Marcus Lashley on Deer Density Dependence and Directed Seed Dispersal

We're joined by Dr. Marcus Lashley today for a discussion on density dependence in deer populations, and more interestingly, when populations break from this typical relationship. We also spend time discussing challenges of habitat management in the lower coastal plain and how seeds get moved into freshly thinned, burned, or disturbed habitat units.

Transcript

SPEAKER_00 0:02

Welcome to Wildlife Investment, where we discuss wildlife research, habitat, hunting, and land management with our panel of leading resource managers. Wildlife Investment, resource management by scientists.

Dr. Bronson Strickland 0:41

In this episode, well, in this episode, joined by Mariah Bogus and Dr. Marcus Lashley. So good to see both of you. Marcus, you haven't been on the podcast in a while, so good to see you, good to hear from you.

SPEAKER_02 0:55

Yeah, likewise. I know that we have seen each other more recently than I've been on the podcast. Sure glad to be back. All right.

Dr. Bronson Strickland 1:04

Well, we want to, I hope this does not end up being just biologist talk and theoretical stuff, because I I think it has a lot of practical information here. We want to talk about the concept of density dependence. And in all of the experiences that we have had and places that we work, we've seen kind of some deviations from the norm and how we interpret that and what we can do about it. And I guess I'll start by trying to describe what density dependence is for folks that aren't biologists. And essentially density dependence is a process where as the density increases, the amount of food, it could be some other resource, but for us as deer managers is typically related to food. As the number of deer per unit area or density of deer increases, the amount of food resources decrease. More deer, more mouths, they consume more of the food. As such, the quality of the deer, their body weight, their antler size, et cetera, decreases because now they are in a food limitation. Food has become limited on the resource, and then over time deer gets smaller and smaller and smaller. So that is the underlying mechanism theoretically. When a biologist comes in and says your deer is small, your antlers are small, et cetera, lactation rates are low, you need to harvest more deer. By harvesting more deer, you free up food resources, you have less deer, but the quality of those deer increase. And I would say, generally speaking, you you can't get away from that. Is that even in regions where we would and and mentors of mine have said it's it's largely a density independent system, I would counter by saying it's still density dependent. It's just the environment is not stable enough for a requisite number of years to allow the population to respond that way. So I I'll I'll give South Texas as an example. My former mentor advisor, Charlie DeYoung, he he calls it essentially a density independent system, meaning that if you're on a ranch, particular ranch and you went in and deer condition was relatively low and you advocate a you know a heavy dough harvest, heavy deer harvest and heavy dough harvests, you may or may not get a response in body weight a year or two later because it was not paired with having a reliable source of food in that environment. So how that could play out is you go in this fall, winter, and you remove 30, 40, 50% of the dose. Like, all right, we've reduced the number of mouths this coming year. We're gonna see a response because there's more food per deer, but you don't get any spring rainfall. And so all you have is brush, you're not gonna have the Forb community. So the condition of the deer did not respond to the removal of deer the year or two before. So that is why that in that system they would be called more density independent. And then, oh, go ahead.

SPEAKER_02 4:44

I was gonna say, Bronson, I think it's important to distinguish between like a functional or operational density dependence where you can pull that lever easily, and and the process of density dependence, which is a foundational concept in ecology. And what I mean is there has to be density dependence at some level that is functionally otherwise not possible. But whether or not the the that you can apply that concept in a management strategy that real easily might depend very much on the kind of environment that you're in.

Dr. Bronson Strickland 5:25

And y'all check my logic here. To me, where you can count on it is where you have a stability from year to year, a stability of resources. When the availability of resources because of the environment becomes erratic, that's where the density dependence falls apart and it's reliability of a response.

SPEAKER_02 5:46

So n let me just say on the in the case of South Texas, where rainfall is really creating night and day between years, right? In terms of the f forage quality abundance. Right. So, you know, in a in poor rainfall years, let's pretend we line up a bunch of those. Whether you have one deer, ten deer, a hundred deer, they're all eating brush. You're not really changing what like they don't have the choice to eat eat high quality stuff because somebody else didn't eat it anymore. Whereas in a you know, in that system in a rainfall year, the entire place explodes with the diversity of Forbs, which are extraordinarily high quality, and it doesn't matter if you have one deer, ten deer, a hundred deer, they're not going to exhaust that until you get to an extraordinarily high level of deer. Right? Whereas on the on on the other side of that with the poor quality, you'd have to have an extraordinarily high amount of deer before they would have gotten rid of all the brush. Which is where you would see so sort of like this you this wide range of densities of deer in that environment at the low end of quality and the high end of quality, there's a wide range of deer density that are essentially going to have equal quality.

Dr. Bronson Strickland 7:21

Yep. And yeah. Thanks for that clarification. Uh so you you can kind of work through that now and see, well, what could we do in that system to decrease the effects of the environmental variation? From having a good quote, rain year, you know, every three years, every four years. Well, you you see supplemental feed. Yeah. And so that's, you know, the past 20 plus years, that that's a quick it's an expensive fix, but but that's how you do it.

SPEAKER_02 7:55

And it's also illustrative that extreme environment that is a that's a way to circumvent the the extreme thing, but it's not necessarily as practical or effective in other environments where that you don't have those extreme swings and nutritional uh like available nutrition from year to year.

Moriah Boggess 8:17

Yeah. No, but it doesn't stop its application. I mean, all across the southeast, right? We've got people spending a lot of money on supplemental feed, and all it is is just adding a little bit of cream on top of the sundae that's already there, which is all the natural vegetation.

SPEAKER_02 8:32

Well, and uh, you know, we can get all into this, but uh a lot of the where where it rains, including in Texas, when it rains, and when what when it rains there, it's always funny to me because it it rained this year and it was like yeah, an inch and a quarter total rainfall or something. You know, that we we got more rain since we've been on this in this part of the world. That actually is probably not far off because it's raining every single day right now. That is interesting, even in that extreme environment, but certainly across a lot of this, if you have adequate sunlight and you're getting rain, the forb community in particular that is responding to that, essentially all of those plants are higher quality than what you would put in that feeder. So an argument could be made that the feeding could decrease the quality of their diet.

Dr. Bronson Strickland 9:31

Well, it did. I wouldn't say it increased the quality of their diet. It decreased the quality of the vegetation they consumed. They started selecting plants that they normally don't, that would be lower preference, meaning a greater proportion of grass, a greater proportion of browse than they would normally consume because they had a the high concentration of supplemental feed in their diet. And nobody's gonna exactly know why they do it, but it would get more into kind of a Fred Prevenza kind of brought this to light with the balancing out nutritionally and getting too much of one thing. And you think of food, we say it all the time, but the plants are a vehicle for nutrients and chemicals. And when you're getting all of those, sometimes you can get too much, or sometimes it needs to be complemented with another chemical or fiber or something like that. And so it was very much like a deer is mixing the different plants and mixing its diet to get what it needs holistically. It's doing the same thing with supplemental feed in its diet. But it wasn't going, the deer were not then going and doubling down and getting more quote nutrient-dense plants like Forbes. It's almost like they're having to buffer the supplemental feed with a greater than normal amount of grasses and and the browse that they normally don't consume.

SPEAKER_02 11:11

Isn't it kind of uh it's definitely interesting, but it's also remarkable and also really frustrating that you you have gone through all this effort to improve their diet, and then they go they're they're not gonna just eat the feed, right? They're gonna eat a bunch of other stuff. So what they do in response to you providing them all this high quality feed is decrease the rest of their diet to pull the average quality down to the same thing it already was. Right.

Moriah Boggess 11:47

Yeah, you like a way higher price.

Dr. Bronson Strickland 11:49

Yeah. They ought to be getting the 20% uh protein from the feed, and then the Forbes and their diet quality ought to be 30% crude protein. Well, they they can't do that. Yeah. They can they can't live on that type of diet. You know, they're not adapted to that. So yeah, you're exactly right.

SPEAKER_02 12:07

Yeah. Well, I don't think we were intending to get into a supplement supplemental feeding episode. You know, I I had I don't know if the audience is aware, some of them might be, but I did a lot of work with deer nutrition and diet selection, and not not the same kind of work that you have, Bronson, in this area, but I've done a a lot of work more diet selection and habitat oriented, I guess, from my perspective with deer, but there was one interesting conundrum that that I was trying to address during my PhD work. And it it was sort of like the South Texas When It Doesn't Rain argument, where in a lot of the lower coastal plain the plant community generally is fairly poor. You think about it being palmetto and what's another good one? Like uh Gallberry. Yeah, I was I I could think of Alex G Glabra, but I couldn't think of the common name. Yeah, so like gallberry. Deer will eat that, but that's not very good. You know, it's poor quality. And you don't necessarily want to sustain your deer on that, although it is meeting the basic requirements for life. Right? They can eat a lot of that and meet that baseline nutrition, certainly not peak development nutrition, but they can survive on it, right? And there there was a lot of of a suggestion that the same thing would happen in that lower coastal plain where we wouldn't have this density dependent response. Because all of the plants are poor, it doesn't matter what the deer density is, they're all going to be eating crap, right? So that was something I wanted to address in in my study up at the Fort the Fort Bragg Military Installation, which is sand hills. It's it's actually I went and looked at soil productivity, and it is the poorest soil productivity class in the range of whitetailed deer. So it's bad, right? And in that landscape, they are it's wide open, it's open forest conditions, and they are frequently burning, especially in the growing season. And I know that you guys are familiar with a lot of this work and and some of it you've been involved with later on where we followed up and done some really cool stuff with this. But one thing that was kind of shocking to me in that system is that even in that terrible soil productivity class, there were still plants like ragweed and beggar's lice and uh the bone sets, several things, pokeweed, partridge pea, a lot of plants that we think of being high-quality plants, they still are present in that landscape, although the productivity of those plants is fairly low. But those high-quality plants are still present. So that kind of led us down this path to look at this idea of density dependence through a little bit of a different lens. First of all, I've just told you some of those high-quality plants are present. Well, are they still high quality? That origin the original data that we collected there showed yes, and then we followed up with a big experiment that Craig Harper and Mark Turner, I guess, was the lead author on it. But you know, people that that folks on here have heard of. A lot of us were involved and did it all over the eastern United States and showed a pretty clear pattern that the soil productivity is limiting the availability of those, but is not limiting the quality of them. The plants are still high quality, so it did seem to be a there the potential for that density-dependent response did to sit seem to be there, and we just showed if you get really extreme where you you move the deer density really low in that low productivity system, we did eventually see an increase in body weight. The counter to that, I think, is uh illustrated in some sites, and I think important. There are two ways to elicit that response. Like we've got two levers, right? One is to decrease deer density, the other one is to increase food availability. And that may not be something that can be accomplished at Fort Bragg because of the soil productivity where it's already open, there's plenty of sunlight, there's lots of fire. We do see this pulse and resource quality of the plants, especially with growing season fire, where the quality of those plants is even pulsing, it's it's exacerbated by the timing of fire, which is cool and a way to augment that landscape's nutrition availability for sure. But in a lot of the soil productivity regions, if we open up the canopy and add fire, you will overwhelm the deer nutritionally. I mean, it it's just there you're it's so limited on the landscape, and then you add those two key ingredients, and the qu the availability of high-quality forages just shoots through the roof. And that's the other way that we can deal with this this density dependent issue, right? We're kind of more like the Texas when it rains category then, because everything is good food when it rains. It's the same same principle in other parts of the range. As long as the the productivity is not super limited from a soil productivity, you can produce an overwhelming amount of high-quality forage if you're managing the habitat to do so.

Dr. Bronson Strickland 18:25

You're essentially in that case, you're you're mimicking being in a an agricultural region, overwhelmed with a lot of of good food. Yeah.

SPEAKER_02 18:34

Right. And we're kind of that's the side of this density dependence continuum that I want to be in. I don't want to be in the situation where I have to decrease density. I'd much rather be in a situation where we could carry really high densities and still everybody is eating a super high quality diet. Because now we're managing the habitat quality to be, you know, extraordinarily productive. And that's the effect. You can carry more deer at a high quality because of the habitat management. Right.

Dr. Bronson Strickland 19:13

And by doing such, you increase the opportunity for outliers. Yes. The more buck fawns that you produce, and with the caveat that they that you maintain a high quality diet. Right. You can't sacrifice the diet for that. But the more that you can carry and you can maintain that high-quality diet, the more buck fawns you produce, and we got to account for dispersal and all that stuff later. But essentially, the more opportunity you have for the 160s, 170s, 180s.

Moriah Boggess 19:49

One thing that that kind of fascinates me about all of this subject is with the South Texas example, it's really clear what the limiting factor is. Like if we could snap our fingers and create a couple inches of rain every spring, we could alleviate that that restriction. We'd have a lot more forbes on the landscape. We obviously have the sunlight and bare ground, but we don't have the water. Right. If you're in central Mississippi, it's almost always just a sunlight issue. And I think that so often we all talk about those tools that can be implemented in that kind of situation where you walk into any industrial forest and you thin. If you're in the Piedmont to Mountains, like you're going to get a really good response on most soils. There's there's going to be enough species richness that there'll be some really good stuff in there. A lot of the species that you mentioned, Marcus. This is the thing, because I I used to live in the coastal plains, pretty close to where your study site was there, Marcus. And the thing that fascinated me there was even on a well-managed property, similar to that one where there's fire happening pretty frequently, you had a lot of sunlight and a lot of water. Like those two things are not necessarily limiting factors on those properties. But what is the limiting factor, it seemed like, is that mid-succession, the essentially the dominant Forbes, the first woody species to come into a site. And that's those the gallberry, it's all of the waxy leaf species, the bay species, and they're so well fire adapted. River cane can be really dominant there as well. They do so well with fire, they can be top-killed, and within half a growing season, they're four feet tall again, and they're covering up all the soil, and nothing can really establish. And it seems to me like I obviously that that system is is way more challenging, regardless. Like it's always gonna be kind of an uphill battle. But if you are in that sort of system, the the the best thing you can do is try to set back those species that are they're not trees, they're all the brush that just becomes so dominant in those understories. I mean, even a year after fire, all that gallberry that comes back in there and those others, if you could. go through and disc them or you know even use an herbicide treatment. You will get back some of the species like you mentioned before, but the thing that I noticed is that even then it's still not you never get to that same level as the Piedmont. You can get you know you can improve toward it, but you never quite reach that level. Yeah man the the soil productivity is poor. So hydrology affects that a lot too.

SPEAKER_02 22:22

Yeah I I think that is you know an important thing to to consider is what is the limiting factor and it's you know we focus a lot on systems that rain and and uh soil productivity even are not the limiting factors. They you know it I guess in South Texas is water so it's really clear cut there, although they don't have a lot of control over that.

Moriah Boggess 22:52

So they that requires another intervention which is the the supplemental feeding at least in you know in in a lot of our systems we have more control over what the limiting or whichever limiting factor it is it's something that we have some control over, like the amount of sunlight penetrating for example you know that that is a a great situation to be in because we can pull that lever and not have to pay whatever it costs to to run a feed program at that same to provide that same amount of nutrition right or with have to roller chop and spray the understory of pine stands like if we were talking about in the lower coastal plain.

SPEAKER_02 23:37

Yeah and uh that is particularly when you interf interrupt the fire process that can be really costly to get it back into a situation where you can to can come back to that like we talked about this earlier before the show started in some parts places in the the southern coastal plain because of the plant community that responds to a fire free interval. And when I say fire free I might be talking about a three or four year interval. It ain't long right we start to accumulate so much fuel that it can be a real problem to re-enter the stand with fire. And the system that you've worked in Maria for your masters you know full well once you kind of reach closed canopy and you start to get a bunch of those invading hardwoods that typically were in mesic sites and now they're getting into the up ones, it becomes a real problem to even enter the stand with fire because it's not flammable. Right? So we're in in all of those cases we're having to take some extraordinary intervention to deal with a a problem that was created in the system that's hampering us from using the tool of choice. Right? I feel like I'm rambling but I wanted to get back to the timing of fire. One thing that we we've done a lot of work on now and I think it there's pretty clear evidence all the way round for for what I'm about to say we do see if you move around the growing season we see this really clear effect when you change you know so now we've got the a tool of choice especially in the southern coastal plain but I would argue for deer and turkeys one of our most effective tools over a lot of their range would be fire. But tweaking the use of that fire might change the the outcome in favorable ways. So interval of fire, how frequently you're applying it is the primary filter first, as long as there's enough sunlight. So again we've dealt with another limiting factor so it's not most limiting anymore. But the fire frequency then becomes a really important filter because it's broadly affecting the structure and especially for turkeys that structure could be absolutely critical. And then the composition is is your next order right that the frequency is not necessarily dictating the composition at least in all the ways that we would want to to manipulate the plant community. So what we've learned from a lot of our work with the timing is that if you move around to growing season there are a few key things from a deer management or turkey management even standpoint that that might be real important for us. One of those in the short term what you I was talking about the resource pulse idea a lot of the these plants that are low quality that we don't typically think of as good deer food like the the uh the gallberry we did a cool experiment that we with when I was with you there at MSU Bronson that we dubbed mineral stumps it's another example of the same idea. When you topkill plants and they re-sprout for for what we think is probably this this skewed root to shoot ratio so you just think about that plant has a huge root system and not much of a shoot the above ground biomass for that period of time and the way the plant responds it essentially makes nutrients more dense in the the vegetative part the part that deer can eat when you move around to the fire being in like a May June July August timeframe the resprouting tissue after a fire is extraordinarily high compared to the baseline availability. So you get this short-term benefit where all of a sudden all these forages that we wouldn't think of as being high quality have become extraordinarily high quality for a short time period in that pulse after fire. And that can be a real benefit because then deer start to eat things and they're high quality that they normally aren't eating and they can even help you deal with that problem. Right? We saw this with the the red maple experiments that we did where we were topkilling them at different times and when we did that at a particular time which in that case was in June the deer actually helped us kill the tree. Like it started re-sprouting and they were they were browsing on it but that intense herbivory was kind of helping playing in our favor. So if we move the timing around a little farther into the growing season we see another thing start to happen and the hardwoods when you topkill them later in the season they're also more vulnerable to fire at that time so you tend to have a higher outright kill. And we also tend to see a lower dominance of native grasses. So native grasses generally are good but you don't want to see of grass right so I've seen this time and time again where folks have too much of a good thing and their fields are all just chalk full of native warm season grasses. So moving that timing of fire around especially in that context can help you shift away from the dominance of grasses and unwanted hardwoods and we also see a higher forb response to fire around that time of year. So you can see how the same tool we're even changing just a little bit the context in which it's used and starting to steer the community in different directions or get different benefits from that same tool. And I think that's really important to think about for any tool, not just fire, when you have unique situations that you're trying to address problems and you have you know just a handful of tools at your disposal to do that, it may take some creativity in how you use those tools to to maximize the effectiveness of it. I don't know if that seemed like I rambled on but hopefully that made sense.

Moriah Boggess 30:26

No it it did. And I think so I'm I'm kind of in the middle of my gardening journey. I love to garden and in the last couple years I've I've got into doing a whole lot of it and one thing I've noticed from gardening that applies directly to old fields is that you can disturb, you can till up your plot, you can disturb it and then do the same thing a month later and you will get completely different responses. And the best thing I can compare that to or liken it to is maybe it's a poor germination time and some stuff's going to die out and somebody's gonna so you know one weed say is going to become very dominant in my my garden. Then if I till it in May I'm gonna have a whole different set of conditions temperature wise as well as weather patterns wise. And I've noticed the same thing in a little oil field I have kind of experimentally burned from late last summer, fall through winter and then even early spring in different patches this this past year. And the response from the seed bank I have all of the same species in those different patches but what is dominant varies by that time. Like one is just American burn weed and I have a little bit of some some other forbes coming in another one it's nothing but staghorn sumac. Another one a bunch of pokeweed and I did nothing different except fire timing. So just to kind of pile on to what you said there, Marcus, for the people out there who are wanting to experiment there's no bad time to do fire and there's so much to gain by experimenting in the shoulder seasons into summer and in any other time you can get it to light because you're likely just going to produce more diversity and we always preach how you know heterogeneity is so important. And we can't always predict exactly what's going to happen you know condition wise it's going to sort of shape that response because I mean you might get hit with two weeks of drought and the first flush of stuff kind of dies out but something that's really drought hardy is going to take over that patch. And the only reason you get this really cool patch of dysmodium say or some other really hardy forb could be nothing else than just the conditions that lined up with your disturbance. And those experiences have really kind of opened my eyes just to just the need to constantly be disturbing when you can because you just never know how that's going to shape the future of that plant community.

SPEAKER_02 32:55

Well and that I mean exactly what you're saying has driven a lot of my intellectual time trying to figure out why do we get different things out of the same process like the same practice in different places we get different outcomes trying to understand what is dictating outcome. But what two things from that when I go meet with a landowner it it it I don't think there are any exceptions to this and I'm doing this because I'm acknowledging what we just said that you have different contexts and you get different things out of the same practices sometimes in those different contexts. So encourage all of them to let's tinker around some intelligent tinkering here where we're going to try a few things and you're on your property in your context and then you know we might do that at small scale and evaluate the outcome and when we you know maybe we try a couple different times of fire we try some different kinds of thinning strategies in one case some different approaches to the field management where we take a parcel and try something a little different than what they're accustomed to to evaluate that response and then we we uh scale up the things that are giving us the response that we want. So I think some of that is healthy and it's also you know adding to diversity if you're you're tinkering around to try different things like that. And that could apply to other things other than habitat management as well. But one thing I was going to add, Mariah I don't know if you are aware that we finished this, but I think that it was it started while you were in your graduate studies where we started looking at are the plants that are responding just in the seed bank or or not? Because I exactly what you observed kind of has been really troubling to me. For a couple of reasons. One, if there's if you've got some woods that have been woods for 150 years, cloves canopy hardwood and then you open it up was ragweed and pokeweed and whatever else shows up in that opening in the seed bank it's been there 150 years. You know they that kind of I I don't know if that's true or not. I'm just like you know trying to reconcile that in my head and another I'm trying to think of another oh another thing that is a problem with that is if you actually go and there are people that study this I'm not one of them but they've published on it if you try to predict the plant community based on the seeds you find in the seed bank it doesn't. Yeah that's really consistent in the literature so I'm like well what is why is that how could that be so we embarked on this other journey where we were looking at season of fire and tracking seed dispersal by the bird community and we found a couple of really cool things. One when you burn you have the same sort of magnet effect on the bird community a lot of them especially ones that disperse seeds as you do on deer. If you burn generally six weeks later deer are going to show up they you know they're that's a magnet on them. The same thing happens with the bird community and it was really cool because we were able to demonstrate that when you burn and we did it in a really cool design where we were burning different patches and monitoring with and without the burning them over lots of years so they're changing back and forth between whether or not they're burned, the bird community that dispersed seeds would be tracking the fire and they're dispersing seeds to the burned areas that happen to be a bunch of species that are really good at colonizing burned areas, especially a lot of things that produce a seed or fruit that are really readily eaten. Some work now specific to the timing that you were just talking about where it dawned on me that the bird community is probably eating whichever seeds are available right now. And I kind of hypothesized that if we burned in October what is available for the bird community to be eating to disperse in would be different than what it is in May, right? And that is exactly what the data showed. And it was an absurd number of seeds also like we're we're looking square meter right which is you know for people that don't think in meters like a what a yard and a third or something by a yard and a third it's not that much area. And the amount of seeds that the bird community are directing into that small thing is just absurd. Yeah and it's a lot of stuff that you really want to colonize especially when you burn in the fall or like late summer into the fall what is being dispersed into that area is is essentially all good stuff. And uh so all that to say just like a fun little ecological moment I I think that a lot of the stuff that we're seeing colonize is being dispersed in it's it's showing up in response to the fire and that might explain some of the the differences that we're seeing with timing especially of forks yeah the the best example I would picture with that is like an old fence row or a like a grub pile.

Moriah Boggess 38:38

I can think of one right now that I was on a property I was on last summer where the grub piles had been burned but there was just the most distinct strips of pokeweed down every opening just as straight as a line about six feet wide huge domes of poke weed from poke weed is a phenomenal example of this it is extraordinarily good at getting to really precise places I don't understand it I think it's through a precise system.

Dr. Bronson Strickland 39:09

Yeah yeah well and we saw it the other day Mark it's a completely different mechanism but another viable mechanism with flooding you know when a when a river gets out of its banks you got so much seed is in that water and being you know dropped on the landscape.

SPEAKER_02 39:27

So yeah and it's at the same time of kind of cleaning the slate and then and over long periods of time especially affecting the productivity of the substrate like a setting the stage for things to colonize is you know very similar to fire in that way. But another one that we saw that I didn't realize the extent that some folks are dealing with is the ice damage. Mm-hmm it was pretty extreme in the place we were at. Absolutely absolutely and there's going to be some good things in the short term from that I mean uh I think they're gonna see a a real big increase at least short uh for a short duration of forage availability quality for deer to kind of bring us back to what we were talking about originally.

Moriah Boggess 40:22

That's right that's right I have one just thing I have not thought this through so shoot it down if you will or if it can be but all you're talking about disturbance facilitating dispersal makes me think about wind dispersed seeds. Marcus have have you spent much time intellectually on that and like I'm guessing like a more open sand is probably more susceptible to wind dispersed seeds, right?

SPEAKER_02 40:48

Yeah it's actually really wild to think about and there there are people that study that but it's a different mechanism but what you see when you open up a canopy gap for example is it creates the way I understand it and going off the cuff here it creates turbulence in the wind that tends to direct seeds into that gap. So the all of these examples that we're talking about I kind of had a a prong of my research program that we went really far down this path because the more I dug into it the more I realized we probably need to understand this but from a habitat management standpoint, all of this is called directed seed dispersal and it's this idea that plants are somehow dictating where their seeds end up and getting them into favorable places to grow. And that makes a lot of sense but it what does like from a an ecological sense like the plant should get to places that it can grow well but it what didn't make sense is how can it achieve that. It has to have some sort of deliberate mechanism and some of them are examples like this with with wind where the sort of like they're taking advantage of the way that wind in that case is changing and they may there are some examples with water as well the seed is a has a particular buoyance so that it ends up in a particular elevation during flooding that is optimal for it to grow in like that's cool. But the the one that was more of a black box was the example where they are using animals to achieve that which is where where the work was focused.

Moriah Boggess 42:38

So well yeah it's a really cool idea that a lot of the plants that you see responding to to things have mechanisms built in to get to where that happens when it happens I guess it's really just another is another layer of the build it and they will come but at a it's a different level completely because we always think about that as like you open up the canopy you burn the plants there they respond but building off the theory you're talking about Marcus you're also creating all this momentum which is super cool because you're creating a small environment kind of a microsite that now all of the actors that play with that plant community like the birds and the deer and the things that are going to be in a in a grassland or a brushy area are going to start using that and directing seed there and the wind and all these other things that we don't even think about but it's it all goes back to just create that create that environment that we're trying to develop. Yeah.

SPEAKER_02 43:39

I think all of this to say there's a lot of complexity there was a a a famous person who said this at one point I can't think of their name because I have terrible terrible name recollection but uh he said that not only is it more complex than we think it's more complex than we can think. Which I just that has always resonated with me. So I think people we probably got a little too far into the weeds, and there was that was a pun Bronson for you. Yeah, I got it. But I like it really that's probably too far down that path for a lot of what people want to think about, but it is really important because of what you just said, Mariah. We go under this this concept of we need to get more sunlight in and burn, and then plants are just there, right? And oh, I got all these Desmodiums and Lesbedisas and and you know just partridge pea and ragweed, and that was awesome. And then I do that same thing over here, and that didn't happen. So understanding those underlying mechanisms can help us predict when you're gonna get what you want and when you aren't. And we have a good handle on some of those. Like, you know, the previous land use history is is playing a really important role in that. So if you're managing fields, that can be really important. Or if you're in a pine plantation that used to be a cotton field, that in that context is very important. But that's not all of the story, I guess, is is my point. And you know, that's I think something that is a beauty of wildlife investments is we have a bunch of people that are thinking about all of that in their other work as scientists, and trying to bring that to the table here when we are giving recommendations. Like this is a there's a complex thing going on here, and we're trying to understand all of that complexity to come up with a strategy that you can implement that's gonna be successful in your context for you.

Dr. Bronson Strickland 45:45

Yeah, there's a complexity with more like what you're saying, Marcus, with the the vegetation, the community, the diversity, how it gets there, how to manage it, what are our tools for management? There's a complexity with the animals as well, like where we began, the animals and their phenotype, and you know, what's causing them, the the numbers and their quality, etc. What to do about it? What intervention do we need? You know, what levers you mentioned earlier do we pull? Is it the habitat? Is it the population? Is it both? Usually it's both. And we're at a real critical time of year as well for people to think about. I think you just opened a lot of people's eyes, Marcus, with I know a lot of people have never considered, my goodness, all these ways seeds can disperse and birds facilitating that and flooding, etc., etc. We got a really important time of year for people to think about the next couple months, especially I would say August, September, but certainly July, August, September, the the influence of that on our on our deer quality. I'm sure also turkey as well. But the the severity of the summer, things, things that you can do and manage for, are are your deer living in good habitat right now? Do do those mothers have a lot of food to eat? Where I'm at, our bucks are somewhere at 30 to 40 percent done in terms of on their antler growth right now. So are they going to have good food to eat, those bucks, to finish up that last half of antler growth? A lot of fawns can be hitting the ground all over the all over the country. They really haven't started as much here, but that's about to happen. And that's gonna affect those deer in the short term, and that can be a five-year effect with these bucks and what we call maternal effects. Is gestation gonna be a struggle for that mother to have good nutrition? Is lactation gonna be a struggle? And that can impact those bucks' phenotypes for the rest of their life. So very, very important time of year. I think it was good us talking about the things we talked about and thinking about density dependence and what are we gonna do this fall to manage density and making sure that our our deer herd's in good shape. So that's all I've got. If unless y'all have any closing thoughts or remarks.

SPEAKER_02 48:20

Well, Mariah, you did say any time is a good time to burn. I would put one caveat, unless you have a burn van.

Moriah Boggess 48:29

Otherwise, I'm right there with it will carry very well, but yeah, you're you're probably right.

Dr. Bronson Strickland 48:35

You'll have a good fire.

SPEAKER_02 48:37

Yeah, it is a good time for burnt like that process to carry out, but it is a bad problem to implement it. Yeah, I I get that a lot. Folks respond with, well, I can't do that because I'm in a burn pan all the time right then, you know, at that time of year. And there's that's a real you know problem that uh people deal with. And the same thing, you know, some of the tools may not be at your disposal. If you're in the the greater Atlanta area, you're gonna have a real hard time getting a burn permit with to deal with smoke because of that conflict. Like that that's a real issue. You know, you may be in a context where herbicide is not some of them are not as on the table at all or not as usable because of the context you're in. So we recognize that uh there's lots of constraints, and we're trying to help everybody get through those.

Dr. Bronson Strickland 49:32

So keep listening. All right.

Moriah Boggess 49:37

Thanks, gentlemen. We'll see you soon. Thank you. Thanks, guys.

SPEAKER_00 49:42

Thanks for listening to the Wildlife Investments podcast.

Moriah Boggess 49:46

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