands land manager, said, “we don’t just produce grasses, flowers, and wildlife, we also produce people.” I don’t know if steward production is part of their long-term management plan, but they seem to approach it with an intentionality that suggests it is. From the little glimpse I saw of it, Nachusa Grasslands has produced a stewardship structure that draws heavily on a capacity that is less tied to The Nature Conservancy, and more attached to the place. The stewards there love the land they work on. That trait gives it a unique resiliency. Organizations come and go over the short and long-term. If we want the successes we have in places to be maintained then we need to make sure we are building stewardship structures that have some independence from the organizations that own the land on which they work. Private lands conservation has focused on empowering non-professionals by necessity. Yet, I think if we take stock of our public and NGO-owned stewardship needs, there is a similar necessity for involving community stewards in a significant way looming on the horizon. I think for many of us it is already here.

 

 

 

Plant a Prairie February 13!

This post was written by Evan Barrientos, one of our Hubbard Fellows.

Have you ever explored a restored prairie and stopped to marvel at how the site was once a cropfield? Do you ever wonder how that transformation happens? Would you like to do it yourself? If so, then do I have an opportunity for you. On Saturday, February 13, 9:00am  you are invited to help seed our newest prairie and wetland restoration at the Platte River Prairies! A potluck celebration will be held afterwards!

It amazes me that prairies like this were cropfields just two decades ago.
It amazes me that prairies like this were crop fields just two decades ago. On Feb 13 you can help plant another.

Last summer, TNC staff and volunteers collected seed from 141 species of prairie and wetland plants, mostly by hand. In August we even hired a contractor to excavate the historic sloughs found on our restoration site. Doing so will greatly add to the site’s biodiversity by creating wetland habitat. Creating diverse habitat is a key part of our restoration strategy, which is why this restoration has sandy ridges, wet sloughs, and mesic ground in between. On February 13 we will start seeding the ridges!

Dirt now, prairie and wetland later. This re-excavated slough and former weed field is ready to be seeded!
Dirt now, prairie and wetland later. This re-excavated slough and former weed field is ready for seed!

Although all steps of our restoration work are equally important, I’m especially excited about seeding this prairie. How often do you get to create habitat? Imagine bringing a grandchild to the restoration 20 years from now, bursting with flowers, birds, and insects, and telling her that you helped plant it. Maybe those prairie clovers over there even sprouted from seeds that you picked with your own hands.

If this sounds like a good use of a Saturday morning to you, please RSVP to evan.barrientos@tnc.org! Volunteers should be prepared to walk over muddy and uneven terrain for up to 2.5 hours in cold weather. Please bring water, clothes and footwear suitable for mud and cold, and a potluck dish or drink if you would like to. We will meet at TNC’s Derr House (13650 S. Platte River Dr., Wood River, NE 68883. On I-80 take exit 300; go south approx. 2 miles; turn right onto South Platte River Dr.; big red brick house on top of the hill.) We usually have volunteers come from Lincoln and Omaha; if you’d like to arrange a carpool you can do so here.

Hubbard Fellowship Post – Ruminations While Disking

This post is written by Kim Tri, one of our two Hubbard Fellows for this year.  Kim is an excellent artist, as well as an ecologist, writer, and land steward.  As you can see, her drawings of animals are exceptional.

A Swainson’s hawk takes wing not 30 feet from me, and I feel vindicated.  It rises from a patch of ground which I’ve just disked, and answers the idle question I had when I began disking that day.  I wondered whether the turning under of vegetation and hence the cover of the little critters living there would attract hawks in search of an easy-to-spot snack.  I’d seen it happen on a prescribed burn which I’d sat in on last year, in the property just across the creek.  Once the flames and smoke died down, we counted at least 20 hawks—most of them Swainson’s—soaring overhead.  They were attracted by the aftermath, the ground cleared of protected cover for the disoriented prey.  The black earth left in the wake of the disk plow reminded me of the fire, and got me wondering.

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For those of you not familiar with the practice of disking, it involves plowing using a disk plot (pictured above) pulled behind a tractor.  Picture by Kim Tri

I should have kept a tally of how many voles, mice, rabbits, and lizards I saw clearly fleeing across the worked ground as I plowed.  Creatures visible to my weak human eyes would be easy pickings for a (much) sharper-eyed hawk.

Sure enough, a hawk showed up after an hour or so and answered my question.  The neighbor was haying in his field just across the fence, which I’m sure was turning up quite a bounty of prey as well.  I don’t have enough agricultural experience to know whether the hawks usually show up around haying time, but the intent circling of the hawks above the neighbor’s tractor made me think that they’ve cottoned on to it as well as they have to burning.

While disking later that week, also I kept (slowly) chasing groups of killdeer.  A contractor had come in with an excavator only a few weeks before to reconstruct wetlands on the property.  The killdeer scuttled around the newly excavated wetlands, where before they had not seemed to give this property much of their time.  They, too, appeared attracted to the open ground where they might find prey.  After all, the wetland excavation as well as the disk plowing had suddenly provided them with some quite preferable habitat.

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A group of startled killdeer flee alongside the track left by an excavator.  Graphite drawing by Kim Tri

It got me thinking about the consequences of our actions as land stewards – the whole ecology of it all.  So often, during a day’s field work, we focus on the plant community.  This makes sense, since it’s really the only thing about our prairies that we can directly manage, and where the effects of our work are most easily observable.  The larger aim, though, is to create a diverse ecosystem with quality habitat for as many faunal species as possible.  We do this intentionally through a variety of practices, such as seeding, prescribed burning, invasive species control, and grazing.

There are plenty of unintended beneficiaries to these.  I did not set out that day with the disk plow to provide a meal to the local Swainson’s hawks.  The objective was actually to clear the remaining vegetation of a low-quality “failed” restoration in order to create a blank canvas for seeding it into a high-quality prairie.  It had been recently sprayed completely to clear out the brome invasion that was its major fault, and since then I’d come to view the area as kind of a dead space.  While looking ahead to what the tract could be, I’d forgotten about all of the things that it still was.  It was still habitat for a wide variety of animal life, judging by the creatures I was seeing.  The cleared ground of the excavated wetlands showed trails of deer and coyote tracks, and even now, after the ground has been completely cleared, the deer and coyotes still keep leaving tracks.

I’ve noticed, too, while mowing fire breaks around our burn units, that there are creatures benefitting.  While making a third pass around with the tractor to widen the line, driving alongside the line I’d already mowed, I noticed many voles and mice scampering out of the clippings left behind.  They seemed drawn to the mowed line, and I felt that I’d just created dream foraging habitat for them.  As well as laying down a dense layer of cover to protect them, I’d just brought down to ground level a cornucopia of seedheads that had previously been out of reach for the little critters.

I acknowledge that there are also species negatively impacted by some of the things we do, but that is a thought for another time.  The mice were definitely not happy about the disking or the hawks, but I hope that we balance this out by working to improve their habitat.

We’ll reseed the disked tract with the seed we’ve collected this year, and in the spring a new prairie will grow, bringing with it an influx of creatures back to the property.  In another few years, it will be burned, and then likely the Swainson’s hawks will come again, drawn by the promise of bounty on the black earth.

A Swainson’s hawk takes flight from a disked field. (Yes, the ground does look that messy) Graphite drawing by Kim Tri
A Swainson’s hawk takes flight from a disked field. (Yes, the ground does look that messy) Graphite drawing by Kim Tri