How Wildlife Withstand Wildfires

Point Reyes is home to a great variety of animals. Half of North America's birds have been spotted in the park, not to mention its reptiles, amphibians, fish, and mammals. How do these creatures respond to a fire? In this episode, Jerimiah Oetting speaks to park scientists to learn how certain vulnerable species might be impacted by wildfires. Join us as we hoot for owls and track one of the more elusive and curious species in the park, the Point Reyes mountain beaver.

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TRANSCRIPT:

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The Natural Laboratory: How Wildlife Withstand Wildfires

[musical intro]

Jerimiah Oetting [outside]: Alright, so...what are we doing?

[about three people laugh as gravel crunches underfoot as they walk]

Taylor Ellis [outside]: Yeah, we're hiking into an area of the Woodward Fire.

JRO [in studio]: That's Taylor Ellis. He's a field biologist with Point Reyes National Seashore. We're hiking along the Bear Valley Trail, where the Woodward Fire burned last summer. I should mention that, as of mid-January [2021], this area is closed to visitors. For good reason: crews are still working hard to make the roads and trails safe.

[gravel crunches underfoot]

TE [outside]: Uh, and, we want to see if we can get an owl detection today. Uh, we're kind of curious if the owl is still using its core area after the fire.

JRO [in studio]: This isn't the typical time to monitor spotted owls in the park. We were hiking in December. It's usually easier to spot the owls during their breeding season, between March and July.

TE [outside]: But we're still gonna go and check some of the known haunts they have and, uh, see if we can find them.

[Taylor mimics spotted owl hooting call out in the woods]

JRO [in studio]: Taylor is hooting for the owls to see if any reveal themselves to us. Six different spotted owl territories were impacted by the fire. Taylor says he hasn't visited all six yet to see how they were affected.

TE [outside]: The ones that I have seen, it looks like it didn't burn very hot in those areas, so most of the big older trees are there, which is important for spotted owls.

JRO [in studio]: This is prime spotted owl habitat, he says. An area with tall Douglas fir trees, some that are hundreds of years old.

Black fire scars stretch up the boles of some of the trees. But the burn was patchy. On one side of the trail, there were charred clumps of sword fern. But then, just uphill, bright green ferns appeared to be completely untouched. This area seemed a good example of a fire that might actually help spotted owls.

TE [outside]: It's not that any fire is good, but, sort of, a low-level fire that doesn't get too hot, which is what they would mostly be if they happened more often.

JRO [in studio]: In the last episode, we talked about how some plants in the park actually depend on fire. But what about wildlife? Plants aren't the only things impacted by fire, and that means the critters that call Point Reyes home are also adapted to recover.

There are a ton of animals here. Almost half of North America's bird species have been spotted in the park. There are mammals, fish, amphibians, reptiles, and thousands of invertebrates. Over 50 of these species are considered rare, threatened, or endangered.

With all the other forces that threaten their existence, how do these animals continue to persist after a fire?

On the podcast today: how wildlife coexists with wildfires. Spotted owls, red-legged frogs, steelhead trout—they're just a few examples of animals you may have heard of that could be impacted by fire. But there's another animal—one you might not even know about, that's unique to Point Reyes. A living fossil—elusive, hidden and all around peculiar. It could be lurking just feet away from a trail and you'd never know.

All this and more, stay tuned….

[intro music]

JRO [in studio]: This is the Natural Laboratory, from Point Reyes National Seashore. I'm Jerimiah Oetting.

[gravel crunches underfoot]

TE [outside]: We just have a really high density of spotted owls in Marin County, um, compared to other parts of their range.

JRO [in studio]: Marin County is one of the last refuges for the northern spotted owl. Populations of the owl have dwindled across their range, which extends from just south of Point Reyes National Seashore all the way up towards British Columbia. The northern variety is one of three spotted owl subspecies. It prefers big old growth forests that have vanished over the last couple of centuries. A robust spotted owl population is a good sign of a healthy forest. Unfortunately, though, the owls are listed as threatened, at both the federal and state levels. What little habitat remains for northern spotted owls has been encroached upon by both humans, and by a close but unfriendly relative—its boisterous cousin, the barred owl.

Barred owls are invasive out West. They aggressively take over spotted owl habitat. Research shows that spotted owls require about four times the territory of barred owls. That means that barred owls can pack more densely into areas that would have once belonged to only a few spotted owls.

This is partially because barred owls eat almost anything. They gobble up many of the foods that spotted owls depend on—like woodrats, deer mice, voles, and flying squirrels—but also amphibians, fish, even other birds. They're bigger and burlier than spotted owls. And they're more aggressive. For spotted owls, that means less resources and less space. They get pushed to the edges of their habitat where they struggle to survive.

TE [outside]: And that's what's happened a lot in places like Olympic National Park and Redwood National Park, both north of us.

JRO [in studio]: But not in Marin County. The first barred owls appeared in Marin in 2002. Since then, they've had a steady presence in the area. But luckily for the spotted owl, they haven't completely taken over as they have elsewhere. Northern spotted owls in Marin County are doing better than pretty much everywhere else in their range.

TE [outside]: You know, I think that might be because there's a lot of food available to them in the form of all the wood rats that we have out here. We'll probably see some of their nests, at least in unburned areas of the forest.

JRO [in studio]: Those woodrat nests can burn up in a fire, removing a vital food source for spotted owls. But fire can also be good for the owls, clearing out shrubs and opening up the forest understory. A more open forest floor makes it easier for the owls to hunt.

TE [outside]: And then they also, of course, want some decent, kind of like, canopy cover, like a kind of closed canopy that they can sort of hide out in, you know, they can perch there, you know, hawks and stuff can't see them from above. And they can just kind of quietly sit there in the shade, um, and just wait for some prey to come along.

JRO [in studio]: For spotted owls, an open understory and a nice overstory is a great balance—one enabled by fire. But spotted owls are predators. And they can fly. For their rodent prey, escaping a fire is a bit of a challenge. And rodents are an important food source, not just for owls, but for animals like bobcats, foxes, and coyotes.

TE [outside]: You might lose some wood rats in the actual fire event, but, you know, they are rodents. They will be back from surrounding areas.

JRO [in studio]: Other terrestrial animals are sensitive to fire, too. California red-legged frogs live in the park. Like the spotted owl, red-legged frogs are federally protected, because they're a threatened species.

Dr. Patrick Kleeman is a research biologist with the USGS in Point Reyes. Most of his work focuses on conserving endangered amphibians.

PK [in studio]: Luckily, our amphibians, locally, don't seem be greatly impacted by wildfire. Of course, any amphibians that are in a terrestrial situation away from a pond are probably going to get burned up. So, it's definitely going to affect individuals, but doesn't seem to greatly affect the actual populations.

JRO [in studio]: Dr. Kleeman says after the Vision Fire 25 years ago, scientists surveyed the breeding ponds known to be important for amphibians.

PK [in studio]: After the Vision Fire, they typically found the same amphibian assemblage at those ponds. And that's great news. And so, other things, like mountain beavers, is definitely a direct effect that can have consequential damage for years to come.

JRO [in studio]: Mountain beavers. Ever heard of them? Despite their name, they aren't a mountain variety of the bucktoothed tree chompers that you're probably thinking of. Nope. These are far stranger.

Seth Bunnell [outside]: Mountain beavers are coprophages. And they're, um, hosts to the world's largest flea. And they're also the only member, the only living species in an extinct family that was once widespread, and they're one of the most primitive rodents.

JRO [outside]: Cool. So, they eat their own poop. They have the largest...or they eat not their own poop, but like…

SB [outside]: Yeah, they eat their own poop.

JRO [outside]: Okay.

SB [outside]: They're very hungry because they live on salad. And they have to eat a lot. And to get the nutrients out...like a rabbit does the same thing. They sort…so they have two generations of droppings, and the first generation of droppings, they eat 'em again to get more nutrition.

JRO [in studio]: That's Seth Bunnell. He's a field biology extraordinaire. He knows a thing or two about mountain beavers. If you didn't catch it, not only do mountain beavers eat their own poop, bu