Fenceline Timelapse

I got my hands on another batch of timelapse imagery for our Niobrara Valley Preserve last week.  I now have images from all nine of the Preserve’s cameras for the 2013 growing season (late April through the middle of October).  The photos from those cameras document the first year of recovery from the drought and major wildfire back in the summer of 2012.  As I work through the many thousands of images, I’ll be sharing some of the interesting stories I see.

I’ll start with a series of images from a camera set along a new fenceline.  As the staff at the Preserve set out to rebuild fences after the wildfire, they took advantage of the opportunity to shift the location of some fence lines.  In this case, they moved the south boundary fence of the east bison pasture and enlarged that pasture to more than 10,000 acres.  The fence was constructed through what had been a traditional cattle pasture (unplowed sandhills prairie that had been conservatively grazed by cattle for many years).  We chose to place a camera along that new fence for two reasons.  First, it was a good place to watch the recovery of the prairie plant community following the fire.  Second, it provided a good chance to look for differences between bison-grazed and cattle-grazed prairie.

Here is a slideshow of images from the 2013 season from May through mid-October.  If you hover your mouse over the images, you can click on the arrows and fast forward (or backward) through the photos to look at changes over time.  The left side of the fence is now bison pasture, while the right side is still cattle pasture.  Below the slideshow, I’ve written about some of what I see as I look through the photos.

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The first thing that’s obvious in the images is the rapid recovery of the prairie’s plant community from an intense drought and wildfire.  In the first image (May 2) it looks like there is nothing but bare ground.  Even the ash from the fire was washed/blown away, leaving almost nothing above ground.  However, as spring arrived, both annual and perennial plants seemed to jump out of the ground and fill the landscape with green vibrant vegetation.  It’s difficult to identify many of the plants, given the scale and resolution of the images, but there are two major flushes of blooms – the very pale pink flowers of wild roses (Rosa arkansana) in June and the yellow plains sunflower (Helianthus petiolaris) in August.  You might remember reading about the abundance of sunflowers across much of the sandhills from an earlier post.

One of the reasons I chose this particular location for the camera was to watch the yucca (aka soapweed or Yucca glauca) plants over time.  There is very little yucca in our bison pastures at the Niobrara Valley Preserve, but it is fairly common in cattle pastures.  That has less to do with bison grazing vs. cattle grazing than with the fact that the bison are in the pastures through the winter and the cattle are pulled out in the fall.  Both bison and cattle will graze on yucca during the winter because while the leaves are tough and spiny, they are green when almost nothing else is.  I think we’ll get to watch through time as the yucca on the left side of the fence gradually disappears through years of winter grazing by bison while the yucca on the right grows relatively unhindered.  We’ll see!  To see the yucca, it’s best to start on the last image of the slideshow (October 21) and look for the spiny green plants surrounded by brown vegetation.  Then you can watch those plants grow as you click from May through October.  Since I haven’t seen the images from this past winter yet, I don’t know if bison have been grazing the yucca, but I sure hope so (for the sake of the story…).

One difference that can already be seen between the bison side of the fence (left) and the cattle side is the formation of a trail along the cattle side of the fence.  I will provide more information on that in a post that will come out very soon, so I won’t talk much about it here except to say that while the formation of numerous trails are definitely a real difference between bison and cattle pastures, they are not necessarily a bad thing.  More on that topic, with a VERY interesting couple of timelapse photos, coming soon.

One last observation is that either the camera or fence moved quite a bit through the season, and since the fence clearly didn’t move, it had to be the camera.  I’m not sure how to explain that.  I don’t think it was being bumped when the memory cards were swapped out every month or two because the movements occurred in between those events as well.  I imagine the most likely scenario is simply that the massive wooden post we stuck in the ground (with concrete) shifted in the sandy soil.  We’ll see if that continues over time or if it settles into a location.  It’s not a problem, just something interesting.

Finally, one of the great things about timelapse imagery is the opportunity to capture beautiful images without having to be there to click the shutter on the camera.  Here are three photos from this camera that I thought were particularly pleasing.

Sunrise on August 19, 2013.

Sunrise on August 19, 2013.

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Moonlit prairie on the same day as the above photo - August 19, 2013

Moonlit prairie on the same day as the above photo – August 19, 2013

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Lightning during the night on June 21, 2013.  Wild rose flowers can be seen in the glow of the lightning.

Lightning during the night on June 21, 2013. Wild rose flowers can be barely seen in the glow of the lightning.

Many thanks to Mike Forsberg, Jeff Dale, David Weber, and everyone else at Moonshell Media that has been working on this timelapse photography project with us.  Special thanks also to the Nebraska Environmental Trust for funding the installation of the cameras as a way to help us better understand the effects of wildfire on Nebraska’s ecosystems.

A Visual Update of Wildfire Recovery at the Niobrara Valley Preserve

Back in April, I wrote about our timelapse project at The Nature Conservancy’s Niobrara Valley Preserve.  Working with Moonshell Media, we’ve got nine cameras set up around the Preserve to document changes over time as the site recovers from a major 2012 wildfire.  We only have photos from April through early July so far, but even those are very compelling.  Eventually, we’ll put together videos that will show the entire timelapse story from each camera, but I wanted to share just a few examples of what we’re seeing so far.

I’ve selected two images from each of three cameras to give you a taste for the kind of stories we’re getting from the cameras.  The first pair of images is from the north ridge of the Niobrara River where the wildfire wiped out our ponderosa pine woodland.  We set up a camera to capture a close-up view of a steep slope.  Overall, erosion is not as bad as I’d feared it might be, but there was some significant soil loss during the first several months of the 2013 growing season, especially on steeper slopes like this one.

Erosion

This photo was taken on April 28, 2013, shortly after the camera was installed.  In fact, you can see some of our footprints in the loose soil in front of the camera.  Note the location of the rocks in the image – particularly the tall one in the top left quarter of the photo.  The pine and eastern red cedar density had been high in this location prior to the wildfire, and few perennial plants were able to grow in the shade beneath them.  Because of that lack of established vegetation and the steepness of the slope, we expected to see significant erosion here.

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erosion b

This image was taken on July 21, 2013.  Some of the rocks from the previous photo have washed downslope and out of the frame. Others have become much more exposed as soil has washed away from them.  Annual vegetation is starting to fill in the bare areas, but is still spotty, and very little – if any – perennial vegetation (grasses, forbs or shrubs) is evident.

We had some undergraduate students from the University of Nebraska-Lincoln collecting data on soil erosion and water runoff/quality this summer.  They are still analyzing data, but it’s clear that erosion was highly correlated with tree density, especially that of cedar trees.  Where the density of cedar trees was high before the fire, very little perennial vegetation grew beneath the trees, so those areas were the most prone to significant soil erosion after the fire.  The good news is that there is still sufficient soil to support vegetation growth, and there are numerous patches of perennial grasses and other plants nearby that can colonize these areas over time.

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The next pair of images shows a broad landscape view of recovery through the early part of the growing season.  Just as in the first pair of images, annual vegetation can be seen colonizing the bare slopes.  If you look carefully at the top right quarter of the photo you can see that the sandhills prairie and woodland along the south side of the river is greening up very well.  The woodland on that side of the river only burned intensively in a few places; for the most part, flames stayed low to the ground and didn’t impact the trees on the relatively cool, wet north-facing slopes.

Landscape

Looking downstream from the north ridge on May 24, 2013.  Some green can be seen in a few areas in the distance, mostly where tree density was low and native sedges and other grassland plants were coming back after the winter. Much of the rest of the landscape is pretty barren.

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landscape 2

The same scene on July 3, 2013.  Annual vegetation has colonized much of the landscape, especially where topography was less steep and tree density had been lower prior to the fire.  The landscape looks lush and green in the distance, but much of that is made up of those short-lived colonizing plants, so there is a long recovery period ahead before perennials take their place.  The future of ponderosa pines on this ridge is pretty bleak for the next several decades.  A few pines survived at the very top of the ridge, but colonization from those and other locations will likely be very slow.  

Over the next decade or two, we hope to see grasses spread back across the slopes north of the river.  Those grasses will be important because they will allow us to use prescribed fire to control the eastern red cedar trees that will also be colonizing the same area.  If we don’t get sufficient grass growth, we’ll have to find other ways to control cedars, which could prove to be very difficult on those steep slopes.

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The third pair of images comes from a camera mounted about 15 feet in the air above the sandhills prairie south of the river.  The camera is pointing straight down at an 8 foot by 10 foot patch of prairie that burned in the wildfire last year.  I am really looking forward to watching this little piece of grassland change over time – not just as it recovers from the wildfire, but also as it responds to future prescribed fires, bison grazing, and weather changes.  For now, these two images show how well the prairie plant community rebounded quickly between late April and early July, 2013.

green

This first photo was taken on April 26, 2013.  There was a little fall regrowth after the late July fire, but the ground was nearly bare through the long winter.

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green2

This photo was taken a little more than two months later, on July 2, 2013.

The second of the two prairie images shows a wide diversity of plants growing vigorously within the 8×15 foot frame of the photo.  There are two grayish-colored plants of leadplant (Amorpha canescens) on the left and right edges of the photo, numerous purple coneflower (Echnicea angustifolia) blooming throughout the frame, and a few yellow coneflowers (Ratibida columnifera) as well.   The small silver-colored spikes throughout much of the image are wooly plantain (Plantago patagonica), an annual plant that is often abundant in sandy prairie after fire or grazing events.  The larger silver plants are white sage (Artemisia ludoviciana).  There are two species of sunflower in the photo as well, including stiff sunflower (Helianthus pauciflorus) and plains sunflower (Helianthus petiolaris), though neither was yet blooming by July 2.  I’m not sure what the blueish green grass in the photo is, but my best guess is switchgrass (Panicum virgatum), which is joined by several other grass species I can’t yet identify from the photo.

It should be fun to watch plants move in, out, and around the frame over the coming years.  Some, such as leadplant, should stay relatively stationary through time, but others -especially plants such as stiff sunflower and white sage, which can reproduce through long rhizomes – should move around quite a bit.  After the area has not been burned or grazed for a year or two, grasses will begin to dominate the frame and most of the shorter-lived plants will decrease in abundance.  However, when we burn the site again, bison will graze the area pretty intensively, knocking the vigor of perennial grasses back, and allow opportunistic plants such as annual sunflower and wooly plantain to rise up once more.  It’s one thing to track that kind of community change with data, but it will be much more interesting to see it visually.

There will be much more to come from these cameras!  While it’s useful to see paired images that show how things look differently a few months apart, videos of numerous images showing incremental change over long periods will be much better.  Those will be put together when we have more images and time to assemble the videos.  Stay tuned!