Most of us involved in prairie management feel like we’re trying to hold back a flood of invasive species that threaten to transform our prairies into something else. For many of us, that flood includes woody plants that can quickly shift a grassland ecosystem to shrubland or woodland. For others, it consists of invasive grasses or forbs that have the potential to form self-perpetuating monocultures and causing catastrophic losses to biological diversity. Invasive animals and pathogens are also huge and growing threats.
Fighting that horde of invaders is time consuming and expensive. Even worse, a changing climate, combined with continued land use changes, continues to tip the balance toward the baddies. The battle is noble and the battle is worth fighting, but – and I’m just tossing this out there for discussion – what if we can’t win?
Seriously, though. What happens if we lose the fight? What comes next?
At both small and large scales, it’s increasingly clear that we’re not going to be able to keep invasives from dramatically transforming some of our prairies into new ecosystem types. A recent study at the University of Nebraska-Lincoln, for example, has documented huge northward shifts in Great Plains ecosystems by analyzing long-term bird data across the region. Much of those shifts are associated with continued woody encroachment. Similarly, scientists in eastern Kansas are finding that while plant diversity does best with ‘intermediate frequencies of fire’, very frequent fire seems to be necessary to hold back the march of trees and shrubs. Frequent fire is being employed (often annually) in many eastern tallgrass prairie fragments too, because of high pressure from woody plants. That high rate of burning, especially in isolated patches, is likely having significant impacts on invertebrate communities and causing unpredictable feedback loops on the rest of the prairie ecosystem and its long-term future.
In the southern Great Plains, those fighting sericea lespedeza (Lespedeza cuneata) celebrate when a new approach simply slows the spread of that invader. Reversing its expansion still seems like a pipe dream in many places. Further north, reed canarygrass (Phalaris arundinacea) monocultures have formed along streambanks and across many wetlands and wet prairies. Local eradication efforts are often fruitless, even if temporarily successful, because moisture conditions, nutrient loading, and seed transport from upstream all enable reed canarygrass to quickly recolonize and reclaim its dominance.
These are just a few examples of major invasive species threats that threaten to overwhelm native prairie ecosystems. We might find new approaches or rally enough public support to repel some of those invaders. On the other hand, we might not. What if we can’t stop them? What if huge expanses of prairie become shrubland or woodland? What if diverse plant communities become largely dominated by a few grass or forb species?
If we focus all our energy on fighting and still lose, that loss will likely be catastrophic. On the other hand, if we take a little time to think about how to facilitate the transformation, maybe we can shape a result that’s better than the worst-case scenario. More importantly, if we start now, maybe we can develop and test some management options for post-transformation landscapes now instead of working from behind after transformations occur.
Ok, everybody stop and take a breath. Good. Let me be clear – I’m not saying we should give up. It’s still important to fight and suppress invasive species and manage for the biological diversity of prairies. What I am saying, however, is that while we’re spending the majority of our efforts building dikes to keep floodwaters at bay, maybe we should devote just a little time to window shopping for boats.
I’ll give you a couple examples of the kinds of conversations I think might be fruitful. Let’s say we have a prairie landscape that, despite our best efforts, is inexorably becoming overrun with shrubs. It seems valuable to start thinking about the implications and possibilities of that landscape as a shrubland. What species of prairie plants and animals might be able to persist with some degree of shrub cover? Which are completely incompatible with that habitat type? What new species of plants or animals might come in with the shrubs and help form new diverse communities? What lessons can we learn from places where this kind of transformation has already occurred?
What kinds of management could we employ in a shrubland to keep the shrub canopy diffuse enough to allow at least some grasses and forbs to grow beneath it? Could we keep enough herbaceous cover to carry fires? Could we maintain enough forb species diversity to support a pollinator community? What is the threshold of shrub density beyond which plant and animal diversity really nosedives and/or can’t recover?
Could we create and maintain some scattered openings within a shrubland matrix that would still host prairie species? What size openings would be needed for various plant and animal species? What kind of connectivity would we need to maintain between those openings to allow populations to interact with each other or shift to new locations over time?
Thinking even further down the road, what might be the next stage of transition after shrubs? A hardwood forest? Is that better or worse than a shrubland? Would we be able to stop or influence that transition if we wanted to?
Under a scenario in which a diverse grassland becomes dominated by one or a few grass or forb species, asking many of the same questions would be productive. It’s important to envision various scenarios and try to understand their implications and possibilities. We should be having these kinds of discussions now instead after a transformation has already occurred.
As we prepare for those conversations, there is a lot we can glean from existing examples of transformed/collapsed grassland ecosystems, or from established ecosystems similar to those being newly created. Parts of the southern Great Plains and elsewhere have already seen major transitions of grasslands into woody cover. What prairie species survived? Were there unexpected benefits in addition to unfortunate losses? How was overall biodiversity affected?
There are plenty of sites overrun with reed canarygrass, narrowleaf cattails, or other similar invasives that can still support many wildlife species if managed for a variety of habitat structure types. In some cases, targeted applications of fire, mowing, or grazing can allow at least a few other plant species to persist within a reed canarygrass kingdom. In more upland sites, there are countless examples of sites where smooth brome (Bromus inermis) or Kentucky bluegrass (Poa pratensis) has spread across entire sites. In many cases, diverse plant communities can still persist under an adapted management regime that keeps those grasses from becoming too dominant.
I don’t have answers to many of the example questions I posed above. I suspect no one does. That seems like a good reason to start exploring them now. It’ll take some time to sort through all the possible scenarios and come up with some possible courses of action. We’ll be able to identify some research questions that will help us better frame those future options. There might be ways to shape the way transitions to new conditions occur – either by slowing those transitions to give species time to migrate or adapt or by supervising the way new communities assemble to help ensure their diversity and resilience.
Thinking about worst-case scenarios is not the same as admitting defeat. It’s a pragmatic approach to a complex challenge. I’m taking lots of steps to prevent my house from catching fire, but I’ve also bought insurance, talked with the kids about evacuation plans, and have my most important documents in a safe deposit box. Having an emergency plan can reduce stress because you know you’ve prepared for the worst.
Look, we know the climate is changing, and it’s literally changing the playing field for plant and animal species. We can see woody encroachment getting more aggressive and we’re seeing more, not fewer, invasive species entering the playing field. Habitat fragmentation, nitrogen deposition, and public apathy, among many other factors, exacerbate the challenges we face. The prairies we’re managing today aren’t the same prairies they used to be, and they’re surrounded by a different and more hostile neighborhood.
On the flip side, we’re getting much smarter about prairie management and restoration. We’ve seen some huge advancements in our approaches to building and maintaining biodiversity and ecological resilience. This fight is far from over and I’m full of optimism and committed to giving everything I’ve got. However, that doesn’t mean we should push forward blindly. Savvy fighters recognize the value of strategic retreats and contingency planning.
Nobody wants to think about defeat or its consequences. I certainly don’t. I also don’t want to think about floodwaters breaking through dikes or my house burning down. Unfortunately, ignoring those possibilities doesn’t make them go away. I think we’d all feel better if we started having some honest and thoughtful discussions about the scenarios we hope will never materialize. Where transformations are inevitable, maybe we can guide them in ways that will preserve as much biodiversity and ecological function as possible.
Chris, I really like the tone and direction of this post. I work mostly in an urban setting and these are the kinds of discussions we have all the time, and I think it is much more productive than just doing battle all the time without an achievable goal or time frame. Thanks for your flexibility and pragmatism. We need that so much right now.
A very realistic look at the world ahead, thanks, Chris. I have seen gradual changes in the Northern Tallgrass Prairie of eastern SD since the ’50s but for soils that remain largely undisturbed I can see utility in managing for some intermediate stage that benefits at least some wildlife species. If there is any reason for optimism it might be that pathogens develop over time that suppress the invaders.
1. Islands of purity. These are small regions where you do intensive management to try to maintain prairie conditions. I don’t know how small these can be and be effective? An acre? A section? A township? Maybe an island of purity is surrounded by a shoal of venial sins.
2. Burning. Ideally aim for alternate years (more survivors of little critters) and burning in small plots (restore critters from edges. Spaced out burns during the fire season may also help.
3. Savannah lands. Recognize that you aren’t going to keep it all, so create an new ecology that is a mix of grass and tree/shrubs.
4. Make monocultures less mono by attempting to introduce more species. This is probably the most controversial. If Reed canary grass is taking over riverine habitat introduce additional wetland grasses into the region.
5. Encourage experimentation.
5a. Make seed available. Set up interested groups to collect and disperse seed.
5b. Create a series of online articles, youtube videos, and a forum on how to build and modify prairie ecologies. Ecology is barely a science right now, just beyond the stamp collecting stage. We need discipline of ecological engineering, but we are a long way from that. However, documented, “throw stuff at the wall and see what sticks” may provide useful inormation.
6. Document what we have. We need to know how to do this, but with image recognition getting better and better I’d like to see if the following approach could be made to work:
* With a mapping software, such as OziExplorer, set up a route on a region. The route should be traversable in half a day.
* Load the route to your GPS. Set the gps to record breadcrumbs on 30 second intervals.
* Verify that your camera’s time is closely synchronized to your GPS (within a second or two.)
* Traverse the route. At each stop take N pictures. 4 should be at the ground on each side of you. 4 should be in the cardinal directions with the center of the image about 20 feet away. Additional pictures as you see interesting things — a plant you never noticed before, and transition line between dominant plant form.
* After you get back, download track data from your GPS. Download your images into a folder, along with the track file from the gps. Use exiftool to add GPS meta tags to the images. Info here: https://exiftool.org/geotag.html
* Upload Geotagged images to a central database.
Work needed: This is a general approach to tracking ecological changes. Photo routine would be different for prairie and desert regions where the vegetative layer is essentially two dimensional versus forested regions where you have tree canopy and understory to include.
A second volunteer group to train the AI to recognize species.
A third group to verify the IDs and to ID new plants tht the AI doesn’t recognize.
Timing is an interesting problem. Daily is obviously overkill. But some plants are only obvious if you catch them in bloom. Would be useful to coordinate with PlantWatch, and then request people to make their photo tours X days after the first blossom of species Y in your region. The better your control, the less trips you need to make. Initially I would try to get monthly trips, but maybe that is too coarse. For some zones, e.g. deserts, you may need to time it to do right after a rain event.
Another mechanism for sampling is a drone. Modern drones can be programmed to fly a gps route. Suppose you program a drone to fly with HD camera pointed down and flying at 20 feet AGL Set the machine to fly X m west, then 1.414X meters NE then 2X M south, then 1.414X m NE then X m West. This describes an angular figure 8. The value of X is chosen to not run out of battery. Or you may want to do your traverse in a generally E to W path, and set the drone to look 1/4 mile north and 1/4 mile south. A drone moving at 20 miles an hour covers a 1 mile circuit in 3 minutes. With a 15 minute battery pack, you get 4-5 flights per battery. Ideally you have a setup where you can use a motorcycle battery to recharge a battery in the field and only need two packs.
Drone sampling and foot sampling are complementary. Closeup will get a better view of short plants, and of outliers. Drone will get overall samples from a larger region.
Ruth here, may I use your 1-6 in a newsletter?
You certainly may. Feel free to expand upon it, or ask me to expand on it.
I live in the southern Kansas Flint Hills, and have seen plenty of former tall grass prairie lost to woody species, but also to cultivation as well as urban sprawl, and construction. The good news is that there are large areas that are still intact, mostly as ranchland. My guess is the areas with the worst woody encroachment are gone forever, but I think we can save the remaining with good land management, and funding. I haven’t really studied it, but the new Great Plains Initiative may be a start. My understanding of it is that it will focus on open areas and try to suppress the woodies there instead of trying to restore highly invaded areas. I’m back and forth on the use of fire, but certainly there are times it can be a valuable tool. We are trying to manage the forage invaders biologically with goats and sheep rather than chemicals, but we are still spot spraying sericea. The old world bluestems have increased in recent years, and control of them is difficult, although I am learning toward intensive grazing of them in May and June to hopefully let the natives choke them out. Anyway, lots to think about and to discuss. Thanks for the good blog.
A couple of weeks ago you asked your readers to take a survey about how we thought you were doing. I participated. I made a comment that of your blogs, the ones I like best were like this one today — they make us think; they may be controversial. I believe your blog today is — hands-down — the best one ever, and I look forward to everyone’s comments. Thank you for this post!
Thank you, Shelley. That’s really gratifying to hear.
The only constant anywhere, really, is change. And our changing climate accelerates that. This situation isn’t unique to prairies. I observed this in Arizona in the 1980s after a series of particularly hot wildfires scorched large areas of ponderosa pine forest at the lower elevational edge of its range. It came back as shrubland. In the shrubby areas that burned at slightly lower elevations than the pines, the burned shrubland came back as desert.
I think it’s very important that we first understand why the prairie is where it is in the first place. What is the prehistory of the site? Was it forested during past wetter (Pleistocene) climates? Why has it changed? Why is (was) it prairie versus forest? I think an understanding of surface geology (thus soils and moisture conditions) and paleoecology are essential. For example, tall grass prairie thrives on the Texas coast along a rainfall gradient that varies from 25″ to 60″ because it’s flat, is poorly dissected by streams (fire could run a very long ways), and often has Vertisol clay soils that trees have a hard time dealing with. And it held prairie throughout the Pleistocene. Dr. Reed Noss is someone I look to for inspiration (Forgotten Grasslands of the South). Don’t make decisions until you truly understand why you see what you see when you walk outdoors.
I encounter situations where invasives seem an unending battle but largely because the native plant community has been so battered. And prairies in a seeming pristine condition that suffer from woody encroachment due to being surrounded by trees. And beautiful prairies that haven’t been burned or hayed in living memory and yet appear pristine (and almost impossible to walk through if you’re less than Wilt Chamberlain height). Herbicide and hand or mechanical removal can be used to lengthen the fire interval. But our environment is undergoing massive upheaval due to climate change as well as human caused carbon dioxide and nitrogen supplementation; two essential elements (molecules) for plant growth. C4 grasses evolved, after all, to do well in a dry, carbon dioxide poor environment. We have to expect change.
I think we need to differentiate between non-native invasive species and native ones. Non-natives often do well because they’ve left their enemies behind on their home continent and can devote all of their captured sunlight into growth and reproduction. Developing a chemical defense system and/or fighting pathogens are very energy intensive! But what happens when those enemies eventually catch up? The species may lack the community connections (evolved mutualisms, etc.) to persist in the face of adversity. Then what? Honeybees are a great example. It took 500 years but wild honeybees are hurting. Some plants whose native pollinators the honey bees displaced and now left holding out empty stigmas. We should do all we can to maintain biodiversity. I don’t believe we know nearly enough to plan or facilitate novel plant communities as some biologists propose, though they’re surely on their way.
The WWII manhatten project was a race against time. So they tried many routes in parallel.
While I agree we don’t know enough, we need to act now. We need to make the best guesses we can and put them into action. Some of that effort is right what you say: Get an understanding of what we have. See my longer reply.
These actions don’t have to be universal. Where we don’t understand we take action on part of the region. take action on many parts of the region. Leave some untouched. Intervene in some to try to restore natural conditions.
It is always better to ask the questions early . . .
Are you finding Old World bluestems on the Konza Prairie? If so, what do you think can be done about controlling them?
You have winning ideas Chris! A: Of course we love the land we grew up in, on and around. B: one or a thousand people studying our precious prairie land cannot affect change without ideas of all shapes and sizes. Therefore C: We get as many people and ideas out there as can be trained and dispersed. D: You rock Chris! Thank you for your work!
Hey Chris, I just wanted to check in and see if you got my e-mail about Saving Bell Bowl Prairie?Â They are due to destroy in on Nov. 1st.Â Your support writing about it would help!Â For any other readers, Bell Bowl Prairie is an ancient, rare original prairie remnant in Northern Illinois that is due to be destroyed for Airport expansion.Â They don’t need to destroy the prairie to expand, alternate plans exist so they don’t have to.Â Plus, the road they designed to run through the prairie is right next to another road that serves the same purpose already!Â This special prairie houses rare and endangered plants, the federally endangered rusty-patched bumblebee, and several endangered and threatened birds use it as well as many Birds of Concern who are already at risk of being listed.Â Please Help!Â This 5 acre dry gravel prairie remnant if 25% of that remaining in all of Illinois.Â Suzanne Coleman
Our modern concept of preserving a steady-state that includes only those species that we think were historically present might need to be reconsidered. “Nature” is actually in a constant state of flux, not just from changing climates, but from constant invasions of new species including viruses, fungi, plants and animals. We might not see them all but microbes, worms and tiny arthropods move through soils affecting the biota just as new invasive plants and animals as well as novel or introduced genetic varieties of existing organisms change the interactions and relationships of existing and established species.
Just in my urban back yard I observe new species of spiders replace others producing a new assembledge every year.
It does make a certain sense to plan for a worst case scenario. However, if prairie management/preservation is pursued with a purely defensive posture (i.e. only preserve the same shrinking pockets of habitat under steady or increasing external threats), then the worst case starts to look like an inevitability in the long term unless the fundamental drivers of the external pressures are removed. Woody encroachment will never get easier to stave off if a prairie remnant is kept virtually surrounded by ever thickening groves of eastern red cedar or common buckthorn on the other side of a fence. A reed canary grass or eurasian phragmites problem will never go away downstream if there is a massive monoculture of it upstream that is never dealt with. In the latter case, the problem needs to be reframed from and Abc prairie issue to an Xzy river watershed issue that can get all/most of the land managers in the impacted area (public, private, prairie and otherwise) to acknowledge a common problem and pull in the same direction. I know, easier said than done and I’m not suggesting that people haven’t tried.
To break out of the defensive crouch means going on the offensive, which will be a very long and hard slog. It will require changing people’s minds about prairies from “Ugh, weeds!” to “Yes, more of that amazing stuff, please!” (the difficulties of which have been illustrated in earlier posts here). It could, probably must, involve pursuing legislation that would encourage different land use practices that directly or indirectly aid in prairie preservation. These could be subtle, like modifying the federal flood and crop insurance programs to strongly discourage real estate and agricultural development in areas that are only marginally suitable for those purposes and only with federal subsidies. More overt (and likely controversial) policies might be outright bans on certain exotics plants with aggressive tendencies and to obligate landowners to remove such plants when found. Even more esoteric things could possibly find their way into a sprawling farm bill such as carbon capture credits for the carbon sequestration in soil under prairie strips (as opposed to shrubby hedgerows) around crop fields that must remain in place for a minimum number of years. It would help to recruit large land holders like highway systems, railroads, and transmission line operators to commit to removing invasive species and to maintain context appropriate native plant populations along their right-of-ways (again legislation could help devise incentives to do so).
Basically, going on the offensive means strategizing active prairie encroachment in as many places as you can. That’s not just expanding large preserves like Konza, but also getting prairie plants into abandoned crop fields and industrial brown fields, active farms and pastures, expressway interchanges, suburban drainage ditches and retention ponds, golf courses, public parks, residential yards. Add to that almost any unused Walmart parking lot sized lawns of Kentucky bluegrass that some school/mall/hospital/office park/etc is spending too much money fertilizing, aerating, watering, and mowing for lack of imagination. Of course, this means accepting that much of it will never be top grade habitat to rival an untouched prairie remnant, at least not for a few centuries. Greater prairie chickens will probably never move in to Gateway Park in St. Louis no matter how many prairie plants are installed in an expert restoration, but that does not mean such a planting is pointless. Then again, Piping Plovers are nesting on Chicago’s lakefront, so the improbable can happen if given a chance. The point of much of this goes back to changing people’s minds.
Expanding prairies is one thing, maintaining them (even halfway adequately) is something else. That requires hands and bodies (and money), more than are at work for the purpose now, and I doubt that many more hands (or money) are eagerly ready and waiting given the current level of public engagement with prairies as opposed to trees, for example. It is easy for people here, particularly those somewhat nature minded, to appreciate a tree, or trees generally. It’s not because trees are necessarily intrinsically lovable. Yes, trees provide storm water retention services, shade that combats the heat island effect, etc., but I am referring something more visceral. It’s easy to appreciate trees, in part, because people see them everyday. People grow up with them, play around them, have weddings under them. They watch them change through the seasons from the comfort of their homes. They see other people planting them everywhere, sometimes with great fanfare, and they see people taking care of them. There are abundant social cues and acquired habits reinforcing the idea that trees are valuable, worthy (not altogether different from the popular perception of Kentucky Bluegrass lawns). Because of this, people miss trees when they are gone. It’s easier to persuade people, galvanize people to protect something that is worthy.
The problem is most people, even nature minded ones in former prairie country, never really see prairies. Most people couldn’t tell a prairie from an invasive weed infested parking lot or a soybean field. If many more people saw prairies or (and this is important) a reasonable facsimile of one as often as they saw trees, then it would be much easier to get people to care about them. When I say more people should see prairies, I am not necessarily talking about a thousand square mile never tilled treeless expanse borne on a mosaic of several molisol types teaming with a microbiome forged over millennia, full of organisms not yet known to science, and from which grow 500 species of plants (100 of which are sedges that you need a microscope and an advanced botany degree to tell apart) supporting a faunal diversity to rival any African safari. No, that is what places like national parks, Konza, Niobrara, and eventually Midewin and Nachusa (here in Illinois) are for, but a lot of Americans never visit such nature preserves. I am talking about something at once far more modest and more intimate, a reasonable facsimile that can be maintained on a little as an acre or two–not a fully planned and manicured garden, but a managed wild space. These facsimiles might have a hundred species rather than several hundred; a microbiome that is what it is and doing the best it can; no bison and apex predators, but a lot of insects and other local wildlife; an abundant succession of seasonal blooms; plenty of grass, but not 90% grass; and maybe a bur oak in the corner for shade because it does need to be easily approachable for people (rather than physically unpleasant on a summer day). These facsimiles would never be fully functional prairie ecosystems in the full meaning of the term, probably too small, but they can have the advantage of evoking the visceral essence of a prairie and being where people are. They could be on some former vacant lots, a section of a park, or otherwise located within the fabric of towns and neighborhoods near where people live, to become a part of people’s lives. If more people see and experience such prairies on a frequent basis, walk through them on the way to school or work, eat lunch in them, watch them change through the seasons, see them cared for and tended to (annual prairie fire festival anyone?)…grow up with them (and miss them when they are gone), then it will be easier to get people to care about prairies generally and easier to do and sustain everything else mentioned above, but that is still a long hard slog.
I’m kind of surprised that there seems to be no discussion of the animals that were once an integral part of prairie life, but is now missing. And, it seems as though it might be worthwhile to discuss what it would take to establish corridors that could make it feasible to reestablish those creatures with their necessary movements.
This idea of preparing for and integrating these invasive species is an idea that’s been bouncing around in my head recently. I think that these invasions will be inevitable, at least in most cases, but I think we also have to brace for the fact that as these natural vegetation regimes get crowded out, so will native fauna. Whether this is an impact on microorganisms or nematodes in the soil from altered soil chemistry as the result of juniper or tamarisk encroachment, or a lack of viable nesting habitat for grassland songbirds because the Siberian elm grows taller than they are comfortable with, the loss of species outside of the plant kingdom will also be inevitable. Maybe some of these potential losses can be useful in gaining public support, but will it be enough? Hard to say.
I will continue doing my part in removing invasive species where I can and educating any that will listen on the subject. This article will be one that I add to my arsenal, as I think it at least puts a light on the conversations that we should start having with each other. These are my favorite kinds of posts to see!
I definitely see a need to incorporate woody browsers and burning into management schemes to help keep prairies open and diverse. However, those schemes are time and labor intensive, and we have to develop better incentive programs and collaborative agricultural arrangements that allow this to happen on public and private lands in ways that benefit the land and the producers, but always with improvement/maintenance of biodiversity as the primary management goal.
I see that beginning to happen, but it will take some fundamental changes in how we use landscapes to make it effective. For example, in order to implement long term management systems, stable land ownership is needed. I see value in public land ownership with prescribed grazing being available to producers, or conservation easements held by individuals where prescribed grazing was a management option that was supported by public funds to support both the landowner and producer.
Land conversion, grazing regimes designed to maximize ag production (like killing everything but grass), and land neglect are the biggest enemies to biodiversity.
On the topic of encroaching woody invaders to natural grassland systems, shouldn’t we be reading that as a reaction to disturbance events? Many of these early successional species rely on increases of nitrogen. If a prairie is being overrun by woody invaders, why do we assume that no dynamic of the natural system is changing? Why do we perceive it as “outside invaders” that we are helpless to prevent? A natural system is a culmination of a million different processes. Changes in species composition is an expression of a change in function.
Why, then, are we quick to assume that we have run out of ideas for managing these places? Why do we assume we 1) know everything and 2) have exhausted possible solutions? Because the notion that “nothing we have been doing has changed” is simply not true. It is much more common now to burn later in the season, into spring, than it ever was before. Fire is nothing more than a different kind of disturbance event (that happens to be beneficial to certain systems in certain ways). And it just so happens that woody encroachment, such as from Rhus, seems to line up with burning later into the spring. Just like how a burned woodland often is soon flushed with Sassafras and Rubus, natural systems are equipped with “weedy” species to deal with the energy imbalance that disturbance brings. Woody encroachment is a relatively immediate response to an event, because they are short lived nitrophiles that arrive first on the scene.
I guess I just find it strange to already flirting with the notion of saying “well, we’ve done all we can” when there is still *so much we do not know*. The study of soil relationships and specifically into soil microbes is a very recent and burgeoning science, for example. How do we know that our management techniques are not causing a self-fulfilling cycle of disturbance? I really am similarly on the side of looking towards the future and accepting some of the futility in “conservation”, but not at the grave expense of assuming our scientific know-how on natural systems is whole and complete. I would like to see some self-reflection on how we manage before we throw in the towel.
I hope I don’t come across as overly negative! I enjoyed reading this article and all the questions it brought within me!
Damaged systems are chaotic, and as such defined by their uncertainty. They are prone to invasions of all kinds. But intact, stable systems are not chaotic and are defined by their certainty – their stability. The management practices you and other conventional managers have been pushing destabilizes intact stable systems and prevents the stabilization of damaged systems. It makes them chaotic and/or more chaotic. Examples of damaging management practices include patch burn grazing and non-dormant season fire. Very astute and seasoned ecologists (Don Kurz, Doug Ladd, Paul Nelson, Gerould Wilhelm, Jack White, Gene Townes, me, et al) warned that such practices would lead to destabilized and degraded systems and that they would not heal already damaged systems. Many of these people’s reputations have been marred because they laid so much on the line to stop this neo-management that is hyper-focused on the intermediate disturbance hypothesis. So, now that these systems are failing, it is really hard for me to not boil over with the fact that you – and the managers of Missouri’s collapsing prairies – ask these questions now. Take your blogpost from October of 2016 where you encourage “beating them [prairies] up” for example. Maybe the belief that degrading prairies will make them healthy is as bad an idea as it sounds. Maybe your assumptions are wrong. Maybe living systems need compassion, understanding, and conscious encouragement within the stable dynamism of their evolutionary trajectories rather than “beating them” into some degraded state you perceive as normal. It is not normal and they are collapsing. They will continue to collapse. I mean, I’m really shocked that managers still, even after all the warnings, have no idea how so many systems are tail-spinning. Please reach out to the professionals that have been marginalized and ask for help. Maybe the ones that have been ignored had something to contribute all along, not unlike the prairies themselves.
I think the most endangered prairie plant communities are early successional ones. There are many native plant and animal species that require disturbance. Summer drought wildfire and grazing. I have an old botany text that describes 3 Awn as dominant in some areas following heavy grazing. I never see that today because old world bluestems fulfill that role.
Disagree. Living systems are complicated. Damaged ecologies may exhibit wider variation than they formerly did.
In general ecological systems are more stable when they are more diverse. The archetypes of chaotic natural systems are arctic systems. Here there are too few species, and so a given predator becomes very dependent on a particular prey.
Example: Lynx and rabbit. Lynx in the boreal forest tends to prey almost entirely on rabbit. Rabbit have some additional predation by fox and wolf, but fox generally are mousers, and wolves prefer larger game. The rabbit population expands until a critical density, then tularemia plague takes out 90% of the rabbit population, followed a year later by the lynx population.
A similar event on a shorter cycle happens between snowy owls and lemmings.
See hudson bay records for northern posts.
Example: Jack Pine forest. Jack pine is a fire succession species. Most seed cones remain sealed by pitch until the heat of a fire melts the pitch. It’s raining seeds. Mouse population booms. Fox population booms. Mouse population crashes, Fox population crashes. A good trapper knows this and so tries to trap the fox population hard during the boom. This softens the crash giving hime at least some fox two-three years from now.
Example: My own woods are a mix of poplar (aspen and balsam), willow (bebbs, meadow, pussy) and white spruce, with a mix of shrubs in the substory. While the main forest is pretty constant, the understory is radically different from year to year. 20 years ago, the main understory was dogwood and wild rose. Then it was dominated by wild raspberry. Then black gooseberry (R. lacustre) started taking over from the raspberry. Most recently I’m seeing a lot more beaked hazelnut, elderberry (which I hadn’t seen until 3 years ago) and mountain ash.
At a smaller level, I’ve seen bracken fern come in, baneberry. snowberry at the very small level it’s a tossup between bishops cap, false soloman’s seal, lungwort,
My present theory is that the small changes are driven by total precipitation
An excellent reply and comment.
Your thoughts on prioritizing management units that have the most promise of success can be applied to the individual volunteer (myself) or work crew level. In the beginning, I spent too much time tackling brush clones by hand that should have been left until we had more resources or managed instead as a desired invaded state. I’ve since learned it starts with realistic site goals that emphasizes prioritization at all levels. From that comes a list of management activities & a prioritized list of management units for each activity. If I consider that, I know what is most important to do at any given time of the year & where to do it. The next thing is to forecast how much followup work will be required in later years due to other invasives occupying the newly cleared patches. Then I try to fit my individual capabilities into that framework. For example, I’m now performing cut stump treatment in a recovering remnant where the brush is scattered, including a few small clones. I decided on that parcel because a lot of invasive work has been accomplished by contractors/volunteers, good quality remnants & new restorations are nearby, removing brush satisfies the main site goal of maintaining grassland bird habitat, I can quickly clear a relatively large area & I have the ability to followup for herbaceous invasives because the cleared patch sizes are small.
The questions you posed about invasion thresholds here & in your 5/9/11 blog makes me wonder about current progress in trying to use ecological site descriptions with simplified state and transition models to define the current resilience/resistance of a site, the degraded state(s) of no return, the desired restoration state(s) & the actions needed to get to the restored state(s). Desired restoration states must be based on projected available resources. Research on the sagebrush steppe ecosystem in the West is intriguing because there are attempts to implement these concepts into real projects, using adaptive management to fine tune. I’d like to know if similar work is occurring for prairies.
“Enhancement of Degraded Shrub-Steppe Habitats with an Emphasis on Potential Applicability in Eastern Washington (BLM Technical Note 443)
“Restoration Handbook for Sagebrush Steppe Ecosystems with Emphasis on Greater Sage-Grouse Habitat” (USGS Circular 1416, 1418, 1426)
“A Field Guide for Selecting the Most Appropriate Treatment in Sagebrush and Pinon-Juniper Ecosystems in the Great Basin (USFS General Technical Report GTR-322). I especially like the idea of boiling this complex topic down to tools like the resilience/resistance score sheet in appendix 8c.
The term “disturbance” is used a lot in discussions about prairie nowadays. That has always bothered me. Some even say that prairie is a disturbance dependent ecosystem and that disturbance is good and necessary. Moldboard plowing is “disturbance”, opening up a gravel pit is “disturbance”, converting a prairie to a housing subdivision is “disturbance”, heck dropping a nuclear bomb on a site is “disturbance”. Are these actions good for a prairie? Obviously not. We need to find different, better wordage for it.
A thought experiment:
Let’s say you put a tractor and plow in a time machine and teleport it back to the prairie 800 years ago. Then plow up 100 acres. Then return to the same spot 100 years later. What would you find growing on that 100 acres? Answer: 100% native plants. Why? Because that is all that would be available to recolonize that disturbed site. Likely you would find a different assortment of native plants than the surrounding un-plowed prairie, but regardless they would all be native plant species that came back into that 100 acres.
If you do that same disturbance to 100 acres of prairie today will the result and outcome be the same? No way. Because there are now so many invasive and introduced species present on the landscape the outcome would be much worse. Therefore you’d better be careful with how you use “disturbance”. You may do more harm than good.
It would be more accurate to describe historic prairie as disturbance tolerant or resilient or adapted. It developed over time to endure major impacts such as floods, droughts, wildfires, and grazing by large herds. But it will only withstand those disturbances, plus new ones such as invasive species and climate change, with our help.
This model bothers me. this will be my first kick at the cat trying to figure out why.
A: The present day prairie is already vulnerable to outsider species. Just leaving it alone will result in changes in 100 years. It will be a gradual change instead of the abrupt change.
B: Your invasives taking over will also be true if you burn the prairie instead of plough it. Although burning is used as a management tool
C: Consider if you had 160 acre prairie in a bubble. Plough the middle half of that. Keep the invasives out, and you have your 800 year old scenario — a different plot of native species.
D: Just what is native? How far from home is allowed to be to be non-native?
E.g. Balsam fir is nominally an aspen parkland native species. As a consequence of being the curator of an orienteering map that covers some 200 km2 I know that patch of mixed farmland, pasture, aspen parkland, river valley, slough quite well. I know of ONE stand of balsam fir and it has under 10 individuals. Manitoba maple is native to SE Alberta. Can I count it as native, 400 km north of there near Edmonton?
E: Just when is native? 30 years ago I knew of one patch of bracken fern near the Genesee Bridge on the N. Saskatchewan river. 20 years ago, I found another patch in a small hollow in my orienteering country. 10 years ago I found a single specimen in my own woods. 5 years ago I had about 100 specimens sprinkled over an acre.
20 years ago, the understory of my poplar forest was mostly burdock and dogwood. I went on a 2 year burdock seed harvesting spree and haven’t seen it since. Wild raspberry took it’s place. Lately the raspberry is being displaced by black goose berry (R. lacrustre) In my map wanderings I hadn’t seen it before, so while nominally native to Aspen Parkland, it wasn’t native to MY aspen parkland.
About disturbance in general.
I agree that the list of things classified as disturbance is poor. I don’t consider a nuclear bomb and a fire cracker to be in the same category even though both are explosive.
Lot of ecologies are at least “punctuated equilibrium” to borrow a term from the evolution boffins. Fire and flood are the two most common of these. My aspen parkland is going to be in trouble lon term becuase we don’t allow fire. On the southern Canadian prairies, we have the pailliser triangle effect where we have a more or less 20 year cycle of normal rainfall and drought. This certainly is one of the drivers of our local ecological year by year variation.
I have 40 acres of pasture that is slowly reverting back to, umm… not sure. I’ve got at least 2 dozen types of grass, some native, some not, some invasive. I’ve got two kinds of thistle, orange and yellow hawkweed, yellow tansy. Wild rose, wild raspberry, fireweed.
The last one startled me. Normally fireweed gets started in disturbed ground. Ditto thistle. Thistle in ungrazed cropland will get choked out.
Ah. I have pocket gophers. Those little wretches make their piles of dirt and act as a promising seed bed for any seed. One animal, present at about a pound per acre that changes an entire ecology.
Anyway, I think we need to look at “distrubances” and possibly do some recategorizing.
Pingback: The Show Must Go On | The Prairie Ecologist