The Beaver is often called a “Keystone Species”, but what does this mean? If we want to be good advocates of our beavers we should all understand this concept. It was introduced in 1966 by R.T. Paine who studied the impact of removing one predator from an ecosystem. (In that case a starfish) Starfish take mussels from rocks and the space they create can then be used by other species.

Paine found that the original 15 species community was quickly reduced to only 8 species when the starfish was removed, prompting his analogy to the collapse of an archway if a “keystone” is taken out. (The keystone is the center piece which holds up both sides of the arch) Beavers have a similar role because their dams create habitat which are used by other wildlife. They raise the water table, create richer sediment, alter the vegetation, and spur bushy tree growth by “coppice cutting” trees. By protecting one keystone species, you actually make conditions better for an entire eco-system of other insects, fish, birds and animals. By the same token, in removing one keystone species, you threaten the viability of an entire habitat. Just another reason why our beavers are worth fighting for.

Did you ever have one of those days when it seems like 17 different threads of fruitless inquiry suddenly come together in one perfect macrame knot? I’ve been having them a lot lately. Today I attended the CCWF meeting to hear fellow subcommittee member Mitch Avalon talk about the hydrology issues for the beavers. I’m so enormously embarrassed that I never attended one of these meetings before; it was easily the most ecologically knowledgeable and committed group of people I’ve ever sat with. The introductions and announcements at the beginning alone were literally like a who’s who of conservation.

There was an update on the bioassessment project, which is currently examining twelve different waterways. Alhambra Creek was part of this in 2005 and that report can be reviewed here. These findings are important to our beavers because they look at BMI in different areas of the watershed. BMI stands for Benthic Macroinveribrates which is the scientific name for a cluster of little bugs that can be used to indicate the health of a creek. Like everything else they impact, beavers affect BMI, and newer research suggests that their impact is dependent on the health of the pre-existing creek. Areas with poor BMI are more significantly helped by beavers, while more robust sections are minimally impacted. The 2005 sampling indicated that our creek was less healthy the farther down the watershed you looked. This means that our beavers are in the ideal spot to cause greatest benefit.

That’s just one of the exciting discussions prompted at today’s meeting. Tim Tucker gave inspiring update on the water-treating parking lot sponsored by the ESA. He was genuinely touched by the students’ effort and enthusiasm and described the project as the best thing he’s been involved with in 25 years. There was also welcome interest in our beavers from the award winning Dow Wetlands , continued support from the Urban Creeks Council, a call for entries in this years creek and watershed calendar, an invitation to talk beavers with the Master Gardeners and a nice connection with the California Department of Fish & Game. The fieldtrip prompted a healthy discussion about beaver effect on salmonids and caught a bevy of baby ducks demonstrating the trickle-down ecology of our beavers. Honestly, after so many suspicious receptions by so many beaver-averse faces this was like Valhalla.

It was one of a handful of moments the beavers have given me where I understood with perfect certainty that I was surrounded by compassionate, intelligent and committed stewards of our waterways, and that our beavers could be welcome among them. It was like falling asleep in the back seat and knowing mom and dad were driving you home safely.

In honor of the very good mood the meeting left me in, let’s celebrate the polar bear’s recognition as a protected species with this feel good video. Look for Worth A Dam tomorrow at the farmer’s market!

Our friends at the Sierra Club put a nice shout-out to the beavers in this month’s “Yodeler“, the newspaper of the SF chapter. The wildlife chair, Terry Preston, is as busy as the proverbial beaver, but has made a huge comittment to our beavers and is working hard to garner their attention and protection. Thanks Terry for inviting me to the board meeting back in February and for getting your members on the beaver-saving bandwagon. I have already received several emails from new supporters who read about the beavers in this recent issue. Hmmm, you’d almost think there was some innate relationship between Martinez and the Sierra Club….

When settlers first touched the shores of North America, there were an estimated 60 to 400 million beavers. Think about that, over two million beavers in every state, which means they were in every creek and lake and stream they could reach. Their fur was so desirable and their habits so easy to predict that by the early 1900’s hunting had dropped the population as low as 100,000. In many parts of North America there were no beavers at all.

That’s a dramatic change, but lets think for a moment about what life was like when all these furry wetlands engineers scurried around the continent. They terraced every meandering creek with dams, caught the water and held it for drier times, and slowed down periods of high flow. In fact the arid western territories weren’t so arid when there were beavers to control the water. The creeks were shallower and changed their banks more often, moving the rich deposit from one side to the other. The soil along the banks made rich habitat for trees to grow healthy and green. Just like in Egypt along the Nile, the rich sediment allowed for hugely productive crops. I have even heard that our pioneers could never have been as successful if beavers had not conditioned the soil for them.

We may not really think about it, but creeks are changing things. The move their path, they meander, they develop. As America grew more populated, we stopped allowing our creeks to change. Creeks were borders, boundaries and markers. That was someone’s land they were meandering onto or away from. We may have continued to let our cattle roam but we started to put our creeks in fences. Riprap, concrete walls, steel piling. We narrowed the options for our creeks, and nearly exterminated their caretakers.

So what happened? Creeks are changing things. If the can’t meander from side to side, that doesn’t mean they don’t evolve. Since they can’t go out they go down. Undercutting began across the continent. Our channels grew deeper and faster and the exposed soil thinner and harder to support vegetation. When I walked our Alhambra Creek with the fluvial geomorphologist Laurel Collins, she pointed out several examples of undercutting in our bed. Development gave the creek no where to go but down, and that means that the flow gets steeper and faster in hard weather, hence the flooding we see every few winters.

When a creek undercuts it is harder to store water, harder to replenish soil and grow crops. Drier areas begin to suffer and wetter areas get overwhelmed. Animals that depend on the creek are also affected, and the game you might have hunted to put food on your table moves farther to find water as well. I started thinking more seriously about this when I read Eric Collier’s book “Three Against the Wilderness” about re-introducing beavers in Canada. He wrote in particular about a complicated waterway that fed several farms. Without beavers to keep the water in a series of dams, the entire area was subject to draught. He hoped anxiously that when they returned they would be able to keep the water during high flow and eek it out through the summer months.

This confused me because our dams wash out so easily during high flow. A little review has shown that any time we receive more than a half inch of rain over 24 hours we’ve had a full or partial washout. So how did these Canadian beavers manage their magic? Are our beavers just slackers, or not as talented at dam maintenance?

No. The answer came from a conversation with Igor Skaredoff who attended the beaver conference in Oregon where they are reintroducing beavers to increase the salmon population. They noticed the dam washout problem as well and decided that beavers need a little structural help to keep the water back. They provide reinforcement to dams, and a foundation starter. Why? Because the landscape has changed since the 1900’s and the writing of Eric Collier’s book. Undercutting has made streams faster and deeper, and beavers, hard workers though they are, can’t keep up.

As in so many ways, mankind has made their work harder. Now that streams are deeper and faster there is less rich soil deposit, and that means less treescape, and less habitat for beavers to feed. At the very time when humans need their dam building to eek out water in drought and minimize water during high flow, our creeks are less able to take care of their needs, and less hospitable to their efforts.

American history is inextricably linked to the beaver. We may as well figure out how to get along.

So Igor and I piled in his jaunty hybrid and drove out to Antioch last night to talk watershed. The scout involved with the tree-planting came too so he could listen to our overview and catch up to date. Igor spoke first about the way watersheds work and it was a great opportunity to think about our creek and how we have treated it.

One of his main points is that creeks need room to live a normal creek life. They need to meander, to move their banks, deposit sediment, and build up resources. When healthy creeks encounter high flows the water is absorbed by the floodplain and things return quickly back to normal.

Very early on we decided creeks were property lines, and we didn’t want them changing on us. Imagine if we used clouds for property lines? We confined creeks with sheetpile and cement to keep our feet and acres. However, creeks that can’t “meander” simply cut deeper into the earth, so we end up with faster, harsher high flows that are threatening to property. One thing he said last night that I had never heard was that confined channels, whether its concrete or sheetpile, have a life expectancy of about 60 years. It’s not like you build them once and all your problems are solved. In fact many of our impermeable surface creeks in California have reached the end of their life span, and require significant maintenance.

I found this description from Toby Hemenway a while back and was fascinated by the implications of how we changed our waterways when we decimated the beaver population. Add to this that a downcut stream has a lower water table, so tree roots can’t reach it and the vegetation along the bank dies off.

You know what a stream looks like. It has a pair of steep banks that have been scoured by shifting currents, exposing streaks and lenses of rock and old sediment. At the bottom of this gully—ten to fifty feet down—the water rushes past, and you can hear the click of tumbling rocks as they are jostled downstream. The swift waters etch soil from first one bank, then the other as the stream twists restlessly in its bed. In flood season, the water runs fast and brown with a burden of soil carried ceaselessly from headwaters to the sea. At flood, instead of the soft click of rocks, you can hear the crack and thump of great boulders being hauled oceanward. In the dryness of late summer, however, a stream is an algae-choked trickle, skirted by a few tepid puddles among the exposed cobbles and sand of its bed. These are the sights and sounds of a contemporary stream.

You don’t know what a stream looks like. A natural North American stream is not a single, deeply eroded gully, but a series of broad pools, as many as fifteen per mile, stitched together by short stretches of shallow, braided channels. The banks drop no more than a foot or two to water, and often there are no true banks, only a soft gradation from lush meadow to marsh to slow open water. If soil washes down from the steep headwaters in flood season, it is stopped and gathered in the chain of ponds, where it spreads a fertile layer over the earth. In spring the marshes edging the ponds enlarge to hold floodwaters. In late summer they shrink slightly, leaving at their margins a meadow that offers tender browse to wildlife. An untouched river valley usually holds more water than land, spanned by a series of large ponds that step downhill in a shimmering chain. The ponds are ringed by broad expanses of wetland and meadow that swarm with wildlife.

The entire article is a great look at the way our beaver-huntin’-habit changed the face of America in ways we never considered. It also reminded me of the fact that our beavers now have increasingly harder jobs of keeping up creeks formed by years of downcutting.

Good thing they aren’t slackers.

So I sent Cheryl’s lovely photo to Lisa Ownes Viani yesterday and she sent it around to her fish buddies, Bruce Herbold, Ph.D. and Robert Leidy. Ph.D. of the EPA. They got out their detective skills and set about counting fins.

well, Rob Leidy and I both think that it is probably a tule perch.  We both also first thought that it was probably some sunfish, but magnification clearly shows the line of scales along the dorsal fin that make it an Embiotocid rather than a Centrarchid and the absence of barring on teh body and the fact that it is in or near fresh water would make it most likely the tule perch Hysterocarpus traskii.

Bruce went onto say that a tule perch was his favorite because of its unique reproduction. Mom bears all the young live! That sounded pretty wild to me, but after learning that our snipe engage in joint custody arrangements, anything was possible. The UCB California Fish Website had this to say about tule motherhood:

Young perch then begin to develop within her, slowly at first, and more rapidly in the final two months. In around May or June the female bears 10-60 live fish. The number of young produced increases with body size and may vary from one environment to another.

It also pointed out that these perch require “cool well-oxgenated water”, a description that many beaver-phobic biologists have warned would never happen because of the beaver dams. But my favorite message came from Robert Leidy, who added this little tidbit:

By the way, I think this is the first record for tule perch from Alhambra Creek, as I am not aware of any historical collections or records!

The keystone beaver strikes again! Let’s just take a moment to enjoy the series of connections necessary for this to happen. Cheryl took the photo because she was out watching for the beavers. I sent the photo to Lisa because I met her through the beavers. Lisa sent the photo on to the top fish biologists in the state who worked to agree on its identification. Robert recognized it was a first sighting. And our wikipedia friend immediately recorded the find on the Alhambra Creek pages.

That’s what I call successful cooperation! And the beavers get the credit for it, which they genuinely deserve. Keep your eyes out for new species down at the dam! A team of experts is standing by….

Taryn Power Greendeer of Wisconsin has slowly been growing support for her beavers and their wildlife water works. There was another meeting about their fate with standing room only attendance. Now she is graced by this bit of lovely environmental reporting by Jim Solberg for the Jackson County Chronicle.

In March, I enjoyed a tour of a farm near Arcadia, Wis., where a beaver dam had made a slough deep enough for Tom and Sue Roskos to paddle their canoe through the Trempealeau River wetlands along their land. Well, another nature-loving couple invited me recently to view a beaver pond and the wetlands associated with it on their property in Vernon County.

The beavers have maintained a dam along a stream going through Bill and Taryn (Powers) Greendeer’s farm for around 14 years. Unfortunately, though, their concern for the beavers and the diverse community of life that has come to depend on them has put them in the center of a conflict with the town board over the pond’s proximity to a town road.

While she was pointing out the rich wetland habitat that surrounded the dam, Taryn expressed hope that the issues raised by the town board and neighbors could be solved while also preserving the wetlands. Bill told me, for instance, that their cattle have been moved so the beavers can continue building farther down the stream. Taryn said she is hoping the birds will be allowed to finish nesting before any further and possibly disruptive actions are taken to lower the water in the pond.

In the four hours I was there on that rather chilly day, I was surprised by the amount of life I saw or heard around the ponds. Three species of frogs were calling in the main pond — the gray tree frog, the green frog and a species of special concern in Wisconsin, the pickerel frog.

Five other species of frogs have also been heard calling there — the American toad, the spring peeper, chorus frogs, wood frogs and leopard frogs — so this wetland is clearly a breeding site for at least eight species of frogs.

We also heard and saw numerous redwing blackbirds that were singing and calling all afternoon. Barn swallows flitted in flocks over the water, feeding on insects that had emerged from the pond, while a pair of mallards and at least one pair of wood ducks flew around.

A pair of sandhill cranes fed below the dams while and a number of great blue herons flew overhead. There is, in fact, a heron rookery hidden behind a nearby hill. As we talked, a secretive green heron made a surprising appearance from deep within the thick growth of willows.

Later, I watched a kingfisher as it dove repeatedly from an overhead utility wire to catch fish, chattering noisily between dives. We saw plenty of fish as we walked around the various ponds. They provide food for many other critters besides the kingfisher, including the herons, raccoons, turtles and trout.

As the sun was setting behind the hills, the green heron posed majestically for me on a stump and as it flew away, a beaver emerged from the water of the creek very near my car. The beaver and I exchanged looks for at least a couple minutes, and the industrious rodent did not seem to be upset as I snapped its portrait.

Ahhhh this is a lovely and familiar tale! Take care of your beavers and beavers will take care of your wildlife and watershed! Thanks for letting us read about their magical effect and observe their impact on you as well. I am reminded of the summary I just put together for my upcoming beaver talk in Oakland.

Many of you will have heard  how beavers change their environment: their dams recharge the aquifer, improve water quality, augment fish diversity, and bring a host of new birds and mammals to their ponds. We expected that. What we didn’t expect was for an entire community to become part of the environment that was changed. Come learn how these uninvited guests are still teaching the city of Martinez that beavers can be “Worth A Dam”.

I stumbled across this beautiful bit of beaver writing by Kathleen Kudlinski for the New Haven Register in CT the other day and thought you would enjoy it too. I was going to just post excepts to whet your appetite, but its so delightful I decided to post the whole thing. As compensation for my thievery you must click on the charming illustration above and go to the website so their statistics record visitors to her article. I like her writing and appreciation very much, but there are 6 or 7 secret things that we know about beavers that she apparently does not. Lets see if you can guess what they are.

The beaver slid off a bank this week, surfacing nearby to stare at us. We stared back, breathless. A midafternoon sighting of this nocturnal animal^₁ seemed magical and fleeting. Except that this beaver did not flee. He swam around in front of his lodge, eyeing us. Were we dangerous? Apparently not². He slapped his broad scaly tail against the water and waited to see if we would flee. We did not. He slapped again. Clearly, we’d interrupted some important beaver business.

His mate would be waiting inside the stick-and-mud lodge they’d built together years ago. Beavers mate for life at 3 and live up to 29 years³. That means this whiskery old guy may have been living in beaver bliss with his darlin’ for over 20 years. Like all beaver parents, they’ll have two or three nearly grown offspring under their roof. Ma beaver had a litter of kits in early spring, while the big, old yearlings stayed on for a while to help with the new young’uns, and then moved out this summer to start new lodges of their own.

The beaver slapped again. Sunshine glittered on his wet fur, his bristly whiskers and the fresh mud he’d slathered onto his lodge. In winter, that mud freezes and will form a great barrier to keep coyotes, foxes, dogs and bears from digging them out. These predators could never reach the beaver’s front door, a hidden underwater entrance leading to a dark, dry den a yard or so across.

The sun could shine on this pond because, over the years, this enterprising couple had gnawed through dozens and dozens of trees, punching a hole in the forest canopy, their massive, ever-growing rodent teeth working like living chainsaws. Saplings fall with a nip or two. We’ve seen these beavers drop two or three medium-size trees in a night. A maple, 16 inches across, is nearly chewed through next to their pond. We took care not to stand underneath it.

Once the beavers fell a maple, birch, willow, aspen, poplar or other fast-growing tree, they strip the bark off. They’re only after the tender, nutritious cambium layer between bark and wood. This time of year, they may eat water lily tubers, clover, apples and the leaves, but their main course is always cambium⁴. To keep at fighting weight, 40 pounds⁵, beavers have to fell many trees just to stay alive. Not one stick of wood goes to waste after it is stripped clean. It is all used in dam- building and maintenance, lodge construction and improvements, or stocking in an underwater cache for midwinter snacking.

All of this busy-beaver activity makes them a keystone species in the ecosystem. A beaver colony changes a moderately productive woodland into a sunny wetland, bursting with life. The beavers’ work supports thousands of species of mammals, fish, turtles, frogs, birds, ducks, dragonflies and a myriad of water insects and invertebrates. Almost half of endangered and threatened species in North America rely upon wetlands, and so do we.

The beavers’ multiple dams slow water flow and absorb excess floodwaters, prevent erosion and raise the local water table. Several feet of silt build up behind old beaver dams. When polluted water trickles through this fine mud, particulates are strained out. Toxins, like pesticides, are broken down by bacterial action or simply the slow trickle of time. Water is far cleaner after it goes through this natural treatment plant.

Once 60 million beavers reported to work in North America. They were hunted and trapped for their glossy brown fur, but that’s not all. We hardly notice the territory-marking scent of a beaver, but two special properties made it sought after. The smell of this “castoreum” is especially long lasting, so perfumers use it as a base ingredient in their products. Also, for some reason, beavers concentrate one chemical, salicin, from willow trees, which is transformed into salicylic acid.

Today, we know that chemical as aspirin, but Native Americans and early settlers sought it for fighting pain^?, lowering fever and reducing inflammation. But it was competition that nearly did the beavers in⁶. We like our land dry for farming and development. Beavers like it wet. They lost. We nearly drove them to extinction by the early 1800s. Now, beavers are on the rebound. There’s nearly 14 million in the United States today. Mostly, that’s because we’ve learned to live with them.

The cranky old beaver slapped his tail one last time at us this past week. We decided to retreat to our cabin. A quick glance back through binoculars showed him already at work again, getting the place in shape for the winter ahead.

Contact Guilford naturalist Kathleen Kudlinski at kathkud@aol.com, or write her in care of the Register, 40 Sargent Drive, New Haven 06511. She is the author of 39 children’s books, including, “Boy Were We Wrong About the Solar System!”

Well that was a lovely glance at the value of a keystone species and the value of that moment in busy human  life where we stop and consider the natural world. Thanks Kathleen for reminding us that beavers have a huge impact on their environment and are fun to watch! As a woman whose been seeing the Martinez Beavers four times a week for the past four years I have some additions/corrections I hope you won’d…

Don’t worry. Baby beavers weren’t on the menu. But carp, minnows, perch and crayfish beware! There’s an otter in town. Two at least, because Moses filmed a huge one just a few days ago and now look!

This was a little fella, long and sleek and fast. Cheryl and Jon dashed about looking for the right place to photograph as he selected the choices spots to fish. He didn’t use the gap to cross the dam (otters hate to be predictable). He crossed on the bank farthest from the street.

Our beaver pond is a haven for fish eaters. The irresistible temptation to fish that captures the fancys of teens who should know better, is even more powerful for Otters. They have nothing but success in those crowded waters, making it worth risking some human contact. He even followed a few fast fish into the round-fence filter for the flow device! I sent this picture to Skip who was very excited about the prospect of being able to demonstrate that 6×6 wire allows wildlife access to the area! He thought the filter needed a loving touch up though, and asked if he should come out before the next storm?

After the otter cleared away, the main feature came out to play. GQ came upstream with three kits in tow looking lovely. All in all it was a pretty exciting evening. What are you doing this weekend?

Photos: Cheryl Reynolds

I couldn’t leave the above title without this…