Sharon Brown of Beavers:Wetlands & Wildlife

City leaders and citizens of Martinez, CA deserve much credit for their enlightened response to the presence of a beaver family in a downtown park. It is fitting that the home of John Muir demonstrates how cities can coexist with our land’s keystone species.

Martinez has done the right thing, despite some obstacles. People and officials have spent considerable time and resources to find and implement a win/win solution. In the process, Martinez is becoming famous as one of the best sites for urban wildlife viewing nationwide.

Since California has lost more of its original wetlands than any other state, it is appropriate that a California city shows the ways to restore these vital life support systems. When the beaver pair moved into a man-made wetland in Martinez and began to improve it, they reminded us that working with nature gives the best results. Making use of the beaver’s ability to restore vital wetlands can alleviate today’s major environmental problems.

As the climate crisis brings more costly floods and droughts, it becomes even more important to understand how restoring beaver dams and wetlands can decrease the damage done by such extreme weather events. When water is held in a series of beaver ponds, there are less droughts upstream and less costly flood damage downstream. Plus, the lush plant life of beaver wetlands absorbs carbon dioxide, the major greenhouse gas.

Beaverworks also slow the flow of streams and keep water on the land longer, so that pesticides and other toxics can be broken down. Silt is filtered out at the dams. Thus, beavers can help solve our problems with both water quality and quantity.

Yet another benefit of the Martinez beaver pond, and others, is providing habitat for many other species—including almost half the threatened and endangered species, according to U.S. EPA. Having a beaver wetland within city limits gives residents and tourists a wonderful opportunity to reconnect with nature.

We urge the city’s leaders to continue their good work and not be swayed by a few complaints. Our nation’s future wellbeing depends upon the enlightened coexistence with nature that Martinez demonstrates so well.

Sharon T. Brown, Wildlife Biologist
Beavers: Wetlands & Wildlife

There are all kinds of things that could be written about last night’s meeting but I want to start here: our side did a helluva job. We did our homework, knew the material and made the best possible argument for responsible stewardship. From Mitch’s compelling hydrology summary, to Igor’s outstanding announcement of supporters, to Councilman Ross’ assertive and confident fiscal challenge of the mayor at meetings close, the field was ours. Our beaver t-shirted public (thanks santa) was smart, compassionate, and remarkably patient. We had read the report and understood where to ask questions. We knew the issues to focus on and could demonstrate the clear benefit of our time. If some didn’t know before, last night showed clearly whose team to be on and whose footprints to watch. The council wouldn’t vote last night and we’ll have to do it yet again but all great performers are asked back for an encore and now we know just what to wear.

The contrast was stark and compelling. It was a “powerpoint-vs-folded-cardboard” kinda night. Well done!

******************************************

This was sent by Skip Lisle to the council yesterday and read at the meeting by our own Cheryl Reynolds.

Dear Martinez City Council Members,

You are on the brink of an important decision on how to deal with your beavers. As you know, there are only two fundamental, and very different, ways to address beaver-human conflicts. One is through “extirpation,” which requires the removal of beavers now and, typically, in perpetuity as others continue to arrive. This might be described as a “soft” defense because it leaves nothing physical in place that reduces the vulnerability of properties between the time that new beavers arrive and when they are, once again, trapped. The other alternative is to build tangible, “hard” defenses that protect properties in a long-term manner regardless of the presence of beavers. The flow device we installed in January, which controls water levels by controlling damming behavior, is an example of this approach.

Martinez is not alone in confronting the beaver issue. Conflicts between beavers and people are widespread in both urban and rural areas. Across this continent and in Eurasia, beavers are recovering and slowly reoccupying their historical range, including Martinez, after being nearly destroyed during the Fur Trade (ca. 1600-1900). Partly because of this modern reality, I have spent the past 15 years resolving beaver-human conflicts in many areas of the world. Everything in my experience has convinced me that a hard defense is almost always more effective, efficient, and economical than just endlessly interdicting animals. In addition, it allows for the possibility of capturing the many values associated with having this native species, and other wildlife, present to view, study, and enjoy. In Martinez, there is also the added and fairly unique potential for ecotourism. Moreover, given that this issue is politically contentious—as it often is in other communities as well—non-extirpative defenses represent an excellent compromise that keeps political conflict at a minimum.

I admire your commitment to protecting the properties and property owners of Martinez while also weighing the attitudes and opinions of a diverse public. For a variety of reasons, I believe that a strategy based on controlling beaver behavior will serve your city’s interests far better than one based on eradication.

Skip Lisle, M.S., President

One place we hear fairly consistent beaver support is from our young people. High School or Elementary School the beavers tend to be fairly popular in the 2-18 voter block. If you think young people don’t understand the importance of their environment, prepare to be impressed. Check out Rona Zollinger’s ESA class and their effort to make an eco-friendly parking lot, reported in the Contra Costa Times and the Pleasant Hill Record.

Then sit down with the morning coffee to read 9 year old Noa N’s outstanding class essay on the Martinez Beavers.

The Beavers

The beavers are a small group building two dams in Martinez. Have you ever SEEN a beaver at all or even in a town?! If you have remember this: You are blessed.

Just last night my mom and I went to downtown Martinez and watched the beavers for two and a half hours. I kept on saying to my mom, “Just one more beaver.” But when we saw the next beaver I tried not to say anything that would make my mom remember what I said. She wasn’t going to listen anyway if I did; she was too busy watching the beavers. My mom sometimes said “We will stay for just five more minutes,” and I pushed until my mom made it ten minutes. Then we stayed for about forty five minutes. What I’m trying to say is: They are fascinating.

People think the beavers are so cute, but they are more than just cute. Other animals live in the habitat they create. No wonder a Native American tribe believes that the great lord put Beaver there to bring peace to earth!!! The beaver family consists of a mom, a dad and last year’s babies (4 were born and 2 died.). The mother is pregnant and you will probably see the kits first in June.

You might think nothing could go wrong with these cute beavers but you are wrong. The beavers are one of the subjects being talked about at Martinez City Council meetings and some people are suggesting killing them because of flood control. We got to meet with the mayor at our school and he said (thank goodness) that he decided that he was NOT going to kill them (Yahoo!!!!). He also said it was unclear what their future was going to be.

Beaver Deceiver

The City Council used an invention to trick the beavers in a way that will make them not build their dam any higher. People call it the “beaver deceiver.” It is a pipe that runs through the dam and makes it so that the beavers cannot hear the water flowing through their dam. “How does this trick them?” you might ask. Well, the beaver deceiver is a pipe that goes through the beaver’s dam, sucks up all the water and jets it to the other side. This tricks the beavers into thinking that no water is leaking through the dam, thus stopping them from making it any higher or fixing any leaks.

I hope that beavers leave before anybody hurts them, and if they are not going to hurt them, I hope they stay. The beavers are special because they help citizens learn more about their city, help bring citizens together, and bring wildlife from afar to Martinez for citizens to get in touch with nature.

Now that’s a child we need on our side! Aside from his persuasive enthusiasm, he has the science just right. He’s obviously been watching, listening and learning a great deal. Thanks, Noa & Mom for agreeing to post your first-class essay on the website. I hope your teacher marched down to the dam site that very night. Any other Beaver-writers can always contact us at mtzbeavers@gmail.com for inclusion. Our beavers need all kinds of advocates.

Fur-Bearer Defenders is a non-profit society dedicated to the prevention of cruel trapping. They are located in Vancouver, Canada, and were involved in the Surrey Beaver situation. They have been around for several decades, worked on a couple continents and know all the excuses humans give for harming wildlife. We swaped stories and invited the program coordinator, Fannya Eden, to guest blog.

And Build: Signs of a Healthy Estuary

Today’s guest blogger is Lisa Owens-Viani from the San Francisco Estuary Project. I met Lisa when she contacted me for photos of our beaver family to include in the 2008 State of the Estuary Report. Since then I have been bothering her with questions, which she very kindly answers when she can, or sends them along to others who might know. Read her post in its entirety; she’s a science writer who really understands the relationships between healthy waterways and healthy habitats.

When the beavers first appeared on Alhambra Creek in late 2006, I thought it was a quirky anomaly, probably not a long-lived phenomenon, but hopeful and interesting. Yet almost two years later, they are still here, managing to survive amid humans, flood control, and politics—and even reproducing. I can’t help but wonder if the restoration projects the city, creek advocates, and flood control folks have engaged in over the past decade at the mouth of the creek as well as upstream weren’t part of the enticement for the beavers, particularly the delicious willows planted as part of biotechnical bank stabilization efforts. Now that the paddling, diving, yellow-toothed critters are here—and seem to be content and thriving—we face a challenge: to see whether, even in an urbanized landscape, we can restore these ecosystems for the creatures that once lived in them, and co-exist despite challenges. The high level of public interest in the beavers is certainly a vote for peaceful coexistence, and regulatory and flood control agencies are trying as well, with Martinez City staff helping beaver expert Skip Lisle install a pipe to lower the dam height in a way the beavers wouldn’t object to.

Geographically, the beavers have lodged themselves not only near the mouth of Alhambra Creek, but also mid-Estuary, in the Carquinez Strait “chute” that connects the Bay to the Delta. This area, where the fresher waters of the Delta meet the saltier, ocean-influenced waters from the Bay—the San Francisco Estuary—is the end point of a vast watershed: the Sacramento and San Joaquin Rivers, which flow into the Delta, drain approximately 40 percent of the state. The San Francisco Estuary Project, where I work, is one of 28 estuary projects throughout the United States that are part of the National Estuary Program. Mandated by Congress in 1987 to improve the quality of estuaries of national importance, these programs each establish a Comprehensive Conservation and Management Plan to meet the goals of Clean Water Act Section 320.

In 1993, the San Francisco Estuary Project completed its Comprehensive Conservation and Management Plan (CCMP). When the CCMP was signed in 1992, 44 signatories representing hundreds of stakeholders pledged to “achieve and maintain an ecologically diverse and productive natural estuarine system.” Like the 27 other national estuary projects, the San Francisco Estuary Project is a forum where region-wide issues are aired, a source of support for policy development and project work on a watershed/ecosystem basis, and a provider of up-to-date information on the San Francisco Bay Delta watershed and the many sub-watersheds that comprise it. Every other year the Estuary Project convenes a “State of the Estuary” conference at which scientists and policy makers present the latest information on the Estuary’s condition. The latest State of the Estuary report—“A Greener Shade of Blue”—can be downloaded at www.sfestuary.org under “Documents.”

The Estuary Project partners with environmental organizations and non-profits, local, state, and federal agencies, and businesses and industry from the 12 counties surrounding the Bay-Delta, and the public to implement the CCMP. Over the Estuary Project’s 20-year history, the Project and its partners have implemented many of the actions in the CCMP and fostered an environment out of which an array of new programs and partnerships have hatched and flourished. The Estuary Project provides funding and technical assistance to agencies, municipalities, and organizations to implement the recommended actions contained in the Management Plan. Each year Estuary Project staff, in partnership with the Implementation Committee, made up of representatives of the Project’s many partners, develop a work plan directing activities for that year. The Friends of the Estuary is the Project’s non-profit partner; Contra Costa Public Works Department’s Mitch Avalon and Friends of Alhambra Creek’s Igor Skaredoff are both active members of its board. The Friends are charged with helping develop public involvement, education, communication, and advocacy programs for the Estuary and serving as a watchdog for CCMP implementation.

Other Estuary Project partners include the state Coastal Conservancy and the Bay Area Open Space Council. In July, after conducting a public survey, the agencies chose the slogan “Nature Within Reach” for a new Bay Area license plate. The money from license plate purchases will go towards more open space preservation, trails, and wetland restoration. More wetland restoration in turn will hopefully mean more protection against climate change and sea level rise, and more habitat for more wildlife. “Nature Within Reach” won the survey, I think, because so many of us in urban areas value living near the Estuary and its wildness—with opportunities to see wildlife like the beavers close to home.

Alhambra Creek’s beavers may be a sign that the Alhambra Creek watershed is healthy enough to support creatures like this, at least in part due to the restoration work done by the city, Public Works Department, and Friends of Alhambra Creek. The Urban Creeks Council and others have spotted steelhead in the creek as well, another sign of health. The beavers and the steelhead show that restoration efforts can pay off: that one watershed can make a difference, and that we can restore the Estuary by restoring its watersheds, large or small. As Mitch Avalon puts it, “The local watersheds feed the Bay. It’s like a human body—if you’re eating poisoned food, your system isn’t going to be healthy. These watersheds provide rearing habitat for species that go down and live in the Bay—you’ve got to look at it as a whole system.” For more on the restoration work that has taken place on Alhambra Creek see http://sfep.abag.ca.gov/pdfs/newsletters/insert_june06.pdf.

Watch for an in-depth story on the beavers by well-known local natural history writer Joe Eaton in the October ESTUARY newsletter (download past issues at www.sfestuary.org). Every other month, ESTUARY presents the latest news on Bay-Delta water issues, restoration efforts, and the many programs, actions, voices, and viewpoints that contribute to implementing the CCMP. To receive the October issue as part of a free, three-month trial subscription of ESTUARY, contact Paula Trigueros at the Estuary Project ptrigueros@waterboards.ca.gov.

Guest Blogger: Lisa Owens Viani of the San Francisco Estuary Partnership.

As sea level rises, and the climate changes, how will the San Francisco Bay Estuary and its wetlands, watersheds, and wildlife—including the ever-so-clever, charismatic Martinez beavers—respond? Sea—and Bay and Delta—levels—are predicted to rise as much as four and a half feet by the year 2100. One way of responding to this threat is to make our watersheds more resilient, or better able to withstand change. To do that, we need less hardscape—concrete and pavement—and more green, as in trees, shrubs, reeds, and rushes.

We need to slow, spread, and sink our stormwater runoff (to quote my friend Brock Dolman, of the Occidental Arts and Ecology Center) instead of shooting it straight into the Estuary; by slowing, spreading, and sinking all of that water, we replenish groundwater, reduce flashy runoff and erosion, filter pollutants, and create more resilient, more flexible watersheds. We can daylight creeks (dig up and bring those in pipes back above ground), revegetate the ones in concrete channels, open up and restore creek mouths where they enter the Bay in pipes, restore more wetlands—nature’s “sponges” and buffers against sea level rise—and create many more “green stormwater” projects. Beavers, too, could play a big part in a more resilient landscape, helping to recharge groundwater, slow flashy flood flows and stream bank erosion, and restore habitat for our threatened salmonids.

On September 29-October 1, 2009, the Estuary Partnership will examine some of these questions—and many more issues affecting the Estuary—during its 9^th biennial State of the Estuary conference, entitled “Our Actions/Our Estuary.” In addition to keynote speakers from Stanford University, NOAA, and the Pacific Institute who will address climate change, other sessions at the conference will focus specifically on the status of the fish, birds, and other wildlife that use the Estuary, and the status of their habitat. On the second day, watershed restoration activities being promoted by cities surrounding the Bay will be highlighted. Featured cities include San Mateo, Emeryville, Hercules, and San Francisco. Guest speaker Tom Liptan, from Portland, will describe his city’s groundbreaking green stormwater projects, and the Ella Baker Center’s Jakada Imani will talk about how we can put people back to work again around the Bay through green jobs. Time Magazine’s Michael Grunwald gives the keynote address that day, sharing lessons learned in the Everglades.

On the third day, scientists and others will address new contaminants of concern in the Bay, how to retrofit our older urban and suburban landscapes in order to tackle water and air quality concerns, and how to deal with the trash epidemic in the Estuary and Pacific Ocean. We’ll learn about the latest efforts to restore subtidal (beneath the water) habitat in the Bay, and from a variety of environmental groups about how they are engaging local communities and students in their watersheds. Click here for the entire program or to register.

More From our Foreign Correspondent: Alex Hiller

Susanne Horne Max Planke Molecular Ecology

Criminal Intent on beaver fossils:

How can you be sure the injured beaver from the road shoulder is not a stranger in the night but legally belongs to its geographical habitat? - Just show a tissue sample to Susanne Horn at Max-Planck-Institute for Evolutionary Anthropology in Leipzig, Germany and get its DNA analyzed.

In her lecture she mentioned a DNA probe of an injured beaver recognizing it as member of the inherent Eurasian beaver species Castor fiber and not of the North American species Castor canadensis it was suspected to be according to the untypical color of its anal gland secretion. DNA research was done on the data basis taken from dozens of  tooth and bone samples of ancient beavers throughout Europe.

Beaver Populations can be distinguished even locally by the genetic  DNA sequences. Extensive hunt in the 19th century had led to the extirpation of beaver in most parts of Europe except for a few relict populations thus providing a bottleneck in the genetic diversity.

According to the Symposium`s student award winner of the 2nd price, Susanne Horn, “ancient DNA can provide information on the indigenous beavers of a certain area. These results reflecting the history of this species, can now be taken into account by maintenance projects, when planning the relocation of beavers.

Speaking of anal gland secretion (AGS) the 1st price of the student’s award was won by students from Telemark University College, Bo, Norway, on investigation “whether information about age and territory ownership (social status) is coded in the AGS of male Euroasian beavers” ( c.fiber ). Experimental scent mounts in a field study using a free ranging population in Telemark, Norway, as well as chemical analysis confirmed the preliminary suggestions:  The older son of a male intruder appeared to pose a greater threat to resident beavers than the younger son and the intruder itself, suggesting “that dominant beavers carry a `territory owner`badge making them perceived as less a threat than beavers without a territory. ( Helga Veronika Tinnesand, Susan Jojola, Frank Rosell )

Regarding beaver territory the participants of the Symposium were shown the findings at a prehistorical beaver site and its suggestions on the development of the beaver species:

Excavations at an ancient peat bog on utmost northern Canadian Ellesmere Island disclosed in its permafrost ground well preserved bones, sculls, claws and teeth of prehistorical beavers as well as hundreds of sizzled sticks with teeth marks at age of 3 to 5 millions of years ago  (in short = mya ) just before Ice Age. Natalia Rybczynski of Canadian Museum of Nature, Ottawa, who led the excavations, did research on the form follows function relationship regarding ( 1 ) swimming, ( 2 ) grooming claw and ( 3 ) woodcutting .

Rybcynski`s findings to ( 1 ) were, that the stream-line body , its modified webbed hind feet  and modified tail developed 23 mya with its tail as a “propulsive structure” while swimming for getting thrust. The specific form of a flattened tail developed only 5 to 10 mya whereas the ancient grooming claws ( 2 ) had presumably developed 30 to 35 mya and could be distinguished easily by their specific shape different from regular claws at hands and feet throughout millions of years. Woodcutting behavior ( 3 ) could be proved by investigations in National Zoo of Washington, DC: Video analysis of beaver teeth in action cutting wood gave evidence that beaver make use only of one incisor in adjacent position at one side of their jaws, that means beaver gnaw sidewards providing a mean cut width of 60 % of Incisor width. Exactly the same pattern was analyzed on the sizzled sticks of 3 to 5 mya from Ellesmere Island.  As a result wood-cutting behavior in beavers is presumed to have developed 23 mya. What still remains to be unsolved according to Rybczinski is the development of dam-building behavior of beavers.

Sticking to the teeth of beaver fossils, Dr. Clara Stefen, Curator of Mammals at Senckenberg Museum of Natural History , Dresden, Germany, presented her research on length to width ratios of upper and lower molars of beaver sculls to determine the evolutionary progress.

Best

Alex Hiller

Skip Lisle & Alex Hiller at 2009 Beaver Conference in Lithuania

Hi Heidi,

you are receiving the summary of the first lecture day - September 21, 2009, - at the 5th international Beaver Symposium. I had to solve unexpected difficulties in getting Internet access. Proudly wearing your “Worth a dam” T-Shirts Skip Lisle immediately recognized his adventures in Martinez , CA, when getting sight of me just after breakfast. Another participant from Denmark pointed at my T-Shirt telling me that he knows about it via Internet

Skip is well known to the citizens of Martinez, CA, for the construction of a “castor master” beaver dam flow device in Alhambra Creek one and a half year ago. His talk at the end of  the second lecture day was the most practical and instantly useful of the whole conference. If anybody wondered what could be done about flooding problems regarding co-existence with beavers, Skip would have the proper solution at hand.

From the presentation of Peter Busher: Darwin and the elephants

“Beavers, in a population sense, can be regarded as `mini elephants`, since they are also relatively large (for rodents), long lived and have few predators (other than humans) in most natural situations.”

Prof. Peter Busher from Boston University, Massachusetts, as chairman of the scientific committee referred to Charles Darwin who developed 250 years ago on the population dynamics of elephants his evolution theory. DarwinŽs famous book “The Origin of Species by Means of Natural Selection or the Preservation of Favored Races in the Struggle for Life”was published in 1859. Moreover in 2009 it is the bicentennial of Darwin (1809 - 2009 ).

According to Busher Darwin had developed an exponential growth equation, that given one elephant cow starts calving at the age of 30 for the consecutive 60 years until death meanwhile giving birth to a calf every three years  that reaches maturity itself following the same scheme we should expect 19 million elephants to live on earth within a surprisingly short period of time. In fact we know that such kind of equations cannot come true according to loss of habitat, hunting, disease, accident, wildfire, extended drought etc..

Busher insisted on long-term investigations “since any short-term study does not allow
a full understanding of the natural pattern of change in beaver populations: The general long-term pattern is one of slow initial growth, exponential growth (traditional “J” shaped curve ), decline and stabilization around a carrying capacity”.

For example the number of beaver sites in Voyagers National Park, Minnesota, increased from 50 to 360 between 1940 to 1985 whereas the number of beaver individuals throughout the entire state of Massachusetts increased from 22500 to 65000 within 8 years from 1994 to 2002 according to Busher. What was rich growth, what was poor
growth ?

Change in population size occurs regardless of the density, populations fluctuate over the time, finished Peter Busher his lecture that could be regarded as a proper measure for the numerous detailed presentations following on that topic.

Among the presentations were investigations on the reasons of population change, such as food competition among elk and beavers researched by Glynnis Hood, assistant professor at the University of Alberta, Canada:

Caused by overpopulation elk chewed down tree saplings knee high in Elk Island  Park Alberta, Canada.  On the contrary, according to Hood “beaver turn down a vertical forest into a horizontal” by felling trees in order to forage on leaves and twigs. It were the beavers smart enough to adapt their foraging behavior, given array of forage species, ”which potentially buffers the effects of competition between elk, deer and beaver.”

Other topics of the first lecturer day were beaver biology and paleontology at the International Beaver Symposium being performed from Sept. 20 - 23, 2009, in the little eastern European country of Lithuania sited between Baltic Sea and Russian border. Mild temperatures and sunshine made it easy and comfortable to stayand socialize .

On the red pine shaded conference center at a marvelous lakeside in Dubingiai north of Lithuanian capital Vilnius  99 beaver enthusiasts of almost scientific background from all over Europe were joined by 6 leading North American beaver specialists, among them Peter Busher and Skip Lisle.

More to come!

Best
Alex Hiller

Alex’s most difficult summary was the report from the last day of the conference where beaver density and trouble spots were discussed. He wrestled with this article with enormous care, and I think did an outstanding job. At one point he wondered if writing the names of professors who gave unpopular advice was a good idea, since the “internet is forever” and people might change their minds eventually. I was forced to admit that he is much, much kinder than I am, but assured him he could decide either way. (I have always considered the internet to be a snapshot in time, and if you were caught saying bad things about beavers in that snapshot you will just have to deal with the consequences!)

After some mulling, he decided to let his report stand. I offer it in it’s entirety with the only possible title:

The Good:

“Hot spots” were beaver sites called by Prof. Alius Ulevicius from the Faculty of Natural Sciences at Vilnius University, regarding the richness of nutrients and organic material as well as  the structural alterations to eco-systems: Beavers “create specific complex habitats” consisting of different environment elements “like beaver ponds, standing dead wood and debris, beaver dams, lodges, etc.” Its impact on the hilly moraine landscape depends on its location more than its size.

The alterations created by beaver sites in relation to the landscape of densely inhabited beaver territories does not exceed population fluctuations of 6 to 7 percent according to Prof. Alius Ulevicius. Thus to be said for Lithuania, that went through a boost in beaver population starting in the mid-forties of last century leading to an estimated beaver population of about  89 k to 121 k individuals “near to its carrying capacity” counting an average 7.8 beaver sites per 10 square kilometers.  (7.8 beaver sites per 3.86 sq.miles.) In comparison we learned that Minnesota, USA, has got an average of 10 beaver-sites per 10 sq.kilometers ( 3.86 US-sq.mi ) equaling about  2 and a half beaver sites per square-mile with alterations to the landscape in the surrounding territory of 13 percent.

Nevertheless you will find beaver sites in Lithuania not only at lake shores, river and stream banks but also on both sides of roads and highways, most likely lodges at open drains on surrounding meadows of slush green  surrounded by healthy stands of aspen, willow, maple oak as well as pine forests as we were shown on our guided tour to neighboring beaver sites within about 15 sq.kilometers around Dubingiai Conference Center on September 23, 2009, as the final day of the 5th International Beaver symposium.

Despite beaver density, do not expect a flooded countryside with dead wood all around: Lithuania appeared to be one of most beautiful countries throughout Europe in all shades of green with its healthy meadows and forests, numerous lakes and almost undisturbed nature. Have a look on the Lithuanian website ( www.maps.lt ) screening the entire country far better than google maps. “The maximum effect of beaver impact should be expected where beavers are able to alter the hydrological characteristics of water bodies such as small streams, drainage canals and small swamps.”

Indeed the beaver impact on open water drainage succeeds to 18 percent and accelerates at lakes and stream banks: Research on selected 555 segments of 500 meters ( 550 US-yards ) each alongside lakes and streams showed 82 to 100 percent of beaver impact:Beaver made canals collect surface water thus providing larger wetlands from its additional water supply.   The mean burrowing intensity was up to 30 burrows per kilometer ( 0.63 US-miles ) discharging  in average 30 cubic-meters ( 1 cubic-meter is 1000 liters, 1 cubic-foot is about 28 liters, equaling about 1071 cubic feet ) of soil subsurface ground into the canal-bed.

By this means beavers create huge underground infrastructure for a number of forestrial vertebrates  like otters and the invasive species of American mink that can frequently be found in Lithuania at beaver-sites  feeding and resting, moreover sheltering and breeding in beaver-made burrows and lodges.

The Bad:

The negative effect of inadvertent habitat creation for those semi-aquatic predators was later mentioned by Prof. Vladim Siodorowich from National Academy of Sciences of Belarus, Minsk, on his investigations about beavers as prey supply. Most obviously is beaver impact on the plant communities of beaver meadows with its relatively high species richness due to increased soil dampness, acidity and nutrition. From a conservationists point of view any alterations in a territory with its indigenous plant and animal communities are to be evaluated critically.

Prof Ulevicius called “man and beaver” the main disturbance factors on eco-systems questioning which concept of land use will be the most appropriate regarding beavers that create “highly productive patches that attract and involve higher trophic levels on landscape scale” at the one end of the scale and man “highly favoring the effective use and export of accumulated goods” on  the other end.

The Ugly:

Among the lecturers from Lithuania and other eastern European countries that focused only on disturbing impacts of beavers that were consolidated on their specific investigations was Prof. Romanus Lamsodas from Watermanagement Institute of Lithuanian University of Agriculture recommending “hydrologic regime” to be taken over beavers settling in open drains in localities relevant for concentrated agriculture .

Prof. Olgirda Belova from Lithuanian Forest Research Institute , Kaunas, demanded an  “eliminating norm of 15 to 20 percent” of the beaver population by hunting and trapping for the reason that the main six woody species of the beaver diet are important for biodiversity conservation and need to be protected against growing beaver population. “Appropriate structured harvesting” topped it all and was suggested by Göran Hartman from Norwegian Institute for Nature Research in numbers of 15 to 20 percent of the beaver population as a self-financing method that could provide a positive incentive for landowners and will effect the stabilization of the beaver population. At the same instance he suggested distinct care “as the species is vulnerable to overharvesting.”

Whew, more Good:

This all was said before Skip Lisle and Duncan Halley talked about non-lethal methods of beaver-management. By the way, licensed live-trapper Sherri Tippie from Denver, CO was shown setting Hancock live-traps in the slide show removing beavers from creek of  mid-town Aurora, CO , in the effort to relocate them to sheep ranchers in the Rocky Mountains for all the benefits beaver hot spot provide to animals and to landscape. Hopefully the well proved and cost effective methods of non-lethal beaver management will lead to awareness of viable alternatives to hydrologic regime, eliminating norms and structured harvesting in the mind of those “scientists on demand” as I would consider them according to their unacceptable conclusions, presumably under the pressure to value short-term financial savings higher than long-term ecological effects.

“The Americans are far ahead of us” was noted by one lecturer remarking on the positive effects of beaver-sites on areas experiencing drought from global warming.”Be prepared for the long game” according to an expert of the Scottish Beaver Trial.

Much Appreciated Guest Blogger: Alex Hiller

(Clint Eastwood comparisons entirely my own.)

Skip Lisle (left) & Alex Hiller (worth a dam t-shirt) at the 5th Annual Beaver Symposium