Friday, May 30, 2014

Vern-Freeman Diversion Part 2

Above is a picture of water in southern California. Look closely because it is going away... Now what you are looking at is one of the main channels leading to the dozens of acres of man made ponds that recharge the aquifer on the Oxnard plain. The water is diverted from the Santa Clara River at this specific spot because of the congruence of the river leaving a wide valley and maximum percolation utility for the aquifer. Why is recharging the aquifer so important? Because growing strawberries in a semidesert. And because agriculture is taking out more than is being put back naturally. And because strawberries do not grow on salt water. And salt water intrusion occurs in places like Oxnard when freshwater groundwater reserves are tapped so long and hard that salt water creeps in. And it takes about 40 gallons of freshwater to combat 1 gallon of saltwater. Despite all these measures, it is quite possible that the water situation in Ventura county will be handed over to the feds through a process known as adjudication. Because we could not handle our resources responsibly the adults will have to step in.

What should be immediately apparent to you is that the Saticoy settling ponds as they are affectionately known are mainly dry. These ponds should be full this time of year doing their job recharging the aquifer. But nothing.

Depressed yet? I do not want to get you on a complete downer but it gets worse. Although the pools create habitat for numerous birds and there are some fish (non native for the most part), reptiles, and amphibians that use the ponds - what you should notice is that all emergent vegetation is completely scoured away. No willows, tules, cattails - all plants that would thrive in such an environment and provide crucial habitat - are scoured away to prevent clogging of the gravity fed system of pipes, berms, and levees.

Now the word mitigation gets used a lot when discussing the complex matter of nature being steamrolled by human wants and interests. It usually goes something like this (to paraphrase) "We are going to do so much damage to the system, I mean just completely disrupt things that for a little pity party we will do this little token of appreciation over here for you (insert park, nature center etc etc)." 

Well how about this for mitigation? Let the settling ponds re-vegetate and naturalize a bit, providing habitat for wildlife. It might take a little bit of extra work keeping the culvert clear, minimizing disruption and what not. But why can't it be done? Perhaps these extra costs could themselves be mitigated by allowing fishermen and bird watchers onto the property for a nominal fee? Kayaking anybody?

My point is this: the Vern-Freeman diversion though it provides a necessary service to the agricultural economy of this region can not escape the burden of proof that it, like all man-made water diversions/dams, has imposed a huge burden on the evolutionary, geological, and ecological processes of the Santa Clara river watershed. Is United Water doing all that it can in its power to mitigate these damages?

Well as I pointed out above I do not think so, but in all fairness as my last post addressed they are doing much more than they have in the past by taking a pro-active approach to fish passage, designing a new fish ladder, getting a cool fish camera etc etc.

And finally, this being a beaver blog after all, what is the connection to beaver? You should know that the Sespe River is the primary tributary of the Santa Clara River- providing about 40% of the flow into the river. And if you are up to date on your beaver studies in socal you should also know that a primary piece of data used in the Lanman et al paper on historic range of beaver in California was a beaver collected in 1906 on the Sespe prior to statewide translocations of beaver. Beaver are native to this watershed. While some parts of the Santa Clara do become dry sandy washes unsuitable for beaver other parts such as the diversion and upriver in Santa Paula contains some flows year round. Beaver could live here. Take a look at the video below on how the channel is maintained to see the habitat here for them.

And take a look slightly upriver in the city of Santa Paula. You will notice good flow, abundant riparian vegetation, and where some diversions have created some faux beaver ponds already.

And check out the habitat on the Santa Paula Creek, a tributary nearby:

Santa Paula Creek
Now if you think like me you have already made the connection. Humans divert river water into man made ponds to allow water to slowly percolate back into and recharge over drafted aquifer. What furry, buck toothed critter do we all know that does that already? And does it for free while at the same time providing abundant habitat for other critters? Hmmmm.... United Water engaged in multiple law suits with  environmental groups, fish groups, municipalities over water rates, looming adjudication. Beaver involved in 0.0 lawsuits. Charge nothing for their water. Allow fish passage. Allow percolation.

One specific issue at the diversion was the issue of high sediment load in the water. Before going into the Saticoy ponds the water is shunted through a series of settling ponds where the sediment is allowed to drop out of the water so as not to gunk up the pipes.

One word of encouragement. According to Steve Howard, senior fisheries biologist at Freeman, they decided not to trap out the badgers who have begun colonizing the dry settling ponds. Even though their aggressive digging could destabilize earthen berms they opted to utilize the mustelids as rodent control for a booming ground squirrel population. Maybe if United Water decides to take a "let nature do the job" attitude towards badgers there is hope for beavers and United Water collaborating in the future? Perhaps as a collaborative partner in groundwater recharge?

"The arrogance of man is in thinking he is in control of nature and not the other way around."
                                                                                                                                         Godzilla 2014

Dinosaur trap at Vern-Freeman (cowbird trap-nest parasite)

Wednesday, May 21, 2014

Leave It to Beavers... some thoughts

First of all if you missed it or just want to see the beaver epicness all over again here. Video was having trouble loading however...

So it has been a week since PBS premiered Leave it to Beavers and as you may know the show was a resounding success. I personally thought the show did a great job of distilling all the different strands of knowledge, controversy, and potential that go with beavers in today's world. The personality driven stories of beaver rescues and rehabilitation were well done and well received. The whimpering cries of infant beavers, very child-like, will doubtless drive up interest and passion for beaver based on the cuteness factor alone. I never knew that the young were so vocal myself. But I have to admit, what made the most impact for me out of all the segments was the part on Suzie Creek in Nevada.

To see the transformation of that creek from a greasy little cattle trodden dribble of water to a lush oasis of life with a robust riparian corridor- that really reinforced the importance of beaver in arid lands and inspired me to keep up what I am doing. One of the two scientists in that scene likened beaver ponds to little savings accounts of water on the landscape. In a climate regime where snowpack is becoming less dependable as a source of water retention on the landscape it is beaver ponds that stockpile and release water slowly into the landscape. Perfectly done.

And the other section that really stuck out to me was the underwater footage, I just love scenes of beaver swimming underwater. SOOOO COOOOOL. Seriously if I could just have a video montage of beaver swimming underwater I would watch that video on loop more times I should mention even on a beaver blog.

The three dimensional landscape of beaver ponds, I think mentioned during the section in Canada (Alberta?) was also a stand out for me. The amount to which beaver penetrate  into and modify the substrate in their own ponds was awesome. Beavers will take the mud from the bottom and fill in their dams with it. In deepening ponds beaver increase invertebrate diversity and also provide deep, cool refugia for heat sensitive fish. In deepening their pools beavers lower the amount of surface area exposed to the sun, less evaporation occurs, and beaver ponds keep and retain the water better than surrounding areas.

Anyways congrats to PBS on producing such a timely doc on beavers and keep fighting the good fight!!!

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Sunday, May 18, 2014

Southland Beaver Visits the Vern-Freeman Diversion Dam Part 1

Among the river systems of southern California it is the Santa Clara River that offers perhaps the most promising hope for restorations. Unlike the Santa Ynez river it is not dammed. Unlike the Los Angeles, San Gabriel, and Santa Ana rivers it is not channelized. As the largest river system in southern California that is not dammed and not channelized the Santa Clara has garnered much attention from groups such as the Nature Conservancy who are working to protect large chunks of this watershed. Many unique and imperiled species utilize the Santa Clara River as habitat. Riparian species of concern include western pond turtle, unarmored three spine stickleback, tidewater goby, southern steelhead, pacific lamprey, Santa Ana sucker, arroyo toad, southwestern willow flycatcher, least bell's vireo, western yellow-billed cuckoo, and red-legged frogs- among others. Additionally the Santa Clara River maintains connectivity with many of its tributaries the larger including Sespe Creek, Santa Paula Creek, Piru Creek, and Castaic Creek. Several of these creeks, most notably the Sespe, are undammed and offer miles of prime steelhead habitat and produce ocean bound smolts annually. Regular readers should recognize Sespe Creek as the source creek from which a beaver specimen was captured in 1906 by Dr. John Hornung and was a foundational piece in the recently published paper by Lanman et al proving the historical presence of beaver in coastal southern Californian streams. But more on the prospects of beaver reintroduction into this watershed later.

Despite the rosy picture I paint the Santa Clara has some definite issues. Chief among these are invasive    plants and animals (especially the giant reed Arundo donax), agricultural and urban runoff, groundwater pumping, agricultural diversions, and last, but not least, the Vern-Freeman diversion installed in 1991. For a brief history of the dam check this out. This diversion was built to direct flows from the river to recharge the Oxnard aquifer and protect against salt-water intrusion. The Oxnard plain is an agricultural hub. Chances are if you eat a lot of strawberries you have probably ate an Oxnard strawberry, which was watered by water provided by the Vern-Freeman diversion, which was water taken from the Santa Clara River. While at first the diversion was hailed as a major success - increased reliance on high water crops, miscalculations on the amount of water that can be withdrawn, the recognition of southern steelhead as federally endangered species in 1997, and several drought episodes including the current one - have all compiled to put the diversion and the agency that runs it, United Water, through some very pressing times. United Water has went through and is currently engaged with several lawsuits ranging from municipality water rates to securing better flows and passage for fish movement.

It is in this context that southland beaver was permitted to view and be granted access to the diversion by the senior fisheries biologist employed at United Water's Vern-Freeman diversion dam, Steve Howard. For reference sake the diversion is located about 1/2 between Santa Paula and the ocean on the map above.

Senior Fisheries Biologist Steve Howard explains Vern-Freeman Diversion Santa Clara River

Now, here I want to thank Steve again for spending two hours of his time taking me around and answering all of my questions. I was pleased to find out he is a true fish guy and this was good news because I had long held negative connotations for United Water with regards to their fish work. But Steve seems like the right guy for the job and as we talked I could see he really was making some strident efforts for steelhead and lamprey (don't forget the lamprey!!) in this river. I learned that because of downstream down cutting of the river due to quarry work, the diversion was actually offering some benefit by preventing the down cutting to continue upstream.

So what kind of fish passage does the Vern-Freeman have? Well watch the video below as Steve explains the Denil fish way they use, why it is not the best system for the river, and how they are going to improve it. World exclusive on southland beaver!!

Denil Fishway on Vern-Freeman and New Passageway Coming!!

Did you catch all that? The problem with this particular fish passageway on this particular river is that when the Santa Clara rages, it really rages. Steve told me he has seen the river in such flow that as it crossed the diversion wall, it scarcely dropped in height at all. Now for a steelhead trying to find its way upstream in such a torrent, in flows that come and go quickly, it may miss it's opportunity to pass by keying in on the area of highest flows (the diversion wall itself) and missing the passageway. Let us look a bit at the Denial fish passageway.

Denil Fish Passageway

Now if a steelhead makes it up through the ladder, how would Steve know that it made it through? Well it turns out that the steelhead on this particular passageway are some of the most highly scrutinized fish in the world. Steelhead have to pass through a point where they are on motion detection camera from two angles as well as infrared detection. Pretty sweet...

So despite all the difficulties with steelhead on this river going through this particular diversion- have any made it through? Turns out yes, in 2012 two mature ocean-grown steelhead made it back up and through the diversion. Steve has the video to prove it which I will show below.

Well need less to say Steve said he was jumping through the roof when those two steelies made it through in 2012.

Some may wonder- why are all these resources and water being given to a fish?

Now for me southern steelhead are some of the coolest fish around. I mean big fish like those two make it up through largely intermittent to totally dry rivers during brief high flow events in a mad dash to their spawning grounds in perennial, spring and snowmelt fed streams. For any readers here from more wetter parts of the world the picture below shows how much of the lower Santa Clara looks the vast majority of the year, if not a sandy wash.

Until it looks like this:

And even with all the crap we throw at them they still make a go at it.  People can learn a lot from this fish in my estimation. That fish to me is very inspiring, more so than most humans at least.

More to come including how channel maintenance is achieved, fish traps, settling ponds, percolation, bird life at the diversion, problems with badgers and I ask the question: 
Is the Vern-Freeman diversion doing what beaver would do naturally? (and for free)

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Wednesday, May 14, 2014

The Beaver Zeitgeist Continues: PBS Premiere Tonight of Leave it to Beavers

Get Excited!!!!!

"Beaver are definitely a keystone species in an aquatic ecosystem. A keystone is like a bridge and you have that one stone that will hold that whole bridge together- that will lock it in. If you pull that one stone out it all collapses in on intself. Beaver lock the aquatic ecoystem in."

Sherri Tippie

Why Beavers Build Dams

"One technique is to slice 1/2 way through and let the wind do the rest."

"The incisors are strengthened with iron which makes them orange... they grow continuously and even self sharpen."

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Can Beaver Ponds Actually Reduce Invasive Species?

American bullfrog (common in CA but not native)
One of the chief indictments against beavers, especially in areas where they are not yet established, is that the modifications that they make will greatly augment the available habitat for non-native invasive species. Now depending on where you live this can be a whole assortment of wetland loving critters. Beaver ponds being lentic habitats, that is they are bodies of slow moving waters, invasive species that are attracted and benefit from this environment include a whole slew of things where I live in California. But the usual suspects include both signal and Louisiana crayfish, African clawed frogs, American bullfrogs, catfish species but most commonly bullhead, large and small mouthed bass, and common carp. There are others but these are the main culprits. They all love sluggish, stagnant water- and they like it warm. Beaver ponds can create certainly make for warmer waters in the shallower parts of their pond.

Stagnant Pool on Santa Clara River Oxnard. Duane Nash
Although it makes intuitive sense that beaver modifications would greatly augment the habitat for these destructive invasives, as is often posited, we should not be satisfied with mere assertions but actually investigate this question more assiduously.

Let us look and see if there are any characteristics that unify these California invasives. As mentioned earlier they like the water slow and they like it warm. It should also be noted that the species I listed above are all highly fecund. They make a load of babies. A common carp can produce about a million offspring in a season. So when conditions are right, food is plentiful and the water is warm- every species listed can reproduce and grow fast. The big down side to all these non-natives is that not only do they crowd out the natives and out compete for spawning sites, critical refugia- they are more often than not highly predaceous on them during one or more of their life stages. For instance bullfrogs can eat hatchling western pond turtles, carp can eat the eggs of all fish/amphibians but not the adults.

Bullfrogs Eat Everything

Yep these invasives in California are especially troublesome due to their often voracious and omnivorous dining habits. Some such as the African clawed frog- a problem in the Santa Clara river watershed -are just ridiculously gluttonous. These weird, fully aquatic, frogs were actually commonly used as proxies for pregnancy tests!!

African Clawed Frogs Are Piggies

But with regards to these nasty invasives- predatory as they may be- these animals are not top predators. Bullfrogs, bass, crayfish are better thought of as mesopredators "middle predators". They eat animals, but animals also commonly eat them. And at least in California these non-natives have a host of predators that can and do eat them such as raccoons, herons, mergansers, garter snakes, and ospreys among others. The trick is to get the predators to the prey....

Please do yourself a favor and watch professor Walt talk about his experience with beaver on the upper Verde river of Arizona. The whole video is outstanding but what is most interesting and pertinent to our discussion here starts at about 3:30. Here he goes on to describe that although the river system he is discussing, the upper Verde river, has an invasive species problem his qualitative observations (he is a professor) have suggested that beaver ponds have actually lowered invasives while natives have rebounded.... How is this possible?

The key player in this scenario Walt posits is the river otter (Lontra canadensis). With the return of beaver ponds otter have returned to the river as well. These deep, slow pools give the otter the habitat it prefers. Otters, like any predator, have an optimal foraging strategy. Why waste your efforts on catching multiple small prey items when you can catch a few larger animals and get the calories you need without all that extra effort? And in these beaver ponds the larger, non-native fish such as bass and large bullfrogs are being preferentially preyed on by otter. The smaller, quicker, and more cryptic native fish and amphibians are being consumed as well but not to the same extent. Several interesting ecological processes are putatively occurring here.

1) Beaver, a keystone species, is living up to its name in providing habitat conducive to otter.

2) Otter, being top predators within the aquatic realm have reestablished and are starting to exert strong top down control. Top predators are now recognized as crucial elements in optimally functioning ecosystems.

3) These invasives, which prior to the return of beaver and otter to the system, were enjoying optimal success due to a phenomena referred to as "mesopredator release hypothesis" now have to contend with a growing and hungry population of river otters.

4) Being larger, commoner, and more conspicuous than the native aquatic organisms otters feed on the non-natives preferentially. Again, exerting top down control and following optimal foraging strategy otter start to make significant impacts on the ecology of the ecosystem.

5) With their chief competitors and predators lessened in population density due to otter predation native species can expand.

6) Because beaver ponds allow interactions between native and non-native species this allows non-native species to evolve defenses against them, which in the long run may be most pragmatic because it is highly unlikely that humans will exterminate completely non-native aquatics.

And in this manner beaver ponds may actually be minimizing the impacts of non-native species on the upper Verde river of Arizona.

Beaver Lodge and dam Upper Verde River. Nature Conservancy
Now obviously much of the story involving beaver/otter/invasive species on the Upper Verde river of Arizona is anecdotal, we need proper peer reviewed studies, but I would like to add my own observations on beaver ponds and invasive species on the Santa Ynez river in Santa Barbara county. As I detailed on  a recent post the Santa Ynez has dropped precipitously due to drought and the low amount of water in Cachuma reservoir. But I also suggested that these beaver have developed strategies for dealing with the low water. Never the less it was a bit of a disturbing site to see and photograph the wonderful beaver ponds dried up.

Dried beaver pond. Santa Ynez river CA. Duane Nash
But as distressing as this image is here this is where I will suggest such occurences may be actually doing some ecological benefit. Compared to many of our native fish/amphibians the invasive aquatic organisms are highly dependent on water. Bullfrogs are very aquatic compared to native amphibians which can survive drought and go underground and into dormancy. When these beaver ponds start to dry up, although they served a great home and sanctuary to non-native species when there is water, these very same beaver ponds may serve as death traps.

Bullfrog Tadpoles Stranded in Drying Beaver Pond. Santa Ynez River.

Now as the video above succinctly documents, these bullfrog tadpoles- whose parents probably enjoyed life in these lush, well vegetated ponds -are most likely doomed. Birds, raccoons, or simply lack of water will do them in.

Another common sight I witnessed in these drying beaver ponds were loads of chewed up Louisiana crayfish remains. Most likely raccoons did the damage, wading birds will simply swallow the crustacean whole.

Unlike the situation in the Verde river, we do not have river otters in southern California nor is there any suggestion that they were ever native here. But, in addition to raccoons, what we have a lot of is abundant and diverse avian predators of aquatic animals.

Santa Clara River estuary. Great Blue Heron and White Pelicans. Duane Nash. March 2014
The photo above is of the Santa Clara river estuary in Ventura county and you can see two high level avian aquatic predators. The great blue heron is a startlingly efficient and ruthless predator. It is a bird that really denotes the dinosaurian heritage of birds. As you can imagine great blue herons love beaver ponds and as I was exploring the Santa Ynez during this dry spell I kept on disturbing a flock of great egrets and one loud, croaking pissed off great blue heron. These guys were having a buffet on the stranded crayfish, fish, and tadpoles left in the ponds.

Heron/Egret tracks on drying beaver pond. Santa Ynez river
Great Blue herons are efficient predators but let us not pay short thrift to American white pelicans. These birds may actually be the most efficient and diligent of all freshwater predators, maybe even more so than river otters. Unlike our brown pelicans, white pelicans are cooperative predators of freshwater and estuarine environments. They do not plunge dive but they cooperatively shoal fish in shallow water.

So not only are white pelicans cooperative feeders they can also snag and swallow huge fish- including pretty huge carp, a non-native fish and probably what the white pelicans in the Santa Clara estuary were feeding on. I found this video Nygren Pelicans feeding frenzy that really highlights what a mass feeding spectacle a group of white pelicans can achieve, I highly recommend it.

White Pelican going after Asian Carp. Bill Rudden

White pelicans have already been posited as a control on invasive Asian carp in the Great Lakes region and so why not Californian waterways? Well, white pelicans will not frequent narrow, confined channels. They like big, wide shallow bodies of water. In California this is primarily lakes/reservoirs/estuaries. But it is not without reason to suspect that big beaver ponds could provide such foraging habitats for white pelicans. If you do a little internet sleuthing you can find pics of white pelicans in beaver ponds or even standing on beaver dams. Maybe white pelicans are another species that has been setback due to loss of beaver habitat on this continent?

Osprey with carp

Well hopefully you found this post interesting. The more I look at how complicated some of the issues I highlight are the more I see it is important to stay away from blanket statements. Can beaver ponds benefit invasives? Sure. But if you have abundant top predators the opposite may occur. Non-natives are expeditiously slaughtered and the native return. Beaver ponds, by actually creating the ideal habitat for non-natives, may actually be creating an environmental cul-de-sac that allows top predators to move in and decrease non-native populations- perhaps leaving the natives to repopulate.

Great Egret and Great Blue Heron. Fillmore fish hatchery. Fillmore CA. Duane Nash

Don't forget Leave it to Beaver tonight on PBS!!!

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Wednesday, May 7, 2014

Lampreys Get No Respect

Salmonids, and in my neck of the wood that is the steelhead/rainbow trout, get loads of attention with regards to the interaction between these species and beaver. Salmonids are game fish, they are symbols of pristine watersheds, they taste good, and they have an attractive elegance all of their own. And if you are a reader of this blog and other beaver blogs you are probably well aware of the numerous benefits that beaver modified watersheds offer to salmonids- larger deeper pools for fry to grow up in, woody debris and muddy bottoms stimulating invertebrate food chain, deep pools for protection from predators, cool thermal refugia through hyporheic exchange - but I don't want to talk about salmonids today. Today I want to talk about the other anadromous fish that often times shares watersheds with beaver and salmon. Smile for the camera I am looking at you Mr. Lamprey.

That the Pacific Lamprey (Entosphenus tridentatus) is historically one of the more maligned native fish, and I use the term fish here loosely as lamprey pre-date fish, is in no small part due to it's grotesque appearance and parasitic adult stage. I want to highlight that it is the adult phase that is parasitic as the juvenile phase plays a not too small role in river ecology as we will talk about later. It should also be reinforced that the parasitic adult phase do not limit their feeding to salmonids but also latch onto marine mammals and other fish. And as the picture below, taken at about 400 meters deep in the Monterey canyon off central CA feeding on a hake, attests they range deep.
But they do not latch onto fish when they return to coastal river systems nor do they always kill their host. Lamprey prefer similar environments as  salmon to return to and lay eggs. It is not clear if lamprey return to their natal streams but they range from Alaska to southern California. Like salmon they do not feed on their return migration. Unlike salmon lamprey can not maintain speed in high velocity channels for long and will swim at bursts and then sucker on to rocks/branches/debris to rest. But as the photo below attests this allows lamprey to traverse falls that even salmon can not get up such as in the pic of Willamete falls below. Unfortunately fish passages that work for salmon may fail for lamprey.

Williamette Falls lamprey harvest. credit Dave Herasimtschuck. Freshwater Illustrated

Take a close look at this picture of lamprey just carpeting Willamette Falls on the Columbia river. Such a scene, as many native American elders of the Pacific Northwest will tell you, was quite typical during the several runs that occurred annually on many rivers. Notice that the lamprey can literally scale waterfalls through their suction abilities. Pretty cool no? Native peoples of the Pacific Northwest who have seen the lamprey decline precipitously in just several decades have sounded the battle cry to save this little understood but pivotally important creature. Please take the time to watch video linked below.

"How do we let something- 450-500 million years old -go extinct? Shame on us, the whole lot of us for not paying attention to what was going on"

"We are a big family we are the circle. So when one of us is in trouble that is when the rest of us have to do something and step in"

"They amaze me, they are amazing creatures. My brother eel is cool- he is just flat cool."

So while native American cultures of the Pacific Northwest have long heralded lamprey as an important part of the their world the rest of us are slowly waking up to the importance of this creature. The USFW have actually created a cutesy cartoony lamprey character "Luna the Lampery" for lamprey awareness. 

Check out their page The Pacific Lamprey Experience. Lamprey may be so important that their continued survival may be pivotal to the health of salmon fisheries. How is that so? you might be asking They parasitize and sometimes kill salmonids?

Turns out the lamprey youngsters, which are called ammocoetes, are not parasitic at all. In fact they do not even eat flesh- they filter the water, cleaning up algae, detritus and other bits from the water - and also burrow into the substrate. For these reasons they are often dubbed the earthworms of the river. 

At this stage, which may last 7 years, ammocoetes serve as food for a number of critters- especially salmonids. There are loads of examples of steelhead stomachs being found just crammed with these guys. So although later they parasitize salmon, for the majority of their life they serve as food for them. And through their filter feeding abilities they promote cleaner, and therefore more well oxygenated environments that we all know salmonids love.

As adults lamprey returning to spawn also may actually help salmonids. Because their flesh is richer and oiler than salmon and they are easier to catch than salmon- predators may preferentially take lamprey thus acting as a buffer to salmon predation where their migrations are coincident.

And finally after returning lamprey spawn and die their bodies can provide nutrients that promote an enriched food chain for salmon fry.

And now let us all tie it all back together with the beaver. From the USFW page on lamprey: Shortly after hatching in freshwater streams, lamprey larvae or ammocoetes drift downstream into areas of low velocity and fine substrates where they burrow, and live as filter feeders for up to 7 years. Hmmmm..... low velocity and fine substrates..... where might we find such habitat? Does anyone know of certain buck-toothed rodent that might actually create such habitats?

To drive the point home even further here is what the USFW says on their page The Pacific Lamprey Experience: Urban development, forestry, and agricultural practices have resulted in a loss of wetlands, side channels, and beaver ponds, which the Pacific Lamprey ammocoetes prefer.
Beaver side channel pond. Santa Ynez river

Yes salmon need lamprey and both salmon and lamprey need beaver.

Randy L. Rasmussen. The Oregonian

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Thursday, May 1, 2014

Beaver Safari on the Santa Ynez River II: Surviving the Drought

As you may know the Santa Ynez river in Santa Barbara county has one of the more robust populations of beaver in southern California. I went to the Santa Ynez last September and found lots of beaver sign. At the time I was not aware of the strange water regime that this river is subjected to. When farmers downriver from the Cachuma reservoir are sucking air in their wells and need some agua, the Cachuma water board has to respect their senior water rights- because you know respect your elders - and so like some proverbial releasing of the Kraken water is let loose from the dam to reach them and recharge their wells. And so in hindsight it now appears evident that I had visited the river during one of these senior water rights releases. With this in mind I wanted to revisit the river and see how it, and possibly its beavers, are doing in a drought year and before any releases have occurred. The answer- things are looking pretty dry!!

For some comparison below is what the river looked like last September during the water release at the same spot.

Water makes quite a bit of difference does it not? One of the benefits of a largely dry river is it gave me a chance to investigate and get into places that I suspected were beaver ponds but were difficult to reach during high water. For instance in the wet picture you can see a little side pond which I suspected was beaver constructed. But instead of a full on dam the ingenious engineers had simply diverted off a side channel of the river, bermed it up and willows/vegetation grew over the beaver constructed water works. When I walked along the berm I found some old beaver gnaw marks as seen below...

But does this drying river, remember it is only the end of April, forebode danger for the beaver population on this river? Well as I mentioned earlier  there is a good chance for a senior water rights release later this year but regardless there were pools further upriver that were full of water and may indicate refugia for beaver and other aquatic/amphibious critters. And there is much to suggest that beaver are a lot more adaptable when it comes to changing capricious water conditions than might be generally expected. Looking upriver from Alisal bridge (Solvang) things looked a little bit more promising with regards to water.

Again though, for reference, below is the pic I took in September last year during the water release.

In fact if you look at the little side pond to the left, where it gets a few feet deep I found a western pond turtle- a threatened species -on this trip. So life was finding ways to hold on during this dry spell.

Western pond turtles of course are a species that I have often posited would benefit greatly through beaver habitat as they prefer slower, more relaxed bodies of water to inhabit. Going a little further upriver I came across a fairly large pool- deep enough to swim in - against a steep oak shrouded hill. There was one particular spot I was interested in, the deepest spot, because on the steep bank there was dense brush and felled trees. It looked like the perfect place for beaver to dig a secluded bank burrow and I would highly suspect that they do here.

Now one thing you will notice in the video are a couple of little rock dams both downriver and upriver from this spot. I did not think too much of them at the time, figuring they looked man made. But what if beaver made the little rock dams? Perhaps these rocks are just the foundation for a future dam? One thing I noticed during this visit as opposed to the last visit was that fresh beaver activity on trees was not found. Maybe the beaver, feeling restricted to the few big pools left were not venturing out to fell/or feed on trees but were staying close to these deep water refugia and feeding more on the aquatic plants/algae growing abundantly there? The more I explored the more I found evidence supporting my theory.

Weird hugh? I mean hikers all the time make such features to cross streams and there are people that go down here. But if these rock berms were made by people why two of them right after each other? And there is no trail on the other side just thick bush... Maybe these beaver just really like rocks?

Anyways, rock-working beaver aside I continued upriver to a spot where I knew of some nice beaver ponds in a maze of sedges and willow thickets. Last time I went here these ponds were waist deep and just really cool to explore. This time it was a little bit different...

Yep this beaver maze was a shell of it's former self. And there literally were tons of shells lying around from Louisiana crayfish that were consumed en masse after the ponds dried up. I bet raccoons were some of the main culprits but I saw loads of marauding great blue herons and great egrets just  slurping up whatever critters were left in the last muddy pools. One slimy mud pool was interesting because it was dominated by bullfrog tadpoles. If you have not seen bullfrog tadpoles they are not your normal everyday polliwogs and are pretty big and ugly, just like the adults. Anyways I will talk more about the issue of invasives utilizing beaver ponds in a future post so I will save that stuff for later.

Yes I know the below pics are a little depressing but I have faith the beaver have seen this happen before and know how to adapt. But you can see some nice and very obvious dams and the ponds that they would have created.

Where do the beavers go when their ponds dry up? The vegetation may offer a clue. The above chewed willow stump, like the earlier pic, is obviously not a fresh chew. And as I mentioned earlier I saw no freshly chewed trees on this safari. This is in sharp contrast to my last excursion when I saw so many freshly chewed trees that I stopped photographing them. And while there was no fresh chew on trees I did see some uprooted sedges, with their rhizomes chewed off, a well known beaver treat. And not to far from the dried up beaver ponds I found another large, deep pool. Likely retaining water due to shallow bedrock forcing groundwater up here I suspected this pool may serve as a beaver refugia. And then I saw a pretty obvious trail through the emergent water plants which grew in abundance here.

Were does this trail lead to? A pool with some deep spots bordered by a relatively steep bank. And guess what I found when I investigated the bank. Some very probable and likely beaver bank burrows.

You can see one that enters at the water level and another slightly obscured at the upper right. I also went and filmed two other potential beaver burrows as seen in the video below.

So I think I have got a pretty good grasp on how beaver utilize the Santa Ynez river, or at least a fairly good working hypothesis.

During periods of high flows and water releases beaver are able to utilize more of the riparian area safely and efficiently. These times may also coincide with the greatest dam building activity. Tree felling and consumption is relatively high as beaver are never too far from the safety of water. Indeed sometimes the trees are growing in the water.

During periods of low or no flows, a shift of range and diet occurs. It is well known that many beaver switch to a diet of succulent sedges/water plants/algae during summer months. For the beavers of the Santa Ynez such a change may be less of a choice but a matter of necessity. Because large, deep pools are at a premium and such pools withdraw away from the riparian edges where such trees grow- tree felling and consumption places a significant risk to predation to beavers as it pulls them away from deep water and is a relatively noisy and cumbersome affair. Instead beaver concentrate on algae/aquatic vegetation and remain as cryptic as possible due the relative lack of water cover.

Steep banks of alluvial soil bordering perennial, deep pools may offer critical refugia for beaver living in this habitat especially during times of low flow.

Such conditions, steep alluvial banks bordering deep, perennial pools, may offer another set of criteria when looking at potential sites for beaver restoration in arid habitats.


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