Hubbard Fellowship Post – S’Mammals with Jasmine

This is a post written by Jasmine Cutter, one of our 2014-15 Hubbard Fellows.  All photos are by Jasmine.

Howdy, Prairie Ecologist friends!
I remember how much I looked forward to the Fellows’ posts before coming to the Platte River Prairies, so I apologize for the glacial pace of my updates.  A considerable amount of my time and brainspace over the last two months has been occupied by small mammals (or s’mammals, as I prefer to call them). There are definite challenges to undertaking a project during the growing season (namely balancing project time and stewardship time), and throughout the process of the project and the summer there have been some unexpected surprises (mostly good), and a lot, a lot of learning.

Mike Schrad, Nebraska Master Naturalist and my small mammal project mentor.

Mike Schrad (left), Nebraska Master Naturalist and my small mammal project mentor.

In the briefest of terms, I’ve been tromping through our Derr sandhills (a unit which includes both restored and remnant prairie on the edge of the Platte River Valley), battling cows, thunderstorms, and a lack of sleep in the pursuit of learning more about the small mammal community in this unit. I was initially drawn to this site because the Derr sandhills contain pocket mice (Perognathus flavescens) and Northern grasshopper mice (Onychomys leucogaster). The pocket mice are minute, streamline and silky, whereas the grasshopper mice are beefy and aggressive (and probably also soft, but getting your finger near enough to find out is tricky), yet, despite their differences, they’re both endemic to sandy soils. As these critters are relatively unusual, my study will give us a chance to learn more about their habitat preferences, and hopefully enable us to manage the site in a way that ensures the continuation of healthy populations. Although these two species have remained the most endearing through out my study, my affection has also expanded to include shrews (they have venomous saliva and black-tipped teeth!), voles (ferocious teddy bears) and harvest mice (very agile and keep a neat nest). Deer mice tend to have a heavy parasite load and botfly sores (not to mention the possibility of hantavirus and carrying lyme disease), and therefore are often pretty icky. At this point, I am done with trapping for the most part. Soon, I will be collecting vegetation and site data for each trap site (that’s ~370 sampling points!), and this winter, I will be seeing if there are any relationships between the presence of certain species and site characteristics.

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Beefy lil grasshopper mouse, so-called due to their carnivorous diet. At night, they sing to defend their territories.

Pocket mouse. The clip on its tail is what is attached to the scale used to weigh them. While it is undoubtedly a little uncomfortable, there is no permanent damage. The clip is a helpful way to hold onto animals so I can take a photo. It’s essential to my study that I am able to document how the pelage (fur) color varies between individuals.

Pocket mouse. The clip on its tail is what is attached to the scale used to weigh them. While it is undoubtedly a little uncomfortable, there is no permanent damage. The clip is also a helpful way to hold onto animals so I can take a photo. It’s essential to my study that I am able to document how the pelage (fur) color varies between individuals.

Scary shrew teeth. Unlike the rest of the similarly-sized critters I caught, shrews are not rodents. They are in the order Soricomorpha. They are mostly carnivorous and have saliva that paralyzes their prey.

Scary shrew teeth. Unlike the rest of the similarly-sized critters I caught, shrews are not rodents. They are in the order Soricomorpha. They are mostly carnivorous and have saliva that paralyzes their prey.

There have been a few surprises during this project. For example, I have discovered that cows don’t like science. They have eaten my flags, licked my traps several feet off my transect, and squashed a few for good measure. If only their curiosity could be used more constructively!

One of the best surprises was opening one of my traps and finding a least weasel inside! I was waaayyy more intimidated by this critter than it was by me. Despite its ferocity, it was impressively lightweight. This littlest weasel was longer than the thirteen-lined ground squirrels that I also caught that day, but considerably lighter. The ground squirrels maxed out my 100 gram scale, whereas the weasel was only 70 grams! The weasel was also impressively smelly, living up to the family name of mustelidae.  I was a little worried that no other small mammals would go into that trap the next night because it smelled of predator, even after I sprayed it with Lysol. However, the harvest mouse I caught the next night was undeterred. No wonder s’mammals have such a short lifespan. Another surprising find on a different transect was an embarrassed-looking leopard frog. My bait seems to attract a lot of crickets, so I imagine that’s what lured the frog. And the cutest capture was these two baby voles that managed to wander into one trap.

Thirteen-lined ground squirrel (Ictidomys tridecemlineatus). When I open a trap, I gently plop the critter into a bag in order to minimize handling exposure. I can weigh, identify and sex the critter while it’s in the bag. It’s safer for me, and the animal is only in there for a few seconds to a minute.

Thirteen-lined ground squirrel (Ictidomys tridecemlineatus). When I open a trap, I gently plop the critter into a bag in order to minimize handling exposure. I can weigh, identify and sex the critter while it’s in the bag. It’s safer for me, and the animal is only in there for a few seconds to a minute.

Weasel tryptic. Although none of these manage to capture the full length of the weasel (Mustela nivalis), they do manage to capture what you’d be likely to see - a reddish blur.

Weasel tryptic. Although none of these manage to capture the full length of the weasel (Mustela nivalis), they do manage to capture what you’d be likely to see – a reddish blur.

Baby voles!

Baby voles!

In addition to the excitement of peeking into every closed trap, there have been other perks to the project. I’ve gotten to see way more sunrises and sunsets than I would have otherwise. I love the freshness of the mornings, how the grass glows orange, and the spiderwebs glisten, and how much my mood (and finger mobility) improves once the sun crests the sandhills. I’ve gotten to hear the weird robotic chirpings of the swallows at sunset. The light at these times is able to make pretty much any photo look amazing, so it’s a little less discouraging to compare some of my photos to Chris’. I have also really enjoyed the slower pace of sampling, of covering my transect by foot. I spend a lot of time in the prairies, but infrequently do I have time to slow down and appreciate how the prairie community changes meter by meter. I have gotten to know my transects well, and I look forward to seeing if/how the patterns I’ve noticed play out in the data.

I’ve taken thinking like a s’mammal maybe a little too much to heart. Whenever we visit a new prairie, I think, ‘this looks like good pocket mouse habitat, I wonder if they have any? I wish I had my traps…’. I am also really grateful that so many mammalogists have been willing to donate their time and resources. I’ve learned a lot about species identification from them, and it’s exciting to make new connections with other institutions.

Sunrise!

Sunrise!

My pile of science. Traps generously lent out by Montana State University and Kansas State.

My pile of science. Traps generously lent out by Montana State University and Kansas State.

Pocket mouse pockets. They store seeds in there to bring back to their nest cache.

Pocket mouse pockets. They use external fur-lined cheek pouches to store seeds until they can bring them back to their nest cache.

This is not to say that this project has not had its challenges. I would say the main struggles have been setting reasonable goals (never a strong suit), keeping track of all the moving pieces (Do I have all my equipment? Am I recording all the right info? When do these traps need to be mailed back to Montana?), not losing things (Luckily the two mice than ran off with my scale clips were recaptured the next day!), and figuring out how to do the majority of the sampling by myself. It has been a long, time-intensive process for just five sampling transects. And, the project has not been without its dangers. The most dangerous part of the study has definitely been cacti. You wouldn’t believe the number of cacti I’ve accidentally kneeled on, or kicked into myself! I don’t recommend it. But, when these aspects of fieldwork start to get me down, I remind myself that I caught a weasel, and that’s pretty freaking cool.

Posted in Hubbard Fellowship, Prairie Animals, Prairie Natural History | Tagged , , , , , , | 11 Comments

Continuing Wildfire Recovery at the Niobrara Valley Preserve

When I was at the Niobrara Valley Preserve a couple weeks ago, I spent some time exploring the area north of the river where the 2012 wildfire ripped through oak savanna and ponderosa pine woodland.  As discussed in earlier posts, the density of trees, especially eastern redcedar, fueled a fire that killed nearly every pine and cedar in the 3000 acres of Preserve land on the north side of the river.  Most oaks and other decidous trees were topkilled, but many resprouted within a few weeks of the fire.  I have been following the regrowth and recovery of this part of the Preserve with great interest, and trying to help the Preserve staff as they think about how to manage the area in the future.

Here is a series of photos from an uphill hike I took on September 18.  The photos are roughly in order of elevation, starting at the river road (just above the floodplain) and proceeding upslope to the ridgetop at the north edge of the valley.

Hemp and marestail

On the first slopes above the river road, hemp (Cannabis) and marestail (Conyza) dominate the understory of a woodland that now consists mainly of skeletons of eastern redcedar and oak trees.  Most of the oaks have resprouts from their bases, however, and a few still have live branches up high.

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Marestail and cedar skeletons

The abundance of marestail (a native pioneering species) is especially interesting to me because it’s the same species that usually dominates two-year-old prairie plantings.  This is the role it plays in ecosystems, and it plays it well.  It’s difficult to see very much below the marestail, but when I looked closely, I found scattered grasses, sedges, and wildflowers – a good sign of future recovery.

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ragweed

As I walked higher and got into the prairie-covered slopes, ragweed (Ambrosia) replaced marestail as the visually dominant plant in the formerly shaded areas beneath cedar trees.  The ragweed is playing the same role as the marestail – quickly filling in the open space until a more permanent plant community establishes.  That community should move in pretty quickly in cases like that shown in this photo, in which a cedar tree is surrounded by prairie.

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prairie

Higher up the slope, large areas of prairie had not been encroached upon by cedars, and recovery after the fire was just as predicted – quick and easy.  The vegetation was still a little thin, but that was more of an aftereffect of the 2012 drought than of the fire.  In this image you can see the scattered cedars further downslope (such as the one featured in the previous photo).

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Oaks

Almost every bur oak tree I saw was vigorously resprouting from the base.  Those numerous stems should thin themselves down to three or four major trunks over the next decade or so.  Some of the branches were already 6-8 feet high, so recovery is proceeding quickly.  These oaks were growing along the edge of one of many steep draws scattered along the north side of the river.  As I was wading through 3-4 foot tall marestail, I couldn’t help but wonder if that dense growth and the presence of mountain lions in the area explained the near absence of deer browsing on the oak sprouts (Ecology of Fear).   I don’t know if the deer felt it, but I sure had moments of discomfort, knowing that if a lion was hiding in the weeds nearby, the steep slopes and thick vegetation would make escape nearly impossible.  It made my hike a little more exciting, but I didn’t stay down in those draws very long…

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Sedges

I was surprised and pleased to see numerous examples of large sedge patches growing under the marestail forest, especially on the steeper portions of draws.  I don’t remember seeing many sedges last year, so either I missed them or they are expanding rapidly.  Either way, they will sure help stabilize those slopes as other plants move in to join them, and they’ll also help carry fire when we restart fire management of the area.

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Pine woodland

High on the slopes, where ponderosa pine and eastern redcedar had dominated just a few years ago, the scenery was every bit as spectacular as it had been before the fire – just different.  Marestail was abundant here too, but there was quite a bit of grass and wildflower cover as well, and several shrub species were flourishing, including smooth and skunkbush sumac, chokecherry, snowberry and others.  Despite the density of scorched tree trunks, the overall feel of the slopes was not one of death and destruction, but rather of abundant life.

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Ridge top

Even the very steep erodible slopes at the very edge of the ridge top were full of previously established perennial wildflowers and shrubs, as well as colonizing annuals.

I came down the slope after my walk with a great feeling of optimism.  My greatest worries about this area of the preserve had been that

1) Invasive plants would fill the slopes before the native vegetation could recover, and we’d be faced with the difficult challenge of attacking those invasives in difficult terrain.

2) Numerous eastern redcedar trees would colonize the slopes before there was enough vegetation to carry prescribed fires to knock those cedars back.

3) Soil erosion would be so severe that the seed bank needed to reestablish the native plant community would wash down the slope, along with the topsoil those plants needed to grow.

None of those three have occurred – or at least to the extent I feared they might.  There has been some erosion, but much less than I anticipated, and it doesn’t seem to be affecting vegetation recovery much.  I haven’t seen any truly invasive plants yet – which doesn’t mean they aren’t there, but they sure aren’t roaring in.  Finally, the recovery of the vegetation has been fast enough that we should be able to start running prescribed fires up the slopes within the next few years.  I didn’t see any little cedar trees on my walk, and while I’m sure there are a few around, the abundance is much less than I feared, and our ability to use prescribed fire should make it fairly easy to control them, except on the steepest slopes.

Most of all, the beauty of the Niobrara Valley has survived the wildfire.  The pines are gone from some parts of the valley, but are still doing well in other areas nearby, including other parts of the Niobrara Valley Preserve.  Whether or not (or when) they’ll return to the site of the 2012 fire is still an open question.  Regardless, there is abundant life on the slopes north of the river.  Just because those slopes will be dominated by different species than before doesn’t change the scenic or ecological value of the site.  It’s still one of my favorite places on earth.

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Photo of the Week – September 25, 2014

Dufourea

A small male bee (Dufourea marginata) waits hopefully for a female to come by his sunflower.  The Nature Conservancy’s Platte River Prairies, Nebraska.

Some people have the mistaken impression that I know a lot about bees.  Those who know me better understand that while I have a decent understanding of the ecology of bees and other pollinators, my identification skills are very rudimentary.  Fortunately, I have become friends with Mike Arduser, formerly with the Missouri Department of Conservation, who has a comprehensive knowledge of bees in the Central United States.  I sent Mike these photos a couple weeks ago and he generously identified the bee species for me, and provided a little background information as well.

The elongated mouthparts help identify this as a member of the genus Dufourea.  (But you probably already knew that.)

Mike says the elongated mouthparts help identify this as a member of the genus Dufourea. (You probably already knew that.)

According to Mike, the bee species I photographed on stiff sunflower (Helianthus pauciflorus) is a specialist feeder on sunflowers.  It’s a common late summer bee in the Great Plains, but rare further east in the tallgrass prairies of Missouri, Illinois, etc.  The bee nests in the ground and seeks out sunflowers for pollen and nectar.

Another male.

Another male.

During the morning when I photographed this species, I saw quite a few different bees.  Most of them were males, and didn’t seem to be feeding on sunflowers as much as just hanging around the edges of the flowers – apparently waiting for a female to stop by.

I almost always embarrass myself when I go out on a limb with bee identification, but this bee looks like a female to me.  Look at how much fuzzier the rear legs are - a common sign of females because those hairs help store and transport pollen back to the nest.  The bees in the other three photos above don't appear to have the same kind of fuzzy legs.  (Ok, now Mike or someone else can tell me how wrong I am.)

I almost always embarrass myself when I go out on a limb with bee identification, but this bee looks like a female to me. Look at how much fuzzier the rear legs are – a common sign of females because those hairs help store and transport pollen back to the nest. The bees in the other three photos above don’t appear to have the same kind of fuzzy legs. (Ok, now Mike or someone else can tell me how wrong I am.)

I’ve only been learning about bees for a few years now.  It’s amazing how many different species – and behaviors – I see, now that I’m looking for them.  Before sending the photos to Mike, I was able to recognize these bees as being in (likely) the same species, and figured most of the ones I was seeing were males, based on their behavior.  I still have much to learn, but paying attention to bees has certainly changed the way I see our prairies.  As I wrote last fall, I’m definitely looking at our prairies through “bee goggles.”  We’re not managing our prairie exclusively for bees, but they definitely factor in to our management decisions – not just because they are important themselves, but because promoting quality bee habitat is a great way to help ensure quality habitat for many other species as well.

Posted in Prairie Insects, Prairie Management, Prairie Natural History, Prairie Photography | Tagged , , , , , , , , | 4 Comments

Caterpillar Crossing

While driving through central Nebraska last week, I couldn’t help notice all the fuzzy creatures crossing the highway in front of me.  They weren’t raccoons, deer, or even voles.  They were tiny little caterpillars, and they were moving FAST.

This was a common site along Nebraska highways last week.

This was a common site along Nebraska highways last week.

I’m not entirely sure why the caterpillars are on the move, or where they are going.  Some internet searching turned up some university extension and similar pages that infer that the caterpillars are simply searching for a good place to spend the winter.  That could be true, but if so, they sure don’t seem to be doing it in any organized fashion!  There were just as many caterpillars crossing the road from left to right as there were from right to left.  It made me wonder if they just kept going back and forth…  (tiny little brains.)

As I drove, my scientist mind was spinning, despite my best intentions.  I kept track of the land cover types on both sides of the road, trying to figure out what kind of habitats the caterpillars might be leaving or heading for.  If there was a pattern, I didn’t see it.  The caterpillars crossed the road in places where there were soybean fields on both sides as well as places where there were miles of sandhills prairie on both sides.  They didn’t seem to be heading from high ground to low or from tall vegetation to short – or vice versa.

Another one.

Another one.

My photographer brain was also in full gear, which meant I had to keep stopping to take photos of the little buggers.  Fortunately, the roads I was traveling were not very well populated with other vehicles, but I still had to be discreet to avoid uncomfortable conversations.  Whenever I heard a vehicle coming I just pretended I was stopped to make a phone call or just to admire the view.  Otherwise, I would have ended up having conversations something like this:

“You okay?”

“Me?  Yeah, I’m fine.”

“Oh.  I just wondered why you were lying in the middle of the highway.”

“Um, yeah.  I was actually taking a photograph of a caterpillar.”

“A caterpillar.”

“Yeah.”

“In the middle of the highway?”

“Well, yeah.  I wanted to know why it was crossing the road.”

“Is that a joke?”

“No, but now that you mention it, it might not be a bad start to one…”

“So you don’t need any help?”

“No, I’m good, but thanks for asking.  I’m just trying to get some pictures.”

“In the middle of the highway.  On your belly.”

“Well, yeah.  You see, I’m a prairie ecologist.”

“Oh!  Why didn’t you say so?  Carry on then…”

Fuzzy caterpillar crossing the highway west of Taylor, Nebraska.
Anyway, I did manage to get some photographs of the commuting caterpillars.  I’m glad I did because seeing them up close made me realize there were several different species of them making the crossings.  I also (I can’t believe I’m admitting this) timed them to see how fast they were going.  What? I was just curious…

I wish the caterpillars well on their journeys.  There were surprisingly few smooshed caterpillars on the road, so I’m assuming the majority made it across the road.  I hope that means they found a nice place to spend the winter, or whatever they were looking for.

I also hope no one saw me photographing them.

Fuzzy caterpillar crossing the highway west of Taylor, Nebraska.

You probably don’t care, but in case you’re wondering, the caterpillars were making the 32 foot trip across the highway in about 80 seconds.  If my math is correct, that means they were traveling about 4.8 inches per second.  That’s moving right along for a tiny critter with stubby little legs!

Posted in Prairie Insects, Prairie Natural History, Prairie Photography | Tagged , , , , , , , , , | 20 Comments

Our New Mechanical Seed Harvester

Seed harvest is a big part of our work here at the Platte River Prairies.  We don’t do as much complete restoration (converting cropland to high-diversity prairie) as we used to because we’ve just about run out of land to restore.  Instead we’ve shifted most of our seed work toward overseeding degraded remnant prairies that are missing many prominent wildflower species.  As a result, instead of harvesting from 230 plant species a year, we’re mainly focusing on getting as much seed as possible from about 30 to 40 species.

Nelson Winkel harvests Maximilian sunflower seeds by hand.

Nelson Winkel harvests Maximilian sunflower seeds by hand.

Most of our seed harvest is by hand, and when needed, we’ve been able to get adequate seed for up to 200 acres of cropland conversion work per year that way.  We’ve also used mechanical means to supplement our hand harvesting, including a couple different combines we’ve owned and pull-behind seed strippers we’ve borrowed from partners.  The mechanical harvesters have been helpful for getting big patches of seed from some grasses, sedges, and a few forbs.  However, the combines we’ve used aren’t very flexible about where they can go (hills and wet areas are tough) and the seed strippers’ brushes haven’t been aggressive enough to remove seed heads of some of the species we really wanted big quantities of – especially for our overseeding work.  However, a recent grant from the Nebraska Environmental Trust, via the Nebraska Game and Parks Commission, made it possible for us to purchase a new mechanical seed harvester.

Here, Nelson is harvesting grass seed with a mechanical seed stripper borrowed from Prairie Plains Resource Institute.

Here, Nelson is harvesting grass seed with a mechanical seed stripper borrowed from Prairie Plains Resource Institute.

After exploring a number of options, we decided to buy a seed stripper from Ned Groelz at Graywind Industries, Inc.  Our friends at Prairie Plains Resource Institute bought a pull-behind stripper built by Ned many years ago, and we liked a lot of its features – especially the ability to remotely control the harvester’s brush on the fly (turning it off and on and adjusting its height while driving through the prairie).  When we ordered our machine, we told Ned we were hoping to harvest large amounts of seed from plants with tough-to-remove seedheads and we weren’t sure a brush would be able to handle those.  He said he’d play with some ideas and see what he could do about that.

When Ned delivered the machine to us, he had a big grin on his face – a sure sign that he’d come up with something for our tough-to-harvest seed problem.  His solution was to replace the harvester’s brush with a more aggressive tool that included “stripping elements” – metal fingers, essentially –  made by the Shelbourne Reynolds company.  (Shelbourne Reynolds sells an attachment for combines that strips, rather than cuts, the grain from crops such as wheat and rice.)  Ned adapted their design for use in his pull-behind seed stripper and he was dying to know whether it would actually work.  Just to be safe, he designed the machine so that we could easily remove his experimental portion and replace it with a tried-and-true brush if we wanted to.

A close-up of the Shelbourne stripper elements included in Ned's new harvester design.

A close-up of the Shelbourne stripper elements included in Ned’s new harvester design.

Ned was so interested in testing his new design, he came out a couple weeks ago to watch it in action.  Without going into a lot of details, let me just say – it works great!  So far, we’ve tested it on wild bergamot (Monarda fistulosa), stiff sunflower (Helianthus pauciflorus), and Illinois bundleflower (Desmanthus illinoiensis), as well as a few others.

The

Nelson and Ned watch the new stripper as it harvests seed from Illinois bundleflower.  The machine is offset from the UTV so the UTV doesn’t smash the vegetation down before it is harvested.

The stripper removes some stems and leaves, as well as seed pods, but leaves most of the plant behind.

The stripper removes some stems and leaves, as well as seed pods, but leaves most of each plant behind.

Ned and Nelson evaluate the performance of the new machine and talk about ideas for further improvements.

Ned and Nelson evaluate the performance of the new machine and talk about ideas for further improvements.

Hand-harvesting will still be an important component of our prairie restoration work. Many plant species are scattered here and there across a prairie and hand-harvesting is the only feasible way to obtain their seeds.  However, other plants occur in big patches, and this new machine is going to let us quickly harvest large quantities of seed from those, which will be a tremendous boon to our overseeding efforts.  We’ll need to do a little more seed processing (using hammermills and screens to separate seeds from the pods, stems, and leaves picked up by the stripper) than with hand-harvested seed, but that should go pretty quickly.

One of my favorite aspects of prairie restoration is the innovation displayed by people trying to come up with new effective ways to harvest seeds.  This new mechanical stripper is one more addition to a long list of those innovations.  Keep ‘em coming, folks!

For more information and pricing of Ned’s mechanical seed harvesters, contact him at:

Ned Groelz – Graywind Enterprises, Inc.

2927 W 700 S
Syracuse, UT 84075-9764
Mobile: 801-803-0412
E-mail ngroelz@gmail.com

I want to be perfectly clear -this post was not sponsored by Graywind Enterprises, and we paid full price for the seed stripper and its components.   All the opinions about this equipment and how it worked are just my opinions.  My intent is to let others know of the existence of this machine in case it can help move prairie restoration and conservation work forward.

 

Posted in Prairie Restoration/Reconstruction | Tagged , , , , , , , , , , , , , | 5 Comments

Photo of the Week – September 18, 2014

I’m writing this from The Nature Conservancy’s Niobrara Valley Preserve in north-central Nebraska, where I’m attending a prescribed fire planning workshop.  The weather up here is beautiful, and the prairies are already wearing their autumn colors.  The most conspicuous color on the landscape is the bright red of smooth sumac, which contrasts wonderfully with the more subtle browns and golds of the grasses.

Smooth sumac and prairie along the Niobrara River at The Nature Conservancy's Niobrara Valley Preserve.

Smooth sumac and prairie along the Niobrara River at The Nature Conservancy’s Niobrara Valley Preserve.

This photo was taken in one of the few parts of the Preserve that wasn’t impacted by the big wildfire of 2012.  I walked and photographed areas that were affected by the fire as well, and I’ll post some of those photos and descriptions soon.  In short, everything I saw is looking great; no significant invasive plant issues, complete recovery of grasslands, and positive developments under the burned pine woodland areas.

 

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Konza Prairie Trip Part 3 – Questions About Frequent Prairie Burning

A few weeks ago, I wrote about our trip to the Konza Prairie Biological Station in eastern Kansas.  On that trip, we learned about research results showing that frequent spring fires (one or two year frequency) can prevent encroachment of tallgrass prairie by trees and shrubs.  Less frequent fire allows shrubs, especially dogwood and sumac, to invade.  Pretty simple – we should be burning tallgrass prairie at least every two years, right?

Hang on just a minute, Sparky.

As you might expect, there is more to the story.  It turns out that the frequent spring fire (with no grazing) regimes at Konza has other impacts.  One example is that frequent fire favors grasses over forbs and decreases plant diversity over time.  Prairies that are burned every year or ever two years develop a grass-dominated plant community in which many forb species are difficult to find.  So, frequent fire is bad for plant communities…  Right?

Annually-burned tallgrass prairie at Konza Prairie, in the Flint Hills of eastern Kansas.

Annually-burned tallgrass prairie at Konza Prairie, in the Flint Hills of eastern Kansas.  August 2014.

But in other tallgrass prairies, especially in more eastern prairies such as those in Illinois, researchers are seeing very different impacts of frequent fire.  A paper by Marlin Bowles and Michael Jones, for example, found that frequent fire “stabilizes” plant communities in the Chicago, Illinois area, and that plant diversity was positively correlated with fire frequency.  In fact, their results are almost the exact opposite of what was seen at Konza.  In the Illinois study, frequent fire decreased the dominance of warm-season grasses and increased the diversity of summer wildflowers.

Frequently-burned prairie at the University of Wisconsin-Madison Arboretum.  Clearly, frequent fire is not incompatible with plant diversity...

Frequently-burned prairie at the University of Wisconsin-Madison Arboretum. Clearly, frequent fire is not incompatible with plant diversity…

What the heck is going on??

If we could answer that question, we’d be miles ahead of where we are now in terms of understanding prairie ecology.  I can come up with lots of potential reasons for the difference between frequent fire application in Illinois versus Kansas, but I can’t confirm or deny any of them – we simply don’t know.  As I think about why prairie plant communities might become more dominated by grasses over time, I wonder about factors such as small scale plant diversity, soil productivity, and the soil microbe community – all of which may correlated with each other.

Eastern remnant (unplowed) prairies tend to have a higher density of plant species (e.g., plant species per square meter) than western prairies. High species density could potentially help suppress grass dominance because of the variety of competition strategies each of those plant species employs to take and defend territory.  Those strategies include allelopathy (releasing chemicals that retard growth of nearby plants), rhizomes (underground stems that can connect even fairly distant stems of the same plant together), root density/depth, and many others.  It seems logical that communities with that kind of well-established complex competitive environment would present a major challenge for any species (grasses or otherwise) trying to become dominant.  Maintaining consistent growing conditions by burning or haying annually might facilitate stability within those plant communities because it essentially maintains a stalemate; no plant species is ever given a window of opportunity to gain advantage over its neighbors.  Or this could all be balderdash – I’m just throwing out ideas here.

Does the rich soil organic matter content of eastern tallgrass prairies help suppress grass dominance?  It’s probably the major reason for the higher plant species density in those prairies, so maybe.  On the other hand, research at Konza and elsewhere in more western prairies shows that adding nitrogen to prairies (increasing productivity) increases grass dominance and lowers plant diversity.  Hmm.

Soil microbial communities surely have a very important influence on plant diversity, but (as discussed in a previous post) we don’t know much about them yet.  I’m optimistic that our understanding of soil microbes will grow tremendously during the next few decades, but the complexity of that world might mean that it will take many more decades before we start to get a grasp on it.  In the meantime, we can use it as a convenient scapegoat.  If something you don’t like is happening to your prairie, it’s probably a soil microbe problem…

Those of you who read this blog frequently may be surprised that I haven’t mentioned insects or other animals yet.  Let’s talk about them now, shall we?

It’s very important to remember that even if frequent burning seems to maintain high plant diversity in (some) prairies, a prairie is much more than just plants.  The use of frequent fire tends to create fairly homogenous habitat conditions across a prairie.  Regrowth rates are similar across the whole burned area, so vegetation height and density is relatively uniform.  Dead material, including both litter and standing dead vegetation, is scarce.  Because habitat diversity is limited, so is the diversity of creatures that rely on that habitat.  In taxonomic groups ranging from grasshoppers and spiders to mice and birds, research shows that habitat diversity is positively correlated with species diversity.  Creating habitat heterogeneity – through grazing, patchy mowing, or other means can help facilitate a more diverse animal community.  Burning in a less regimented way can help too, especially if that means splitting a prairie into multiple management units and burning only a subset of those each year.

Habitat

Heterogeneous habitat structure, including tall, short, and mixed-height vegetation – like that shown here – can help maintain diverse invertebrate and wildlife communities.  Grazing is one great way to manipulate vegetation structure, but isn’t feasible at all sites.  Grazed prairie at The Nature Conservancy’s Platte River Prairies, Nebraska.

In small isolated prairies, it’s also critically important not to burn (or mow) the entire prairie at the same time.  With limited opportunities for species to recolonize from other prairies, a fire that kills all of the individuals of a particular species (e.g., an insect that overwinters in the stems of grasses or in the litter along the ground) can mean the end of that species’ existence in that prairie.  Maintaining a floristically diverse prairie without a full complement of invertebrates doesn’t seem like success to me.  On the other hand, I also appreciate the difficulties associated with managing small prairies.

To wrap this up, I think there are two really important points to make about fire frequency in prairie management.  First, there are some big questions about why frequent fire seems to maintain high plant diversity in some prairies but encourages grass dominance in others.  Figuring out the answers to those questions may be one of the more important keys to prairie conservation success.  Second, even if frequent fire maintains high plant diversity and repels invasion by shrubs and trees, it still might not be the best choice for a prairie management strategy.  There is much more to a prairie than its plants, and even if you don’t much care for invertebrates, birds, reptiles, or mammals (and how could you not?) those species – especially the invertebrates – are strongly tied to the long-term viability of the plant community, so it’s probably not good to ignore them.  To be clear, I’m not saying people who use frequent fire are evil destroyers of animals.  I’m just raising a flag of caution and pointing out some potential tradeoffs.

Prescribed burning is an important management tool, but its impacts on prairie communities can be complicated.

Prescribed burning is a valuable management tool, but its impacts on prairie communities can be complicated.  It’s important for prairie managers to recognize and account for both the negative and positive impacts of fire.

Those of us who work with prairies are used to the seemingly overwhelming complexity of grassland communities and the way those communities respond to management.  In fact, for many of us, it’s a big reason we love prairies as much as we do.  While we still have more questions than answers about effective prairie management, we have enough information to go forward with.  Most importantly, prairies are pretty tough, so excepting drastic measures such as broadcast spraying with 2,4-D (and maybe burning an entire tiny prairie), we have the latitude to try out lots of ideas and see what works.  We’ll learn as we go.

In the meantime, it’d be great if all you researchers out there would get cracking on the issue of disparate effects of frequent fire in eastern versus western prairies.  It should only take a few decades to figure it out…  Right?

 

Posted in Prairie Insects, Prairie Management | Tagged , , , , , , , , , , | 14 Comments

Photo of the Week – September 12, 2014

It’s grasshopper season!

Vehicles driving through the prairie on a late summer morning are quickly covered with dew, grass pollen, and GRASSHOPPERS.

Vehicles driving through the prairie on a late summer morning are quickly covered with dew, grass pollen, and GRASSHOPPERS.

By the end of summer, most grasshoppers have completed their five or so molts and have become adults – complete with functional wings.   Now, as we walk and drive through our prairies, these fully-formed adult grasshoppers (along with katydids and tree crickets) seem to be everywhere.  They explode from our feet like popcorn – especially in areas of shorter vegetation.  And they’re hungry.  We see them feeding on sunflowers, goldenrod, grasses and almost every other kind of plant in the prairie.  As in other groups of species, the diversity of grasshopper species (108 species in Nebraska) leads to a diversity of feeding habits.  Some feed high in the canopy, others low.  Some feed mainly on grasses, others on forbs.  Some eat from a wide range of species, others from just a few.

This grasshopper was feeding on the pollen of stiff sunflower - an apparent favorite of many adult grasshopper, katydid, and tree cricket species.

This grasshopper was feeding on the pollen of stiff sunflower (Helianthus pauciflorus) – an apparent favorite of many adult grasshopper, katydid, and tree cricket species.

Another grasshopper species (probably) also feeding on stiff sunflower.

Another grasshopper species (probably) – also feeding on stiff sunflower.

Tree crickets get in on the stiff sunflower pollen feeding frenzy too.

Tree crickets get in on the stiff sunflower pollen feeding frenzy too.

Predators, of course, respond enthusiastically to the profusion of grasshoppers.  Rather than taking over the world, late summer grasshoppers become the targets of any creature that can catch up with them.  This includes birds, mammals, reptiles, and large invertebrate predators, but also tiny parasites and microbes.  To hungry predators, grasshoppers are just tasty machines that convert vegetation into protein-rich food – and they’re EVERYWHERE!

'Hoppers and their kin, but they can also be skilled at keeping themselves hidden when they see a potential predator.  This katydid didn't like me sticking my camera lens in its direction.

‘Hoppers and their kin, but they can also be skilled at keeping themselves hidden when they see a potential predator. This katydid didn’t like me sticking my camera lens in its direction.

The prairie is also a noisy place when grasshoppers, katydids, and tree crickets reach adulthood.  Much of the communication between these species is through sound, and it can be hard to hear the rustling of autumn prairie leaves in the wind over the buzzes and whines of insect courtship.

Besides leading females to males, that incessant insect noise acts as a warning to herbivore and predator alike…

“You’d better eat up now – winter is coming!”

 

Posted in Prairie Insects, Prairie Natural History, Prairie Photography | Tagged , , , , , , , | 8 Comments

Using a Tree as a Giant Diffuser for Macro Photography

I want to start by acknowledging the irony in this post.  As someone who has spent a lot of time killing trees in prairies and urging others to do the same, it’s pretty funny that this post is all about the positive aspects of having a big tree in a prairie wetland.  In my defense, I’ve never said there shouldn’t be ANY trees in prairies, and I’m writing this particular post as a photographer, not an ecologist.  Matt H and other tree lovers – this one’s for you. 

I was out on the edge of one of our restored wetlands last week as the sun was coming up.  The wind was calm, the weather was cool, and I was hoping for some nice close-up photos of flowers and insects.  Most photographers know that first light is a great time for photography because the sunlight is soft and warm as the sun pops over the horizon.  Often, a little haze or thin cloud cover near the horizon can extend that period of nice diffused light as the sun rises higher.  Last week, however, there was no haze or cloud cover to help out, and I only had about 10 minutes between the time the sun breached the horizon and the point at which the light was too bright to make good photos.

Fortunately, (I can’t believe I’m saying this) there was a big cottonwood tree nearby and I had the opportunity to use a little trick I’ve found useful for extending my time window for close-up photography.  Essentially, I just followed the shadow of the tree as the sun rose into the sky.  I didn’t take pictures in the shade, exactly, but neither did I take pictures in the sun.  I used the very edge of the shadow.

Here's my elegant diagram of how to use the diffused light found right at the edge of the shadow of a tree in the first hour or so after sunrise.  I find a composition near the edge of the tree's shadow and then wait until the light just starts to pop through the top of the tree's leaves to snap the shutter.

Here’s my elegant diagram of how to use the diffused light at edge of a tree’s shadow during the first hour or so after sunrise.  As the sun rises, the tree’s shadow shortens, but in the soft edge of the shadow, the light is beautifully diffused and perfect for close-up photos.  I find a composition just inside the edge of the tree’s shadow and then wait to snap the shutter until the rising sun’s light just starts to pop through the upper leaves of the tree.  Then I move closer to the tree, find another subject, and start the process again.

The boundary of the shadow created by a big tree is not a hard edge.  Instead, there is a narrow zone of diffused light between complete shade and bright sunlight.  That narrow zone creates some nice opportunities for photography.  Essentially, I just follow the shadow as it moves across the ground.  I find potential photo compositions inside the shadow and then take the picture as the edge of the shadow passes by.  I have to work quickly because the shadow moves right along, but I usually have enough time to get several shots of each subject in nice light.

Here are some photos from from last week’s tree-diffused light.

I had time to take 4 or 5 quick shots of this great lobelia (Lobelia siphilitica) before the shadow moved away completely and the light got too bright.  The Nature Conservancy's Platte River Prairies, Nebraska.

I had time to take 4 or 5 quick shots of this great lobelia (Lobelia siphilitica) before the shadow moved away completely and the light got too bright. The Nature Conservancy’s Platte River Prairies, Nebraska.

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Several species of beggarticks (Bidens) grow along the edge of wetlands along the Platte River.

Several species of beggarticks (Bidens) grow along the edge of wetlands along the Platte River.

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Field mint (Mentha arvensis) is another wetland edge plant.  Plants in the mint family usually have a pronounced square stem.

Field mint (Mentha arvensis) is another wetland edge plant. Plants in the mint family usually have a pronounced square stem.

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This damselfly was the only one I successfully photographed - out of more than a dozen I stalked.  I crept slowly up to it with my tripod while it was still in the shade of the tree and then got my photo as the shadow's edge came across it.

This damselfly was the only one I successfully photographed – out of more than a dozen I stalked. I crept slowly up to it with my tripod while it was still in the shade of the tree and then got my photo as the shadow’s edge came across it.

Interestingly, our staff has had several discussions over the years about whether or not we should cut down the big cottonwood I used as a photo diffuser last week.  There are some good ecological arguments for taking it out.  For example, large trees act as perches for predatory birds and can affect the way other birds use nearby habitat.  Migratory sandhill cranes (a focus of our wetland management) tend not to roost near trees, and many breeding bird species avoid nesting near them as well.  In addition, trees often act as gateways for invasive plants because they create a different microclimate that favors some invasives (especially cool-season grasses) and because they attract perching birds that drop seeds of other invasives.

Good ecological arguments can be made for keeping the tree too – including some that are similar to the arguments against it.  It’s kind of nice to have a big tree for eagles and other large predatory birds to hang around in because predators are important players in the ecosystem.  Orioles, red-headed woodpeckers, kestrels, and many other bird species – including some of conservation concern – nest in big cottonwoods.  Also, the plants that grow beneath cottonwoods are not all invasives, and include some nice native species such as Jerusalem artichoke, Virginia wild rye, and many others.

To be honest, the biggest factor that has swayed our discussions about the tree is its size.  No one has really felt like tackling the job of cutting it down, so the arguments to keep it have gained the upper hand.

I guess that’ll be ok…

 

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

Photo of the Week – September 4, 2014

It’s not often the wind is calm enough to get a good sharp photo of a spider in its web, but everything came together nicely late last week as I walked around one of our restored wetlands.  There were a number of long-jawed orbweaver spiders (Tetragnathidae) in their webs, but this one was the most accomodating…

A long-jawed orbweaver in early morning light.  The Nature Conservancy's Platte River Prairies, Nebraska.

A long-jawed orbweaver in early morning light. The Nature Conservancy’s Platte River Prairies, Nebraska.

Of course, I missed a great shot of a nearby spider that had caught a mosquito.  The light was great, the composition was going to be fantastic, but my tripod leg bumped the grass stem holding the web and the spider hightailed it to safety.  Oh well.  I still got to see and enjoy it – I just can’t share it with you.

 

Posted in Prairie Insects, Prairie Natural History, Prairie Photography | Tagged , , , , , , , , , | 3 Comments