This article from Audubon is well worth reading. It sheds light on questions we’re discussed at length here.
Recent ‘Megafires’ Imperil Even Fire-Loving Forest Birds
Many birds, such as owls and woodpeckers, thrive in forest habitats created after fire. But the hotter, bigger, more destructive megafires out West might be too much even for them.
After the King Fire, Jones returned to his research site to see how California Spotted Owls responded to the devastation. The massive fire swept through more than 97,000 acres, which included 44 percent of the study area and 30 of the owl’s 45 known nesting sites within it. Jones tracked the owls, which had already been outfitted with GPS receivers and colored leg bands, and found that a year later the birds had abandoned the most severely burned areas where more than 75 percent of trees died. These severely burned areas represented 50 percent of the fire’s total burn area.
It’s not that California Spotted Owls avoid all severely burned areas after fire—just the largest patches. They rarely venture more than 325 feet deep into a severe burn, Jones found in follow-up research at the King Fire site. But do they recolonize smaller patches that burned severely? To find out, he also studied owls in three western national parks in the Sierra Nevada where forest managers intentionally set small fires, and let natural ones burn, to maintain healthy, historical wildfire regimes. He saw that the California Spotted Owl returned to smaller patches even if they burned intensely, while avoiding larger ones—maybe because wide expanses with fewer trees are home to less prey or offer less cover from predators, such as the Great Horned Owl. “To us, that suggests again there’s this adaptive response,” Jones says. “Owls are adapted to frequent, low-severity fires,” not intense megafires.
The article also discusses black-backed woodpeckers:
Even the Black-backed Woodpecker, long-considered a bird that thrives after intense fires, apparently has its limits. The woodpecker flocks to burned-out forests to feast on beetle larvae that infest dying and dead trees. However, Andrew Stillman, an avian ecologist at the University of Connecticut and Tingley’s student, made a surprising discovery when he attached radio transmitters to adult and juvenile birds over the course of seven years.
As expected, adult woodpeckers primarily kept to severely burned areas. “But the juveniles were a different story,” Stillman says. “Right after leaving the nest, these young birds flew to areas with live trees remaining after fire.” He suspects they preferred these areas because the living trees provide protection from predators. This species, too, needs pyrodiversity.
“Our conventional thinking was that more severe fires might be good for certain species that thrive in burned forests,” Stillman says. “But our research shows that even fire-loving species need variation in burn severity to survive.”
— Thanks to Nick Smith for including the link to this article in his Sept. 30 Healthy Forests, Healthy Communities email.
10 thoughts on “Owls and Megafires”
“But megafires like the King Fire have disrupted this historical cycle. Their relentless intensity often leaves less pyrodiversity. Instead they create larger areas of sheer destruction.”
I like “pyrodiversity.” But that statement, implying that we’ve got too many too large patches of severely burned areas (from “mega”fires), is not based on this research. That’s a “natural range of variation” question. This article also says, “So much fuel has built up that California needs to burn 20 million acres of forest to catch up, according to one estimate.”
Then, there’s also the camp of folks who want a pre-human landscape, in a human-dominated world.
I think they are saying there are many large patches of severely burned areas with negative bird consequences.
Did there used to be more historically, what kind of intensity? That’s the NRV question. Which would go back to “when, exactly, historically?” during Native American burning periods? Who was monitoring spatial patterns of intensity then.. how do we mimic NA burning practices.
Would it be OK to burn up towns, birds, watersheds, powerlines and so on if the pattern of severity burning was within NRV?
I agree that they were saying there are negative bird consequences. But that doesn’t answer the question of whether those consequences are something that should be avoided.
The NRV question is not just “historically,” but “sustainably,” based on current and projected future conditions.
It would generally be ok to burn up owls if that was within NRV. I agree that there may be a point where a species is currently depressed to the point that more artificial conditions might be needed to sustain them through the bottleneck.
But isn’t “sustainably based on current and future projections” a different word, with a different meaning? Why not just use that word then.. if that’s what is meant.
The Planning Rule starts with “sustainability” in §219.8. “Ecological integrity” is the main way to achieve ecological sustainability. The definition of “ecological integrity” (§219.19) makes it operational based on the requirement for dominant ecological characteristics to be within the “natural range of variation.”
Where the Forest Service messed this up is in the definition of NRV, where they heavily stress historic conditions, but say they are not a target or desired condition, which contradicts the Rule. It helps to look at the section on NRV itself (§12.14), which says:
“When assessing whether an ecosystem has integrity, the Interdisciplinary Team should use the natural range of variation as the ecological reference model, unless the PAST information regarding the selected key ecosystem characteristic is lacking, or the system is no longer capable of sustaining key ecosystem characteristics identified as common in the PAST based upon likely FUTURE environmental conditions.”
“The Interdisciplinary Team may use alternatives to the natural range of variation approach for assessing integrity as described in section 12.14b, when PAST information for key ecosystem characteristics is missing or the system is no longer capable of sustaining key ecosystem characteristics identified as common in the PAST.”
EXCEPT – this also contradicts the Rule unless you change “natural” to “historic.” It is also obvious (by the terms I have HIGHLIGHTED) that this is the intent of this language, to recognize the limitations of HISTORIC. (See also §12.14b – “Alternative to the Natural Range of Variation Approach: “assessing for integrity by identifying the conditions that would SUSTAIN these key ecosystem characteristics.”)
I guess we’ll see just how well the owls survive, with less and less old growth. THAT is the future of much of the Sierra Nevada. It is their nesting habitats that are the most at-risk to wildfires.
I also think we need numbers of known nests destroyed per wildfire. Again, the simple presence of owls in burned areas means nothing. Turning high quality nesting habitat into low quality foraging habitat is very, very bad for the birds.
the number of nests/ territories and their condition post-fire is generally known. The territories in the King Fire were particularly well known, as they were part of the Eldorado demography study area. While some people play with the data to suggest fire doesn’t adversely affect their habitat, it clearly does when it affects the majority of the territory at high severity. Will they leave if only 10% of their territory is burned? Probably not, but if 50-100% of their territory is burned, it just won’t provide the cover, the cooler microclimate, and the prey for spotted owls. We know what their habitat is- the more of it that is removed, the less likely they will remain.
Another ‘cover issue’ involves spring snowstorms in the Sierra Nevada. It is known that mortality occurs when we get strong, winter-like storms in April and May.
Again, I think it could help if we selected unoccupied habitats and found trees to build nests in. Owls usually use established nests but, if those are burned, will the owls be able to build a new one (or more, over the next few years, post-fire)? Additionally affecting nesting habitat, and actual nests, is the bark beetle mortality. Will the existing nest become unusable after the tree dies?
Should we increase the amount of ‘active owl management’ on USFS lands? It IS clear that we are in the midst of the tipping point, and any delay means disaster for the remaining owls.