Achieving Success with Plant Succession

Season of burning can have a profound impact on vegetation response. The plot on the right was burned in August 2009 following an application of glyphosate. Burning in late-summer (followed by a wet fall) resulted in a canopy of broomweed a year later. The plot on the left was not burned.

Article and photos by DALE ROLLINS, PH.D.

The habitat manager’s primary tool is the process of plant succession—the orderly, predictable process of change in plant communities over time.

A corollary to this is “Rollins’ Rules of Plant Succession:” (a) know your plants and (b) know how to manipulate them. Know which plant species or plant communities are important to your desired species of wildlife, which in in my case is quail and then know how to use “Leopold’s tools” of axe, plow, cow and fire to foster that plant suite.

The ability to identify the top 25 plants on your property is a prerequisite—so do your homework! Get yourself a good region-specific field guide or explore some of the apps on your smartphone such as iNaturalist.

Depending on the tool used and the timing of its application, succession can either be advanced or set back. For example, a fire conducted in early April in North Texas tends to favor the taller grasses like little bluestem and Indiangrass, while a fire conducted in August might favor more forbs such as broomweed and western ragweed.

A burn followed by grazing will favor forbs regardless of timing as the cattle will preferentially graze the grasses and give the forb community a relative advantage. One should strive to appreciate these interrelations in plant community dynamics.

Two types of succession are recognized: primary and secondary. The former is when a lichen begins growing on a rock, literally starting at ground zero. As habitat managers, we’re more interested in the latter.

To envision the process of secondary succession, let’s start with a stand of native grasses, e.g., in Clay County near Henrietta. If we plow up the native grasses (no, I’m not recommending this, but it’s been done extensively over the past 140 years…only used as an example here), and then walk away for a year, what plant communities might we expect to find?

The plowed field would initially spring up in “early successional species” like common sunflower, pigweed, kochia, broomweed and some weedy grasses like Colorado grass. These species exemplify the idea: “Nature abhors a vacuum,” or stated more colloquially, “Mother Nature is not a nudist.”

Her edict is to simply protect the soil surface and keep it in place. Early successional plants are essentially an ecological Band-aid to protect an open wound.

As time marches on, these plants would be replaced with perennial forbs such as western ragweed and short-lived perennial grasses such as sand dropseed. After another 30 years has passed much of the original plant community has perhaps reappeared and re-established itself on the landscape, barring subsequent disturbance. Over most of Texas, various species of woody plants (mesquite, huisache) would encroach on the site. Chances are you’ve witnessed this process on lands enrolled in the Conservation Reserve Program back in the mid-1980s.

BEHIND THE COUNTY AGENT’S DESK

I worked closely with county Extension agents across West Texas for more than 30 years. Ask any county agent what his or her most common question is about plants, and I’ll wager they will reply, “What is it?” followed by “How do you kill it?” I encourage them—and you—to insert this question between those two: “What is it good for?”

Many county agents’ offices are adorned with a color poster called “Common Weeds in Texas Pastures.” Perhaps you’ve seen it. I’d remind them that most of the “weeds” thereon are key seed-producing plants for quail, and if they’d give me a bottle of white-out, I’d rename the poster to reflect that. “Weed” doesn’t have to be a four-letter word.

Even the botanical neophyte knows some of the “problem” plants. But if they endeavor to be a “Student of Quail” I exhort them to increase their plant vocabulary. Some plants offer a “V8 moment” due to their simplicity.

Here’s a soft toss: Where does one tend to find cowpen daisy? Around livestock pens! Why? Because anything that serves as a point-attractant for hoofstock results in a “sacrifice area” characterized by plants like cowpen daisy or buffalobur. So why not spray such areas to control these “undesirable” plants? Perhaps, but first consider Ralph Waldo Emerson’s

Re-starting plant succession with early-successional species like sunflowers usually, but not always, follows soil disturbance. This pasture was sprayed for pricklypear control about a year earlier. The sunflower response observed here is a response to the decaying cactus and perhaps nutrients being released in that process.

Cowpen daisy sometimes "replaces" sunflowers as an indicator of soil disturbance as one moves further west. This colony was a product of a burned brush pile in March 2020; the photograph was taken six months later in October 2020.

This proliferation of early successional species in Archer County was a result of cattle grazing and a seasonally abundant rainfall.

question, “And what is a weed but a plant whose virtues have yet to be discovered?”

As Yogi Berra reckoned, “You can observe a lot just by looking.” Check out where you’ve burned brush piles about six months ago. Perhaps you’ll see something common like sunflowers or cowpen daisy, but sometimes the response is more cryptic.

Wildmercury is a nondescript little forb that produces a seed about the size of No. 6 lead shot; the seeds are consumed by quail. One never sees it in abundance, but if you check out burned piles, or summer burns, in the southern Rolling Plains, and you know what it looks like, you’ll spot it fairly frequently. Perhaps a note interesting only to a plant ecologist and a quail geek, but inquiring minds want to know.

About 25 years ago I met a landowner named Bourke at his place in Coleman County. His first question of me was “how do you kill that yellow sticker-weed (buffalobur)?” As we stopped his vehicle in a one-acre patch of buffalobur, I asked him why he wanted to kill it, as it produces a nice seed for quail, which resembles small lava-rocks like one might put in a gas grill.

We hadn’t driven another twenty yards when a covey of bobwhites flushed as testimony to my point. Given his name “Bourke” I dubbed him “Buffalo Bourke” to commemorate the teachable moment. I think he has a better appreciation for such botanical incorrigibles today.

JUST ADD WATER

Some type of soil disturbance, accompanied by rainfall, triggers the start of secondary succession. Soil disturbance takes many forms, including hoof action by livestock, grazing practices, brush control especially by mechanical means, road maintenance or pulling a tandem disc. Less conventional methods might include rooting by feral hogs, burning brush piles or earlier in history buffalo wallows.

The timing of when a practice is implemented can alter the plant community quite vividly. Check out the webisode “Disking for Quail Habitat in the Rolling Plains” (https://www.youtube. com/watch?v=RQzmvhQBYZU) to see what a difference of only two months makes in the plant response. On sandy loam soils in Fisher County disking in December tends to promote more sunflowers and insects than discing in October or March.

As this pattern likely changes on different sites, soil types and latitudes, I encourage you to do some “strip disking” demonstrations on your property to see which month(s) provide the most desirable plant community for your management goals. Keep in mind the importance of rainfall after the practice is implemented; a December disking followed by six months of drought becomes a June disking by default.

DON’T TRY THIS AT HOME

Caveat emptor! Sometimes soil disturbance brings undesirable consequences, even to a quail geek like me. The infusion of various exotic grasses such as K-R bluestem and Lehmann lovegrass take advantage of an “open wound” and then proliferate. These “improved” grasses ultimately may claim the landscape and suppress diversity of other plants. Check with local experts in your area to ensure an attempt at improving plants for quail doesn’t wind up backfiring.

Finally, if you have sandy soil, you’re probably painfully aware that soil disturbance often equates to sandburs. And when your pants and your bird dog’s paws are covered in sandburs, it’s difficult to think of any good that could possibly stem from them.

When confronted with a pointed question on a range tour in Wheeler County in 1988 I proclaimed that every plant out there has significance for quail, but we don’t always understand when or how. As we stood in boot-high sandburs, one skeptic carefully pulled up a sandbur plant and thrust it in my face, then asked indignantly, “Just what good are these for quail?” It was an “en guarde!” moment.

Confronted with the question, beads of sweat popped up on my forehead in the fear of being caught in a contradiction, and thus tarnishing my reputation and also the credibility of my premise about plants. Just in the nick of time my colleague, J. F. Cadenhead III, the Texas A&M AgriLife Extension Range Specialist at Vernon, came to my rescue when he retorted, “They slow down bird dogs don’t they?”

Touche’!

That story has been codified in the quail literature (mine anyway!) as Cadenhead’s Corollary and reminds us that “quail do not live by seeds alone.” Some plants that are important for quail may be unpalatable to many of us, so seek and appreciate their contributions anyway.

Be that as it may, if you know how to conduct soil disturbance and not cause sandburs to flourish, please share your secret with me (drollins@quailresearch.org).