Hubbard Fellowship Blog – Olivia Marvels at the Persistence of Plants

This post was written by Olivia Schouten, one of our Hubbard Fellows this year.  Olivia is an excellent scientist, with strong expertise in plants and plant communities, as you’ll be able to see from this post.  

As a biologist with broad interests, I can usually find something to love in all living things, but I’ll admit that plants have a special place in my heart. This is probably a good thing, since I’ve spent the majority of my education and professional life cultivating my knowledge of plants. I’ve found that they are often underappreciated and often overlooked, which is a shame, because plants are some of the most amazing organisms out there (in my humble opinion).

Plants, in most places, not only form the basis of the food chain, but also provide the structure of habitat. A forest with towering trees is very different than an open grassland or a sparsely vegetated desert, and the animals that live there respond accordingly. Plants are eaten, trampled underfoot, exposed to the whims of the weather, and just generally beaten down by the world around them, all on top of competing with each other for resources and space. But while plants have it rough, they are also really good at persisting.

Trees are an excellent example of just how persistent plants can be. I was reminded of this earlier in the summer when I came across a grove of cottonwoods in one of our Platte Prairies while searching for musk thistles. At first glance I thought one of the cottonwoods had recently fallen and the leaves hadn’t died back yet. On closer inspection, however, I realized that the tree had probably fallen years ago, and instead of dying, the parts of the trunk that now contacted the earth had sprouted roots and continued on living. Branches had grown up from the trunk,and now looked essentially like three trees, all connected by the same fallen trunk.

This cottonwood, in true tree fashion, just refused to die. Photo by Olivia Schouten

Trees are clearly hard to kill, as anyone who’s tried to cut down a deciduous tree in your yard knows. Once the tree is cut you have to treat the stump with herbicide, otherwise the still-living roots will simply sprout again. Nearly every tree we cut here on the Platte to keep our prairies open needs to be treated with an herbicide. While it would be nice to not have to use chemicals in our stewardship work like this, that resilience of trees can also be a blessing. After the wildfire at our Niobrara Valley Preserve a few years ago, much of the forest along the river was killed. However, the oaks along the slopes are re-sprouting from their roots, as only the tops of the trees had been killed in the blaze. Because of this, these forests have a jump start on regenerating after the devastation of the fire.

It’s probably a good thing musk thistles are so showy, otherwise it would be much more difficult to find them.  Photo by Olivia Schouten

Since I found that cottonwood looking for musk thistles, it’s probably worth talking about them and their own resilient strategies. As a biennial, these plants only have one chance to flower and produce seeds, so they produce thousands of them at a time. And they can fly. That’s not great for us, considering they are considered noxious weeds here in Nebraska, but as a strategy for this plant it certainly pays off.

But wait, there’s more! Even when uprooted or sprayed with herbicide, if the flowers on a musk thistle plant have been pollinated, they will still produce seeds! So when we control this plant, we not only cut off the root just under the ground and pull it out, we have to collect any flowers, or else nothing will actually have been controlled. This persistent ability of musk thistles makes things more difficult and time consuming for us to control, but you have to admit that it’s a cool adaptation, and in its native habitat, likely very useful.

We collected about three tubfuls of musk thistle flowers by the end of the control season. We let the flowers rot to make sure any seeds were destroyed before throwing them out.  Photo by Olivia Schouten

So far these examples relate back to land management, and how the difficulty in killing plants affects our ability to effectively manage invasive plants in prairies. But we rely on these same tenacious qualities in our native prairies species as well. Chris talks a lot about the resilience of prairies on this blog, and a lot of that depends on the persistent nature of individual plants.

Consider big bluestem, a favorite of both cattle and bison. It can be cropped down again and again to within an inch of the ground over a growing season, but while such trauma might kill another plant, big bluestem holds on until the herd moves on and it gets a break, coming back taller and stronger the next year, until it’s back to full strength within a few years. In addition, even in those years that it’s hammered by grazing, big bluestem will find a way to flower, since all that short and weak vegetation around them makes for a good place to put out seeds.

This patch of big bluestem has been hit pretty hard by cows this year, but that didn’t stop it from blooming.  Photo by Olivia Schouten

Other plants may just find that conditions in a certain year aren’t for them. Maybe it’s too dry, or too cold, or the grasses around them are just too tall. Perennial prairie plants don’t let that stop them, as many will simply take a break, growing very little above ground for a year, relying more on stores of energy in their roots than anything else. To some, it may seem like those plants have died and disappeared from a field. But just wait, when conditions become favorable, most of those plants will show up again, just as strong, and benefiting from that strategy of waiting it out through the hard times.

Now, just because plants are tough doesn’t mean they’re invincible. If put under too much stress even the most stubborn plant will eventually die. Knowing how plants are able to persist can help us more effectively target those plants we don’t want, but also help ensure that our desirable plants always have a chance to let their persistent nature shine!

Introducing: The Prairie Word of the Day

I’m sure many of you are as tired of this blog as I am.  The same old nature photos, natural history, prairie management/restoration information…  It just drones on and on.  Honestly, I don’t know how you manage to drag your eyes through most of my posts.  How much prairie stuff can one person read about, after all?

(…Yes, I’m kidding – there is no limit to how much prairie information one person can read about.  And I am not at all tired of this blog… though you certainly might be, I don’t know.)

Well, the blog isn’t going away anytime soon (why, what have you heard??)  But in an effort to keep it from growing stale, I’m introducing a new feature called “The Prairie Word of the Day.”  …Yes, I know –  a titillating title, isn’t it?  It ought to be, it took me about three months to refine it.  It’s pithy, catchy, and descriptive all at once.  Or at least descriptive.

As with any field, prairie ecology is full of jargon; words that make sense to those of us who spend most of our waking hours thinking about prairies but make no sense to anyone else.  I try hard not to use to much prairie jargon in my posts, but I slip up now and then.  Sorry about that.  There are a lot of fun, but confusing, prairie jargon words out there, so I thought I’d highlight one now and then and try to explain what it means.  I would love to hear nominations from you as well – what undecipherable words do I or others use when talking or writing about prairies?

Ok, without further ado, the inaugural Prairie Ecologist Blog Prairie Word of the Day is:

Tiller

Sure, everyone knows what a tiller is, right?  You use it to prepare your garden for planting.  Or, if you are a pirate, you might use it to steer your ship.  (If you are a pirate and read this blog, PLEASE let me know.  Prairie-loving pirates is a demographic I would love to reach out to.)

However, if you are REALLY into prairies or botany, you might be familiar with a third definition; one that is related to grasses.

Tiller

Although it is used somewhat inconsistently, a tiller usually refers to the aboveground shoot of a grass.  In other words, if you were to look closely at a grass plant you’d see that most of them have multiple stems at their base.  Each of those stems is a tiller.  Usually, the term tiller only applies to shoots that emerge from buds at the base of other tillers, not from seeds.  Thus, when a grass seed germinates and starts to grow, the first shoot that pops out of the ground is not a tiller.  It’s just a shoot.  I guess.  But after that, every new shoot that comes out of the ground from that plant is a tiller.

Tillers are primarily important, as far as I can tell, because professors like to make graduate students count them.  As in, “Hey Sara, take this 1 x 1 meter plot frame out to that prairie, lay it down and count the number of grass tillers inside it. (snicker)  Then do that 99 more times. (guffaw!)  Then we’ll move on to the next prairie.”

Grass greening up in the Derr Sandhills about a week after a prescribed fire.
The tillers of this bunchgrass are all bunched together.

 

A related botanical prairie word is “sward” which basically means a bunch of grass.  Well, not really a “bunch” because that’s its own term (grasses like little bluestem are called bunch grasses because they grow their tillers tightly together and look neat and tidy, as opposed to grasses such as prairie sand reed that across the prairie like they own the place).  A better way to describe a sward, then, is that it’s an area of grass.  However, I don’t think there’s any restriction on how big that area of grass has to be, which makes the term less useful.  That’s probably why you don’t hear it used very often.  Except by grassland poets trying to rhyme something with “charred”.  As in, “Lo, the land was black and charred.  No trees remained throughout the sward.”

There are an awful lot of tillers in this sward.  Too many to count - even for a graduate student.
There are numerous tillers in this sward. Too many to count – even for a graduate student.

If botanists were funny, they might say something like, “Arrr, Matey!  Take over the tiller smartly while I decide whether to shoot this lubber or run him through with my sward.”

(I’m kidding, of course.  Botanists can be very funny.  Sometimes on purpose.  Also, many are quite hirsute.  Except on top, where some are pretty glabrous.)

Well anyway, that concludes the first ever installment of The Prairie Word of the Day.  I hope it was instructive.  Please nominate terms (in the comments section below) you’d like to see included in future Word of the Day posts and I’ll try to use as many as I can.