S2E16: Protecting Desert Bighorn Sheep from Habitat Loss and Disease

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0:00:08 - (Joe G.): Think the deserts are barren wastelands? Think again. It's time for 90 miles from needles, the Desert Protection podcast.

0:00:28 - (Chris Clarke): Hey, welcome. This is 90 miles from needles, the Desert Protection podcast, and I'm your host, Chris Clarke, and we got a couple of updates real quick. First off, if you hear a little odness in my voice in this episode, this is because I'm on day 17 of a COVID infection, tested almost negative yesterday, hoping for a complete negative the next time I test, which will be probably the 26th. Anyway, all is well.

0:00:55 - (Chris Clarke): Both of us in this household have caught it and are going through it and have had the obligatory paxlovid rebound, and we are on our way to post Covid lifestyle. So those of you who have reached out and asked us how we're doing, just want to thank you and say we are good and we will be better. More importantly, some of you will have seen this on social media already, but for those of you who do not partake of such things, and I applaud you for that, my co host, Alicia pike, who put a lot of effort into making this podcast amazing over the last two and a half years, has gone on to do other things.

0:01:37 - (Chris Clarke): We will miss her, but we are incredibly grateful for all the wonderful things she brought to 90 miles from needles. And we expect nothing less in whatever it is she's going to pursue in the months and years to come. In the meantime, we will be scouting around to add maybe three or four additional rotating cohosts to this thing, and some geographic diversity would be nice. We will talk more about that in a subsequent episode.

0:02:05 - (Chris Clarke): But right now, Alicia, thank you for everything. You are awesome, and the desert owes a debt of gratitude to you. Now, as I said earlier, I am recording this on day 17 of my Covid bout, which is also day 24 of December, 2023, which means that all over the desert, little children are anxiously awaiting that sound of hoofbeats on their rooftops, which, of course, in the desert, are the sounds of desert bighorn sheep.

0:02:43 - (Chris Clarke): Because we don't have reindeer here. We are talking about desert bighorn sheep in this episode, and we are privileged to have in our virtual studio with us Dr. Christina Aiello. Christina is a kick ass bighorn sheep biologist. She is doing some amazing work researching how the sheep are doing in the Mojave desert and how they are adapting to the changes that we make in their habitat in the Mojave. So it's a pleasure to have her here, and I hope you enjoy this interview.

0:03:16 - (Chris Clarke): Christina Aiello, thanks for joining us.

0:03:19 - (Christina Aiello): Thanks, Chris. For one, I'm really excited to be invited on this podcast. I'm a big fan and have been listening from afar and soon will be listening from just in your backyard. Excited to move back to the desert community and really establish myself there. I am a research associate with Oregon State University, but oddly enough, all of my research is focused on southern California, in the Mojave region, around major national parks like Mojave National Preserve, Joshua Tree National park, and Death Valley.

0:03:50 - (Christina Aiello): And I came to work in the desert first and foremost on studying desert tortoises. I'm sure a lot of listeners are familiar with the desert tortoise and all the conservation issues surrounding that species. Curiously enough, a lot of the ecology and a lot of the conservation threats are very similar between desert tortoise and desert bitcoin sheep. So it was a pretty natural transition for me to work on desert bitcoin after studying desert tortoises for about eight years in southern Nevada and southern California. So it was a really nice fit for me. I am focusing primarily on threats to habitat, habitat fragmentation on bighorn sheep, which kind of hits home for me, because one thing that really drew me to the desert, and I think this is because of my upbringing in a major city.

0:04:40 - (Christina Aiello): I grew up in Chicago, where your view is often obscured by many buildings, and any green spaces are pretty far and remote and require you to travel outside your local area. So the thing that I love about the desert is just the expansiveness of it. That ability to just take in these huge vistas and see large tracks of somewhat undisturbed lands and really just view the world, maybe as it once was before we started developing everything.

0:05:08 - (Chris Clarke): I'm intrigued by you mentioning that the bighorn face some of the same threats that tortoises face. And I'm assuming we're not talking about ravens eating baby bighorn, although I certainly wouldn't put it past the ravens. Can you expand a little bit on that?

0:05:23 - (Christina Aiello): Yeah. I think one of the major threats hitting both species is this habitat loss and habitat conversion to human systems. Developments like large scale solar expansion of military bases, urban areas, really just this conversion of natural habitat to a system that's no longer providing the resources they need. Both species are hugely impacted by that. I think desert bitcoin may be uniquely because they move over such larger landscapes within their lifetime. They are much more impacted immediately by fragmentation because they do move quite a bit. They have much larger home range and use much more area within their lifetime. So I think there are differences there. But in addition to habitat loss, they both face similar threats from diseases. They both get a respiratory disease caused by a mycoplasma and human involvement. Human introduction of that pathogen through various routes exists in both circumstances.

0:06:21 - (Christina Aiello): And then just the large scale threats of climate change and the shifts we're seeing in the mojave to kind of drier and more severe drought conditions is going to cause problems and already is causing some issues for both species.

0:06:36 - (Chris Clarke): By way of providing a baseline for folks who might not know too much about desert bighorn sheep, what are ideal conditions for a desert bighorn? What do they really want to see in the landscape that they're in?

0:06:47 - (Christina Aiello): I would say in the desert environment, it's a little different than what you might imagine for bighorn sheep in general, because bitcoin as a species have a pretty large range, so they do occur in more alpine, rocky mountain type habitats. But the desert Bitcorn is a little different, clearly more desert adapted, but they still are sticking to the higher elevation, rockier terrain. The mountains scattered throughout these large, expansive desert valleys, they primarily are sticking to those mountains. But because the resources are a little more sparse relative to really high elevation alpine habitats, the forage and the water that they need is pretty spread out, and it can be really unpredictable. Bitcoin will make use of high elevations where the forage is a little more consistent. They're getting a little more rainfall and getting better green vegetation to forage on, but they sometimes will have to utilize lower elevation ranges where the forage is a little more unpredictable. They're having to use a number of different patches of habitat in order to get enough of the resources that they need. So you will see desert bitcoin moving quite a bit between multiple areas in order to forage, accessing different natural springs as well as human developed water sources that we usually call guzzlers, and also finding safe spaces to lamb and rear their young. So in order to avoid predators, female bighorn sheep will really target the really steep and rugged areas with good open visibility, where they can detect predators from afar and keep their lambs safe.

0:08:27 - (Christina Aiello): Rocky and real rugged terrain is really what bighorn sheep target and love, especially the females. Males, since they're bigger and stronger, can use a lot more varied terrain. You find them in the low hills sometimes and in the low, flat valleys occasionally as they move between areas. But they're a little less susceptible to predators and can use a little more habitat than the females can.

0:08:50 - (Chris Clarke): I know that among the forage plants that bighorn like are catclaw, acacia, which they seem to really enjoy eating and don't have any trouble with the thorns and their gums, which I find hard to imagine, but what else are they looking for when they're out?

0:09:05 - (Christina Aiello): Yeah, big corn are fairly general in their foraging habits, but those shrubs that can really tap into the groundwater, that can really weather out those dry periods are really important for them. Shrubs like acacia are really important because when a lot of other things are dry in the landscape, because of their really deep roots, they're able to produce these green leaves when a lot of other forage, is pretty low nutrition, has low nutritive quality, and is pretty dried out at that point.

0:09:34 - (Christina Aiello): Those graining shrubs are very important grasses. So bunch grasses are very important. They will graze on the annual plants and a lot of the fresh new growth is really what they're targeting. A lot of the shrub plants as they're producing those fresh new leaves, bighorn are going to munch on those. They're really not heavily depleting the entire plant. They'll usually just munch and move on. They're very mobile while they're grazing and making use of a lot of different plants on the landscape, even some cactus as well. And talk a little bit more about that because that's a really interesting behavior, mostly to acquire water, more so than nutrition.

0:10:09 - (Chris Clarke): Yeah, I forget whether I've shown this to you, but I have some iPhone video of peninsular bighorn Ram who is kicking open a pharaoh cactus and eating out the jelly from inside this sort of liquidy thing. And this is a strange situation because the peninsular bighorn are critically endangered. And yet here is this ram right next to a mountain biking trail, showing no concern whatsoever about the people stopping and looking at it.

0:10:41 - (Chris Clarke): Just a striking bit of video which I'll include in the show notes if people want to go look at it. The very picturesque ram devouring a very picturesque barrel cactus.

[Here it is!] 

0:10:52 - (Christina Aiello): Yeah, it's a really interesting behavior and I wish I've witnessed it myself. I've only seen the aftermath of the cactus kind of broken up in this clear devouring of the insides, a really high water content, fleshy insides, and during these really long drought spells, we're seeing this behavior more and more in places that hadn't really been noticed or documented, that they're really targeting in on those barrel cactus to survive those dry periods. And just goes to show that certain plant species you may not think is important for a bitcorn, sheep under certain conditions become hugely important and just an asset on the landscape and their ability to move and access those resources.

0:11:34 - (Chris Clarke): And fortunately, it looks like we're going to have another wet winter in the desert so that those cacti will get a little bit of a break from being foraged on. I know you've done a bunch of work in California and in Nevada as well. Do you get on the other side of the Colorado at all?

0:11:51 - (Christina Aiello): I've pretty much been focused on southern California, southern Nevada. I have a project on Bighorn and Great Basin National park in Nevada. So that's probably about the furthest extent, but really honing in on that southern California mojave, and a little into the kind of Colorado sonoran transition area as well, where bighorn occur. And there's not a lot known, actually, about those populations in the southeastern section of the California desert region.

0:12:22 - (Chris Clarke): What are the threats that are revealing themselves to desert bighorn in this particular area? I assume urbanization is a big one.

0:12:31 - (Christina Aiello): Yes. So urbanization, and then all of the infrastructure that comes along with it, so all of the roadways, transmission lines, energy sources, that all come with these expanding urban areas are reducing available habitat, fragmenting available habitat, and forcing bighorn to restrict their movements to smaller and smaller areas. And I think you mentioned the peninsular population, which has much heavier protections because they are so isolated, and that's because of all the development around them. They've pretty much been cut off from the rest of the desert bighorn range, and that's caused them to become more genetically distinct, genetically isolated, and have the risks of inbreeding and all of the negative effects that come along with that.

0:13:17 - (Chris Clarke): Wondering how that issue of isolation of populations might be playing out elsewhere in the desert.

0:13:25 - (Christina Aiello): Yeah. So one region that I'm a little wary of, its long term health instability is the southeastern section of the desert around Blythe. There are a number of mountain ranges, lower, hotter mountain ranges, that are susceptible to the effects of climate change. There used to be, historically, populations of bighorn supported by those mountains, but have been locally extirpated, so there were no longer reproducing and consistent populations in a lot of those mountains.

0:14:00 - (Christina Aiello): And it's been a target area for a lot of solar development, I think, because there is this lack of evidence of current use by certain species of that area. So it has been targeted for large solar installations which now clutter the valleys in between these mountains. But recently, during one of my research projects, I've targeted this region to do some surveys to assess whether we think bitcoin are still using this habitat and using some of these mountains. And we found evidence that they are moving through and using those mountains.

0:14:32 - (Christina Aiello): There may not be a consistent reproducing population in every single mountain range. But we are seeing evidence that they're going through. They're utilizing some resources there for some period of time. So it's still being used. And I worry that if we just write off that area as, oh, it's not currently sustaining a population, let's target our developments there. That could result in isolating those habitats that are being utilized to some degree right now.

0:15:00 - (Christina Aiello): They have the potential to be recolonized and a population could establish down there. But if we target our developments there and isolate them, we reduce the chances that bighorn could reestablish in that range. And we're essentially artificially contracting their range when we do that. I think some of those fringe habitats and the edge where populations might come and go, this is the natural thing for bighorn. They really act as what we call a meta population, which is a collection of populations that interact with each other. And so that dynamic of losing some populations and then regaining them later is all part of their ecology.

0:15:36 - (Christina Aiello): Yeah.

0:15:36 - (Chris Clarke): And that's the kind of situation that the Endangered Species act at least tries to address through the idea of critical habitat. Even if a species isn't there at the moment, that area could be crucial for the recovery of the species. And of course, that doesn't help desert bighorn, because I think a lot of people are really surprised to find out that they are not particularly protected. There's a weird category in California of fully protected species in which the state allows trophy hunters to go out and shoot them every once in a while.

0:16:11 - (Chris Clarke): It's an Od version of fully protected, but I think a lot of people would assume that there's some kind of federal protection of these guys. It's startling to a lot of folks, I think, at this point, with the threats that we see to the species, that there isn't any substantive protection. Really?

0:16:31 - (Christina Aiello): Yeah. And I worry a little bit about how we list species and what some of the criteria are, because what I see happening is sometimes we get to the point where it's too little, too late. We wait until species are at the very edge, and then recovery becomes such an uphill struggle. There's not a great system in place to catch them early in that process, unless you have really good data. And in order to get really good data, you usually need money and funds, and that's hard to get in a species that's somewhat ubiquitous. I wouldn't argue that bitcoin are by any means doing as well as they once were. They used to be much more widespread, experienced a really steep decline, an early european settlement of the west, and have had an uphill battle and are doing much better, but definitely not at the scale that they used to occur in this region. So it's an interesting situation where they were doing much worse off.

0:17:34 - (Christina Aiello): We've made a lot of positive gains, and the populations are doing much better relative to that low point. But I think if you were to go back in time, still a lot of work to be done to bring the species to its full potential in the desert region.

0:17:47 - (Chris Clarke): So one of the places where I've used your work in my day job is in trying to make a high speed rail project better suited to the landscape that it travels through. In particular, a strange high speed rail project from the eastern suburbs of Los Angeles up to Las Vegas, almost entirely in the median of Interstate 15. You and your colleagues up at the Epslab have been doing some pretty interesting work, looking at, among many other examples of fragmentation, the effect of this high speed rail project on bighorns if measures aren't taken to mitigate the damages to connectivity. I wonder if you have some thoughts about that whole project.

0:18:37 - (Christina Aiello): Yeah, the I 15 high speed rail project was an interesting situation because it's one of those types of development that you think scientists and environmentalists should be all on board for, because it's about more efficient travel, reducing our emissions, having a high speed rail to connect these areas that produce a lot of traffic on Interstate 15, moving back and forth between LA and Las Vegas, it's a route I've traveled quite a bit for my own work, and the traffic is horrendous. I will not argue for the need to improve that corridor for human movement. But at the same time, the existing highway was already impacting wildlife movement and limiting connections between habitat in the north and the south side of these interstates. There's a lot of great desert wilderness on both sides of that highway, and it's such great habitat that wildlife were still attempting to use it. So desert bighorn sheep were trying to cross the highway, and they get struck by vehicles occasionally. And very rarely, you get an individual that makes it across and tries to use the habitat, but it's not anywhere near the extent of movement we would expect between this habitat, given how it's arranged, how bighorn sheep move across the landscape, and with this high speed rail going into this highway corridor.

0:20:03 - (Christina Aiello): And essentially what they'd be doing is building more structures that would essentially cut off the ability for bighorn and other wildlife to move across the road at grade. It's a very risky movement, but they still will try it with the high speed rail there. That would be cut off entirely and leaving only structures like underpasses and culverts for animals to get across. And those structures work for some wildlife. It all depends on the species, their behavior, and their tolerance of certain situations and structures. And some species will use underpasses to move under roads and highways.

0:20:42 - (Christina Aiello): Bighorn sheep generally do not like underpasses. It really has to be a nice big open structure, really close to the rocky terrain that they prefer, again, triggering that avoidance of predators and their just desire to stay safe. A lot of the underpasses along these highways just aren't built in those locations that are suitable for bighorn to find and to use them. We did a number of years of research studying those structures, studying bighorn movements on the highway, and determined that the high speed rail, as it was designed, was not going to help bitcoin in any way, shape or form, was actually going to reduce their ability to move across that highway corridor and to access those habitats. And so we propose, based on lots and lots of data and research, locations where overpasses would be a really great idea to help facilitate those movements, to help Bighorn reconnect with habitat that historically they used to probably travel between quite a lot. There's actually historic trailing that you can see from bighorn moving back and forth.

0:21:51 - (Christina Aiello): That's so well established that even though they haven't traveled that path for over 50 plus years now, you can still see signs of the trailing that they used to use to move back and forth. So this used to be real important, regular movements. And if and when these overpasses are built, we would love to see a resurgence of those movements and this historic behavior restored in these populations.

0:22:17 - (Chris Clarke): Let's step away from our interview with Christina Ayelo for just a moment to take on a parenthetical issue, which, despite being parenthetical, is nonetheless incredibly important. One of the most important sites for crossings over this high speed rail project that we've been talking about is adjacent to the proposed Soda Mountain Solar project, which, if built, would provide a serious disincentive to bighorn sheep for using the wildlife crossing that we're fighting to put in over the high speed rail project. My dear friend Louise Matthias, the poet who is the author of the traps from Fouraway books in 2013, and lark Apprentice from new issues, western Michigan University in 2004, and the forthcoming what if the invader is beautiful, lives in Joshua Tree, and she has something to say about the Soda Mountain Solar project and its effect on bighorn sheep.

0:23:10 - (Chris Clarke): Here's Louise.

0:23:12 - (Louise Mathias): It's a breezy spring day, and I've driven from Joshua Tree through the Mojave National Preserve to visit the land around the proposed site of the Soda Mountain Solar project, a recently revived industrial scale solar plant that, if approved by the California Department of Fish and Wildlife, would be located less than a mile from the Mojave National Preserve boundary, making it one of the closest renewable energy projects to a national park in the entire southwest.

0:23:47 - (Louise Mathias): Typically a two hour drive, it takes me almost five. I can't stop pulling over to examine wildflowers and the small skipper butterflies that are their spring accomplices. I count 28 species of flowers, but my favorite, the desert five spot, remains elusive. The flora and fauna of this region tend to get only sporadic attention in the media. No doubt you've heard the term superbloom thrown around over the years, but astonishing displays of life in the Mojave desert are not, as the press and social media might lead you to believe, a rare or startling event.

0:24:33 - (Louise Mathias): They're an everyday occurrence in every corner of the Mojave, if you only take the time to look. Heading out on Zizex Road, adjacent to where the solar rays would be placed, I watched the landscape change from tones of copper and gold to delicate greens, cattails, and vibrant, shiny leaves of the yerba manza edge, the dry lake bed ringed in a white, crusty mineral dust to the soundtrack of nothing but crickets and wind.

0:25:09 - (Louise Mathias): A single desert five spot greets me, its tender pink globes softly swaying. I get out of the car and down on the ground for a closer look, and a raven flies over me, so close I can hear its wings flap. The hair on my arm stands up like the tiny hairs on the flower's stem. When I get up to get back in my car, I see a herd of maybe a dozen big horn sheep, including two lambs with soft, woolly coats and diminutive hornbuds staring right at me can barely breathe as I watch them quietly crossing the dry lake bed, then slowly crossing back to the hills that rise above the road, which will, if something is not done to stop it, eventually boast a view of a 1797 acre solar plant.

0:26:13 - (Louise Mathias): Researching the project's potential harm to the reestablishment of bighorn migration corridors, I can almost understand the skeptics. I had lived in the Mojave for years before I caught my first glimpse of these majestic and elusive creatures. But some years back, a herd moved into the land behind my house for a season I'll never forget. I had the privilege of watching them on a near daily basis. In the intervening years, they have come and gone, sometimes making themselves known to the respectful delight of myself and the neighbors, other times hanging back deep in the vast, craggy, bouldered land that eventually backs up to the Joshua Tree National park.

0:27:10 - (Louise Mathias): If all you've ever seen of this area is the view off I 15 on your way to Vegas, it's easy to assume that nothing much is happening. It takes getting off the main road to understand what is at stake. On the other side of the preserve, not far from the Kell Baker road entrance, stand two porcelain chinese guardian lion statues. Nobody seems to know how they got there. No artist seems to want credit. What can they be guarding in this supposed wasteland?

0:27:50 - (Louise Mathias): Like the bighorns standing on the hills in Zizex, they simply exist in this vast and glorious space. But of course, this nowhere needs to be guarded. It's what needs to be guarded most of all.

0:29:10 - (Chris Clarke): Christina Ayello.

0:29:11 - (Chris Clarke): It's been kind of inspiring, actually, to work on this issue during the course of working on this, looking at some of the work that's been done elsewhere in the desert, like along Route 93 on the Arizona side of Hoover Dam, with wildlife overpasses, that it wasn't like the bighorn were lined up at the ribbon cutting to cross, but it was almost like that. It seemed they were definitely looking for some way to get across that road, and then one appeared, and they used it almost immediately. And so that's just been really wonderful. But also, the work that Arizona Department of Transportation and Game and Fish in that state did on studying the underpasses, I think it was a road between Kingman and Loughlin that they looked at and just found out that even in places where you'd think an underpass would be more attractive to bighorn sheep, they just didn't use them at all, which is pretty interesting to me.

0:30:08 - (Christina Aiello): Yeah. And I think in those situations, even when you have the ideal sighting where you've got an underpass right near some rocky terrain that seems like big corner, regularly near that area, could easily just go underneath that underpass. You often just see primarily rams doing using that underpass, making those movements, because they're a little more willing to take risks than use. So use, especially with lambs, avoid any new and unusual situations. And even if that underpass is in ideal spot near you activity, we find that they avoid using it in many cases.

0:30:49 - (Chris Clarke): So rolling back a little bit to other threats besides fragmentation of habitat, though obviously these are all pretty closely interrelated. I wonder if we could talk a little bit about the respiratory disease that has been afflicting the sheep in the Mojave, at least my understanding is that came in from commercial traffic through Mojave preserve and other places nearby where livestock that died from one cause or another just gets dumped out on the side of the road illegally.

0:31:21 - (Chris Clarke): Do you know whether there's any validity to that story? Is it apocryphal, or does it make sense?

0:31:27 - (Christina Aiello): I have not actually heard that story. Based on what we know about where the disease first showed up and how it spread, there's really no sound theory as to how exactly it was introduced. Often what happens is we call spillover event, where domestic and wild bitcorn sheep come into contact. The domestic animals carry the bacteria that causes the disease, one of the bacteria associated with the disease, and they can carry it without little signs of ill health.

0:32:05 - (Christina Aiello): They are much more resistant to it, and they pass it on to bighorn, which have not evolved with this bacteria, causes very severe illness, especially when it's first introduced to the population and then has lots of long term detrimental effects. Because it is a lingering, chronic illness, it ends up persisting in the population and spreading. But in terms of where it actually came from in the mojave, I think that is not a clear story.

0:32:36 - (Christina Aiello): And as we dig deeper into existing samples collected from bitcoin sheep throughout the range, going back historically to samples that have been banked over time, finding evidence that this bacteria, this pneumonia, had come into bitcorn populations earlier than we once thought, I think there's some historic exposure and introduction of the illness, probably from humans grazing domestic sheep in the area.

0:33:05 - (Christina Aiello): A lot of that has been reduced or shut down in this region, not every region. So there is still some risks in it. I think most of the risk of domestics comes from the fringe or from some unusual circumstances. There are some cases where we've had goats, people taking goats into the national park, and they've gotten loose. Goats can also carry pathogens that can spread to bighorn sheep. So a lot of these unusual situations crop up and causes a bit of a flurry of panic and activity to try and control the potential exposure to disease.

0:33:40 - (Christina Aiello): But then once it gets in, it can transmit pretty rapidly just from natural bighorn socialization and movement. So that's the real tricky thing, is that it is natural for bighorn to interact. That's what they want to do, and they should be moving. So once humans introduce the infection, then it gets really difficult to control. So I think really trying to stop that initial pathogen spillover into the wild population is the best place to start and stop the problem in the first place.

0:34:10 - (Chris Clarke): Now, I know some tortoise biologists who have cautiously suggested that the tortoise population might have seen the major damage that it is going to see from the respiratory disease, that the remainder of the tortoises have some kind of resistance or immunity, having gone through the infection. I'm wondering if you've seen or heard of anything like that with the bighorn sheep, because I know the pneumonia outbreak, at least in the California part of the Mojave, was really big news about ten years ago, and haven't heard too much about it since in the media, and obviously mentions in the news media are not indicative of presence or absence. But I'm just wondering if you've seen anything about the dynamics of the epizootic that the sheep are having trouble with that might point in that direction. Always just on the lookout for any glimmers of hope we can grab.

0:35:09 - (Christina Aiello): Yeah, I think there is some good news there. I think the desert populations in particular don't seem to have as detrimental declines and long term effects as we've seen in some northern and Rocky mountain populations. I think they're also protected in a little bit, and that there's not constant new spillover of new infections, because that's the thing. These mycoplasmas that cause us pneumonia, there are different strains. So if a population gets infected with one strain, a new strain can come in and cause a whole new outbreak. They're not necessarily resistant to that.

0:35:47 - (Christina Aiello): So I think they're protected in that way where there's not as many routes for new infections to come in. But I also just think that there is some signs of resistance, at least in some populations, doing better than others with the disease. And a lot of that so far, the data has shown, can be attributed somewhat to robust genetic diversity in those populations. Really well connected populations in good quality, consistent habitat, where that population has been able to build up really diverse gene pool and gives them the materials they need to fight infections, develop resistance. You really need genetic diversity to deal with those new threats like that as they come up. I think that's been the glimmer of hope, and that has also been the rallying call for trying to maintain and improve connectivity between these bighorn populations, because there's a lot of benefits that come with connectivity and genetic diversity.

0:36:45 - (Chris Clarke): So these wildlife crossings are really a public health measure for the bighorn, in that sense?

0:36:50 - (Christina Aiello): Yeah, I think so. And there are infections that humans can get from ungulates we could pitch it in that way if we need to, protecting ourselves from the next new bighorn pandemic.

0:37:02 - (Chris Clarke): Stop kissing those bighorn! There's a lot of bleak going on in the world that we inhabit, especially those of us who are concerned about desert wildlife and landscapes and ecosystems. And as you study these target species that are struggling, what do you do to keep going? How do you keep going in the face of bad news about that, the objects of your study, or even just other things in the desert or elsewhere that you care about, how do you keep moving forward?

0:37:32 - (Christina Aiello): That is a good and difficult question because I will say my entire career, granted, I'm not that old and haven't been at this for too long, but even in that span of time, I have seen so much change and so much loss of the populations and the habitats that I've worked in and studied, and it's both affected me and also driven me to continue. And I think one of the things that offers me hope and willingness to keep at it is when I work in some of these areas where it's at the edge, the interface of human development and wildlife habitat. And it's this gray area. So, like working along highways and walking underneath underpasses to set up cameras where a normal person in that situation would look around and be like, this is degraded. This is gross. There's piles of trash. There's this loud traffic going back and forth.

0:38:31 - (Christina Aiello): But after really revisiting and spending a lot of time at those sites, you start to notice via the data we collected on cameras and also just looking around and observing that the wildlife, they still use, these degraded areas, it's in some ways still habitat for them. We write that off as it's disturbed and therefore not worth protecting or worth studying. But I'm always amazed at how resilient animals can be. And they will make use of a bad situation that we hand them, and they will keep doing what they do and get as much from that landscape as they can, regardless of what we've done to it. So I think watching their resiliency and just seeing in these areas, they're still behaving and doing what animals do gives me a little hope and encourages me to not just write off these areas and to continue to work to protect and improve them as best I can.

0:39:31 - (Chris Clarke): Christina Aiello, thank you so much for joining us. And next interview we do, hopefully we'll be out in the rocks somewhere looking at sheep.

0:39:41 - (Christina Aiello): That sounds great. It was a pleasure, Chris. Thanks for inviting me on the podcast.

0:39:45 - (Chris Clarke): Well, that's it. For this episode. Want to thank you for joining us. Huge thanks to Christina Aiello and to Louise Mathias for being part of this episode and I'm looking forward to hiking with both of you, or each of you, but preferably both of you, in 2024, now that we're all in the same place.

90 miles from Needles is going on the road in late January and throughout February, we're going to be visiting the Death Valley area, Las Vegas possible event in Searchlight, Nevada, going to Oregon Pipe National Monument and Tucson and El Paso and Carlsbad and Big Bend, and possibly, depending on the weather, further north into the Rio Grande Valley, Taos, Santa Fe, and westward across the Arizona Strip and southern Utah.

0:40:37 - (Chris Clarke): We will have more details on itinerary and potential public events in your area. If you are part of an organization or a campaign in the general southwest that's more or less along this route that wants to get interviewed for the podcast, please reach out to Chris at 90 miles from needles.com and we'll see if we can set something up. In the meantime, we are incredibly grateful to those people who have joined our crew of supporters since the last episode.

0:41:09 - (Chris Clarke): They include Tina, thank you. And Peter Vlastelica, as well as Cindy Siegel, my old friend from way, way back in the 20th century. Joshua Jackson Lewis Desprez, Catherine Kelly, Casey Wiley, Mary Buxton. Mary, it's nice to hear from you. Mark Hefler, Robert Bagel with another one of his generous donations, Alan Songer, Lucette M. Powellin, Susan Rukhiser, and to those of you whose names we do not have, but who donated to our givingtuesday campaign on Facebook and Instagram, thank you so much.

0:41:53 - (Chris Clarke): We know that this podcast is going to be a little bit different going forward. Perhaps a little bit less philosophizing, a little bit less sound of footsteps crunching on gravel, more interviews. Going to be redoubling my efforts to get voices other than mine in this podcast. But we think we got a good year ahead of us, and we are incredibly grateful for your support. You can join the ranks of our supporters by going to 90milesfromneedles.com/donate, and in the meantime, we hope that you have a wonderful end of year look for us early in January. Please take care of yourselves. That pandemic is still going on. As you can tell from the hitch in my throat. I had a mild case, as did Laura, my beloved wife. We are still going through the sequelae of that infection. And while it was a mild, it was no joke. And we were considering visits to the ER at different points throughout.

0:42:52 - (Chris Clarke): Keep masking. This new variant evades immunity from vaccinations and from previous infections pretty well. We were both fully vaccinated, and we still got it. Please be careful. Take care of your elders and those among us who are in less robust health. Mask up when you go out. Stay alive. We'll talk to you next year.

0:45:25 - (Joe G.) 90 Miles from Needles is a production of the Desert Advocacy Media Network.