Watching the wildfires devastate a major U.S. city has many of us wondering: Could it happen here?
But, while you might assume that wildfires are not something that can happen in the desert scrubland of the Sonoran Desert, Ben Wilder, director of Next Generation Sonoran Desert Researchers based in Tucson, says that’s changing — fast.
Wilder said their research shows our ecosystem is changing — and making us more at risk to wildfire than ever before. Wilder joined The Show to talk about it.

Full conversation
BEN WILDER: I mean, I think one of the big shifts we need to make, mentally and in action is, we now live in the desert in a fire prone ecosystem. And that's a big, big change both in terms of how we think of the desert, and also how the desert has functioned for hundreds of years, if not longer.
LAUREN GILGER: OK, so tell us why that is. This has to do with invasive plants, it sounds like.
WILDER: That's the, that's the culprit, that's the mechanism behind it. So, the invasive species, especially we're talking about grasses, or some small forbes, you know, annual plants. And these are species that either respond to winter rains and or summer rains, and starting the late 1990s, early 2000s, for various reasons, some of which we don't really know very well, they started to expand dramatically. And that kind of coincided with the drought period too we've been experiencing, and they essentially create fuel that links the vegetation throughout the desert, that then can carry fires.
That's a difference than the desert has previously been, that I think, many of us that know the desert when we hike, you kind of just think you can kind of not get yourself stuck by cacti because you kind of can dodge them, walk around them. But, that space around the fields or around the vegetation is being closed up by these invasive species, either annual grasses after wet winters, or perennial bunch grasses, these grasses that grow in response to summer rains.
GILGER: So we're, we're shifting ecosystems essentially in the Sonoran Desert here from patchy kind of desert scrub to grasslands. That's a big shift. Do we know any reasons why this happened, how these invasive plants got here?
WILDER: So we actually know how they got here and almost always the answer is us, so people brought them in for cattle forage or erosion control primarily, and both for Mediterranean ecosystems, so regions that have dry summers and wet winters, or sub-Saharan African ecosystems with arid conditions.
Not too different from our own, but when the key difference is these species are from ecosystems that have fire as part of the ecosystem dynamics. You know, they recruit very well after fire. And so, here in the Sonoran Desert, they are out competing native species. And then if a fire does happen that they're able to carry the fields, they grow back even stronger after the fire.
GILGER: OK, wow, OK. So, are we seeing this happen? Are we seeing wildfires happening in desert regions that didn't used to see wildfires already today?
WILDER: Very much so. The first inflection point was around 2005, and then the second one was in 2020. And what these two years had in common was El Nino conditions that drove a lot of winter rain. Now, with the invasive species fuel sources that have such large areas, the fire spread dramatically and in 2020, especially in the Valley, if you're familiar with the Telegraph or the Bush fires, the culprit to invasive species, and there are, you know, hundreds of thousands of acres of the desert burned.
GILGER: So the fact that we haven't seen a major wildfire super close to the metro area in Phoenix or in Tucson, is that just luck at this point? Is this a matter of time?
WILDER: So, there's a combination of factors here. So, you have the fuel source, now increasingly with these invasive species. You have ignition points, which are urban primarily, especially along roadsides and roadsides and these invasive species that go together very well because that the extra moisture and the heat along the asphalt is a kind of perfect environment for these weedy species. And then the third element is, kind of climate ingredient, which is dry, hot conditions and wind, and that comes together most frequently in June in our region.
And so it's just kind of a matter of time until these pieces click together, like happened in 2020 with the bushfire and others. So yes, it is kind of a matter of time until these conditions come together and I think one of the big fears is that the worst case scenarios of when you have, in our region that is kind of looking in June, it can be other times of the year too. But, we have 115-degree heat, incredible winds, and then a fire breaking out that just is impossible to control.
GILGER: Let me ask you about what, what should be, what could be done here? Like what could local and state governments be doing? What do you think they should be doing to address this kind of new reality?
WILDER: Well, you know, I think one of the things that is a positive and what we're talking about is, this is a very much a process. You know, you, you talked about the transition of ecosystems, we call it “grassification” of the Sonoran Desert, and it's happening in real time. But, it's not a fait accompli. It's not, it hasn't been done.
So, real active management can absolutely be taken in a couple of ways, you know, the most important thing with invasive species and the dynamic we're talking about is when you have a new population of Buffelgrass or Fountain grass, or especially Stinknet, get rid of it. You know, don't just sit there and be like, “Oh it's small now, OK, it's fine.” It's like, no, you know, take an afternoon, you know, be careful about, you know, spreading the seed or what not, but just get rid of that freaking patch in your backyard.
So, that's an easy thing we can do, and that's at multiple scales, right? That's your backyard and neighborhood association, city parks, cities, county, state, right? I think it's about mitigation and then steps and so fire breaks are a really important thing and thinking about how we manage fire in the desert.
I know working with Tonto National Forest and other land management agencies, what is the role of prescribed burns? Or what steps can we take to avoid the multiple thousands of acres of lost landscape? Because once these fires do happen, the desert will never come back the way it was. And so there's a lot of things we can do to really mitigate the threat of fires, and now is the time to do it.
GILGER: Is any of that happening at this point? Like, is this even part of the conversation? As you said, this represents a really major paradigm shift to, just in, how we think about where we live.
WILDER: It is, it is starting, but the resources and the addressing the problem is not scaling with the scope of the problem itself. I think one of the things that I'm seeing, is there's so many problems and threats and challenges that need to be addressed that this one keeps sliding down the list because it's not actively burning because it literally, but the problem is when you do get the worst case scenario, all those ingredients coming together, it's too late to act.
And so now is the time to be proactive and the cost of taking action now are orders of magnitude less and in some ways, you know, priceless, if you're talking about the loss of life than not acting or acting after fires happen. So yes, things are happening, but they need to scale up.