The Tyranny of Nativehood, Species-in-the-Sierra Style

This range map is from the California Nature Mapping Program

Here’s the link and below are excerpts.

If beaver will perform a useful hydrological function in an era of coming drought, does it matter how “native” they are? Do they have to have been shown (by whom? how many?) to be in a drainage, a watershed, a mountain range? If Kokanee are not native, should they not be celebrated?

If the “ecosystem” needs all species that were there at some point in the past, and yet the different species like different conditions, and managing the conditions to make sure they are all provided for takes lots of money, and neither California nor the Federal government is rife with money..

I found this discussion fascinating, because, like the fire issue, within the discussion is an idea “nativeness in the past” that is said to determine today’s policy.

The articles have caught the attention of the California Department of Fish and Game, which is re-examining its beaver policies in the Sierra, said Matt Meshiry, an environmental scientist with the department.

“If they are a native component, then we need to examine land use and species management … in terms of maintaining and preserving the ecosystem,” Meshiry said.

Pister, the retired fisheries biologist, is skeptical, saying beaver have harmed golden trout – the California state fish and a native species – in the eastern Sierra.

“We found beaver dams prevent migration and genetic interchange between populations while silting in the best food-producing and spawning areas,” he said. “Trout would grow larger in beaver ponds, but at a biological price.”

And of course, population differentiation from separation of populations, and interchange or migration, are both important evolutionary processes.

But this year, beavers built a dam not far from the facility, threatening to flood it and a trail. The Sierra Wildlife Coalition urged the Forest Service not to disturb the dam, suggesting a piping system be installed to permit water to flow through the dam, preventing flooding and protecting beaver – or that the level of the pathway be raised.

On Sept. 26, Forest Service crews dismantled the dam instead. The beaver weren’t harmed but Guzzi fears for their future.

“They have to stockpile food for the winter because they don’t hibernate,” she said. “So this is taking away their food. And they could starve.”

“It’s a strange corner for the Forest Service to be backed into because it’s all artificial,” Guzzi added. “It’s a little ironic, to say the least.”

Heck, the Forest Service spokeswoman, acknowledged the subject is challenging.

“There are a lot of complex issues,” she said. “Are you dealing with two non-native species and balancing their needs? Are you balancing a native and a non-native? There has been quite a bit of conversation.”

She also said dismantling the dam was the right decision.

“Essentially, we were hoping we could discourage them (the beaver) from rebuilding in that location while allowing downstream dams to persist.”

“It’s one thing to suggest things. It’s another to be the entity that has to implement solutions,” Heck added. “We have to look at what the maintenance load would be (and) whether it’s actually going to work.”

Also up for discussion is the focus of the popular fall festival on a non-native species.

“It does take some thought about how to shift an event like that,” Heck said. “What would that new theme be? How are we going to talk about both the kokanee and native species?”

It’s strange that all these folks, most of whom contain large numbers of non-native genes, are having this discussion. Somehow it seems to have gotten into folks’ understanding that non-natives are undesirable. Some are, but we need to decide which ones, and agree on why they are undesirable, if so, what can we do about it, can we afford it, and will it work- not judge a species solely on its ancestry.

3 thoughts on “The Tyranny of Nativehood, Species-in-the-Sierra Style”

  1. I was one of the founding members of the beaver cult, I did my MS work on stream rehab using beaver and checks dams on the Fremont NF in E Oregon. I have given more lectures on beaver than I can count.

    Since then I have arrived at a more nuanced view, I recognize their considerable benefits, no doubt about that. And no doubt that they can raise water tables and restore wetlands with all their benefits. It is apparent to me that much of the channel incision we see in places in the West is due to elimination of beaver. My MS work was on identifying incised valleys with clear evidence of formerly high water tables where restoration using beaver or check dams might enhance riparian areas and perhaps perennial flows.

    But, age and experience, and a wealth of scientific work shows me that despite other benefits, flow restoration is unlikely in most places.

    I have little doubt that in places beaver can dampen flood flows but much more so in places dominated by summer storm events when storage behind dams is already low, but much less likely in places dominated by spring snow melt when dams are already full.

    In the one place with a published study showing such flow captures in the Adirondacks, it was a very small basin where there had been no rain for 2 months.

    As for storage enhancing other dry season flows in the absence of summer storms, don;t bet on it.

    Michael Pollock (NMFS) did some calculations which few of the beaver proponents seem to have read carefully even when they cite him. I engaged with him on this topic, telling him that too many people were grabbing his work without thinking it through. I have seen too many ridiculous claims by people on this.

    If I recall correctly, Pollock said to store enough water in alluvium with a 20% porosity, you need alluvial deposits 12 m deep, 150 m wide and about 3 km long to store enough water to maintain one cfs for several months. Not many places have that and much valley alluvium is much lower porosity, with low permeability strata preventing much deep infiltration.

    I was involved with a long discussion on this 18 months ago, thought to publish a critique. Gordon Grant , hydrologist with USFS PNW station has also done recent work on alluvial storage and flow enhancement and he is much more skeptical than me. Too skeptical maybe since there are a few places where channel restoration using check dams has resulted in perennial flows ( For instance, Trout crk which drains into lake tahoe and Alkali creek where Burchard heede worked with check dams in the White River NF. There are a few others needing scrutiny.)

    But, they are amazing critters and I can’t get enough of them although let’s face it, they really can be a pest but manageable.

    I saw that 1939 CA fish and game report on pre settlement beaver distribution in the state and was surprised at how little of the Sierra had evidence of beaver. They could have had low populations that were trapped out very early by the Spanish americans, but I am perplexed as to why there were not more of them in the Sierra?

  2. the important thing about this, as Pollock describes, is that pond storage adds up to much less than people assume, the main storage is in alluvium where possible. I saw a presentation by the lands council people in feb 2011 at the beaver conference and although I laud their efforts, there were some real problems with their calculations.


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