Photo of the Week – March 19, 2015

Proof that I’m a biologist:  While driving along a gravel road near our shop this week, I stopped and backed up to see if I’d seen a small snake or just a piece of debris in the road…

A redbelly snake (Storeria occipitomaculata) found in Hall County, Nebraska.

A redbelly snake (Storeria occipitomaculata) found in Hall County, Nebraska.

I’m glad I stopped.  It turned out to be a redbelly snake, a species found in only a few counties in Nebraska.  I think it’s the third one I’ve found in our Platte River Prairies, dating all the way back to when I was working out here as a graduate student in the early 1990’s.

Not a lot is known about the habits or habitats of redbelly snakes in Nebraska.  When I got home with some photos, I contacted herpetologist Dan Fogell to confirm the identity of the snake and learn more about it.  Rather than getting a lot of information from Dan, he instead peppered me with questions about where and when I found the snake because he’s trying hard to gather data and better understand the species.

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This was a big snake (for a redbelly). It was close to 11 inches in length, which is about the maximum size for this species.

 

Jasmine (one of our Hubbard Fellows) held the snake to show the colorful underside it is named after.

Jasmine (one of our Hubbard Fellows) held the snake to show the colorful underside it is named after.

This particular snake was on a gravel road between two crop fields when I happened upon it.  The road ditches were full of old matted-down smooth brome grass.  It didn’t seem like particularly friendly habitat for wildlife.  Was the snake living in those ditches?  Or traveling to other habitat?  There was a small woodlot a couple hundred yards away, and a stream across the cornfield to the north…  We released the snake where we found her, so whatever habitat she’s looking for, I hope she finds it.

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There are a lot of species we just don’t know much about – not just tiny invertebrates, but also relatively large (and beautiful!) vertebrates.  It’s another reminder of how important the collection of basic natural history information is.  Conservation is difficult, but even more so when we don’t even know much about the species and natural systems we’re working to conserve.

I’m grateful that I had the opportunity to see and admire this snake.  I hope my kids get the same chance.

Posted in Prairie Animals, Prairie Natural History, Prairie Photography | Tagged , , , , , , | 13 Comments

Hubbard Fellowship Blog – The Trouble With Fences

This post is written by Dillon Blankenship, one of our two Hubbard Fellows.  

Back in December we kept pretty busy with fence work. The barbed wire fences at a few sites needed to be repaired, and some had to be taken down and rebuilt from the beginning. Single wire electric fences were taken out altogether and will be replaced this spring to accommodate new grazing configurations.

The barbed wire fences we removed were old and in bad shape. Their wire was loose and rusty; t-posts were bent over or leaning.

When we acquire properties, fences are often in bad shape.  This one has multiple layers and ages of barbed wire and needs to be removed and replaced.

When we acquire properties, fences are often in bad shape. This one has multiple layers and ages of barbed wire, has shrubs and trees grown into it, and needs to be removed and replaced.

I am struck by how dramatically the landscape is changed by the mere removal of a fence. Despite the remaining row of interspersing trees or scraggly smooth brome, fencelessness returns a semblance of the infinite horizon. Of course, I want to see the trees and brome erased too, but these things take time and getting the old fence out of the way begins the process.

Even when the next piece of land is a dusty field of corn stalks – much less imposing post-harvest- the lack of fence is liberating. I am free to view the landscape as it once was and I imagine that wildlife can more freely roam about the planet.

Though it is easy to romanticize the open range, fences obviously have some utility.

Barbed wire fencing is a relatively inexpensive way of delineating property boundaries. It confines one’s own livestock and/or protects crops and pasture from being damaged (by stray vehicles, your neighbor’s cattle, etc.). In our restoration work on the Platte we use fences not just to keep cattle in, but also (using single strand electric) to manipulate where and when they graze to suit our particular management objectives – such as controlling certain plant species or promoting others while maintaining a diversity of habitat types.

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Barbed wire fence is the most common type of fence used in most pastures.  It is strong and effective.  It is also visually prominent, and whether or not it is attractive depends upon your point of view.

Though these are compelling reasons to keep fences around, I remain frustrated by the inconveniences they create. I have already mentioned the aesthetic inconvenience. To my eye – even with agriculture playing a prominent role in the landscape mosaic – the Plains look more expansive and beautiful without fence lines. The image of an unfenced pasture is striking for its rarity.

Fences can also be problematic for certain wildlife. While deer are pretty good at jumping over most fences, animals further west like bighorn sheep and pronghorn need special accommodations for safe passage. Free-roaming bison, of course, have little hope in our highly fenced world – we must confine them to their own big area saying “this is yours, but go no further.” Even birds are affected, sometimes colliding with and becoming entangled in barbed wire. Field fences, though not insurmountable, present their own challenges for ground dwelling creatures.

This duck got hung up and died on a fence along the edge of a wetland.

This duck got hung up and died on a fence along the edge of a wetland.

My biggest complaint is that fence lines are often poorly managed. They can be difficult to work around when treating invasive species, which makes them prime habitat for encroaching trees and exotic plants. Substantial tree lines are common along fences in central Nebraska. In many cases, I suspect the fence came first. While a fence itself is usually not too problematic from a grassland habitat perspective, fences that grow up with trees begin to act as fragmenting agents – deterring grassland bird nesting and generally diminishing the openness favored by grassland species.

So where does that leave us?

There are already a lot of good ways to mitigate fence impacts for wildlife – increasing visibility for birds and using smooth wire with particular spacing for large mammals. Sometimes wooden fences are better alternatives, though more resource intensive (got any spare cedars?). While these address the wildlife objection, they don’t do much for the aesthetic or management elements.

Single-strand, smooth wire, electric fences are simple and temporary, offering reprieve from the oppressive four-strand barriers and better accessibility for management – you can drop the wire and drive right across. Moreover, when you move these fences every year like we do, fence-line management is less of a problem because the following year any given line-site will be back in the management regime of fire, grazing, and manual treatment. This system suits my preferences well, but its greatest assets are also its ultimate downfall.

Even when electrified, single wire fences are often not enough to keep cows in – and, I imagine, never keep in sheep or goats. Also, deer are pretty good at going right through, knocking the wire off the insulators – which is hard to monitor when you have a lot of wire out there. I was going to say that their temporary-ness was another drawback – a guarantee that you have to work fence every year. However, tree and exotic species management need to happen every year anyway, so maybe it wouldn’t be that much work and I feel like removing 20 years of trees from an unmaintained fence probably takes much more time than monitoring and moving temporary fences.

Bison fence at The Nature Conservancy's Broken Kettle Grasslands in Iowa.

Bison fence at The Nature Conservancy’s Broken Kettle Grasslands in Iowa.

My dream of fencelessness is really thwarted at scale. At places like TNC’s Niobrara Valley Preserve with over 50,000 acres to manage, you really just need a sturdy fence that doesn’t have to be constantly checked… or so I thought. I recently learned about innovations in fencing that have been experimented with over the last decade. I had been thinking that something like the invisible fences people use for pets might be an interesting option to scale up, but there are better systems already in play.

Instead of building (or burying) an actual fence, there are folks putting GPS collars on cows and then using digital mapping software to “draw” fences on the landscape which deliver a slight shock (like an electrified fence) when cows cross the satellite-imposed boundary. These digital fences can be placed at property boundaries, around sensitive vegetation or aquatic features, and across a pasture to suit a particular grazing regime – all with the swipe of a computer cursor. It could be modified on the fly, which is even easier now that so many people are carrying smartphones (this technology is already being utilized for things like increasing center pivot irrigation efficiency via monitoring and adaptive management). Doesn’t that sound incredible? No fences breaking up the landscape (which is aesthetic, but also means less work for ranchers), safer corridors for wildlife, less potential for tree encroachment, and better accessibility for managing invasive weeds. Cool.

The system is bound to have its own problems – technical glitches will happen on occasion (with the software or and the collars), there will be new opportunities for trouble-makers to tamper with private property (“digital cattle rustlers”), star-up costs, you name it – but I really like the potential something like this has for prairies and the ranching community.

Nonetheless, most of us aren’t quite there yet, which brings me back to the old-fashioned fence. For now I guess I’ll have to get over it and get on to other things; just manage my own fence better and become hardened to the unavoidable taunting of unnatural tree lines and fence rows on the landscape.

It feels good to vent a little bit here. As it warms up I cease writing and return to work on the post and wire repairs. I return to the prairie and reflect on these musing, “Alas, this is a necessary, if unfortunate evil” and the new fence goes up. I find solace that its days could be numbered.

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Photo of the Week – March 12, 2015

We conducted our first prescribed burn of the Spring this week.  It was very small – about an acre or so – surrounded by gravel roads.  The first burn after a long winter is always a little rocky; everyone’s a little out of practice, the crew isn’t yet used to burning with each other, and equipment hasn’t been fully tested…  So it was nice to start small, though the low humidity and warm day made it plenty exciting, even within a small, safe unit.

After the smoke cleared and everyone headed out, I stuck around and poked around in the ashes a little.  I found a patch of prickly pear cactus scorched by the fire, and liked the patterns of color and texture, so I grabbed my camera.

Prickly pear cactus after a prairie fire.  Fire doesn't kill the plants, but does set them back for a while.

Prickly pear cactus after a prairie fire. Fire doesn’t seem to kill the plants, but does set them back for a while.  The Nature Conservancy’s Platte River Prairies, Nebraska.

I was mesmerized by the colors and patterns in the scorched cacti.

I was mesmerized by the colors and patterns in the scorched cacti.

I photographed scorched cacti for an embarrassingly long time.  Then, since my knees were already black with soot, I wandered around a little more and photographed a few other interesting post-burn scenes.  I’m a little eccentric that way.  Here are some of the other images from the day – enjoy your weekend!

Tall dropseed (Sporobolus compositus) on ashes.

Tall dropseed (Sporobolus compositus) on ashes.

Common mullein leaves, fuzzy and partially blackened by fire.

Common mullein (Verbascum thapsus) leaves, fuzzy and partially blackened by fire.

Partially burned seed pods of fourpoint evening primrose (Oenothera rhombipetala).

Partially burned seed pods of fourpoint evening primrose (Oenothera rhombipetala).

The remains of a milkweed pod (Asclepias syriaca).

The remains of a milkweed pod (Asclepias syriaca).

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Every Little Bit Helps

I’m getting excited about this upcoming field season.  For the first time in several years, we’re going to be attempting to harvest seed from as many prairie plant species as we can.  Between about 1997 and 2005, we spent much of each field season hand-picking seeds from a broad diversity of species – often ending up with over 200 species by the end of the season.  It was exciting and fulfilling, and we were often able to create up to a couple hundred acres of new prairie habitat each year.  Since that time, we’ve focused less on converting cropland to high-diversity prairie (we ran out of cropland!) and more on harvesting large amounts of fewer species to overseed degraded prairies.  I’m not sure we’ll be able to harvest as many as 200 species this summer – we’re pulled in many more directions now than we were in our “glory years” of seed harvesting – but making the attempt will be fun.

A clonal patch of bracted spiderwort (Tradescantia bracteata) in a 2002 prairie planting.

A clonal patch of bracted spiderwort (Tradescantia bracteata) in a 2002 prairie planting.  It isn’t hard to find these patches (when they’re blooming) despite the fact that we had only about 1 cup of seed spread over about 70 acres.

During those glory years, we worked hard to build the most diverse seed mixture possible.  We used to joke about how many seeds we had to get from a plant species before we could add it to that year’s harvest list.  It kind of felt like cheating when we’d only find a handful or two of seeds from a species but would add it to the list anyway.  However, we justified listing those species because of conversations with people who had much more experience than we did (especially Bill Whitney with Prairie Plains Resource Institute) who claimed that even a few seeds would usually be enough to establish a species in a new prairie.  Besides, we figured if the species was appropriate to the site, tiny populations would spread out over time.

Now that I’ve had up to 17 years to watch the establishment of plantings I personally harvested seed for, I can testify that Bill and others were right.  Sometimes, just a few seeds really are enough.  That knowledge is awfully good for morale when we’re on our hands and knees searching for violet or pale poppy mallow (Callirhoe alcoides) plants to harvest from.  Those are just two or many examples of plants that are short, have widely scattered populations in our prairies, and are difficult to find at seed harvest time because the surrounding vegetation has grown tall enough to obscure them from sight.   To make things worse, neither of those species produces many seeds per plant, so even when you find a plant, you might only get 20-50 seeds out of it.  Knowing that those 20-50 seeds are worth finding makes crawling on hands and knees seem much less tedious.  Ok, a LITTLE less tedious.

Violets are difficult to find after they are done blooming.  Even when you find them,  each plant produces few seeds (and you have to get them before the pods pop open and toss the seeds away...)

Violets are difficult to find after they are done blooming. Even when you find them, each plant produces few seeds (and you have to get them before the pods pop open and toss the seeds away…)

Last week, I finally found time to finish data entry from my 2014 plant community monitoring of some of our restored prairies.  Looking through the long-term data trends, it was gratifying to see hard evidence that small amounts of seed really do turn into robust plant populations.  Here are a few examples.  (Warning: this next portion of the post includes actual graphs of actual data.  If you are turned off by graphs or data, please skip to the last paragraph now.)

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Data from a mesic restored prairie with sandy/loam soil and scattered sand ridges.

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Data from an upland sandhills restored prairie.

In the above two graphs, similar trends can be seen for populations of stiff sunflower (Helianthus pauciflorus) and Missouri goldenrod (Solidago missouriensis).  These data were collected from approximately 100 1×1 m plots across each site, and the graphs show the % of plots within which each species was present.  The top site (mesic) was sampled annually and the bottom (sandhills) was sampled every other year.

It might look as if Missouri goldenrod is a rare plant in these prairies, but remember that in order to show up in more than a couple 1×1 m plots, it has to be fairly abundant.  Stiff sunflower, on the other hand really is ubiquitous.  Interestingly, only about 3 gallons of fluffy/stemmy Missouri goldenrod seed was in the mix for the  70 acre mesic site and 10 gallons for the 110 acre sandhill site.  About 5 gallons of sunflower seed (still in hulls, with some stems included) was planted in the sandhills and 3 gallons in the mesic site.  Both are fairly respectable amounts of seed given that they were hand harvested, but they were spread pretty thinly across 180 acres.

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The second two graphs (above) show two perennial species, a grass named Scribner’s panicum (Panicum oligosanthes) and the short-beaked sedge (Carex brevior), as well as the annual grass six-weeks fescue (Vulpia octoflora).  The two perennials seem to be on a slow steady climb in abundance across both sites, which is excellent.  Meanwhile, the annual appears to be doing what annual plants should do, which is to flourish during periods when competition from surrounding plants is temporarily suppressed.  We had harvested very little seed for all three of these species that year, so it’s gratifying to see that they are becoming part of the established plant community.  Specifically, we had:

– only 7 cups (!) of seed for the short-beaked sedge across 180 acres (both sites combined).

– about 2 gallons of stemmy seed for Scribner’s panicum.

– 3 1/2 cups of six-weeks fescue (tiny seeds) for the sandhills and 1 cup for the mesic site.

I knew we hadn’t collected much seed for these species, but I was still surprised by how little we’d had when I went back to check the records.  There are many other examples I could share of species that established very nicely (and/or are increasing over time) despite small amounts of seed in the planting mixture.  Some of those species established fairly quickly, but most are slowly increasing in abundance, either through clonal (rhizomatous) growth or because each new generation of plants puts out more seed to spawn the next generation.

Fourpoint evening primrose (Oenothera rhombipetala) established well in the sandhills restoration despite only 2 cups of seed planted.  The biennial species is episodic in its abundance, but

Fourpoint evening primrose (Oenothera rhombipetala) established well in our sandhills restoration despite less than 2 cups of seed planted on 110 acres. The biennial species is episodic in its abundance – just as it should be.

The seed we harvest this coming season will be planted on about 50 acres – far fewer than the 150-200 acres we planted each year before we ran out of cropland to restore.  However, regardless of planting size, the major challenge is still to find and harvest seed from a diverse mixture of plant species.  We’ll be digging out our old lists of species, harvest times, and notes about where the best plant populations can be found.  Then we’ll strap buckets to our waists and start picking seeds.  It should be a fun year!

…and on those days when we’re laboriously searching for tiny plants hidden beneath tall grass, we’ll remember that with seed harvesting, every little bit helps!

Click here for more information on prairie restoration in Nebraska.

 

 

Posted in Prairie Plants, Prairie Restoration/Reconstruction | Tagged , , , , , , , , , | 16 Comments

Photo of the Week – March 6, 2015

Ok, it’s not a world class photo from an artistic standpoint, but it tells a story.  I just wish I knew what the story was…

Hot cross buns?

Hot cross buns?  Little mounds of snow apparently pushed up by a small mammal tunneling beneath the snow.   Restored prairie at Deep Well Waterfowl Production Area, west of Aurora, Nebraska.  February 2015

I noticed these two small mounds of snow last month in a restored prairie west of town.  I was scurrying around with my camera as the sun dropped quickly toward the horizon, hoping to get some photos before the light disappeared.  The mounds were maybe 3 inches in diameter, and when I looked straight down at the left one, I could see a small tunnel leading straight down.  If I hadn’t been distracted by the fading light and my self-imposed urgency to use it photographically, I would have done the smart naturalist thing and dug around to see what the tunnels looked like.

My guess is that these were formed by a tunneling vole that needed to push some snow up and out of its tunnel, but I’m not sure I’ve seen this before.  There were no tracks above the snow that would have indicated a deer mouse or other similar creature.  Any other suggestions?

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Hubbard Fellowship Blog – Plains Pocket Mouse

This post is written by Jasmine Cutter, one of our Hubbard Fellows.  She has been studying the way small mammals use our restored and remnant prairies.

Remember when I said I was going to highlight some more of our small mammal species? Well, at long last, here’s the second installment!

The plains pocket mouse.

The plains pocket mouse (Perognathus flavescens).  So Cute!  Notice the small eyes, small ears, and white dot under the ear.  Top tends to be brown/buff-colored, with a yellowish line along its side and a white underbelly.  Photo by Chris Helzer

Arguably the sleekest and most adorable of the critters I caught, the most distinguishing feature of the plains pocket mouse (Perognathus flavescens) is its fur-lined cheek pouches. Fur-lined cheek pouches!!! Imagine if, when you opened your mouth, on each side there was a little fur-lined pouch that ran all the way back to almost your shoulders! Gives me the heebie jeebies to think about, but pretty awesome if you’re a pocket mouse. The diet of the plains pocket mice is almost entirely grass and weed seeds, and the pouches allow them to carry seeds back to their burrows and cache them.

Based on what I read, it’s thought that the purpose of these pouches being fur-lined is to conserve spit. Pocket mice and their relatives (other pocket mice, kangaroo rats, kangaroo mice) are often associated with arid environments and these critters are all extremely water efficient. The thought is that if pocket mice had a hamster-like pouch, then every time they spit out the seeds they were carrying they’d be wasting precious moisture. If the pouches are fur-lined, then no spit wasted!

fur-lined pockets

Look at those cheek pouches!  Remember, I was only holding this critter for a few seconds before I released it.  only a temporary undignified moment, and then back to the sandhills!

These adaptations help the plains pocket mice go for six weeks without water! Most of the moisture they need is obtained from seeds and their kidneys are extremely efficient. Furthermore, their habits also lend to water conservation; pocket mice spend most of the day underground in burrows where it’s cooler and more humid, they plug their entrance holes to keep in moisture (and keep out predators), and they can change slow their metabolism (enter torpor) when it’s too hot or too cold.

The other crazy thing about the plains pocket mouse is that it is not closely related to any of the other rodents* that I caught. Those other rodents  — northern grasshopper mouse, deer mouse, harvest mouse, voles — all belong to one taxonomic family Cricetidae (which includes true hamsters, voles, lemmings and New World rats and mice), whereas the plains pocket mouse is from the family Heteromyidae. Heteromyidae includes kangaroo rats, kangaroo mice, and pocket mice, though none are technically rats or mice. In fact, the plains pocket mouse is more closely related to pocket gophers than to any other rodent I caught!

This is a very simplified phylogenetic tree of the Order Rodentia. Phylogenetic trees show the inferred evolutionary relationships among species based on similarities/differences in physical and/or genetic characteristics. So whenever two branches come together, it's understood that the join represents the most recent common ancestor. FYI, there are a lot of other critters in the Order Rodentia that are not shown; there are 5 suborders I'm not showing and many branches that diverge from those suborders. Also length of lines is for convenience and doesn't represent any timescale.

This is a very simplified phylogenetic tree of the Order Rodentia. Phylogenetic trees show the inferred evolutionary relationships among species based on similarities/differences in physical and/or genetic characteristics. So whenever two branches come together, it’s understood that the join represents the most recent common ancestor. FYI, there are a lot of other critters in the Order Rodentia that are not shown; there are 5 suborders I’m not showing and many branches that diverge from those suborders. Also length of lines is for convenience and doesn’t represent any timescale.

All this is very interesting, but doesn’t help you identify a plains pocket mouse if you saw it in the field… In my mind, its key identifying features include its small size (usually 7-15 grams, 99-150mm nose to tail tip), small ears usually with a white dot below them, grooved upper incisors (if you hold them by their scruff, you’ll see a line down each upper incisor), and of course, their cheek pouches! They tend to be dark on their back, with a yellowish (“buff-colored”) line on their sides and white/pale underneath.

They are most frequently found in (usually sandy) areas with friable soil. Sandhills are a good bet, as are other fields that have open sandy patches, especially ones that are grazed so they’re more open. In general, plains pocket mice seem to prefer sparsely vegetated areas (hopefully my data will test whether that holds up on our properties).

The author collecting vegetation data for her small mammal research project.

The author collecting vegetation data for her small mammal research project.  Photo by Chris Helzer

In terms of why we care about them, well, they have awesome cheek pouches and barely need any water!!! What else do you want?? Just kidding, there are many more reasons why it’s worth paying attention to them. Most importantly, we still don’t know that much about them. Not a lot is known about their mating or winter habits, and until recently there were sizable gaps in our understanding of their distribution in Nebraska (see Geluso and Wright 2012).

The plains pocket mouse can be found throughout the Great Plains – from Northern Mexico to Minnesota and the Dakotas; yet, it’s local distributions are less well understood. There also seem to be noticeable differences between critters on the western end of their range and the eastern end. So much so, that there are two recognized subspecies of the plains pocket mouse. There is a western subspecies, P. f. flavescens and an eastern subspecies, P. f. perniger.** The eastern subspecies is considered rarer and has been deemed a Tier 1 At-Risk species by the Nebraska Game and Parks Natural Legacy Program.

Look!  A photo of me taking a photo of a pocket mouse!

A photo of me taking a photo of a pocket mouse!

Our Platte River Prairies are right at the edge of the alleged dividing line between the range of the western subspecies and the range of the eastern subspecies, which makes it an especially interesting place to study them. Are we seeing the eastern subspecies, or the western? At this point, the answer seems to be “yes!” Hopefully our population(s) will help the experts to parse the differences between the two subspecies and their range. Trying to define ranges is always tricky, especially because sometimes it’s hard to tell whether a species is actually not in a place, or if people just haven’t looked for it there.

All of this is to say that there’s a lot more work to do! It’s exciting to study a critter that is still fairly enigmatic, and I’m excited to see what future studies discover both in terms of life history knowledge and range/subspecies questions!

* Rodents are from the Order Rodentia, i.e., all the critters I caught except the shrews, the weasel, and the frog.

** The differences between the subspecies are very nuanced and my previous description (and pictures!) should still allow you to identify them as a plains pocket mouse.

Posted in Hubbard Fellowship, Prairie Animals, Prairie Natural History | Tagged , , , , , , , , , | 4 Comments

Photo of the Week – February 27, 2015

Here are two photos that are completely unrelated to each other.

Why?  Because I feel like it.

So there.

An old truck in a snowy prairie.  Leadership Center Prairie - Aurora, Nebraska.

An old truck in a snowy prairie. Leadership Center Prairie – Aurora, Nebraska.  February 2015.

Long-horned bee (Melissodes sp) on stiff sunflower (Helianthus pauciflorus).  The Nature Conservancy's Platte River Prairies.

Long-horned bee (Melissodes sp) on stiff sunflower (Helianthus pauciflorus). The Nature Conservancy’s Platte River Prairies.  August, 2014.

Ok, I guess both photos were taken in a Nebraska prairie.  That’s makes them kind of related, right?

5 points to anyone who can come up with other good (or at least funny) suggestions of relationships between the two images.

Have a good weekend.

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Ice Jam Flooding

As I mentioned last week, recent ice jams on the Platte River caused some flooding in some of our prairies.  I was able to photograph the flooding from a couple perspectives.  On February 5, we got some aerial footage with our drone, and then late last week, I walked through some of the flooded area after most of the water had receded.

This road was closed due to flooding.  Everything to the right (north) of the road is prairie.

This road was closed due to flooding. Everything to the right (north) of the road is prairie.

windmill

Another shot of the same area from higher up.  The river can be seen at the very left edge of the photo.  A windmill can be seen in the prairie near the right edge.

This was and will be an ecologically-interesting event from several standpoints.  Floating ice and ice jams have been an important component of the Platte River ecosystem for a very long time.  Ice likely played a critical historic role by helping to scour vegetation from sandbars, allowing that sediment to be carried off and deposited elsewhere, and creating valuable habitat for many species – including the ducks, geese, cranes, and other water birds that pass through during migration.  Today, we see much less of that scouring and many sandbar islands and banks have become relatively permanent and covered by trees and other perennial vegetation.

river channels

River water flowing through prairie.  Most Platte River floodplain prairies still have their river-formed topography of sloughs (old river channels) and ridges (old sandbars).  During the flood, many of those sloughs became active (albeit temporary) river channels again.

Before the Platte River’s channels were stabilized and restricted to their current locations by human activity, ice jam flooding might have been an important driver of the shifting of channel locations over time as well.  This year’s flood created new river channels through floodplain prairies and woodland, but as the water receded, it returned to its stabilized channels.  Historically, the river was a broad series of braided channels, and flood events would have changed the shape and location of those channels frequently – though I don’t know how important ice jams were relative to annual high flows from Rocky Mountain meltwater.

I have a few predictions about how this year’s flood will impact prairies, but they are just educated guesses….

The grasslands that were covered by water for a few weeks will get a boost in their soil moisture for this upcoming season.  We’ve had a relatively dry winter, so that soil moisture should create some very different growing conditions for plants in flooded versus non-flooded prairies.  Depending upon a number of variables, flooded areas might also retain more standing water in sloughs, creating valuable habitat for many wildlife species.

fences

Floodwaters carried grass and other debris into fences and pushed them right over.

The flooding carried more than just large chunks of ice out of the river and through the prairies.  It also picked up and carried downed trees and branches, along with other assorted buoyant objects, natural and man-made.  In addition, the ice and water scraped vegetation from some places and deposited it elsewhere.  We burned a portion of prairie last year and left it ungrazed as a seed harvest site, so it was covered in tall big bluestem and other grasses.  The ice essentially shaved some of that area as it came through, scraping away most of the standing vegetation and leaving behind a site that now looks as if it had been intensively grazed.  That shaved off grass was deposited further downstream along obstacles (such as fences) and in high spots as the water levels dropped.  As a result, some areas of prairie are now covered by a foot or so of fairly dense thatch.  It will be fun to watch how that thatch affects vegetative growth and wildlife use.

shaved

This area was burned last spring and ungrazed.  Before the flood, it was a stand of tall dense big bluestem and other tall grasses.  The ice and water essentially shaved the tall stems and leaves off and carried them away.

This Canada goose appeared to view the

This Canada goose decoy appeared to view its new surroundings with equanimity (look it up, Dillon) after being deposited by receding flood waters.

this

A second decoy looked a little less at ease.

thattch

This layer of flood-deposited thatch is about a foot thick.  It will be interesting to see what impact it has on vegetation beneath it.

I’m guessing most of the impacts of this flood will be positive, or at least interesting, from a land management standpoint.  One exception is that we’ll have some fairly major fence repair to do this spring.  A bigger concern is a potential influx of invasive plants carried in to our prairies as seed or vegetative material from the river.  Phragmites, reed canarygrass, and purple loosestrife are probably the most likely and potentially serious invaders, but others such as Canada thistle, salt cedar, and Russian olive are also possible.  We’ll need to be vigilant over the next few seasons to make sure we catch new populations of those invaders before they can become well-established.

This ice

Ice fields like this make it difficult to travel across the prairie and get a full picture of what was flooded and what wasn’t.

Once the remaining ice melts away,  we’ll get out and explore more of our flooded areas.  After we have mapped out (at least generally) the boundaries of the flooded areas, we’ll watch and evaluate what impacts the ice and water actually have on the prairie this season and beyond.

And then we’ll  see how good my predictions are…

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Photo of the Week – February 20, 2015

Nebraska’s Central Platte River always becomes a focus of attention about this time of year as migratory ducks and geese descend upon the river by the thousands and millions, followed shortly after by a half million sandhill cranes.  This year, the river grabbed our attention a little early when ice jams shunted flowing water across several thousand acres of nearby land, including some of our prairie.  I’ll provide some more descriptions and photos of that event next week, but for today, here are two images I took yesterday as I walked around an ice field sitting on top of that prairie.

(And don’t worry, the flood shouldn’t cause any major damage to the prairies, though we’ll be watching closely for a potential influx of invasive plants brought in by the water and rebuilding a few fences.)

Ice

A crust of ice across the top of a prairie slough cracked apart as the water receded beneath it.  The Nature Conservancy’s Platte River Prairies, Nebraska.

ice

A prairie slough, normally a groundwater-fed wetland, flowed with river water for a week or so during the flood.

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More Timelapse and More Wetland Restoration

Having just downloaded nearly two months of images from the timelapse cameras at our Derr Wetland Restoration Project (I showed photos and video from this site last week as well), I went through the images to see what stories the photos might tell.  Long term, of course, those images will help show changes in water levels, habitat conditions, and many other aspects of the site, but even in the short term, the timelapse images tend to have interesting stories to tell.

Canada geese on the Derr Wetland Restoration.

Canada geese on the Derr Wetland Restoration.  January 24, 2015.

This batch of photos showed the wetland hosting quite a few Canada geese.  That’s not a new occurrence – I’ve shown that in prior posts from this timelapse project.  However, it’s good to see them back again this winter, especially because much of the wetland has become more fully vegetated during the last couple of years, and I’m glad they weren’t just coming to hang out on bare sand.  Comparing this year’s photos to the photos in that prior post also shows that the water level in the wetland is considerably higher this year.  Some of that is because of this winter’s high groundwater levels, but it’s also because the beavers have a couple of big dams just downstream of these images.

Another interesting story from this batch of photos has to do with ice.  This wetland is valuable habitat for many species because of its relatively consistent water availability – water levels go up and down, but I’ve never seen it completely dry, even during some pretty severe drought conditions.  However, the wetland is also valuable because the strong groundwater influence at the site means the wetland rarely freezes completely over (water flowing from underground helps keep the water temperature warmer than if the water was just sitting on top of the ground).  Among other things, this means there is usually a place for waterfowl to land on open water during the winter months.

The site does freeze over at times, however, and apparently it can happen pretty quickly.  The following two photos were taken 15 hours apart, and the first photo shows completely open water on one evening and the second shows the site nearly frozen by the next morning.  The temperature dropped significantly overnight, but the speed at which the wetland surface froze still surprised me.

photo 1

5 pm. January 31, 2015.  32 degrees F and 6 mph wind.  Ice free.

photo 2

8 am. February 1, 2015.  10 degrees F and 35 mph wind.  Two inches of snow and nearly complete ice cover.  Clicking on photos will bring up a larger and sharper version of them.

Only a few tiny areas of open water remained after the cold night.  The ice was thick enough, at least in places, to support the huddled group of geese near the right side of the photo.  The wetland remained in this mostly (but never completely) frozen state for a few days, but by the morning of February 4 a line of open water appeared along the main stream flow corridor, and by February 6 the big numbers of geese returned.  The  photo below was taken on February 7.

geese again

Geese again  February 7, 2015.

The geese apparently adapted to the freezing of the wetland just fine, though I’m very curious to know where they went during the five days they were gone.  I’d also like to know why they felt it was ok to return when there wasn’t enough open water for all of them to swim in, and it looks like most of them just stood on the ice anyway!

Regardless, one of the fun things about timelapse photography has been the ability to see changes – sometimes very rapid changes – in the habitat conditions at places like this wetland.  Sometimes, those conditions can literally change overnight!

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