AoR 24: Matt Germino, Bunchgrass Roots Fight Cheatgrass

Perennial bunchgrass roots are the prize fighter in the wildland boxing ring with cheatgrass, and bacteria may be sitting this one out. Matt Germino, range scientist with the US Geological Survey in Idaho, describes recent research on how bunchgrass roots compete with invasive annual grasses below the soil surface. We discuss concepts of resilience and resistance, the ecological mechanisms involved in competition, monitoring measurements that are good indicators of root dominance, and eventually discuss discouraging research on Pseudomonas flavescens, the bacterium hoped to be a silver bullet against cheatgrass. You can find more information on the research discussed here at the USGS Forest and Rangeland Ecosystem Science Center website: https://www.usgs.gov/centers/fresc And you can reach Matt Germino at mgermino@usgs.gov. Many articles on the Rangelands journal website are Open Access and do not require a paid subscription to the Society for Range Management or the journal. Check it out at https://www.journals.elsevier.com/rangelands. WE NEED YOUR FEEDBACK! Please take 2 minutes to complete this short survey to help us continue funding the podcast: https://wsu.co1.qualtrics.com/jfe/form/SV_9Y3fUWlQdBsyBZX TRANSCRIPT: https://bit.ly/2OJBoeQ

Transcript

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>> Welcome to the Art of Range, a podcast focused on rangelands and the people who manage them. I'm your host, Tip Hudson, range and livestock specialist with Washington State University Extension. The goal of this podcast is education and conservation through conversation. Find us online at artofrange.com.

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My guest today on the Art of Range is Matt Germino, a rangeland scientist with the US Geological Survey out of Boise, Idaho. Matt has been studying rangelands for a while now with a focus on restoring sagebrush rangelands following fire, especially repeated fire on landscapes that are dominated by invasive annual grass. Matt and I met recently at the Society for Ecological Restorations International Conference in Cape Town, South Africa. For those who might still be undecided about whether to listen to this episode based on the title, we're going to be talking about factors involved in bunchgrass competition with cheatgrass and other invasive annual grasses and then talk about research that has been completed but is not yet published regarding the cheatgrass-fighting bacteria that had been in the news off and on, Pseudomonas fluorescens. One of the requirements of good science over the long haul is replication, not just replication within an experiment but multiple researchers repeating the experiments that others did in order to test them. And a team that Matt's been part of has done just that with this bacteria and you'll want to hear about it. Matt, welcome to the show.

>> Good morning, Tip. Thanks for having me.

>> I know you've been in Idaho for a while but tell us about your pathway to becoming a federal range scientist in the Great Basin. How did you get there?

>> Well I actually am originally from the east coast, from Massachusetts, but I was interested in plant community and physiological ecology of wildland plants. And that brought me out to the University of Wyoming in the early to mid 1990s. I did a PhD there on the topic and then took a postdoc position at Montana State University where I began working in rangelands and then [inaudible] hired by Idaho State University onto their biology faculty to focus on teaching research in this area. I did that for about ten years. During those ten years and during the [inaudible] with large wildfires that were unprecedented and at the same time we're seeing large increases in exotic annual grass invasions and other problems associated with fire. And I became more and more interested in applying what we were learning from our research on the basic ecology of these semiarid rangeland ecosystems. And then in 2011, a position opened with the US Geological Survey. And USGS is the science on [inaudible] and the scientists through the USGS that focus on ecosystems, forests or rangelands have a really great situation that were able to do their science firstly in conjunction with land management. And that's [inaudible]. It gives you a window to seeing how my research can be most directly used and it's offered a pipeline to translate our science into actionable land management.

>> Yeah. I love that. That seems like one of the themes of some of your work. The listeners who are what I call "range nerds" may be aware of the regular feature in the Society for Range Management Rangelands Journal called "Browsing the Literature." Jeff Mosley from Montana State did that for a number of years and you recently took that over. I really think this is a useful feature. Do you do that column because you owe a personal debt to Jason Karl or because you think real people who make a living off of rangelands should know about current science? I apologize if I answered that for you. I meant to give you something besides a yes or no question.

>> I say Jason Karl owes me one. My motivation was first that it forces me to read the most current literature. So through that column I only review literature that was yet to be published. So I dig into all of the online first or just accepted articles. And because I'm not doing that column just for myself, it forces me to think about many different [inaudible] of rangeland ecology management. And so it helps me broaden my knowledge base and also very important it gives me a chance to translate and digest the scientific literature for land management so that they can go to this column and within five or ten minutes, they can get a pretty good idea of what's coming down the pipeline for science. And the idea is that they can quickly see whether or not there's any research that's very relevant to their needs and they can find the articles that I've cited and delve further into them, if you will.

>> I think that's great. One of the assumptions or I guess guiding ideas behind the podcast is that anybody who's involved in actually managing rangelands needs to pull from a wide range of subject matters and expertise and topics in order to do a good job at it. One literary scholar said one time that people should read promiscuously and I think trying to understand a wide variety of range science is pretty critical. Well let's jump into some of the research that you've been involved in recently. You know, reducing invasive annual grass dominance on rangeland is a pretty big goal and a pretty big deal, not just a big goal in terms of the scale of the problem, but I guess an audacious goal in terms of the apparent difficulty of the problem. Most people would rather not think about the amount of public money that we've spent on chasing that problem but it feels like the scientific conversation has shifted a bit toward more of a systems approach to solving the problem. In other words, not a narrow focus on whether plateau herbicide is the silver bullet but on how we can manage whole ecosystems and try to understand all of the different interactions in a way that promotes desirable perennials, discourages the things we don't want like exotic invasive annual grass. It's got to be economically feasible for it to be actually implemented on a large scale and gets long-term results. And I really think rangeland health is not so dissimilar to human health. We have to keep all the body systems functioning you know at high vigor because they're all connected. And I really think wild ecosystems are quite a bit like that. What are your thoughts on what I feel like is a good shift away from narrowly-defined questions and answers which is how you do good science but putting all that together into a larger understanding of ecological relationships that are interrelated?

>> I agree. So things have really moved away from this idea that number one we're going to completely get cheatgrass out of our landscapes. I don't think actually many people thought that was going to happen. But more importantly, managers are realizing that species like cheatgrass are here to stay. And if all we do is focus on cheatgrass, we're probably going to get stuck with even worse invaders and by the way those new invaders like medusahead and [inaudible] are indeed a lot more noxious and a lot more problematic. And so we can focus more on thinking about what are our objectives for the landscapes and I'm really amazed at how people are collectively thinking about the values that we have for those ecosystems like ecosystem services, like what is it going to take to get sustainable rangelands, wildlife needs, what exactly do the wildlife need, soil stability, ecosystem processes like carbon sequestration and moderation of hydrologic cycles, preventing erosion, et cetera. So that whole ecosystem project I think is indeed important. And along the same lines we're unlikely to have any tools, similar tools that become available that are mandatory. Just like you're not going to cure cancer by covering up the symptoms with pain killers. Human medical system has been, even though it's never good enough for us, we have to acknowledge that we've had a lot of success. Doctors treat sick patients just like land managers treat patches of land and doctors, medical profession have a good knowledge base available to them from PhD MDS like medical research and those doctors are able to read the symptoms on other patients to underline mechanisms and prescribe treatments that both address the symptoms but more importantly get at the root causes of the illness. And usually prescriptions are things like number one let's boost the immunity of the patient or the patch of land by giving it rest where rest is needed and making sure that the person or the ecosystem is as healthy as possible and thus able to have immunity against disease. And so the analogy of the disease would be this invasion by exotic species that create undesirable ecosystem conditions. So are we likely to have a chemical or something like that that's going to solve all our problems? It seems very unlikely to me. However, chemicals can be a very effective part of what we might call an integrated pest management approach. That really has to do with focus. We've got to think about both causes and the symptoms of the problems that we're dealing with. The symptom is the invasion. The cause of the invasion likely involves depletion of desirable native species that might compete with the exotics, lands' demise that could be due to a suite of things, some grazing practices, historic disturbances.

>> Yeah, a couple ecological terms that I think start to get at these ideas of health are "resilience" and "resistance." The terms have been thrown around a lot in the last ten years kind of like sustainability, you know, you start to lose meaning, but there are some pretty specific meanings for both resilience and resistance that I think are key here. Can you define both of those?

>> Yes. So Dr. Jeanne Chambers, Dave Pyke and many other researchers have compared and contrast factors that lead to invasion and recovery after wildfires centered on this concept, these concepts that led to the stability of ecosystems and plant communities. So resistance, when we talk about resistance, we're thinking about the ability of the ecosystem or the plant community to keep its composition. And most specifically we refer to resistance to invasion by exotic annual grasses. And resilience refers to the ability of the ecosystem or the plant community to rebound and recover after a disturbance such as wildfire. And the two are interrelated. Resilient ecosystems oftentimes have better resistance to invasion.

>> So an analogy to a human immune system, resistance would be a strong immune system that doesn't get sick in the first place. Resilience would be the ability of a person's body to recover quickly and rapidly fight off a disease once it's taken --

>> Yes, that's a pretty good analogy. Resilience refers to the overall health of the human. It's a bounce back after any kind of injury or sickness. And resistance is the ability to prevent any kind of invasion by bacteria or viruses.

>> In the paper that you sent me that's about to come out in "Rangeland Ecology of Management," the one titled 'Bunchgrass Root Abundances and the Relationship to Resistance and Resilience of Burned Shrub-Steppe Landscape' you say that perennial grasses are some of the key providers of both resilience and resistance in the landscape. What are some of the actual ecological mechanisms involved in grasses providing resilience?

>> Great question. That paper actually I think is now in print and available to your listeners. And if they can't get a copy of it, they can always email me and I can send them a PDF. So how is it that these perennial grasses provide resistance and resilience? I think a key part of it is below ground. In order to be resilient, these perennials have to have the ability to re-sprout. So number one, they've got to have [inaudible] stems that are usually right at the soil surface or usually just below the stem soil. But more than that they need to have roots that can feed the water and nutrients to the new sprouting buds. Resistance, I think is larger the function of lateral root abundances in the bunchgrasses. So bunchgrasses, obviously they're bunchy. That means that they're normally surrounded by bare soil or maybe soil that's covered with cryptogamic or biological crusts but generally bunchgrasses need to have areas around them where the roots can provide more water and nutrients. Bunchgrasses tend to be a little bit taller in stature and they're not super heat building in the sense of sagebrush and so they do need to draw some of their resources from areas around that. And perennial bunchgrass roots by picking up water and nitrogen preempt or take away or suck up the water and nitrogen that invaders like cheatgrass really need. Cheatgrass tends to more readily be in areas that have very large gaps between perennial plants, perennial bunchgrasses especially. And in those very large gaps, there tends to be fewer perennial bunchgrass roots and, therefore, more moderate nitrogen available to the invaders. That's our theory.

>> That's interesting. The idea of lateral root abundance being critical rather than root depth is interesting because I think most people would associate root depth with the ability to plant to access water during periods of time when plants that are shallow rooted maybe can't and, therefore, they have a competitive advantage but I can see that maybe both are implicated. Are both width, lateral length abundance and depth important?

>> They are for sure. But I think that the perennial bunchgrass roots, I mean I think that they are generally getting the depth that they need pretty quickly. So on the Soda wildfire on the Oregon/Idaho border burning [inaudible], my field technicians and I went out and dug up the roots for about 500, almost 500 bunchgrass plants and cheatgrass or others that were burning near the bunchgrasses. And even for the relatively new long seedlings of the bunchgrass in drill seeded areas, the bunchgrass roots were almost always deeper than the annual grasses. So there's two things to think about. One is if the perennial bunchgrass roots are too shallow, sure, we would not expect survival and, therefore, we'd expect very minimal resilience from the bunchgrasses but I think given enough time the young bunchgrasses can indeed establish the deeper roots. And yes, that is important for extending their growing season every year providing the water that's needed to have good seed crop and could [inaudible] bunchgrasses that [inaudible] but also are critical for wildlife [inaudible]. Sage grass is not going to need to hide amongst the tall bunchgrasses. So deep roots are for sure important.

>> So what kind of stressors then take grasses out? If those are the factors that cause grasses to be competitive and stabilizing for an ecosystem, you know grasses are not bombproof, what will take them out or cause them to be weak and, therefore, less competitive --

>> Most of the bunchgrasses are pretty good at recovering after wildfire. Some exceptions can be the Idaho fescue is less apt to recover compared to other bunchgrasses. It tends to be factors such as some grazing strategies [inaudible]. Cows obviously like bunchgrasses. They're a lot more palatable than our other species like sagebrushes or exotic annual grasses. So extended spring grazing for example can [inaudible] can sometimes lead to depletion of the perennial bunchgrasses. And that's especially true when you combine drought stressors. So if you get several years of dry springs combined with inappropriate grazing, you can lose your perennial bunchgrasses and leave your ecosystem un-resilient and not resistant to invasion.

>> The stressors compound each other. I think with regard to Idaho fescue, I'd read some research out of maybe the PNW Experiment Station that grasses like Idaho fescue that have a higher stem and leaf density down by the soil surface are most prone to generate enough heat the kill the meristematic tissue in the ground when they burn and, therefore, are more susceptible to mortality --

>> Yeah, I think that can happen. Another thing that can happen is some types of grazing [inaudible] will deplete the bunchgrasses from areas away from sagebrush so that you end up having the residual bunchgrasses surviving close to or sometimes even underneath sagebrush or other shrub crowns. And then when the fire happens, obviously the heat is greatest with wood in the high leaf area of the shrubs and that causes more mortality of the bunchgrasses.

>> What are some measurements, methods that have been historically used or maybe are currently being used to gauge bunchgrass health? How do we measure? That seems like a pretty difficult thing to get at --

>> Yeah, that's a really critical question and I want to extend the question a little bit further. I'm told by rangeland conservationists and the people who do post fire rehabilitation [inaudible] that they really need metrics of bunchgrass maturity to help guide post fire grazing resumption decisions. Usually there's a couple years of rest after fire but then the question is, when are those bunchgrasses ready to withstand grazing resumption without compromising the health of the bunchgrass in the long run. And unfortunately, we don't have a lot of scientifically supported metrics for bunchgrass health. We think that it's likely to involve things like the diameter of bunchgrasses at the ground that's called basal area. So you measure that and you simply pull up the foliage from the bunchgrass and use calipers or just a regular ruler and you just measure the diameter of the stem to soil connections in the bunchgrass. And usually in order of like an inch or two for established young plants and sometimes can be 10 inches or 15 inches for some taller, bigger bunchgrasses. Also and that will tell you how established the plant is. Obviously, a bigger diameter is going to indicate an older plant, presumably a plant that's less likely to die during the drought cycle. We can also look at whether or not the plants are having good seed crops. That's a pretty good indicator of the health of the population of bunchgrasses. Height, I'm not sure that height is a great indicator in general because height varies so much from year to year and is a function of the weather. However, for young seedlings, we did find that height does correlate with how much root they have and whether or not the plant is likely to get tugged out of the ground by cows. We didn't actually go out and measure that. We simulated with tugging out by cows by tugging with our hands. So unfortunately, we don't have a scientifically quantified prescription for what could be measured to widen bunchgrass health but these are some variables that we are looking at now [inaudible] to direct measurements of the resistance and resilience of bunchgrass lands.

>> Yeah, let's talk about this research that you just published because it sounds like that may be leading us toward tweaking some of those methods. Most people are aware that when you do research, it starts with a clean question or a set of questions or maybe a statement of expected results. And so you listed five predictions that you were testing with this particular research project. Are those predictions things that you believed would be true or were they just statements of a hypothesis that you were going to test?

>> So I think of hypotheses as statements of how nature works, so we might hypothesize that roots, root abundance and the activity of roots of bunchgrasses is the mechanism underling resistance and resilience. And no one project can definitively answer that question but a given experiment could test some predictions that are consistent with that hypothesis. And so the five statements that I've made are actually predictions. There were things like we predicted that the resistant/resilient area that roots of bunchgrasses would be deeper than annual grass roots. And of course, if they're not, then we know that those bunchgrasses probably have a low likelihood of surviving. The second thing was we predicted lateral root abundances in the bunchgrasses would vary with factors that we think normally affect the health of bunchgrasses and their resistance and resilience [inaudible]. Those would be things like slope aspect and elevation. As you go up in elevation, you think that bunchgrasses generally are more vigorous and that their [inaudible] are more resistant [inaudible]. We also predicted that exotic annual grasses of cheatgrass would be less abundant wherever perennial bunchgrasses have more of those [inaudible] of groups. And we also predicted along with this that the gap, the f bare soil gaps between the perennial bunchgrasses would be smaller where those exotic annual grasses were less abundant. So those are kind of the science things. And then we wanted to kind of extend these questions to things that are more readily usable by land managers. And so we also asked if the lateral root abundances of the bunchgrasses could be related to things like basal diameter, which you can measure pretty quickly and easily. Lateral roots are so hard to measure and that's why we have [inaudible] even though they're so important in rangelands, in semiarid rangelands, there's hardly any studies on roots. And in the future, there probably won't be many either. So the key thing is what can we measure above ground to get a good indication of what's happening below ground in the roots. Is the diameter --

>> And basal diameter, just to interrupt you, basal diameter is one of the things that we have measured in bunchgrasses to try to get at their vigor, assuming that that's a good proxy for --

>> Absolutely. So there are some data, some agencies monitor but not all. And if we find that basal diameters do relate to roots, then it would make a case for putting more effort into measuring basal diameters and monitoring how basal diameters change.

>> Right. So what did you find?

>> We did find that unsurprisingly perhaps the roots of the bunchgrasses were in all but like a couple of plants, they were deeper than the annual grass roots. It's not too surprising because you know we were just measuring these bunchgrasses on a natural landscape that had been burnt and I think that any bunchgrass that had roots that were shallower than these very shallow cheatgrass or medusahead roots that bunchgrass probably wouldn't survive and wouldn't have been there for us to measure. But even still, we think the rooting of the bunchgrasses was evident even in the seedlings of the grasses that came up from [inaudible]. Bunchgrasses, that were [inaudible]. So okay, that's pretty good insight. We observed what we expected to see. Lateral root abundances they did vary with the landscape features. They're definitely more, they definitely vary. Most importantly we were kind of surprised that the expectation that cheatgrass and medusahead would be less abundant where lateral roots were more abundant but we actually didn't observe that. There was no evidence for that; however, the annual grasses were more abundant in areas that had large basal gaps, large bare soil gaps between perennials. And the perennial bunchgrass roots were also scarcer in those large gaps. So it's almost like we've got indirect relationship between the perennial bunchgrass roots, the bare soil gaps and cheatgrass abundances. And the importance of this is that it tells us that those bare soil gaps are probably pretty important to focus on for monitoring. They're probably a pretty good frame to tune to when you're trying to quickly assess resistance and resilience of a site. And there's other research by my colleagues that has pointed to this in the past including those publications. Dave Pyke and his colleagues have focused on this [inaudible] providing a below ground root-based evidence for [inaudible]. This was a surprise to me. I actually did not -- I always thought of gaps, canopy gaps as being important to the vigor of the bunchgrasses next to them and I figured that a tall bunchgrass will have a lot of roots in their soil gaps and that will make it hard for cheatgrass to invade. Obviously, I wouldn't expect that in very large gaps but I was kind of surprised that a gap, our data showed that a basal gap, bare soil gap larger than 16 centimeter diameter, so what is that, that's about 30 centimeters, so about a two-foot diameter gap is where anything larger than that you are at much greater risk of having annual grasses come in because the bunchgrass roots are going to [inaudible].

>> Is there any difference between canopy gap and basal gap in term of the effectiveness of measurement or did you just test one of those?

>> We didn't measure canopy gaps. Canopy gap refers to like the leaves of the bunchgrass kind of like [inaudible] and kind of spread outward. The canopy area is much larger than the basal diameter or the basal area. We only measured the basal gaps. The reason is that canopy gaps are sort of variable from year to year. They're [inaudible] part of the target for managing.

>> In terms of monitoring, it would also be highly dependent on the timing of measurement relative to grazing. You know if you graze in June and you're measuring it in July, you're going to missing some canopy probably.

>> Absolutely. Whereas basal diameter does not change much. It's really going to steadily increase or [inaudible].

>> And if you've got a plant community with more than say 16 inches annual precip, oftentimes there's not much of a canopy gap but you may still have basal gaps that can be measured.

>> Yeah, that's right. A lot of times the canopies are overlapping one another and [inaudible]. Plus, these are pretty brutal environments and if you try to make precise measurements of [inaudible], sometimes it's a little bit trickier because things are kind of blowing around --

>> Yeah, I've tried that.

>> Yeah, whereas basal diameter is really easy. Basal diameter is also -- One thing I like about it is it's also really easy to monitor aerially after fire. So you get these green rings for the first little bits of [inaudible] after fire where the basal diameter and the basal area is really evident. That can be useful information in the planning of fire response. Plus, fire conditions obviously are really pivotal for managing during the [inaudible] of the desirable bunchgrasses and undesirable exotic annuals.

>> So is that -- Is the basal gap, the size of the basal gap a passive feature of the landscape that's based on precipitation, soil type, plant variety or is it something that can be manipulated? So say you've got you know a shrub-steppe at 1000 feet elevation that has large basal gaps, is there a way for management to decrease the basal gap or is that just something that you're stuck with and it's useful to know that? Can it be manipulated?

>> Well yeah, I do think it can be manipulated where you have drill seeding or aerial seeding. The density of plants probably relates inversely or negatively to [inaudible] dynamics. Over time, there's probably some natural thinning that occurs but in the short run, within five years after drill seeding, if you had seeded very densely I think it's reasonable to predict or expect that the basal diameters might be smaller. There's not a lot of research on that particular question and we could use some more studies looking at that to see if this prediction actually is going on.

>> That was the method used on the Soda Fire. I've actually been on a couple of those seeding locations inside the footprint of the Soda Fire. And the drill seeding was spectacularly successful, at least in the place where we were. You know, you've had a hillside that had not been seeded and one that had been seeded and they were night and day with very, very little cheatgrass present inside of the drill seeded area.

>> Yeah, there was some highly successful treatments for sure. And one of the factors that led to the success was the layering of herbicide treatments with the exotic annuals and deferring the resumption of grazing after the treatments were implemented. So normally grazing is deferred for two years after fire. In the case of Soda, grazing was deferred for at least two growing seasons after the last treatments of seeding with herbicide [inaudible]. And by the way, the listeners might be interested in know that on the Soda Fire we experimented with using herbicide first in the first year after fire and then waiting until year two to drill seed and then vice-versa. And then on top of that, we used a range of different hand plantings and multiple seedings. In some cases, they even did multiple herbicide treatments. And that layers of treatments I think was really critical for enabling land managers to come up with a successful restoration or rehabilitation. Another thing we should probably talk about is it's likely although perhaps not yet proven that grazing practices, especially the timing of grazing resumption after fire, probably affect basal diameter development. There is some literature that gets at this but we could always use more direct tests of these ideas to help us know exactly like what grazing intensity, what season of grazing, what species of bunchgrasses, different site types, different elevations, real data from all those different kinds of scenarios and settings in order to really understand these questions.

>> Yeah. A couple questions on that because this is a pretty big deal in the livestock industry. You know, if you had 90% of your BLM ground burn up, you know having to wait three years before getting back on to it can be an economic hardship. And one of the things that has been proposed is that grazing after seed shatter likely doesn't have the same negative effect if that was done say year two after a fire instead of waiting later. What are your thoughts about grazing after seed shatter as opposed to, would that still have the same negative effect as grazing during the active growing season, which seems like it's pretty obvious that's a problem?

>> We have some preliminary studies on this effect of spring versus fall grazing after fire. We don't have conclusive results yet on it. My expectation is that I'm predicting that the fall grazing will have less negative effects than the spring grazing for the reasons just mentioned. And we're actually observing that some modifications of grazing permits that are happening on especially, you know I've seen some of these have happened after the Soda Fire for example. And in many cases stripling and spring grazing is now being either shifted into the fall or sometimes put into rotations that alternate spring and fall. The point is to alleviate some of the spring grazing or end of summer grazing and shift it back in time to protect the seed [inaudible] and also there's other benefits too but you may end up with greater productivity by allowing the bunchgrasses to retain their foliage in the spring until they're fully matured. Now in the fall obviously you're not grazing foliage that is going to be supporting much additional growth for that year before winter comes.

>> If you don't mind, let's talk about cheatgrass-eating bacteria for a few minutes. I think this is a really interesting situation. In the world of even conventional agriculture there has been a dramatic increase in understanding in the role of bacteria and other microorganisms in mediating soil processes that make nutrients available. So I think and good bacteria are superheroes but maybe Pseudomonas fluorescens isn't quite as omnipotent as we had hoped. So you've done some research in that. What specifically spurred you and your colleagues to do some research on this bacteria?

>> Land managers were starting to use disease-suppressive bacteria. They were investing pretty significantly into it.

>> Expecting that it's a silver bullet?

>> Expecting that it was going to be a silver bullet. Again, as we mentioned before, I generally think it's very unlikely we're ever going to have silver bullet solution to get rid of exotic annuals. And so we're observing that land managers were starting to use disease-suppressive bacteria. The idea is we're spraying low densities of the seeds of the [inaudible] dry bacteria onto the landscape. It's dehydrated when you spray it on. And the bacteria then grows in the first year into [inaudible] producing a chemical that inhibits root growth in annual grass seedlings. So there's a lot of nuances with that whole strategy or expectation for how bacteria can be increased naturally in the soil on site. But the main reason why we got into this is land managers were also not 100% sure whether or not these bacteria [inaudible] was going to work and so they actually asked us to get involved and start conducting reproducible, well-replicated [inaudible] experiments testing the bacteria in ways that people would believe the results. There's been a lot of studies now.

>> Yeah, because some of that initial research by Ann Kennedy was published in 1991. That's been quite a while ago. You would think that there would be a few other studies since then besides ones conducted by her that would have some results. But there hasn't been much?

>> Well actually just in the last -- Very recently there has been. So [inaudible] publication 2018 that was the first paper showing the effects of one of the strains of the bacteria in rangeland soils and it showed -- She made the case that the bacteria was very highly effective in rangeland settings. Since then, a number of other researchers have tried to reproduce those results and they haven't been able to put it with the particular strain that Dr. Kennedy used as well as two other strains that are available. There are papers that have been accepted and are in press in the "Journal of Rangeland Ecology Management" in a special issue that's forthcoming. All of those papers have negative results for the effectiveness of the bacteria. In other words, the bacteria did not affect anything in a wide range different rangeland settings. That doesn't mean that the bacteria can't be effective. It just means that using the bacteria that you know has recommended and prescribed, nobody's been able to get the bacteria to work in the rangeland settings.

>> Yeah, that's interesting. One of those papers is one of yours, I understand?

>> Yes. That's right. Several. One, I'm the coauthor on one and two of other studies were ones that I led or actually [inaudible].

>> Okay. And yours included experiments with potted plants as well as field trials. Is that right?

>> We have not published -- Yes, that's correct. One of them did have potted plants. We used the same bacteria that Dr. Kennedy used in the study led by the USDA Agricultural Research Service, the same organization that Dr. Kennedy is part of but by a different researcher Dr. Kurt Langhart [assumed spelling] of Montana. And in that study a number of, an experiment on where the bacteria were applied or were not applied was used in a number of different locations throughout the state of Montana. Additionally, the bacteria were tested in pots and also Petri dishes. And saw effects in the Petri dishes but not in the pots or in the field.

>> Some of what I've heard anecdotally is that the bacteria has some effect when soil incorporated into a cropping situation, which is maybe what it was intended for?

>> Possibly. You got to think about soil microbes and soil fertility. Rangelands, the soils -- In semiarid rangelands where exotic annual grasses are a problem generally are still pretty infertile and they do not have a very high abundance of organic matter or microbial biomass like fungi and bacteria in general.

>> To feed the bacteria?

>> Yeah. It's they're relatively infertile. There are extreme environments. Most of the landscapes are categorized as steppe environments, which means they get very hot in the summer and very cold in the winter. And the soil surfaces where most of the nutrients are and where you would think most of the bacteria would be are pretty extreme environments for bacteria to grow in general. It doesn't mean that there are no bacteria. There are. It's just the bacteria that are there are probably very locally adapted to [inaudible] site conditions.

>> Uniquely suited to that conditions, yeah.

>> Fungi are relatively big players in the soil microbial communities. Fungi tend to be a little bit more adapted to dry soils. And we know a lot more about how fungi affects these ecosystems than we do bacteria. We know bacteria are pretty important for converting organic into, reducing nitrogen and play a role in the springtime for converting forms of nitrogen and so the nitrates [inaudible] plants can take up. In contrast with fungi, we know a lot about how there's five different species of fungi that are major pathogens on the exotic annual grasses. Black fingers of death, head smuts, they're pretty common. And maybe your listeners have probably actually seen these fungi on exotic annual grasses. We've never been able to figure out how to leverage this fungi in restoring these landscapes. My point is that we don't know so much about bacteria especially in the soils in these ecosystems and [inaudible] are probably pretty harsh places to try to grow certain strains of bacteria.

>> Well, if you don't mind, could you summarize what we think we know right now and by we, I mean the scientific and management community about trying to slow down invasive annual grass, both treating it and preventing it from coming in, in the first place?

>> So number one, deciding whether or not to intervene is a key question. Cheatgrass can reside as subdominant or a nondominant part of many different kinds of plant communities. That does not include like low elevation sagebrush steppe [inaudible] which is where most of the problems lie. So number one, deciding whether or not to act, sometimes our actions are disturbances in the plant communities themselves and the actions, the seeding and the herbicides [inaudible] sometimes may not actually improve things. It's possible that it can in some cases make things worse. And then number two, getting on new invasions quickly. And when I say getting on them, I mean either alleviating the factors that are causing the invasions particularly livestock management factors or some kind of disturbance or suppressing, trying to suppress the initial invasion with herbicides or areas that haven't been invaded but are at risk because they have a depleted abundance, lack of abundance of desirable perennial bunchgrasses. There might be places where seedings or plantings of the bunchgrasses could be very effective. Generally speaking, for areas that cheatgrasses have already taken hold is becoming dominant. I believe we really need to look at how grazing is used. It doesn't mean you should be literally grazing, just opportunities to look at the timing and intensity of grazing. In some places where annual grasses are really abundant, it may be possible to actually reduce the impacts on fire with [inaudible]. It's not easy to do and it takes a long-term commitment to use a tool like that. There's probably some settings where grazing, where reduction of grazing or increase in grazing in very targeted areas might be beneficial. It's pretty well recognized that if intervention is going to involve seedlings and herbicides that we're more likely to see success if that intervention were more programmatic in approach rather than [inaudible]. We've seen all too many treatments that are just kind singular herbicide effort or a singular seeding effort with no followup, oftentimes without much monitoring. It's not a recipe for success in these dry ecosystem where drought is common. In another five years, we're likely to see a pretty good drought year, right. So land managers are getting resources on the authority and flexibility to have follow-up treatments or to have phased treatments that combine herbicides and seeds over periods of let's say five years, I think we're much more likely to see success. The point is the biggest message is these efforts have really got to be all hands all lands. I was just on the phone on call with a manager of a national wildlife refuge who was treating 1000 acres [inaudible] side of a fence is much bigger acreage that has a lot of cheatgrass. And so the question for him is, can he work within his own silo of fish and wildlife lands to have a successful treatment or should we really be looking at potentially investing some resources on [inaudible] the land and private lands. That might be a worthwhile strategy to consider [inaudible].

>> Very good. I think that's an excellent conclusion. Does the USGS publish some of the PDFs of this research or is the easiest thing for people to just email you if they're interested in getting a copy of some of the research?

>> They can go to my website at the US Geological Survey on the Forest and Rangeland Ecosystem Science Center. And if they just typed in my last name, Germino, and USGS into a web browser, that'd probably be a good way to go right to the website. And I believe that there's a little button they can click next to the each publication that will go to administration. Administration can sign out a PDF. If they just go on Google Scholar, you should know that many PDFs are readily available on Google Scholar. They're easy to find there. And they can also directly email me any time.

>> Okay. We'll post that website URL as well as your email address on the show notes that are in the description for the episode and they'll also be on the Art of Range website. Matt, thank you for what you do and thank you for your time.

>> I appreciate it, Tip. I really like what you do here with these podcasts and it was great to meet you in South Africa [Background Music]. What a great event that was, so enlightening and then I extend myself to any of your listeners and yourself for follow-up questions.

>> Very good. Thank you.

>> Thanks.

>> Thank you for listening to the Art of Range podcast. You can subscribe to and review the show through iTunes or your favorite podcasting app so you never miss an episode. Just search for Art of Range. If you have questions or comments for us to address in a future episode, send an email to show@artofrange.com. For articles and links to resources mentioned in the podcast, please see the show notes at artofrange.com. Listener feedback is important to the success of our mission, empowering rangeland managers. Please take a moment to fill out a brief survey at artofrange.com. This podcast is produced by CAHNRS Communications in the College of Agricultural, Human, and Natural Resource Sciences at Washington State University. The project is supported by the University of Arizona and funded by the Western Center for Risk Management Education through the USDA National Institute of Food and Agriculture.

Mentioned Resources

  • You can find more information on the research discussed here at the USGS Forest and Rangeland Ecosystem Science Center website: www.usgs.gov/centers/fresc
  • And you can reach Matt Germino at mgermino@usgs.gov.
  • Many articles on the Rangelands journal website are Open Access and do not require a paid subscription to the Society for Range Management or the journal. Check it out at www.journals.elsevier.com/rangelands.

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