Photo of the Week – April 20, 2017

I’ve been enjoying the early flush of wildflowers this spring, and have been trying to photograph them when I get time.  Because I already have quite a few close-up portraits of most of these species already, I’ve been trying to use a wide-angle lens to show the flowers in a broader context.  It means lying prone on the ground with the camera resting either on the ground or on my hand to get both the flowers and the landscape/sky behind them into the same frame.

Pussytoes (Antennaria neglecta) at our family prairie near Stockham, Nebraska.

Pussytoes are an easy one to photograph because they are allelopathic and hinder the growth of neighboring plants.  That short vegetation helps pussytoes plants compete with others, but also makes it easier me to photograph them without stray leaves and other plant parts getting in the way.  For other species, I’ve been spending most of my time photographing the flowers growing in sites that were grazed hard last year.  The grazing makes photography easier, but the access to light and weakened grass competition also stimulates more of the plants to flower than in ungrazed sites.  I’ve been collecting data on flowering plant numbers over the last several days, and the data confirm my casual observations.  There are many more flowers in prairie patches recovering from grazing than in patches that haven’t been grazed much in the last year or two.

Prairie violets (Viola pedatifida) in the area of our family prairie we grazed most intensively last year.

Carolina anemone (Anemone caroliniana) at Gjerloff Prairie, owned by Prairie Plains Resource Institute.  They are having a great year in the part of the prairie that was burned and grazed in 2016.

Ground plum (Astragalus crassicarpus) at the Helzer prairie.

More pussytoes at the Helzer prairie, with a little bit of dried manure for flavor.

For pollinator insects, this early spring period can be very challenging because flowering plants are in pretty short supply.  There aren’t many species blooming, and those that are tend to be spread sparsely across large areas.  At least in the prairies around here, last year’s grazing is increasing numbers of available resources for pollinators, including both short-lived and long-lived plant species.  That appears to be particularly valuable this year, given the number of butterfly and moth species taking advantage of strong south winds to make an early migration to Nebraska.  I can’t remember a year when we’ve seen so many of those insects in April, including monarchs (which we’re now seeing frequently), sulphurs, red admirals and many little moths.

Now, here’s a question I hope someone out there can help answer:  Pussytoes flowers are dioecius, meaning that some plants have male flowers and others have female flowers.  My understanding is that pussytoes is pollinated both by wind and by insects.  If the male flowers produce pollen but the females don’t, what attracts insects to move from male flowers to females and complete the pollination cycle?  Do the female flowers produce nectar?  I see mainly flies, and a few bees, landing on pussytoes.  I don’t think those flies could be accessing nectar from deep inside the flower, and I don’t see any evidence of nectar near the top (or in any part) of the flower.  Also, most of those flies and bees seem to be landing on male flowers, and I rarely see them on female blossoms.  Can anyone help me understand why/how this pollination process works?

Posted in Prairie Natural History, Prairie Photography, Prairie Plants | Tagged , , , , | 9 Comments

Not Yet, Monarchs, Not Yet!

Monarch butterflies are leaving Mexico and traveling north, as they always do.  However, they’re coming a lot further north than they typically do in April.  The first I heard about this was a text message from conservation photographer Michael Forsberg back on April 9.  Mike said he had just photographed a monarch butterfly with faded wings in his Lincoln, Nebraska backyard.  “Could this be from Mexico (seems too far north)?  Or could this be a local new generation (seems to early)?”  Yes, exactly.

Mike and I checked with some experts who all agreed that Mike’s butterfly had overwintered in Mexico and had flown all the way north to Nebraska.  And yes, it was awfully far north for a monarch to be spotted at this time of year.  Moreover, Mike wasn’t alone in his observation.  According to Journey North’s website, there have been numerous 2017 sightings of monarchs much further north than they are normally seen in April.

Well, good for the monarchs, right?  They’re getting a head start on the season, and hopefully they’ll have a great year…

…Unfortunately, coming this far north this early is probably not a good thing.  Ordinarily, monarchs that leave Mexico in the early spring fly as far north as the southern United States and lay eggs on milkweed plants there.  The generation that hatches from those eggs then makes their way further north, including to our Nebraska prairies.  By overshooting the southern United States this spring, the early monarchs here in Nebraska have arrived before our milkweed plants are even out of the ground.  There’s no place for them to lay their eggs, and that could lead to big problems.

No, this wasn’t a monarch from this spring. This was photographed in Minnesota in July 2015, a reasonable time and place for monarchs. There is no milkweed to be found yet in our prairies this spring.

Our Platte River Prairies land manager (Nelson Winkel) says he saw a couple monarchs last Friday, and I got to add my own early sighting to the Journey North database this weekend.  As I was driving into our family prairie with two of my kids, I saw a big butterfly out of the corner of my eye and thought “monarch??” but missed getting a good look.  An hour later, though, I had a very clear look at a monarch butterfly in flight, so when I returned home I logged in and reported it.  On Monday, I returned to our prairie to do some work and saw a monarch again (same one?).  I followed it for a while to see what it was up to, and over the next 5-10 minutes, I watched it repeatedly hover low to the ground, fly 10 yards or so, and then hover again.  It sure looked like it was searching for something, and it bypassed quite a few wildflowers, so I don’t think it was looking for nectar.  I’m guessing it was looking in vain for milkweed plants, but I might just be projecting.

It’s too early to know what this year will bring for the monarch butterfly.  The Eastern North American population count in Mexico was higher than many had anticipated, but still far lower than desired.  Habitat loss both in North America and Mexico, pesticide impacts, landscape fragmentation, declines in milkweed populations, and weather events all threaten butterfly populations.  Now, overly-ambitious monarchs taking advantage of strong tailwinds appear to be compounding their own problems.  It remains to be seen how many will arrive before milkweed plants are ready for them, and what impacts those early arrivals might have.  I’m hoping the majority of the population will stay south and make lots of babies that can come up here in another month or so.  We’ll do our best to make them welcome when they arrive.

Want to help make monarchs welcome in your area?  Planting and protecting milkweed plants in your neighborhood can give monarchs somewhere to lay their eggs.  Even better, do what you can to ensure a diversity of blooming plants is available throughout the growing season.  Monarchs are only one of many pollinator insects that are suffering because of a lack of consistent and abundant supply of pollen and nectar.  Plant native wildflowers in your yard and help keep native prairies and other natural areas in good condition so bees, butterflies, and other pollinators can find food for themselves and their offspring all season long.

Posted in Prairie Insects, Prairie Natural History | Tagged , , , , , | 31 Comments

Photo of the Week – April 13, 2017

Prairie dandelion, aka prairie false dandelion (Nothocalais cuspidata) is different from common dandelion (Taraxacum officianale), the one most people are familiar with in yards and weedy places.  Prairie dandelion is a native perennial wildflower, mainly restricted to dry unplowed prairies, while the other dandelion is a non-native species that seems able to pop up just about anywhere.  I’m actually a fan of both species, and don’t mind seeing common dandelion in our prairies, especially as an important early-season pollinator resource, but it’s always a treat to find populations of prairie dandelion.

Prairie dandelion at Gjerloff Prairie.

Prairie dandelion has a similar appearance to common dandelion, but there are some pretty strong differences as well.  The flowers are much larger, for example, and the leaves are long and don’t have the large serrations that common dandelion leaves have.  Prairie dandelion is considered to be a rare plant in many eastern prairie states, but is found across much of Nebraska – though it is certainly nowhere as abundant as common dandelion.

Close up of two prairie dandelion flowers.

While I was photographing prairie dandelion flowers this last weekend, I noticed a small grasshopper nymph feeding on the petals of one of the blossoms.  I took a few photos of it and moved on.  A few minutes later, I walked back past the flower and noticed the grasshopper had moved into a more visible location, so I took a few more photos of it.  When I got home and looked through the photos, my first instinct was that the second set of photos were better because I could see the whole grasshopper and it was better framed within the image.  Upon more reflection, however, I’m not sure.  Since some of you enjoy voting on this kind of thing, I decided to include both images, and you can tell me if you have a preference between them.  Just leave your vote in the comments section below.

Grasshopper nymph #1

Grasshopper nymph #2

It was a pretty tough winter for prairie photography around here; not much snow, and not even a lot of ice to photograph – with the exception of one notable ice storm.  I’m really glad that flowers and insects are finally breaking up the monotony of drab brown prairie vegetation.  It should be a fun spring.

Posted in Prairie Insects, Prairie Natural History, Prairie Photography, Prairie Plants | Tagged , , , , , , | 25 Comments

Spring Obsession

Man, I sure do love Carolina anemone (Anemone carolinianum).  It’s such a beautiful plant in such a compact package.  We have a few plants blooming in our prairie garden at home, but last weekend, I went looking for more of them at Gjerloff Prairie, owned and managed by Prairie Plains Resource Institute.  I don’t visit the prairie often enough to know for sure, but it sure seemed like there were many more patches of anemone than I’d seen in previous years.

There are both blueish-purple and pale lavender-white blossoms at Gjerloff, and sometimes the two were mixed within the same patch of flowers.  Interestingly, the white ones were easier to see at a distance then the blue ones, but both hide pretty well.  I often didn’t see them until I was within 5-10 yards.  They’re short, you see…

While it is a perennial plant, my limited experience tells me Carolina anemone flourishes when the surrounding vegetation is short.  Of course, that could be a function of visibility too, but I’m guessing it doesn’t bloom well when covered by thatch and tall skeletons of plants from the previous season.  (I’d be interested to hear from others about what kinds of response to management they’ve seen with this species.)  In our Platte River Prairies, I most often see them after a summer fire or after a year of intensive grazing.  The portion of Gjerloff prairie I found them in this year was burned and grazed pretty hard last year.  Other plant species seemed to be enjoying the abundant light in the grazed area as well, including numerous rosettes of ragwort (Packera plattensis) and quite a few individuals of prairie dandelion (Nothocalais cuspidata), which was just starting to bloom.  …More on prairie dandelion in an upcoming post…

Several different small bee and fly species were feeding on the pollen of the anemone plants last weekend, including the gorgeous little Lasioglossum species shown above.  I’m guessing the anemone is a very welcome resource for those early-season pollinators.  Carolina anemone makes its pollen easy to access, and when you find one plant, there are usually quite a few more right next to it.  That’s pretty handy for a hungry bee or fly searching for something to eat across a still-mostly-brown prairie landscape.

There are lots of great spring wildflowers, but I have to say the little Carolina anemone is my favorite.  At least this week.  Although that prairie dandelion is sure cute too…  Oh, and how can you not like pussytoes?  And violets…  Hmm.

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Burning For Good Reasons

At the Platte River Prairies, we conduct prescribed burns for various purposes.  Some fires are intended to kill eastern red cedar trees or to suppress cool-season invasive grasses.  Other fires are aimed at removing thatch and old vegetative growth – creating lush regrowth that concentrates cattle grazing in one portion of a prairie.  For each objective, we prescribe a certain set of outcomes that need to be met in order for a burn to be successful, and a parallel set of conditions (especially timing and weather conditions) that will get us to those outcomes.  If we’re just trying to remove most of the old dead growth from a prairie, we don’t need the same kind of fire intensity as when we’re trying to kill cedar trees.  If we’re targeting cool-season grasses (and won’t be following up with grazing), we try to burn about the time those grasses are starting to flower.

On the last day of March this year, we assembled a crew that combined our staff with employees from the Central Platte Natural Resources District and got ready to burn some hilly sand prairie.  Our objective was to remove at least 75% of the thatch and old growth from the burned area so subsequent cattle grazing would be focused in that burned patch while the remainder of the prairie went largely ungrazed.  The forecast had predicted pretty high relative humidity readings, but we thought we’d be ok as long as we didn’t have overnight fog or mist.  Unfortunately, on the morning of the fire, the grass litter along the ground was more damp than we’d hoped and since the sun was hidden behind clouds it didn’t seem likely that litter would dry much.  After considerable discussion and delay, we finally decided to conduct a test fire in the downwind corner of the burn unit to see what kind of burn results we’d get before deciding whether or not to burn the entire 70 acre unit.  We also figured it was an opportunity to learn more about how fire behaves under humid conditions.  At 1 pm, it was 46 degrees F, 71% relative humidity, and we had winds at about 10 mph.

Nelson Winkel, our land steward, had to work pretty hard to get the grass ignited. While it looks like there’s a lot of fire here, watch the video below to get a better picture of how the fire was actually burning.  The flames would flare up when they hit a patch of grass with dry leaves, but the damp litter layer kept the flames from moving very quickly or burning all the way to the soil surface.  (If the video doesn’t work, click on the title of this post to open it in a browser or follow this link: https://www.youtube.com/watch?v=p3Dh2OqzmEk)

The test fire was definitely instructive.  The upper portions of grass plants were sufficiently dry that they burned fairly well, but the dampness along the ground made the fire creep along very slowly, even when pushed by the wind.  Following along behind the fire, I was kicking away ash to find that quite a bit of litter was still unburned and covering the soil.  After we burned an area about 40 x 40 feet, we extinguished the fire and had a group discussion.  The grass was burning well enough that we could probably burn the unit, and much of the area inside the firebreaks would ignite and turn black.  On the crests of the hills where vegetation was dominated by bunchgrasses and there was considerable bare ground beneath plants, we’d probably get a pretty complete burn.  However, in lower areas where there was more dense vegetation, including some cool-season invasive grasses, we didn’t feel like it would burn very completely at all.  In total, we didn’t think we’d reach our goal of removing litter from 75% of the area.  Importantly, the areas that wouldn’t burn well (and thus wouldn’t attract grazing) were the ones we most wanted cattle to graze (to suppress invasive grass growth).  After talking through our options with the whole crew, we decided to postpone the burn until we had a day with better conditions.

You can see from this photo that while most of the dry standing vegetation burned, much of the litter/thatch remained behind.

Here’s our group, deep in discussion about objectives, results, and whether or not to continue with the fire.

It’s never an easy decision to call off a burn when you’ve got crew and equipment on site.  As a burn boss, I’ve had to do that multiple times, but usually when we’re worried about safety because the weather conditions are too far on the hot, dry and/or windy side.  In this case, there were no extraordinary safety concerns, but every fire comes with risks to people and property.  It never makes sense to burn and not achieve the desired result.  We needed near complete consumption of the dead vegetation to attract cattle grazing and carry out our management plan for that season.   Since we weren’t going to achieve that, we didn’t burn.

As it turned out, we only had to wait four days for another opportunity to burn that unit.  On April 4, most of the same crew members assembled and we set up to try it again.   Our weather conditions at 11 am weren’t all that different from our previous attempt (46 degrees F, 65% RH, and 12-15 mph winds) but the grass litter was much drier, and while the sky was cloudy, the clouds were more patchy and the sun was even popping through once in a while.

Our downwind firebreaks were two gravel roads, so it didn’t take long to get those lines lit and blacked out.  At that point, however, I walked out into the black to see how much litter consumption we were getting.  While it was much better than the previous week, there were still some unburned patches.  Since we had solid firebreaks, we paused ignition to wait for everything to warm up and dry out just a little more.   About a half hour later, relative humidity had dropped nearly 10% and the temperature had risen about 5%.  We restarted ignition and pretty quickly finished up the rest of the fire.

On our second attempt, we had much better fire behavior. Here, a fire is backing uphill through vegetation and getting pretty complete consumption.

Nelson is walking through the black in a low spot where not all the litter was burning well. This was while we were waiting for the humidity to drop a little more.

Here are a couple timelapse videos of the lighting of the “flanking head fires” toward the end of the burn.  They are a little jumpy (sorry) because I was just hand-holding my phone and taking repeated photos, but it shows how different the fire behavior was from the slow creeping fire of our first attempt 5 days earlier.  If you can’t see the videos, click on the title of this post to open it in a web browser or click on these links: Video 1, Video 2.

Here is what the burn unit looked like right after the fire. You can see lots of pocket gopher mounds scattered through the black, but also a few small unburned patches. Those unburned areas are perfectly fine with us, and actually provide some valuable areas of refuge for animals (in addition to the 2/3 of this prairie we didn’t burn and other prairies across the road in three directions.)

I’m glad we waited for more favorable conditions to burn this unit.  We wouldn’t have accomplished what we needed to on the first day, and though it was hard to turn down a potential burn opportunity and assembled crew, I think we made the right call.  As it happened, we didn’t have to wait long for a better day, and we got what we wanted out of that fire.  At the same time, I’m also glad we decided to try a test fire on the first day.  It turned into a good learning experience and fodder for fruitful discussion among the crew.  The whole situation was a good reminder that while we can achieve many important objectives through prescribed burning, it isn’t a toy we play with for fun.  Instead, we want to burn only when we can do so safely, and when we can achieve clear and specific objectives.

If you want to learn more about how we combine prescribed fire and grazing to manage for habitat and species diversity, you can read more here.

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Photo of the Week – April 6, 2017

Wildflower season has officially returned to our area.  I was out at my family’s prairie last weekend and found pussytoes (Antennaria neglecta), buffalo pea (Astragalus crassicarpus), and sun sedge (Carex heliophila) in bloom.  Here in my yard, both the pussytoes and Carolina anemone (Anemone carolinianum) are blooming, along with the little blue-flowered weedy speedwell (Veronica persica) that always pops up around our garden and sidewalk edges.  A few bees are moving around too, and there have been several kinds of flies visiting the pussytoes flowers.  Here are a few photos of early spring flowers from this week.

Pussytoes have both male and female flowers. These are female flowers at the Helzer family prairie.

This fly is feeding on the pollen of a female pussytoes flower in our family prairie.

Although speedwell isn’t a native wildflower, I enjoy seeing it every year. It’s often the first flower I see each spring, and always makes me happy.

I don’t know what plant this will grow into, but it was germinating at our family prairie last weekend.

Carolina anemone can be hard to find in large prairies because the showy little flowers aren’t tall enough to be seen from afar. This one is in my prairie garden, making it really easy to find.

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Hubbard Fellowship Blog – The Nature of Human Intervention

This post is written by Eric Chien, one of our Hubbard Fellows.  Eric has a solid background in land management and apparently thinks quite a bit while he’s doing stewardship work.  Here are some of his latest thoughts – I think you’ll find them thought-provoking.

What if I told you our most resilient prairies will likely experience burning, mowing, cutting, shredding, chemical spraying, and fencing for decades to come? Among splendidly diverse native wildflowers and grasses, and a rich assemblage of insects, birds, herps, and mammals, there will be the consistent imprints of boot tread in the soil. The sounds of wind-blown grass, and meadowlarks will be occasionally interrupted by the clamor of metal and engines. We will know resilience not only by the existence of a vibrant prairie pulsing with life, but also by the presence of a sturdy 4-strand barb wire fence, and a two-track road worn to mineral soil.

Managers know that maintaining the function and diversity of prairies is highly involved work. I think the image of that monumental work is viewed somewhat quizzically by much of the public that has not had an opportunity or guide to understand prairies. The notion of conservation as the process of removing human presence and intervention is still widely circulated. Once removed from the yoke of human imposition, the natural world is supposed to largely perpetuate itself; growing more abundant, diverse, and resilient in its respite. That is the idea at least. My experience on prairies tells me that conservation landscapes characterized by little human presence is a mold not applicable to prairies. It probably has not been for 150 years. Considering the long history of Native American land management, it may never have been. What’s more, the intensive management in prairie conservation is representative of what many of the world’s ecosystems will require to maintain their functions into the future. Decades of prairie management suggest that we consider ourselves and our presence not as obstacles or crutches to the diversity of life, but as integral drivers of the processes and forces that maintain integrity and functioning of ecosystems.

The author cuts down a cottonwood tree on the edge of one of our Platte River Prairies. Photo by Katharine Hogan.

On the prairie, we light the fires, control the grazers, and suppress the invasive plants. In doing so we drive species composition and distribution, habitat heterogeneity, and the presence or absence of ecosystem functions; the most fundamental ecological attributes. Our involvement is not out of hubris, nor does it make prairies an artifice. Science and experience tells us that without our involvement prairies nearly always slip into measurably degraded states, or entirely disappear. Chris has written thoroughly on the science and implications around the myth of the self-sustaining prairie and the reasons why management is necessary. Seeing our new role with clear eyes has important implications for our approach to conservation.

Rather than thinking of ourselves as prairie doctors, we should see ourselves as prairie organs. Organs are not optional, and cannot be removed from the whole when the budget it tight. When we set up prairie conservation complexes we need to consider humans with the same gravity we consider plant diversity. Whether it is land management professionals, volunteer cohorts, or farming and ranching families, thoughtful and capable human managers are as important as the native grass community.

People have been lighting North American prairies on fire since the last glaciers retreated and grasslands emerged as the dominant ecosystem in the Great Plains.

What does recognition of that human importance look like at The Nature Conservancy? Since 1994, standard operating procedure in TNC has mandated setting aside an endowment for every new land acquisition with the principal set at minimum 20% of the fair market value of the land. It is a small but key step in maintaining essential human capacity in our conservation lands. We also strive to recognize human importance by making our conservation work relevant to ranching families. The ecological and management knowledge we seek out strives to reconcile economic and conservation needs. The gold standard in our work are solutions that allow people and nature to thrive. This is not just because supporting human communities is important, but because prairies with deep human presence are healthy, resilient prairies.

If at this point you’re thinking- “This sounds like an overly involved prairie person issue.” I say this- Prairies are likely a vanguard for where many of our natural systems are headed. Our ability to find success as drivers of ecosystem integrity and resilience through active management have implications for the future integrity of countless ecosystem types. Resilience processes in forests, reefs, tundra, and countless other systems are being broken down by ongoing fragmentation, and novel disturbances. There is already a need for us to step in and play a key role in the ecology that reinforces the biodiversity, functions, and services those systems provide. That need is only growing. North American Prairies are a proving ground for our ability to do that effectively.

I hope you consider sharing your thoughts.

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Photo of the Week – March 31, 2017

Prairie clover is a term that gets used pretty broadly among the public.  Ok, not necessarily the among the GENERAL public, but among people who have at least some idea what grasslands look like.  I’ve heard the term prairie clover applied to a number of different legume species, including sweet clover.  Botanically, prairie clover – as far as I know – refers only to plants in the genus Dalea, and including familiar species like purple prairie clover (Dalea purpurea) and white prairie clover (Dalea candida).

In Nebraska, we have eight species of prairie clover.  I finally saw large-spike prairie clover this past summer (though not in bloom), which means I’ve now seen all of them.  I’m still waiting for my certificate to arrive in the mail.  I’ve only been able to photograph five of the eight, but I’ll try to do better in the future.  Maybe I can earn the prairie clover photography patch someday.  (I’m just assuming that patch exists.  If it doesn’t, someone needs to answer for that.)

Purple prairie clover is well-known and well-distributed across Nebraska. It is a big favorite among bees, and while cattle will often eat it – especially under relatively high stocking rates – it survives periodic grazing very well in our prairies.

White prairie clover is also widespread across Nebraska and popular among pollinators. This one is hosting both a long-horned beetle and weevil.

While purple and white prairie clover are the best known of this group of wildflowers, the lesser known and more specialized prairie clovers are also worth seeing and learning about.  Golden dalea (Dalea aurea) has gorgeous yellow flowers, but you’re not likely to run across it unless you go searching for it in one of the scattered locations it occurs.  Hare’s foot dalea (Dalea leporina) is an annual prairie clover that is a real enigma to me, and I’ve only seen it in our restored prairies.  Silky prairie clover (Dalea villosa) might be my favorite of all.  It has beautiful long pale pink-lavender flowers and fuzzy sea-green leaves and is common throughout much of the Nebraska Sandhills, as well as other sandy places.

Golden dalea is a beautiful prairie clover found on prairie hillsides here and there around the state.

Hare’s-foot dalea, aka annual dalea, is not a showy prairie clover, but is still pretty. It comes and goes in our restored prairies, often responding positively during the recovery periods following bouts of fire and grazing.

Silky prairie clover has a subtle beauty that fits well in the sandy prairies it inhabits.

The remaining three species in Nebraska are large-spike prairie clover (Dalea cylindriceps), round-head prairie clover (Dalea multiflora), and nine-anther dalea (Dalea enneandra).  Round-head prairie clover just barely comes into the southern tier of Nebraska counties.  The other two are found in scattered locations around the state.

It would be hard to think of a group of wildflowers that contributes more to prairie communities than prairie clovers.  At least purple and white prairie clover provide very high quality forage for herbivores, including livestock.  Bees and other pollinators focus heavily on prairie clovers, and the pollen and nectar are abundant and easily accessible.  The seeds are big and nutritious, and eaten by birds, small mammals, and insects.  During drought years, purple and white prairie clover are among the wildflowers that are mostly still green and blooming, even when surrounded by brown crispy plants, so they keep contributing even in difficult times.  Oh, and of course, as legumes, prairie clovers are nitrogen fixers.  From a land manager’s standpoint, prairie clover is easy to harvest seed from, germinates easily in restored prairies, and survives well under our fire and grazing management here on the Platte River.

If you haven’t seen all the different prairie clovers in your area, I hope you get a chance to remedy that soon.  Personally, I can’t wait until summer wildflower season arrives so I can keep working toward earning that prairie clover photography patch.  Maybe I can talk my wife into knitting me a prairie clover-themed stocking cap to sew the patch onto!

(For you young people out there, a patch is a kind of decorative embroidered thingie folks used to sew onto their clothing to recognize an award or achievement, or to signify membership in a particular club or group.  Trust me, it was super cool.  Your friends would be impressed if you showed up to a party wearing one.)

Posted in Prairie Natural History, Prairie Photography, Prairie Plants | Tagged , , , | 11 Comments

Now You See Them, Now You Don’t (But They Might Still Be There!)

Grazing, especially by goats and/or sheep, is often promoted as a control method for weeds or shrubs.  Depending upon the life strategy of the weeds being targeted, grazing can be effective, but it’s important to set realistic objectives.  As you might expect, many perennial grasses, forbs, and shrubs have evolved strategies for surviving repeated defoliation.  In those cases, grazing may appear to effectively control plants while grazers are present, but the plants bounce back right after grazers are removed.

One of my all-time favorite research projects showcases this exact phenomenon at a site in South Dakota owned by The Nature Conservancy.  Back in the early 1990’s, an estimated 75% of the Conservancy’s Altamont Prairie Preserve was covered by leafy spurge (Euphorbia esula).  In 1994, goats and sheep were installed in separate pastures and spurge was treated by using periodic high-intensity grazing sessions during both early summer and early fall.  Both the goats and sheep were very effective at eating the spurge plants, and after five years, managers conducting walk-through inspections the site felt like excellent long-term control of spurge had been achieved.  Inside small exclosures, spurge was still abundant and vigorous, but outside the exclosures, almost no plants could be seen.  As a result, the goats and sheep were removed and everyone was happy.

One of the goats used at Altamont Prairie and an exclosure showing a dramatic difference between abundant and blooming leafy spurge in ungrazed areas and no apparent spurge in grazed areas. Photos courtesy of TNC’s Minnesota, North Dakota and South Dakota Chapter.

…Until the next season when spurge plants popped right back out of the ground and the pasture looked essentially as it had before the grazing treatment had started.  In dismay, the managers looked for another option and decided upon flea beetles (Apthona spp.), which ended up being a much more successful choice, greatly reducing the footprint of leafy spurge over the next several years.

You’d be excused for thinking the use of sheep and goats was a total waste of effort, but additional data collected at Altamont Prairie adds some interesting nuance.  As it happens, mean Floristic Quality (a kind of qualified plant diversity metric) stayed relatively stable within the grazed area during the five years sheep and goats were present.  During the same time period, mean Floristic Quality decreased significantly in exclosures.  In other words, while grazing didn’t eliminate the spurge problem, it may have stabilized some of its negative impacts for a while.

This, to me, is one of the best attributes of many grazing-for-weed-control efforts.  Even if grazing can’t eradicate many weeds/shrubs from a prairie, it might be a strategy that prevents further spread (eliminating flowers and reducing vigor for belowground reproduction) and/or reduces the weed’s ability to compete with desirable plants.  In a large site where more effective long-term strategies (such as selective herbicide application or biocontrol releases) aren’t feasible across the whole area, using grazing as a suppression tactic in some areas of the site while you kill it in others can make a lot of sense.  In other words, grazing might buy you time to work on a problem that would otherwise seem overwhelming in scope.  (However, it’s also important to remember that grazers will also be eating and suppressing the vigor and reproduction of desirable species with similar growth strategies to the invader you’re targeting.  If you do succeed in reducing populations of invaders, you might also reduce populations of those desirable plants.)

Grazing can sometimes provide effective control of short-lived plants if it prevents flowering and seed production and forces plants to die without reproducing.  Just remember that more seeds are likely waiting in the soil, so it will likely take repeated grazing treatments to reach your goal.  Here in Nebraska, we often use short-term intensive grazing as a tool to knock back the competitive ability of perennial cool-season grasses such as smooth brome (Bromus inermis) or Kentucky bluegrass (Poa pratensis).  We don’t expect the grazing to kill those grass plants (and it doesn’t) but we can allow other plants a chance to flourish for a few years until the invasive grasses regain their vigor.  By repeating the treatment periodically, we can maintain a more diverse plant community.

Periodic early-season cattle intensive grazing helps us temporarily suppress cool-season invasive grasses like smooth brome and reduce its ability to outcompete many native grasses and wildflowers.

Personally, I’ve never used goats or sheep to help with a management challenge.  In contrast with cattle, goats and sheep, feed preferentially on forbs, and I’m usually trying to suppress grasses and encourage forb growth.  However, I do think goats, sheep, and cattle can all play important roles in controlling invasives as long as you don’t expect them to do more than they can.  I worry that landowners and land managers can sometimes end up paying an exorbitant price to someone that brings animals in with the promise of weed control.  It’s important to remember that if you do that, you’re providing food for that contractor’s animals, and that should be factored into whatever price one of you pays the other.  When we use cattle for prairie management, the cattle owner always pays us.  That seems not to be the case with many goat grazing operations.  I’m not saying it’s wrong to pay someone to graze their goats on your land, I’m just saying it’s important to fully process what each party is getting from the transaction.  That includes the forage provided to the animals from your land, the time and expenses incurred by the owner of the animals, and  – importantly – the actual effectiveness of the treatment.

As long as you have clear objectives and a good understanding of the plant(s) you’re targeting, grazing may be a great tool for invasive species control.  Just remember one of the biggest lessons from the South Dakota spurge experiment: just because you can’t see the invasive plant anymore doesn’t mean it’s gone!

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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.)

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