AoR 133: Ruminating on Soil Carbon with Paige Stanley, Jim Howell, Ariel Greenwood, & Chris Wilson

"Decades of scientific research on grazing and soil organic carbon (SOC) has failed to form a cohesive understanding of how grazing management affects SOC stocks--characterized by different formation and stabilization pathways—across different climatic contexts." This quote from the introduction to the review paper "Ruminating on soil carbon: Applying current understanding to inform grazing management" frames the dilemma we're discussing in this episode. How can common management levers that define overall grazing pattern, including timing, intensity, duration, and frequency, be used to optimize mechanistic pathways of SOC sequestration? These authors offer a framework for beginning to answer this important question.

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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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Welcome back to The Art of Range. We have a group conversation today about a topic that seems to be a lot in the news and quite a bit in the scientific headlines. And that is carbon and grazing. It seems like we've got carbon trading, carbon-based economies, carbon taxes, carbon sequestration, greenhouse gases, and cows. You name it. There's an awful lot of talk about carbon. I've had visits with people that are working for these companies that are trying to convert everything over to plant-based diets and trying to get people to stop eating meat because, see, it's like carbon is the self-explanatory justification for everything. And I don't even listen to the news. So this is just what seems to be filtering through everybody's scientific and public conversations these days. We've got a group here that has published a review paper, and I love review papers, published in Global Change Biology titled "Ruminating on Soil Carbon: Applying Current Understanding to Inform Grazing Management." I think that's a great title, and it's a gutsy one given the scope of topics, you know, scientific subtopics that are underneath that category and given the amount of hype that's out there on this. So instead of me attempting to introduce each person, I think I'm just going to go around our virtual room here and ask each of you to introduce yourselves and describe how you got into this. So we've got on the line, so to speak, or on air, Paige Stanley, Jim Howell, Chris Wilson, and Ariel Greenwood. Paige, I think we'll start with you because you have recently been on one of the podcast episodes as a panelist for the Society of Range Management plenary session regarding change on the range. So why don't you introduce yourself and then you can hand the mic off, so to speak, to the next person. Paige Stanley, who are you?

>> Sure thing. And thanks Tip for having us on today. I really appreciate this opportunity. My name's Paige Stanley. I am a research scientist at Colorado State University, and I combine several different disciplines, but primarily rangeland soil biogeochemistry and grazing ecology which I try and use to understand the ways in which grazing management can help us sequester soil organic carbon, and what that means for climate change mitigation, our ability to adapt to climate change and create more resilient rangelands.

>> Great. Welcome back. Why don't we go next to Chris, Chris Wilson.

>> Alrighty. Well, yeah. Yes, for sure. Thanks, Tip, for having us on to talk to you all. I'm Chris Wilson. I'm an Assistant Professor in the Agronomy Department here at the University of Florida, and I'm basically an ecosystem ecologist that works in ag systems, primarily pasture and grassland, but we also do some work in row crops and woody crops and other stuff like that. Had a longstanding interest in the carbon cycle and climate change, and how management of pasture land can impact that and hopefully potentially mitigate climate change just like Paige. And yeah, we use a variety of quantitative and experimental methods to study that. So thank you.

>> Thank you. Jim?

>> Yeah. Hi guys. This is Jim Howell. I own and lead a ranch management company called Grasslands. We take on large commercial ranches for absentee owners and provide a full care management service for them. We have operations in the West United States and Florida and New Zealand, and I spend most of my time bouncing around to those various operations. I live in Fort Collins now. I grew up in Western Colorado and managed my family's ranch in Western Colorado for a long time. And I kind of came across more progressive ranch management type stuff early in my career about 30 years ago. And have been really interested in how my day-to-day actions and decisions impact the dynamics of ecosystem processes and across these dynamic complex rangelands, and have always been interested in the science behind it. And it's just really exciting to be here with scientists that are thinking along and the same lines that I have been for a long time and trying to answer a bunch of the same questions. So it's genuinely an honor to be here with you guys all.

>> Thank you. And thanks for joining us. Ariel what has been your role in this effort? And where are you and how did you get into rangeland science?

>> Sure. Well, my role in the papers is none besides being someone who's kept up with Dr. Paige Stanley's work from afar, and I was honored to be asked to join this call. And I'm just a producer, really. I'm a land and livestock manager. My husband, Sam, and I have a management LLC called Grass Nomads, LLC. And we've worked across a few different states together and individually. These days we are managing a pretty large high elevation lease in Northeastern New Mexico, cow-calf operation. And, you know, I think like many producers, I'm just very challenged and compelled by the difficulty of communicating the positive changes that we can see on the range through our management with maybe more conventional approaches to capturing that science. And so this paper, I think, is just really going to advance our ability to talk about those changes with a much finer degree of detail. So that's why I'm here. I'm just a producer who's got an eye towards a lot of the things that Paige and Chris and the other co-authors are trying to capture.

>> Great. Thank you. And I will take brief issue with your self-identification as just a producer.

>> Fair enough.

>> You know, part of what I like about this, I guess, discipline is that we're working with those of us who are not people who actively manage livestock and produce things that are worth more than our pay, have the responsibility of working with people who do, do real things in the world, real world. You know, whose livelihoods depend on making good decisions in these information domains that we think we know something about. But because it's applied science, that's really not worth much unless we're actively engaged with people who are producing something that has real value, tangible value for human society. So thank you. And I'm excited to have a conversation about this and it's important for us to try to understand your observations of what's going on in the real world and make some sense of it, because those observations are real. Well, I'll admit that I'm definitely partial to ruminants. And so in, you know, in policy discussions and scientific discussions and political discussions about the role of grazing on public lands, on wild lands with regard to carbon sequestration, I likely err on the side of being optimistic, whether that's justified or not, about the potential for grazing on grasslands and rangelands to do good. And part of that is because I think I end up mostly working with the people who are doing a very good job at it and I see the real scientifically defensible benefits of grazing in a way that we're probably going to describe here in a few minutes. You know, grazing in a way that maintains all of these ecosystem services, including both carbon sequestration and conservation, as well as the other ecosystem services that we expect from rangelands. But I'm also a skeptic in the sense that I'm prone to look for things that aren't working well, you know, or what could be done better, and try to understand the mechanisms behind that. And so there's some, you know, there's some scientific thinking there, not just idealism. So in several respects, I feel like people have been talking around this issue or making grandiose claims or making, you know, catastrophic "the sky is falling if we don't stop eating meat" kind of claims for some time. And so the papers really scratches several itches for me. And I would like to thank the group initially for putting it together and for working on these things. And I suspect it'll be satisfying for others as well. A review paper is a lot of work, maybe even more work than doing a research project because, you know, research projects are by definition generally narrowly defined, and you're just reporting what happened, but trying to synthesize everybody else's reports of what happened in their research projects, and to do that in a way that is fair to the breadth of the literature and to make any reasonable conclusions about it, you know, which we often don't want to do, is a real challenge. So how did the idea of a synthesis paper or a review paper come together? And maybe that's a question for you, Paige, if you were the one that got going on this.

>> Yeah, for sure. Actually, I really love the origin story of this paper. It's a fun story to tell. So back, I guess it was a little over a year ago at the Society for Range Management Conference in Boise, Idaho in 2023. That was, you know, I've been attending this conference for a while, but this felt like the first time when soil carbon had really been at the forefront of this conference. There seemed to be critical mass of folks who were interested in it, a lot of sessions where folks were presenting on range soil carbon stuff. And then on the final day of the conference there was a carbon market panel that brought together some producers and some modeling companies who were attempting to issue carbon credits and some kind of verifiers who were trying to issue carbon credits to ranchers. And myself and Chris and one of our other co-authors, Dr. Megan Machmuller, were all at this conference and had been attending these sessions all week. And finally, we were all at this panel session hearing from companies about what they were doing to, you know, sell carbon offsets. And I think the three of us were kind of looking at each other like, hmm, these claims seem a little, you know, sketchy or, you know, we're really familiar with the data that are available and the measurements that have taken place. And like we felt like at the end of that session, there were a lot of remaining questions and maybe some over promises. And we were like, man, how great would it be if we had a paper to kind of guide both researchers and carbon market adjacent folks in the right direction and also something that could be useful and tangible to producers on the ground. And so you know, a few weeks later we had dispersed and we were like, you know what, let's actually turn that idea into something. And so it was just one of those moments of, you know, right people in the right place at the right time coming together to work on an idea. And that's exactly what we did.

>> Well, that is a good story. You present some interesting statistics, I guess, in the introduction to the paper trying to characterize this on the big picture, and it is a pretty big picture. You mentioned in there that 30% of total soil organic carbon stocks are held in ag lands globally, and two thirds of ag lands have grazing as some part of the cycle. Which made me wonder, you know, in the Western U.S., we have a lot of what I would call, you know, wild rangelands that are mostly just native or naturalized ecosystems that other people might think of as -- they definitely don't think of them as agricultural lands in the sense that they're not being necessarily intensively managed with a lot of inputs. And I think that's one of the key differences between rangelands and more intensive agricultural lands, which might include, you know, what we could call grazing lands, that this really works well when you don't apply a lot of agronomic inputs into the system where it doesn't rely on herbicide, fertilizer, seed, pesticides, you know, you name it. But there's obviously a spectrum there because there are rangelands that get seeded periodically because that enhances production. There are drier pasture lands that look quite a bit like wildlands, but they get managed with some intensive effort, even though there may not be a lot of expensive inputs. There's probably several different axes to different spectrums or spectra here that we could describe. But, you know, certainly on the less intensive end of the spectrum, it doesn't really feel like agriculture, even though there's some agricultural output from, you know, that was supported by these wild open spaces. So describe what's included in that statement about the two thirds of agricultural lands that are grazed globally.

>> Paige, I'm happy to take this one if you want.

>> Sure.

>> All right. Yeah, so Tip, you're absolutely right. Yeah, there's a lot of global grasslands, and they're extremely heterogeneous as ecosystems. So you got all different kinds of grazing lands, and I think you did a really good job describing a lot of that diversity. And then you add up, you know, basically all the rangeland together with all the pasture land, which is obviously a lot more common here in the eastern United States. And that's where we get up to about 25% of the global ice free land area is in some form of grazing land. And then it's basically a similar proportion of the total global carbon stock. Now there's a little bit of nuance, like I have a lot of friends who work in high latitude systems, like up in the far north and Alaska and permafrost. And so whether or not you include those soil carbon stocks in the total can adjust how you come up with these numbers. But as a starting point, I think it's pretty realistic.

>> Sure.

>> I might also add one more thing on there, which is that I think that statement and the way people think about these landscapes really highlights the ways in which, you know, different ways in which we slice and dice these landscape we can come up with different numbers, right? So whether we're talking about pasture land or temperate grasslands or rangelands in general, which is kind of an umbrella term, but I think what I love about working in these landscapes is that diversity that we get and, you know, the types of landscapes that are more wild or naturalized, they still have value in terms of food production. Because while we might be managing animals and ecosystem services on these landscapes, at the end of the day, we are also producing food from there. And so they are agricultural in some shape, form, or fashion if they're being grazed by livestock that we use for food. And that kind of dichotomy is something I really love about grazing landscapes in general.

>> I would agree with that. I mean, that definitely is one of the things that has initially attracted me and continues to make me want to go to work in the morning, that these are places where we can produce food for people in a landscape that's doing all kinds of other things besides just producing food. I feel like a broken record on this, but, you know, but if -- I can't remember the name of the organization, but I had a pretty long phone call with a representative from an organization that was trying to move toward plant-based meats. And they wanted a list of contacts from me for ranchers in Washington State who were livestock producers so that they could work on convincing them to convert that land into soybeans or, you know, whatever. But I think it was actually soybeans. And I didn't give them the list. But, you know, it highlighted for me this misunderstanding maybe that, you know, people think that we should not eat beef because it's bad for the planet, but I'd like to -- maybe this group could help [brief laughter] put some scientific defense behind this. But just in terms of ecosystem function and policy, I would be more than happy to support natural lands, wild lands, rangelands that are still in something like a native state with a diversity of plant communities and wildlife that depend on them. I'm more than happy to set that against a soybean field under nearly any circumstances and say that the one is better, whatever better might mean. But I'm happy to say I think that it's better. And I don't know exactly how that comes out in terms of soil carbon, but I want to think that that on balance and in terms of, you know, a systems perspective that grazed rangeland that has some agricultural output is still superior in terms of ecosystem function and even carbon balance than a soybean field. And, you know, part of why I think that is that I'm pretty sure you can't grow soybeans without removing whatever was there before the soybeans. And of course, you know, one of the issues with rangelands and carbon is that a large percentage of the stable carbon stocks are underground. And correct me if I'm wrong, but we get rid of quite a bit of that as soon as we plow it. So maybe that's a whole different rabbit track. But, you know, in the paper you define or you propose a novel conceptual framework integrating mechanisms by which grazing patterns influence pathways of soil organic carbon formation and stabilization. So I think the point here is that grazing influences a lot of acres on the earth's surface and the grazing influences the ecosystem processes and plant physiology and soil microbiology and all of those things in turn affect soil organic carbon. And of course, where we get wrapped around the axle is like so many things that influence can be positive or it can be negative, or it can maybe not have any net change at all. But we have an awful lot of disturbances or ecosystem processes or human influences that are like that. If it's done in this way, then it's good. And if it's done that way, it may be bad or bad in certain specific ways. So I think that I want to believe that grazing in a way that is sustainable, however we want to define sustainable, can be helpful. And again, whatever helpful might mean. So let's visit some about what is helpful, what is the framework and what are some of the mechanisms by which grazing affects soil carbon? And maybe the first thing they ask is, what the heck is soil carbon [brief laughter]?

>> Chris, do you want to take the what is soil carbon and I can take maybe the framework.

>> Yeah, no, I think that makes sense. And yeah, before I get to that Tip, I do want to kind of echo back what you were just saying there. These are ecosystem, like anytime you look at an ecosystem, so I spent a lot of time teaching agroecology, that's a big part of my position here at UF, you got to think about it from a variety of perspectives. And so when you say ecosystem services, right, soil carbon is one piece. There's a whole bunch of other stuff that you alluded to there. It has to do with habitat quality, the biodiversity value that that conveys, watershed, right, the water cycle, the health and integrity of that. And you're always comparing these land uses to different alternatives, right? So in some cases, there might be a decision about, are we going to convert, you know, grassland into row crops? And that could have some of these negative impacts that you alluded to. In parts of country, like here in Florida, you know, frankly, just suburban development is another alternative land use, right? And so you got to just be kind of holistic and clear about, you know, what you're comparing these grazing glands to. And I would agree, I think one thing as an ecologist that really drew me to this whole field of study is that if you put them on a spectrum from like the most intensive row crop you can think of on one side, and then kind of the completely native system on the other, even a planted pasture is going to be more towards that native ecosystem end of the spectrum. At least I would argue that. We see that a lot in terms of pattern of plant diversity, you know, habitat value for different like bird species. There's a whole concept of matrix quality, so how well wildlife can make use of the land that you're using. And we've got a whole framework of land sparing, land sharing. We could talk about that later maybe. But I think we want to focus more on the carbon side. So yeah, just briefly, you know, organic matter in the soil occurs in many forms. Basically, it all originates in the plants. So for the most part, no carbon gets into the soil that hasn't first been fixed by photosynthesis, converted into plant biomass or into some sort of molecule inside the plants that is then deposited either as litter on the soil surface or through these extensive root systems, right? So something that's really cool about grasslands, perennial grasslands in particular, is that they tend to develop these really deep and extensive root systems that help them rebound from stress and disturbance. So why is it that pasture and range can bounce back from these seemingly catastrophic grazing or fire events? It's because they've invested a lot of this energy below ground into root systems, into the crowns of the plants. It can resprout. And so all that root system biomass itself dies, it turns over into the soil. The roots are also constantly, when they're alive and growing, they're leaking organic molecules into the soil, sugars, amino acids, organic acids, and all of that stuff is getting processed by microbes in the soil. And some fraction of that then kind of enters into different kinds of associations with mineral particles in the soil, we can maybe unpack that a little bit later, and gets stabilized in. So it's kind of a cool thing in our field that microbes are both decomposing all this organic matter, but also are themselves the origins and synthesized forms of organic matter that do get stabilized in the soil for a long time. And so you put all that together and we just sort of collectively lump it and say all that is organic matter in the soil. So if you measure it on different like chromatography or other equipment, you're going to find it's a hugely diverse set of things. It's all just basically different carbon based molecules. And that carbon is the central feature, right, from a climate point of view. All of that represents stuff that could potentially turn into carbon dioxide or methane and be released back to the atmosphere. And if it does, then it, you know, acts as a greenhouse gas. But if instead we keep it locked up as organic matter in the soil, then it's avoiding that warming effect. So if we can increase that net balance of organic matter, then that landscape can be said to be offsetting climate change from that point of view. So anyway, that's kind of a whirlwind overview, but hopefully that tees Paige up to talk more about our framework.

>> Yeah, thanks Chris. I think in order to really understand the framework, I might give another, you know, 60-second spiel to the extent that I can on the background of the paper. Because, so I think a couple of things that have been rolling around in my brain for quite a while that that set us up into readiness is that, you know, right now we're seeing the emergence of all of these carbon market spaces that are trying to get into the grassland rangeland grazing space. So these are carbon market in the States. This is the voluntary market that has been developed for a little while on crop lands. And now they're, you know, opening their eyes to the potential of carbon sequestration through grazing on grazing land to, you know, whatever extent that may be. And despite this big window of opportunity we have, I think one thing that I like to bring up with folks is that, well, we're only as good as the data that we have or the data that we're collecting. And if you were to go on Google Scholar or Google in general and type in, you know, grazing and soil carbon sequestration, you would see hundreds and hundreds and hundreds of papers. And yet we actually have very little data that has directly been collected as the result of grazing management. So we don't really have a great idea to help us understand the extent to which grazing management can sequester carbon, and if so how much, when and when does that not happen? How do different locations and climates influence our ability to do this? How do, you know, grazing traditions in different places of the world impact this opportunity? And so we have a lot of questions. And the baseline of literature that we do have on grazing and soil carbon, I think, has caused some frustrations on my end because, you know, you'll find all of these meta-analyses and other review papers and even, you know, direct measurements that we do have dating back to the 1990s. And yet there are still some, I think, overarching issues in our understanding. So for example on grazing lands, these landscapes are really heterogeneous, like Chris mentioned earlier. So the ways in which we measure soil carbon and soil carbon change over time by necessity has to look different than what we would expect on crop lands. So that means measuring soil carbon sequestration from grazing is kind of like finding a needle in a haystack. You need a lot of samples in order to be able to pick up that change and distinguish it from the variety of background noise in that, you know, heterogeneous soil carbon medium. So that's one big issue, is that many, many studies just haven't collected enough samples. And the other overarching issue that, that I see in the literature is the lack of, I think, definition in terms of what is the grazing treatment? So historically, most of the studies that have been done have been on like grazing or grazing exclosure. But then I think like Jim and Ariel could probably testify, well, you know, what is grazing? Grazing can look different depending on where you are. You know, there's rotational grazing, which is a sort of umbrella term. You know, grazing management can take place over a whole variety, this giant spectrum. And so it doesn't really make sense to inform grazing management based on studies like that. And then, you know, you have varying degrees of departure from that and other studies that have tried to measure soil carbon from things like light or heavy grazing. And then you might have the same question, well, what does that mean? What is light grazing? What is heavy grazing? And so the ways in which these studies have tried to define grazing, I think, is another big problem because it's likely, well, a lot of them have not been representative of real life grazing management and then others just haven't defined it well. And so I think understanding the problems in the soil measurements and the ways that these studies have defined grazing are two overarching challenges that led us to trying to answer these questions in the paper. And then the only other paper that has tried to do something similar, you know, was back in the early 2010s. And yet our understanding of soil carbon has really evolved quite a lot over the past 10, 15 years. You know, we once thought of soil carbon as this big overarching bucket, and now we know soil carbon exists in so many different forms, and once soil carbon or carbon is in the soil it acts differently. So some of it stays around for a long time, other types of soil carbon might get re-respired into the atmosphere. Some are more likely to be taken up by microbes or plants. And these different forms of soil carbon can also get there differently and might be managed for differently by producers. And so I think all of these things led us up into this paper where we were like, okay, well acknowledging all of these challenges in the previous literature and our current understanding of soil carbon and our understanding of grazing by talking to producers, you know, that's something that I've worked a lot on, and that's why I have come to really respect producers like Jim and Ariel, you know, folks who are really deep, critical forward thinkers in terms of their grazing management and impacts on ecosystem services is that, you know, there are real levers that producers pull on to change their grazing management. And so then how do we combine our understanding of plants and ecophysiology with this new and improved understanding of soil carbon and real grazing levers used by ranchers into one framework that can help us generalize the ways in which we can sequester carbon from grazing management and inform producers and also better researchers. And so that is how we came up with this conceptual framework where it's essentially all of those things combined into one. And so we've got if you look in the paper, which is open access, by the way, we've tried to combine our understanding of all of those things.

>> Well, that's a good summary. Yeah. It does seem like a lot of what has been said about the relationship between grazing and carbon in the past has to do with, you know, if you stop using overgrazing, whatever overgrazing might mean, then you get some relatively long term response in the soil and plant community or at the plant soil interface that is positive in the sense that there's an increase in root mass, an increase in vegetation production and soil cover. And if you measure change somewhere in the midpoint of that, it's going to be positive. But the positive was only because you ceased using practices that were, you know, maybe excessive defoliation or repeated defoliation, so that there was never any you didn't have full root occupation of the soil profile or, you know, on and on and on, whatever the mechanisms might be. But that's still something different than, you know, what are the main drivers, what are the ecosystem elements that are responsible for soil carbon changes, and how does grazing affect all of those? And are there ways that we can graze in ways that are more positive than just not destructive? Does that make sense?

>> Yeah, absolutely. And I think that that aligns with, you know, our intuitive understanding of these things, right? Like, if you stop repetitive chronic defoliation, then you might expect an ecosystem response that does lead to soil carbon sequestration. And on the opposite end of the spectrum, you know, if you introduce optimal grazing into an ecosystem that might have been under-grazed prior, then you might also expect a change in the right direction. And so I think we wanted to align this like intuitive understanding that we have as people and as ecologists with also anecdotal responses we've heard from producers who have been like, hey, you know, I've been doing X, Y, and Z with my grazing management, and I've noticed a lot more perennial plants or a lot more dense plant cover. And so I think we wanted intuition to align with anecdote, to align with experimental evidence in a way that makes sense and can help us explain all of the variability that we see across the literature. And I would totally invite Jim and Ariel to talk more about those anecdotal experiences that they've seen in terms of their grazing management because, you know, the visual indicators that they have as producers out on the land we know might go hand in hand with soil carbon sequestration. But because you can't lay eyes on soil carbon, you know, it's not necessarily a visible thing, but might be correlated with these above ground things, that's what we were trying to do in the paper. And so I would love to hear more about their experiences on that end too.

>> Yeah. Before we do that, I just want to list, I want to read off the ecosystem elements that you identify as the things that predict soil organic carbon changes and the mechanisms. In the paper you list ground and canopy cover, meaning, you know, how much of the earth surface is covered by plant material, seems somewhat intuitive. Productivity, because plant biomass is, you know, is as you've already said, is responsible for that, is the material of soil carbon eventually. Input allocation, which is maybe not quite so intuitively obvious for people. And we can talk about that. The quality of soil organic carbon inputs, things like the carbon to nitrogen ratio and what's available. And then diversity, either both, or I guess both plant functional groups and species richness. And that has been somewhat controversial. I mean, there's been some stuff published saying that just herbaceous biomass is the driver and that, you know, different species groups, species richness sounds good, but it doesn't really make a difference. But those five things, you know, seem to be obvious in the sense that they have to drive soil organic carbon. And we see some, you know, long-term trends in how each one of those responds to different kinds of grazing over time. And I don't know whether we want to say anything more about each of those five different pieces before we, you know, talk through some of the observational evidence of what the effects are.

>> Yeah, I think that's a great point. So I think what the conceptual framework does is it creates something of an arrow structure from animal to plant to soil. So there are a couple of ways in which herbivores can impact soil structure and soil carbon directly. So that's something like compaction. But by and large, the ways in which grazing influences soil carbon, whether that be by increases or losses, is indirectly by way of plants. And so what we're trying to do here is say, okay, well the how grazing, which is a grazing pattern, which we've defined here as a culmination of how much biomass is taken off, how long animals are grazing, how often they're grazing and when they're grazing, influences plants in five different ways. And these are the ecophysiology elements that we've outlined, which are the ones that you just listed and see, so these are like the things that are most directly related to soil carbon outcomes by way of grazing. So that's the animal to plant or ecosystem physiology arrow. And then from plant to soil, we've got, you know, each of these different ecophysiology elements then has downstream impacts on soil carbon in these different fractions that we've come to understand. And so that's the kind of cyclical outline that we've created in the framework.

>> Got it. Jim or Ariel, how do you see these things playing out in the real world?

>> Well, this is Jim, obviously. Well, first of all, it's really heartening that this paper has actually made an effort to, you know, recognize that grazing can happen in an infinite number of permutations or patterns. You know, that's something that, as a producer, has frustrated me for a long time as I read academic or scientific papers. It's frequently, grazing frequently is not defined to the level that would provide me practical information. As the paper alludes to, either it's grazing or no grazing, or if the grazing is qualified at all, it's typically intensity of grazing or how much biomass has been removed by the herbivore. But as Paige was just saying, there's all these other elements associated with grazing, like frequency and timing and duration, variables that we've been incorporating into our grazing management for a long time. And, you know, to the extent that I like almost quit reading scientific papers in the range science space because there was just so infrequently an allusion to these elements of grazing that are totally under the, not totally, but highly under the control of the grazing manager. And we know that we can influence at least the stuff that you can see as Paige was saying, that at the soil surface level and up, we can influence plant vigor and canopy cover, live canopy cover versus dead canopy cover and plant density and plant diversity and litter cover, and how well the litter is incorporated into the top soil. We've been looking at those dynamics and those variables at the soil surface and intimate detail for a long time, both anecdotally as we just ride across the pasture and look at that stuff constantly. And also in the form of the, you know, fairly rudimentary biological or ecological monitoring transects in which we try to read a variety of indicators that's trying to feed back to our management whether or not our management impact is resulting in a landscape training in the direction we want it to or not in terms of the effectiveness of ecological processes or these eco-physiological elements as they're referred to in this paper. And so it's really good that this paper is broadening the conversation into this greater range of dynamics that goes on out across these landscapes that we can influence with our management. So from that point of view, it was super gratifying, but it's also really cool that that is now being connected down to below the soil surface, into how all those above ground plant dynamics influence how the carbon is not only inputted, but the quality of that carbon and how it actually ends up being sequestered in the top soil. That's something that those of us on in the world of the producer have wondered about and intuited about for a long time, that if things are going really well above the surface, our assumption is that that's being reflected to below surface and things are going well there as well as also but we never really have known that. And so with this work, it's really helping us get our heads around that in a much more precise way. So that's my take on it.

>> I echo everything Jim says, of course. And, you know, to speak candidly, it's been frustrating for the last many years to try to have dialogue with people who aren't necessarily range science researchers themselves, but are looking at inciting the best available data that we have so far in the literature. And, you know, in many cases saying, well, there's just no proof that grazing is good [brief laughter]. And of course, even that can't really fairly be said looking at the literature, but depending on what papers you're looking at or what meta-analysis you're looking at, somebody could come to that conclusion. Because grazing just hasn't been defined or clarified. And you know, there are so many levers that those of us who are managing livestock on landscapes pull. And I've managed cattle in California, Montana, and New Mexico, and a few different places on each one. And it's really interesting what principles are the same but how different enacting those principles are in practice, you know. And in some cases, the animal impact aspect of it, the kind of mechanical interaction is a really important tool that we have. And in other cases, we have to really dial that down. And I think that's what I really liked about the papers, is while it was oriented around talking about soil carbon and drew a lot of really important distinctions there, finally seeing a paper draw these distinctions between timing, intensity, duration, and frequency, which are kind of our bread and butter for people like myself and Jim, who are trying to kind of push the needle wherever we can on rangeland health, those are some of the most primary factors that we're dealing with all the time. And finally, just seeing that named in a paper is really helpful. And my hope is that now that those factors have been outlined and a framework has kind of been developed, it can be added onto, and that this will sort of raise the standard of discourse for other researchers, whether they're conducting actual research trials or writing, you know, literature reviews or white papers, whatever the case may be. This needs to be, to my mind, a bare minimum framework going forward. And, you know, soil carbon, carbon credits are of course a really big thing right now. I don't know a whole lot about it, but my gut tells me that biodiversity credits are going to be the next thing. And I think there's a lot of different ways to -- a lot of different things coming down the pike that will improve our ability to monitor, to a finer degree, the changes on the range. And I think that what Paige and Chris and others have done with this paper is just helped the literature and how we talk about rangeland management, catch up with what the science through these maybe kind of high tech monitoring tools like remote sensing, you know, like the use of drones and machine learning. I think they're helping the literature and their discussions catch up with what is inevitably going to be the standard as revealed by these other tools. And it's just also just validating to see researchers really deliberately try to connect the dots between what producers like myself see on the ground and that they've identified this real gap which has been the source of a tremendous amount of, I think, just consternation and kind of crazy making, you know, for those of us who see these changes, but have no real language to talk about it in a way that doesn't just sound like we're claiming to be the exceptions to the rule.

>> You've mentioned a couple times the different levers that we can pull to modify or influence how grazing affects soil organic carbon through plant communities and plant roots. What are those levers? We've talked about, you know, grazing, timing, duration, frequency, intensity. Maybe talk a little bit more about each one of those because they all contribute to an overall pattern, which is one of the main points of the paper, I think, that the pattern is significant and makes a big difference and contributes to -- I mean, the pattern is what drives any definition, whether in this paper or somewhere else, but any definition of overgrazing, under grazing, optimal grazing, all of that. What are the different elements of this pattern that really defines whether grazing is a net positive or negative in terms of root mass, plant mass and soil carbon?

>> Yeah, I'll start and take a crack at it, and then Paige can clean up after me. So yeah, I mean, the levers that we're talking about here, you know, are those four, intensity, duration, timing, and frequency. And you're absolutely right, I think one of the key things of what we're posing here in our framework is this definition of a grazing pattern that's more nuanced. And I think that's what Jim and Ariel very nicely spoke to there, you know, from their perspective as producers. It's a little bit more closely aligned with how they think about things. So intensity, you know, we're taking it in the sense of the proportion of biomass that's removed during a grazing event. And frequency would just be how often animals are returning to a given patch of ground. Timing is then that crucial aspect of when in the kind of developmental cycle plants are exposed to those grazing animals. So you might imagine that there could be significantly different impacts with the exact same, you know, grazing days per acre that occur in the very early vegetative versus the mid vegetative versus the reproductive stage. So especially things that may have growing points that elevate up, you know, you could really abort that the rest of their growth if you hit them after that point in time. And that can really have a big impact on shaping the plant composition in the plant community. Duration is kind of the, sort of the converse of frequency in the sense that, you know, if you've got kind of a fixed herd and land area, you're either rotating things frequently, which by definition means the duration is short, or you're keeping them in a place for longer, less frequent, and therefore the duration will be longer. And there's all kinds of nuances and combinations of these things. Something that, you know, we mentioned a little bit but don't get into is that there's also all kinds of complexities with grazing behavior. So animals can be more or less selective when they're interacting with a patch of plants, whether they're kind of grazing from the top down or really getting in and picking out portions of the plants that they want, you know, that selection of more and less palatable species. So all of that stuff is going to be impacted by these levers and other stuff that you're doing with your grazing management. So we kind of try to integrate all of that. And that's our Figure 1, which basically tries to tell our whole story in one place in that top panel Figure 1, which listeners can go, as Paige said, it's open access, you know, where we posit that there's some optimal grazing pattern that results in a plant community that's dense, productive, diverse, and able to maintain that large reserve of biomass below ground. And so I guess that'd be kind of the last point I make about this before punting this over, is that I think you have to be a little bit adaptive to what you're seeing in your plant community, and of course, what your goals are for your grazing land, and adjust the different levers of that grazing pattern in order to try to achieve this. And so overall, you know, the way I've been explaining this is that I think this is -- it's really a hypothesis generating framework for us as scientists, as well as a tool, hopefully, for the managers to kind of think about how their grazing is interfacing with these ecosystems. And so we'd say to the extent that you're fostering that canopy cover that, you know, dense, vigorous vegetative growth and that below ground allocation, we are predicting that that's going to result in the better soil carbon outcome. And so I think there's a whole lot of science to do that will be really, really fun and exciting and also really, really challenging where we try to study this stuff at scale in these realistic systems. And just as a note of [brief laughter] empathy with the science, I have certainly published work that was very simplistic in terms of grazing exclosure, so presence or absence of grazing. The reason why we do that is because it's really, really hard to kind of impose your experimental methods, you know, as you start accounting for more and more of these nuances. So there's real scientific challenges there, but I think what we're hoping is that this can help us articulate some of the things that we might want to focus on to take a bit more of a mechanistic approach rather than staying with this, you know, these more simplistic setups for our grazing studies.

>> That is a good summary. I mean, I think this is constantly the problem, and it's been mentioned by others, including Fred Provenza, in trying to do research on complex creative systems, particularly with people managing those systems that are constantly applying different management, hopefully, you know, productively. But to hold everything constant except one variable doesn't represent the real world and is also very difficult to do. And so the challenge to try to describe systems that are even more complex than we have apprehended so far, and what we can describe is already highly complex, and it's bigger than that. That is quite a challenge to try to study in a structured way.

>> Yeah, this is probably one of my favorite things to talk about, and it's one of those rabbit holes. Like, I don't get to go down very often. But I think there are different types of science, right? And I think it's not that we have learned nothing from these experiments that are grazing, no grazing or heavy and light grazing, but it's more that we've come to understand the limitations of those papers, right? And also the limitations of these small randomized complete block designs to inform real grazing management more broadly speaking. So the type of science that I really like to do that makes me feel more fulfilled is that this kind of on ranch research where, so I like to go find ranchers that are using management representative of what I'm interested in and measure outcomes. So the scientific approach is kind of pivoted on its head, right? It's not controlled, it's much messier. We have no replication. And yet I think it then becomes us trying to figure out why we're seeing what we're seeing in terms of the ecology of that grazing management. And so I think, you know, throughout those experiences that I've had in this type of on ranch research, I've gotten to talk to a ton of ranchers and ask questions about, you know, what they're doing and why they're doing it and how they're making decisions and why are they moving this way and based on what factors and how does that change over time? And all of these things seem like critically important context to me. So as a soil scientist and ecologist, I think the why is also just as important as the what in terms of informing land-use history and the potential of that land moving forward. And so asking ranchers these questions, it began to coalesce in my mind that the type of literature that we had and those simplistic types of grazing management we see in studies just isn't the type of management decisions I was hearing from ranchers that I was working with directly. And so that's where this grazing pattern and these four grazing levers came up in the paper, is that we wanted to represent the types of decisions that real producers are making. And I think encouraging also what we do later in the paper is encourage folks who are interested in measuring these outcomes to just talk to ranchers. It seems like, you know, a lot of these problems could have been mitigated long ago if scientists were interested in speaking to producers on the ground. And that could have maybe circumvented a lot of the issues that we've seen just, you know, pervasive throughout the literature in the past 50 years. And I think the other piece of this paper that I'm really proud of is that what we didn't want to do is say, okay, well this type of grazing management is the end all be all for soil carbon sequestration and put a label on it, because we know, you know, right now there's regenerative, there's amp, there's conventional traditional and we didn't really want to get into that. What we wanted to say is, hey, these are the types of decisions that producers can make, which we know influence mechanisms and pathways of soil carbon sequestration that can be positive. And also the use of each of these levers within a grazing pattern might look different depending on where you are. So for example, optimal grazing management in the southeast, you know, in Florida where Chris is, might look different than in New Zealand where some of Jim's partner ranches are, or in New Mexico where Ariel grazes. And so it's the adaptive use of all four of these levers that can be optimized for soil carbon sequestration is what we were trying to get at through this grazing pattern function that we defined.

>> Yeah, and just to maybe give a really specific example of how this has to vary across environments. You hear a lot, you know, in a lot of the plant grazing community, you know, I think particularly coming from maybe the northern plains areas, you know, about these longer rest based adaptive systems or, you know, used to call mob stocking. I'm not sure if that terminology is still popular or not but where you'd have really high density grazing but repeated very infrequently. So kind of going into that in extreme with those grazing levers. Well, if you try to do that with the subtropical C4 forages that we have here in Florida, you're going to have an animal performance disaster. And we've seen that unfortunately happen a few times. So when you're thinking about, you know, how to apply these things, that context is really, really critical. And I think, you know, that's part of, you know, as Paige was saying, why we didn't want to be tied to any specific management prescription or system but more to this holistic understanding of these levers and patterns in a detailed thought process behind the mechanisms that are really important. So yeah, just wanted to give a really specific example that maybe some folks could relate to.

>> No, that's good. I want to make a comment on the paper and then we'll ask a few more specific questions. And it feels like we've just gotten warmed up, but we'll have to stop recording before too long. I don't know if we'll end up maybe doing another one on this topic, but I do want to say that this is a very readable paper, which is really high praise in scientific publishing. And so I encourage people to actually download it and read it, you know, for people who have downloaded a scientific paper and gotten into it and enjoyed the introduction because it provided some literature summary and then got bogged down in methods and materials. I will say that this is a good read from front to back, and that's not a small thing. It feels like it's accurate, relevant, and well written. And as has been mentioned it's open source, so we'll put a link to this in the show notes, but when you read this paper, and I think everybody should read the paper, print it out on actual paper so that you can read it with a pencil and underline stuff, make comments and mentally process it as you read. I want to mention that there's -- before we leave it and potentially run out of time here, in the middle of the paper, you hypothesize three general ways that grazing positively influences these things, input quality, microbial plant community, and soil organic carbon formation. I think it's worth just saying out loud so that folks have some idea of what's in here. You say, and I'm quoting, first, "Defoliation of mature plant tissue encourages growth of newer leaves with a greater nitrogen content, reducing the carbon to nitrogen ratio, and improving plant litter quality by an average of 25%. In turn, higher quality litter enhances decomposition rates and increases the microbial community." Second, "Grazers transformed defoliated plant material into manure, returning a significantly higher quality of organic input with a carbon to nitrogen ratio much closer to that of soil." And before I go to the third thing, I want to say, again, these are things that people feel like they observe and know and can describe, but don't have any backing for it. I mean, this item number one, that the removal of some of the more mature material has potentially a benefit to the soil community is something that I think most people observe and see and feel. This is why indigenous communities, from time immemorial, have burned places because you remove a lot of the standing dead material and it dramatically enhances how much photosynthetic leaf material is working. And then third, the defoliation and subsequent regrowth of plants during the vegetative phase can defer senescence or the, you know, within your maturity and decline of the plant, which increases also the higher quality plant inputs to the soil for a longer period of time. You know, this is involved in reducing the period of time that plants are vulnerable to fire, particularly in semi-arid ecosystems. And so all these things together are involved in, you know, as you say here, upcycling plant materials into higher quality inputs, not just outputs, which might be the case as well, but higher quality soil inputs. And so it's driving more efficient below ground soil organic carbon accumulation, even though you've got some above ground biomass being consumed as part of defoliation. And there again, is where we see this pattern. You know, if you grow it and then harvest it and then grow it, and then harvest plant material, you're converting that plant material into something that's also plant available and then feeds itself. And so you have this spiraling up effect or upcycling, you know, probably until you reach some sort of a plateau in any given environment. That can occur indefinitely, but there's probably some optimum in each given environment with regard to that level of consumption versus deposition. And of course, North America has a really, really wide variety of ecosystem types and potentially applications for what grazing should look like in order to optimize each one of those. What are some of the ways that optimal grazing seems to work in different kinds of environments? Ariel, you mentioned that you've done grazing in New Mexico, and that's a different environment than Florida by a pretty long shot. What does that look like in New Mexico?

>> Yeah. Well, you know, in my mind, I'm listening to this discussion and thinking about the paper and all the different factors that I've highlighted in the paper. I mean, that's one thing that's so great about the paper, is it really, it's kind of a crash course in so many of the just the variables in grazing and kind of land management in general that are rarely mentioned all in the same place, but that producers are often thinking about all at once as kind of a decision making matrix. And so I mentioned that I've managed livestock in California, Montana, and New Mexico, and I'm really interested to hear what Jim has to say too, because he's managed globally. But, you know, places like where I was in California and where we were in Montana, some of those ranches were much more vulnerable to compaction from, you know, if someone got really excited about, you know, like Chris said, mob stocking in the early spring or in the case of California, the late winter or late fall, you could end up with compaction that would set things back and leave rangelands more vulnerable to some of the non-native annual grasses that you have there. Meanwhile, you know, six weeks later, in order to get real performance out of the range, you'd want to be hitting that grass pretty hard and really putting cattle together both to improve utilization for the sake of the cattle and also just to keep some of the, you know, the tame grasses like in Montana from becoming patchy and too senescent. And then, you know, it was always interesting when we would come back to New Mexico after spending the summer in Montana where we managed a few thousand yearlings on a couple ranches there in a pretty high intensity situation. Like I said, it's the same principles at play here, but this ranch is about 6,000 to 9,000 feet in elevation, and everything is just a lot less intense. And that has to do, in part, to lack of water to be able to put cattle together in really large groups, but also the range just doesn't respond as positively to large herds together in a tight area. And one factor that we have here is we have wind, like pretty severe wind some of the year. And if you really kind of pulverize [brief laughter] a lot of your standing material and try to turn it into litter and lay everything down flat, some years you could get incredible results if you get the right rainfall at the right time and luck out. But most of the time you can pretty much count on the wind, but you can't count on the rain and a lot of that stuff will just blow away and all the dunging and, you know, urination that you got from high density, it could be really great if you get the rainfall, but it's not going to do much for you if you don't -- you know, all that nitrogen is just going to disappear from the system before it's -- can be used. So and that's to say nothing really of animal performance, like Jim mentioned or I guess like Chris mentioned, you know, in Florida, but I know Jim has to negotiate all the time, and we're often on that knife's edge of trying to do the most for the land while without compromising our cattle, while also adapting, you know, the genetics of the herd to a place while also trying to stay, you know, in business and raise genetics that are marketable while also trying to find a niche. So of course, there's a lot of things beyond the variables that are discussed in this article or in this paper rather. But it's just fascinating to me how the right thing for one ranch could send you totally the wrong direction and set a given pasture back maybe three years if you do the same thing in a different place.

>> Jim, what would you say are some rules of thumb for trying to optimize grazing in different environments?

>> Boy, rules of thumb, I actually was very happy to hear what Paige said a little bit ago in that they didn't come up with rules of thumb [brief laughter] in this paper, which was kind of good. I don't know if rules of thumb, is the right way to say it, but they didn't come up with any prescriptions or best practices because that's super dangerous to do and pretty much impossible to do because every context is totally unique. And I don't want to necessarily say rules of thumb, but there definitely is a range of factors that need to be taken into account as you move between a range of environments. And a lot of this was first kind of driven home to me when I started traveling to Africa in the mid-'90s. And all my experience up to that point had been in what I came to realize were low production, semi-arid environments, low production versus super high production environments, and still semi-arid, yet highly productive fairly high rain, you know, high rainfall, yet dry for most of the year, Savannah landscapes in Zimbabwe and Kenya and Tanzania. And I realized, oh my gosh, these places need herbivores because the grass senesces and it sits there dormant all dry season, unless it gets cycled back to the soil surface in some way. But holy cow, the amount of biomass that grows here is phenomenal compared to what I grew up experiencing in western Colorado. And surely there have to be implications to that level of productivity, to how we manage that biomass and how we bring our cattle to it in terms of the frequency that they come there, how dense they need to be there when they're -- how dense they need to be when they are there, kind of playing off what Ariel just said, in area semi-arid New Mexico, super high stock density can be a bad thing. Whereas in tropical latitudes and Savannah landscapes in Africa, that super high stock density is required to get this incredible massive forage cycle back onto the soil surface. We're talking about stuff that's, you know, five, six, seven feet tall as opposed to, you know, one to five inches tall. And so again, all these principles are the same, but the details of their application are totally different as we move across these different landscapes. The herbivore is essential. The herbivore has to come to that landscape and cycle that material, but the details of how those herbivores come and the intervals between when they come back change big time. And so I manage properties in high rainfall, quite productive landscapes in Florida where we have recovery periods that'll range from 25 to 60 days throughout the year. And our stock densities are not super high, but they're pretty darn high, and our herds are huge. And so the dynamics of that herd create a lot of -- that great big herd creates a lot of physical disturbance, even though the animals themselves aren't super dense. Tons of detail associated with that that we don't have to have time to go into. But going to New Zealand, our recovery periods in New Zealand range from 45 days to 120 days depending on the time of the year. In western Colorado, Eastern Utah and the ranch had managed in Wyoming, our recovery periods on the rangeland environments we manage will range from one year to two years. So you know, 25 to 60 days in Florida is a lot different than one to two years in western Colorado. So that's just a brief summary of just these primarily production dynamics and potential productivity dynamics that need to come into play as we think about how to bring the cow to the grass.

>> Well, that's a great answer. Thanks for not giving any rules of thumb. And I think that's an accurate response. If there's anything that somebody wanted to say, any other comments that we didn't get to, go for it.

>> I mean, obviously, gosh, there's so much that that could be said, but I just had a question for Paige and Chris, and Tip you can choose to include this or not, of course, but you know, as someone outside of the range science community, how could papers like this function? Like, you know, it's not a research paper, Tip, I think you called it a literature review, but if it is a literature review, it's one that is citing the literature to kind of make the case of the need for more structure and for a framework like this. So how do you hope this will function within the range science community, and what could that look like going forward?

>> Ooh, that's a great question. I think I have a couple of thoughts. One is, you know, the range community is already a bit of an insular space in terms of at least science goes. And so I think what I hope this does is start important conversations that can spur better research and better communication amongst researchers and producers. And I think those two minor things actually would do us a world of difference in terms of better research and research that's more applicable to on the ground producers and also can maybe answer realistic questions about the carbon market space. So I hope it starts conversations amongst these folks. And I also hope that it causes some real -- I don't want to say maybe pause, but reflection in terms of folks that are in the carbon market space in terms of what these things mean, how they're being measured, and who they impact.

>> Yeah, I would agree with all of that. I think a good example is that, you know, you can look up and find companies offering carbon credits for things like adopting rotational grazing, which I would put in quote marks because I think our conversation here should be enough to convince you that the devil is always going to be in the details with that as far as whether we expect carbon gain and how much, and how we would scientifically approach task of even quantifying that. And that's a whole conversation we could have. Paige has a great paper on that topic. It's something that we put a lot of thought into. But yeah, I think trying to tie it together, you know, something that came to mind listening to you and Jim talk is the fact that you are already using a lot of these indicators. And I know some of that goes back to some of these planning processes that folks like yourself use. So you know, I've been thinking like there could be some really cool research to be done trying to almost think about that as citizen science. And how do we link that to for instance, satellite remote sensing, types of measurements that we can then -- you know, my group has worked on that for the case of Florida pastures, but connect it explicitly to some of these indicators that we can then link back into this framework and really start making more targeted predictions so that we can do the kind of outcome-based research that Paige was talking about earlier. And then try to combine that with the best that we could do with kind of experimental, manipulative, you know, plot and paddock scale research which honestly is just going to require a lot of funding. So yeah, my closing hope is just that hopefully this paper stimulates some more creativity both within the research community but also informing these kinds of interdisciplinary projects that, you know, combine researchers and ranchers and land managers.

>> Yeah. Actually, I wanted to just circle back to one final point after Ariel's question. I just had a thought, Chris, while you were talking, which is, you know, Tip, throughout the interview, you had mentioned a couple of times like what a landmine this space can be in terms of, you know, all grazing is bad, or beef and cattle is horrible for climate change and it's got an outstanding greenhouse gas footprint. And regenerative grazing is going to, you know, sequester all this carbon, or these tropes that we've come to hear often in this space. I think what would be the most validating thing for me coming out of this paper is to cause some deeper thought amongst folks who are on either end of the spectrum in terms of all grazing is bad or all grazing is good. I think what I want to come out of this paper is to say that grazing can certainly be good and it can certainly be bad. And the devil is in the details, like Chris mentioned, the who, what, why, when in terms of grazing pattern and how grazing is done and where it's done has different implications for soil carbon that can flip it, good or bad, one way or the other. And there's no one size fits all in terms of management, climate change, profitability, and these things that matter to us as humans.

>> Yeah, the devil is in the details and the details are different. There's a different devil in every different environment, and I think that's the beauty of the complexity of it, and of course the challenge for land managers and the importance of, you know, being a good observer and thinking through what's going on, on the landscape, you know, with some understanding of what these patterns are and what the drivers are. Which is another good reason why people should read the paper, to understand what the different mechanisms are and how what we do with grazing animals influences all of those. I think that's an excellent summary. I also think that one of our downfalls in, you know, what I would call the hard sciences is that we're often looking for single solutions, or we're looking for a single answer, but the answer only works as long as all of these variables are, you know, X, Y, and Z. But as soon as they're G, F, and O, then it's a different answer. And we have to work with that. That's our obligation to try to figure those things out. Ariel, did you have a final comment?

>> Yeah, my final comment would just be that it occurred to me while reading this paper that, you know, and a dimension of the work that we do with livestock is animal impact which is a term used more in some kind of more progressive grazing circles, and definitely the holistic management seem more so than others. It's not a very scientific term but it describes, you know, everything that the livestock are doing besides actual removal of vegetation. So you know, the hoof impact, the dunging, urination, also sometimes just rubbing on and [brief laughter] rubbing and trampling features the landscape. In some cases, those things, those mechanical interactions can be pretty important and yield noteworthy changes. And I can totally see why it wasn't included in this framework, but my hope is that because this framework has drawn our attention to all these different factors that are often ignored and not really articulated in research papers, my hope is that animal impact is something that we can begin to observe and pay more attention to going forward.

>> I'm not sure I've ever felt so unsatisfied by our ability to try to get to all of the content of a given topic and a given paper. But I'm not sure we're going to get there even if we kept talking today because this is such a large and complex topic. So we might end up having some more discussions about this, but for now, I'm actually hoping that the lack of resolution here is a teaser to cause folks, again, to go get the paper and read it. And yeah, I think we should probably have another roundtable conversation about this and maybe even include a few more people. But I think we will have to stop for today. And I want to thank you all for your time and thank you for this paper that did an amazing job at trying to pull together, you know, not just stuff about grazing, but a whole lot of domains of knowledge in how they interact with each other. And that's not at all an easy thing to do. And I sincerely hope that this group will continue both applying this and thinking through what do we not know and what do we need to know and how do we figure it out. Thank you all again for your time today, and I look forward to having to continue this conversation.

>> Thanks, Tip.

>> Thanks so much, Tip.

>> Thank you.

>> Yep. Thanks, Tip.

>> 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.

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This open access paper, published at Global Change Biology, can be read or downloaded at https://onlinelibrary.wiley.com/doi/10.1111/gcb.17223. Please take the time to read this one.