Wolves, Elk, Beavers, oh my!

   Posted by heidi08 On October - 15 - 20142 COMMENTS

1459346_10153585381300301_647114974_n I recently asked beaver-friend Bruce Thompson of Wyoming if I could share his thoughts on trophic cascades. He graciously agreed so you’d understand the concept better. The awesome graphics are from Earth Justice and perfect for the occasion. Enjoy!

While the term “trophic cascade” is new, the ecological concept is not. It is a process set in motion by the addition or removal of a top predator, which triggers reciprocal changes in the relative populations of predators and prey throughout a food chain. This “cascade” often results in impressive changes in ecosystem structure and nutrient cycling. As a simple example, an increase (or decrease) in carnivores causes a decrease (or increase) in herbivores (their prey) and an increase (or decrease) in plants (the “prey” of herbivores).

 One case study from eastern US is how 19th century removal of wolves has been associated with an increase in white-tailed deer and a decline in plants eaten by the deer. Encyclopedia Britannica: “American zoologist Robert Paine coined the term trophic cascade in 1980 to describe reciprocal changes in food webs caused by experimental manipulations of top predators. In the 1980s others used the term to describe changes in aquatic ecosystems arising from factors such as sudden increases in predatory fish populations from stocking or dramatic declines in predatory fishes caused by overfishing.”

So, the phenomena is neither new nor in question, but as with anything as complex as an ecosystem (and involving human opinion) the precise mechanisms and predictable outcomes are.

To me, and most ecologists, it’s absurd to think that the removal of the wolf from so complex a system as Yellowstone (in the 1930′s, I believe) — or its reintroduction after more than a half-century’s absence — would not reverberate through the trophic system. Consider similar results from the removal of YOU from your household ecosystem. ; – )


Anyway, in its simplest use, the word “trophic” referees to anything having to do with eating. In ecology, the “trophic level” of an organism is the position it occupies in a food chain. So, “trophic cascade” refers to a sort of “domino effect” or cascading response within a system, triggered by a change in one or more of the major players within a food chain of that system.

 Impacts associated with the trophic cascade in Yellowstone include:

  1.  Scavengers like ravens, bald eagles, and grizzly bears, are benefitting from the carcasses left by wolf kills;
  2.  Impacts from elk browsing on willow throughout the park has changed measurably since wolf introduction;
  3.   In northern YNP, the number of a half-dozen songbird species that use willow for shelter and nesting was found to be greater in areas of willow recovery as opposed to those where willows remained suppressed, such as from ungulate browsing;

  Bison numbers in the northern range have increased in proportion to the decline of elk numbers;1453297_10153585381190301_1394755555_n

  1. The number of beaver colonies in the park has increased from one in 1996 to twelve in 2009. This is largely attributed to increased willow availability, which the beavers there are largely dependent upon for food and dam building.
  2. The work of beavers, acknowledged as a keystone species by most scientists, in turn reverberates through the system by positive changes in the water table, flood control, small mammal populations, nesting waterfowl, fish nesting habitat, soil development, etc, etc.

People — especially the media — will argue about the specifics of all this till the cows come home, but there is no question in my mind that multilevel shifts in food sources, food availability and use, and dependent wildlife populations have all shifted in innumerable ways since wolf introduction, and that the wolves are directly or indirectly responsible for most if not all of those changes.1459937_10153585381200301_402184108_n

That’s my story, short version.


Thanks for the great explanation Bruce! It all makes so much sense. But if you ask me the wolves are stealing wayyyyy too much credit. I mean all they do is make way for the real heroes. Right?

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Beavers Far and Wee

   Posted by heidi08 On October - 14 - 2014Comments Off

Beaver fence aims to stop pathway flooding in Fish Creek

A beaver appears to be missing a paw from a trapping mishap in Fish Creek Provincial Park. (Ingham Nature Photography )

A beaver appears to be missing a paw from a trapping mishap in Fish Creek Provincial Park. (Ingham Nature Photography )

Calgary officials are trying out a new way to manage beavers that are causing problems in Fish Creek Provincial Park.

The rodents keep packing mud and logs against a culvert in a city-owned storm pond. If left, the dam would cause the pond to overflow and flood a popular pathway.

In the spring, the city’s water services department is going to install something called an exclusion fence — a trapezoid shaped fence made of wire that prevents the beavers from plugging the culvert.

The city used to deal with situations like this by trapping and killing the beavers, but it reviewed that policy after an incident in July. A beaver got caught in a trap, but didn’t die and was spotted struggling to free itself.

Fish Creek Park Beavers

The area in Fish Creek Provincial Park where city officials tried to trap and kill the beaver over concerns it would flood a bike path. (Carla Beynon/CBC)

Upset animal lovers launched a petition to stop trapping in the city. That prompted the review, which revealed that debris got caught in the trap, causing it to malfunction. Since then, the city has been working with the Association for the Protection of Fur-Bearing Animals to come up with non-lethal alternatives.

“We want to go a different route so we don’t actually have to kill beavers,” said water services spokesman Randy Girling. “We don’t want to be known as killers or anything like that. We want to do the best we can for the wildlife in our parks.”

Hurray for Adrien and Fur-Bearer Defenders! They managed to convince the good folk of FCPP that it was better to try something new than claw their way out of any more bad press and public wrath. Adrien says it was hard, hard work. Like pushing a grand piano through a transom. But they persevered and were granted permission to install a beaver deceiver  now. Gosh, I’m so old I can remember when Adrien installed his first leveler!

Sniff, they grow up so fast.

Speaking of the long arm of beaver defenders, I got an invitation this morning to present at the San Pedro Valley Park in Pacifica on beavers. A month after I’ll be talking in Auburn. That’s 133 miles apart for beaver defense. 1670 if you count Utah and Oregon. And Cheryl just visited Big Break in Brentwood where she snapped these videos of our work at the visitors venter!

Pretty cool to be long-range beaver preachers!

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The Trail from Utah to Martinez

   Posted by heidi08 On October - 13 - 2014Comments Off

Hot of the presses I just got word from Mary Obrien that the BRAT (Beaver Restoration Assessment Tool) has just been completed for the entire state of Utah. The complete report and maps are here and I will put a permanent link on the margin alongside the last amazing thing Utah did for beavers, (and the one before that). Here’s a little excerpt  from the executive summary.

This report presents the development and application of the Beaver Restoration Assessment Tool (BRAT), a decision support and planning tool for beaver management, to analyze all perennial rivers and streams in Utah. The backbone to BRAT is a capacity model developed to assess the upper limits of riverscapes to support beaver dam – building activities. Both existing and historic capacity were estimated with readily available spatial datasets to evaluate five key lines of evidence: 1) a  perennial water source, 2) availability of dam building materials, 3) ability to build a dam at baseflow, 4) likelihood of dams to withstand a typical flood , and 5) likelihood that stream gradient would limit or completely eliminate dam building by beaver. Fuzzy inference systems were used to combine these lines of evidence while accounting for uncertainty.

CaptureWith this announcement came a note from Mary that two stalwart Utah beaver champions are coming out to San Rafael for the annual Bioneers conference this month. They are going to a soils workshop and would like to meet Worth A Dam and the beavers if at all possible. For the past 5 years they’ve been hard at work letting beavers turn the tiny incised trickle on their land into this beauty. Their beavers have survived  the last 5 years on mostly cattails because there are no trees to speak of!




P1090548And speaking of beavers eating cattails, here’s a video Rusty sent this morning of  a Napa beaver doing just that. The green water is pond weed/algae and don’t worry, I just read this morning that  cattails are VERY nutritious.

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50 states of beaver

   Posted by heidi08 On October - 12 - 2014Comments Off

Old Fort fifth-graders learn all about water-dwelling rodent

 It isn’t every day that Old Fort fifth-grader Makayla Evans gets to dress up like a beaver.

 Garbed in goggles, a blanket, sound-proof headphones, a trash bag and a pair of gloves, the fifth-grader stood in front of her classmates wearing items that represented different traits the rodent found all across North Carolina possesses.

 “I’m going to hand Makayla this small canister of oil,” said Lake James State Park Ranger Kevin Bischof. “Can anyone guess what that represents on a beaver?”

 “It’s what keeps their coat waterproof,” said one student as Bischof continued handing Evans more items to go with her makeshift costume.

 Bischof’s presentation was part of an hour-long lesson in Joanna Graham’s science class at Old Fort Elementary, which was designed to help students better understand the American beaver.

Now we’re all read about the park system educational brilliance where they dress a kid in a fur coat and put on flippers and say ‘you’re a beaver’. But mind you this is North Carolina, which (if we’re being kind) has a fairly conflicted relationship with beavers, so we are really haooy 5th graders get beaver ed. But this blew me away:

“The beaver is a keystone species,” said Bischof. “If you remove them from an environment, it drastically changes. It takes constant maintenance to keep up a dam, and if a beaver is removed from the area then their dams will eventually deteriorate and change everything in the area where they’ve been.”

You can almost here the unspoken message “So tell you’re dad if he blows up that beaver dam it will be bad for everything”, can’t you? Of course I wrote Kevin right away. And our beaver friends in North Carolina to introduce them. Every now and then I start to think the landscape for beavers is changing all over the united states. Which is a pretty nice thought to have. Oh, and I sent along these:

archbrochurecharm 008


Researchers Say Beavers Are More Than Simple Pests

Yakima beaver relocation was on Scott Simon yesterday of NPR. More good promotion of beaver benefits, although I hate the headline. It reminds me of that scene in Tolkein’s the Two Towers, where the hobbits stumble on the oldest forest.

” What a pity! This shaggy old forest looked so different in the sunlight. I almost felt I liked the place.
‘Almost felt you liked the Forest! That’s good! That’s uncommonly kind of you,’ said a
strange voice. ‘Turn round and let me have a look at your faces. I almost feel that I dislike you both, but do not let us be hasty. Turn around!’ “

In addition to the usual beaver beatitudes there are a few choice quotes that I will offer without comment.


Click to Listen

We try to catch the whole colony because beavers have incredibly intense family social bonds. So without taking the whole family colony, they’re more likely to go right back to where they once were caught in searching for their family members.

[Regarding their naming of beavers] It helps us bring light to sometimes sad instances where family members may have gotten lost behind.



And now that we’re back from vacation I’m starting to think about Halloween decorations. We’re so lucky we may have just the thing! What do you think, too scary?



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Adventures with Beavers

   Posted by heidi08 On October - 11 - 2014Comments Off

More beaver intrigue from Rick Marsi:

Beaver lodge visits make waders required attire

Put on your long johns and waders. We’re going over to the biggest beaver pond around to see what we can see.

 The pond consists of a tangled mass of small willows and alders, flooded to a level of 3 or 4 feet. Near its center, where the beaver lodge is located, the water becomes deeper and relatively uncluttered.

 As we approach the pond through this stand of trembling aspen, don’t be surprised if a woodcock flies up in front of us. The poplar-lined stream banks beavers choose for pond sites also provide prime habitat for woodcock.

 Look at the size of this aspen the beavers have just cut down. It must measure 12 inches in diameter. Beavers won’t inhabit an area that doesn’t offer abundant soft wood trees such as aspen and willow. A tree this size is an easy night’s work for the beaver’s four chisel-shaped incisors.

 We’ll follow this well-worn path down to the pond. Beavers use this route for dragging freshly cut branches to the water. These paths usually lead to fairly open channels that emanate from the lodge and provide beavers with a waterway system that penetrates the most tangled sections of the pond. Hopefully, this channel won’t run too deep, and we’ll be able to follow it to the lodge.

 As we move through dark water, walk slowly and quietly. Test your footing before each step. The pond is loaded with submerged tree branches and muddy drop-offs.

Beavers have added fresh mud and sticks to it in recent days. They’re insulating for winter. Note all the branches they’ve buried underwater to provide an adequate winter food supply. When the pond is frozen, beavers will dive out of an underwater lodge exit to access the branches. Once dragged back to the lodge, each branch will be twirled about by front paws, while its soft outer bark gets eaten like corn on the cob.

Now that’s a fun read. The title gripped me with terror that they were working there way IN the lodge, but the actual column is just  delightful appreciation. It talks about wildlife at the pond, and the varied pond floor which we know means bug variation. And he doesn’t bother the beavers, which is perfect etiquette in my book.

We should take our leave before darkness falls. A northwest wind and chilly water have got me shivering. I wanted you to see this place before ice entombed it, so you’ll be able to come back on your own next spring.

Fun ad this morning for a new notebook. See if you can spot the most impressive photo-shopped image:

And the Yakima outrage from yesterday gets better [worse]. Leonard Houston sent a note this morning pointing out that the beaver left behind had an ear tag. That means they know all about this abandoned soldier. They know his number and they know he didn’t make it into the mothership for rescue.

They just couldn’t be bothered.

closerOr I suppose the kindest possible interpretation is that the beavers they relocated weren’t tagged. And this is one relocating himself into vacated lodge the very next day. Which, come to think of it, is as good as an explanation of why getting rid of beavers doesn’t solve problems as I can think of.


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Why I’m Officially mad at Yakima…

   Posted by heidi08 On October - 10 - 2014Comments Off

 A young beaver explores an old beaver lodge near Ellensburg, Washington, US. Its family was moved as part of a program to trap nuisance beavers and relocate them to the headwaters of the Yakima River where biologists hope their dams will help restore water systems used by salmon and people.


Apparently someone was so busy getting credit for saving beavers that no one bothered to get the WHOLE FAMILY. I know it’s hard knowing how many there are and not all beavers cooperate by climbing in the metal suitcases. But I assume that watching helps you get an idea of how many to catch. We certainly know how many beavers there are in Martinez, This youngster was left behind by mistake after the Rapture took away his family. No one came back for him and only the AP photographer cared enough to take the photo.Which was published on “This week in Wildlife in the Guardian“.

It’s Island of the Blue Dolphins for beavers. Do you think that will be in the Washington Post? I guess we should look on the bright side. When that yearling gets over the shock of abandonment he’ll probably start doing beaver things and then the property owner will kill him like he originally wanted to do. So he won’t be lonely any more at least.


We need cheering up after that story. Here’s a fun headline from Canada picked up by the CBC. I’m glad the councillor is against beaver trapping. But my favorite part is the photo. Because thinking of a beaver swimming on its back makes me giggle.

Screen shot 2014-10-10 at 8.05.49 AM


Projet [sic] Montreal borough councillor Sterling Downey says he recently learnt the city of Verdun reintroduced trapping to kill or relocate beavers on Nuns’ Island.

He says it’s cruel and is calling on his borough to stop its contract with trappers.

He says a more ethical method needs to be used.

In past reports, Verdun officials  said they were using trapping because beavers were destroying trees at an alarming rate and giving some residents headaches.

But some residents have also complained about them, particularly in 2008 after a dog was killed when it got stuck in a trap.

The SPCA says it wasn’t consulted before the trapping was introduced and has now offered Verdun officials other options, such as services from Fur Bearer Defenders, a non-profit with expertise in the subject.

It says trapping also has serious impacts on our ecosystem and it hopes Verdun will reconsider.

Verdun is just outside of Montreal in Canada and clearly our friends at Fur-bearer Defenders have made inroads there. I’m just going to sit and imagine coucillors opposed to trapping because its bad for the environment. And I think you should too.

I’ve been on vacation this week in Mendocino and the coastal lovely fogginess finally comes to an end today. So I spent yesterday making the annual movie of this year’s kit. Jon will never be able to listen to this song again, but I think you should enjoy! Do you realize this is the 20th kit we’ve had born in Martinez since we decided not to kill them?

And finally a big thank you to our musician friend GS from San Francisco who celebrated his mother’s well-lived life by making a generous donation to Worth A Dam with his inheritance. Thanks so much! And we’ll make sure we use it in the service of beavers!


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A Day of Too Much Beaver News

   Posted by heidi08 On October - 9 - 2014Comments Off

Yesterday was crazy with beaver activity in the news, but the awesome part that tipped my scales on the wow-meter was that one of the folks of the friends of the free beavers on the River Tay in Scotland got a Freedom of Information Act request from DEFRA with all the correspondence on beavers in the British waterways.

Screen shot 2014-10-09 at 7.06.32 AM

That means all the emails where they talked about lying, got ready to lie, lied and bragged to each other about lying are there for the world to see. The request had been public around 6 hours when this story was published in the Guardian.


Health watchdog contradicts claims Devon beavers pose human health risk

Officials at the Department for Environment, Food and Rural Affairs (Defra) have repeatedly said that the beavers, thought to be the first in the wild in England for centuries, could threaten human health because they may be carrying a disease that the UK is currently free of.

But Defra documents and emails, released under Freedom of Information rules, reveal that while Public Health England (PHE) is concerned about the disease, it does not believe the beavers would increase the risk to human health from the tapeworm, Echinococcus multilocularis (EM).

“PHE accept that the main risk of an incursion is likely to be through international movements of pets, both legal and illegal… Therefore they are not convinced that the three Devon beavers necessarily represent a significant increase in overall risk,” a Defra official emailed colleagues after meeting with Public Health England.

But that’s the  special lie we picked! Are you saying it doesn’t sound true enough to the experts? We’re DEFRA. We’ll make it true! So they went on their merry way saying there was a chance of disease even though the experts told them there wasn’t. And that’s why THIS was the email heard around the world.

The whole cache is a treasure trove, especially the indignant letters from citizens outraged at the decision and their pained justifying responses.See if you can find mine! It’s nice to know that those things are kept somewhere, although it did give me a mad longing to see the FOIA on correspondence regarding the Martinez Beavers in 2007.

(Mostly I just want to see letters between the mayor and Mary Tappel. But that’s just me.)

If you’re too mature to have fun playing in DEFRA’s dirty underthings, there was also an EXCELLENT beaver report on NPR  KNAU in Arizona yesterday. Click to listen to a short but sweet reminder of why beavers matter.

Screen shot 2014-10-09 at 7.37.08 AM

And just in case you thought the beaver news cycle passed Martinez by, they rolled out the  swanky new website for our sponsor Inquiring Systems Inc yesterday. Check us out under ““projects“.  I think we’re placed according to how many hits we get, because we keep moving around. So CLICK on this, please and remind the world that beavers matter.

Screen shot 2014-10-09 at 7.47.26 AM

I’m very happy they highlighted this quote:



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