Tag: Brandon Keim

THE MUSKRAT SHORTAGE

heidi08 Beavers April 24, 2024

I found this article to be a lovely and elegiac read. Also really informative. I was concentrating on our beavers, I never thought much about the little guys, except for cases of mistaken identity.

The Waning Reign of the Wetland Architect We Barely Know (Hint: Not a Beaver)

[Muskrats] are prolific breeders, raising a dozen or more young per year in times of plenty, as happy and quick to set up house along a drainage ditch as in a wetland sanctuary. Even as other so-called furbearers were trapped to near-oblivion in the 19th and early 20th centuries, muskrats flourished, and they persisted through the thoughtless times before the adoption of federal clean water laws and the advent of environmental agencies in the United States and Canada. They’re the sort of species for whom the International Union for Conservation of Nature’s formal designation of “least concern” has seemed quite appropriate. Impervious would be another term.

Yet, reports of declines continued to gather from throughout their native range, which runs from the Arctic Circle to the US–Mexico border. In 2017, biologists Adam Ahlers of Kansas State University and Edward Heske at the University of Illinois Urbana-Champaign published the most comprehensive analysis to date, confirming that the patterns did not seem to be a function of trapping statistics. Something else was going on—and whatever it was, it was big. Since the early 1970s, muskrat populations appeared to have fallen by at least one-half in 34 US states. In a handful of states, the collapse was near-total, coming in between 90 and 99 percent.

I just check my files and I last filmed a muskrat at the secondary dam in 2014. Around 2011 the phragmites taking over. Did they run out of food?

Another possibility is that muskrat habitats are changing in fundamental ways. Not only have many wetlands been lost to or degraded by human activity, but those that remain may be isolated, making it difficult for muskrats to travel between them and establish new homes. The importance of dispersal, as such movements are technically known, is neatly illustrated by research from northern Alberta’s vast Peace-Athabasca Delta, where the density of muskrat houses—the rodents often build mud-and-grass huts, counts of which are used as population proxies—has plummeted by 90 percent since the early 1970s.

I’m pretty sure our muskrats were bank dwellers, I never saw a single grass hut. But I had beavers on the brain.

Researchers also found that hydrological changes did more than reduce the availability of habitat. They altered the dynamics of life in the delta. Muskrats there could be understood not as a single population but as a network of subpopulations who, in isolation, are prone to extirpation during dry periods and as vegetation shifts. Historically, those subpopulations were replenished by new muskrats arriving from elsewhere in the delta via routes created by flooding; but as the floodplain shriveled, so did the network. The now-isolated subpopulations would vanish, one by one, without being renewed—something that might be happening in the wider world, wrote the researchers, not just in the Peace-Athabasca Delta.

The article talks about muskrats moving nutrients on a small scale. In very still ponds they might be the only thing that does.

A long-legged spider perches beside the scat, perhaps attracted by inAAsects who themselves are attracted to its concentration of nutrients. By such increments ecosystems cohere and flourish, and the tableau makes for a small demonstration of a role played by muskrats: they cycle and transport nutrients. That’s not so important on a river like the Blackstone, says Crockett, where nutrients are moved by large-bodied fish—not to mention sewage treatment plants, of which there is one upriver in Woonsocket and another at the Blackstone’s headwaters in Worcester, Massachusetts—but in a wetland where waters are still, he says, muskrats are much more significant.

In a little while, we enter just such a place, a long, shallow basin adjacent to the river’s main stem where the water is still and profuse with emergent vegetation: pickerelweed, arrowhead, reeds, and pond lilies, rimmed by stands of cattails. “In some of these wetlands, what happens within that one little pocket is all that’s ever going to happen,” says Crockett. “If there is or isn’t an herbivore will make a big difference.”

In these places, grazing by muskrats takes up nutrients locked in plants and spreads them around. And not just from plants: when muskrats eat mussels, which they gather and eat in favored dining spots, day after day, they create mounds of discarded shells that are fountains of calcium on the landscape. Their grazing also helps prevent vegetation from becoming so dense that over time it builds up, forms soil, and turns the wetland into land. The scientific name for what muskrats help produce is hemi-marsh: about half vegetation and half open water, a configuration that has coevolved with a menagerie of wetland species.

Ducks use that open water. Light penetrates it, nourishing plankton and in turn small fish and aquatic invertebrates and a different set of subaquatic vegetation, not unlike sunbeams in a forest clearing. Laurence Smith describes how, when muskrats build houses in cattail marshes, they clear a circle some five or six meters across, and then when they depart, the vegetation regrows. The result is a patchwork of variation across time as well as space. “It’s a form of disturbance,” says Smith. “Disturbance is good. Disturbance provides diversity of ages and decomposition on the landscape.”

It’s funny. but I cant be sure of what (if any) changes muskrats made in Martinez. I know what the beavers did, but maybe they did some too.

In his review of muskrat ecosystem impacts, Ahlers describes how these disturbances produce dramatic increases in plant species richness. One study suggested that muskrats were primarily responsible for an increase of more than 70 percent in the variety of plants found in the disturbed areas of a cattail marsh; by grazing on abundant plants that would otherwise become dominant, muskrats also create space for rare plants to grow. Meanwhile, their houses—a meter or more from the water and up to two meters wide, lasting for a year or two before gradually degrading—become habitat features themselves. “Birds are probably the most conspicuous beneficiaries of the muskrat’s influence on wetlands,” writes Ahlers, including the ducks, terns, grebes, and other wetland avians who use muskrat houses as nesting sites. Turtles, water snakes, and frogs also dwell in them, and even skunks and shrews—more than 60 vertebrate species altogether, by one count.

These animals also avail themselves of the reed feeding platforms that muskrats construct. So do beetles and other invertebrates, and in turn their predators benefit. As the platforms decompose, they even increase local microbial diversity. And where muskrats dig dens in banks along the water’s edge rather than build houses, their burrowing aerates riparian soils, and those subterranean chambers become habitat for reptiles and amphibians. “When you remove them,” says Smith of muskrats, “the ecology of the wetland changes.”

I have a tendency to be a little affronted by the credit folks want to give to muskrats. But I guess they do make lots of little differences.

“A loss of muskrats comes with significant costs, many of which we might already be experiencing,” wrote biologists with Ontario’s ministry of natural resources after documenting muskrat house count declines of more than 90 percent in Point Pelee National Park. “A scarcity of muskrats should be considered a red flag for the state of biodiversity in our wetlands.”

I never about them eating freshwater mussels. But given the amount we saw in Martinez this did not surprise me.

One pattern to emerge from his data and elsewhere is that muskrats have fared just as well in urban as in wilder places. When Smith tested his muskrat DNA detection system, the best locations he found were in cattail-rich wetlands in the city of Providence, one of them downstream from a Superfund site. The Blackstone River was, until not long ago, intensely polluted; an original artery of the Industrial Revolution, its modern contours have been shaped by several centuries of intense human activity. Behind the channel where we saw our muskrat was an old sewage treatment plant. The morning’s songbird chorus made itself heard over the din of a nearby quarry and traffic passing overhead on a bridge of Interstate 99, the Woonsocket Industrial Highway.

Well if more cities coexist with beavers it will help the muskrats too, right? Go read the entire article, it’s very well written. The lovely illustrations are by Sarah Gilman who is the same woman that did the awesome illustration for Ben Goldfarb’s Eager book.

Makes sense.

A CHILD LIFE WITH WILDLIFE

heidi08 Urban beavers September 19, 2019

Two steps forward, one step back. That’s how it is in the

beaver world. This morning there was a report from the Cook Inlet Agricultural Association in Alaska about notching beaver dams to help salmon. (!!!) but there’s also a Great Swamp festival in New York announcing ‘The Year of the beaver!” so I guess we should call it a wash,

And then there’s this, which will give us lots to talk about.

The surprising ways that city and country kids think about wildlife

“Little research has been conducted on children’s attitudes toward wildlife, particularly across zones of urbanization,” write researchers led by Stephanie Schuttler, a biologist at the North Carolina State Museum of Natural Sciences, in the journal PeerJ. Their study found that “children across all levels of urbanization viewed wildlife in similar ways”—for better or worse.

Oh you can tell RIGHT away I’m going to just love this article. Another sad screed about how are young people are more familiar with their phones than they are with their local creek. Cue last child in the Wilderness right away,

The researchers asked 2,759 4th-through-8th grade North Carolina schoolchildren about the animals they liked most and those they found scary, and to rank their five favorite mammals from a list of 20 local and exotic species. Slightly more than half the students lived in suburban areas, while the rest were exurban or rural dwellers.

Dogs and cats proved to be the most-popular creatures. They were followed by pandas, rabbits, wolves, monkeys, and lions—all of them, with the exception of rabbits, exotics who would only be encountered on screen or in captivity. Local species registered in mostly negative ways; kids were three times more likely to find local animals—skunks and bobcats, coyotes and bats—frightening than to like. The students were also creeped out by invertebrates, reptiles, and fish..

Of course everyone on facebook gasped at this, and bemoaned the sad state of our children and wildlife. But as a woman who has thrown 12 beaver festivals, been a day care teacher for 10 years and a child psychologist for thirty I have my own response.

Let’s start with that methods section. Kids between 8 and 14 are on different planets. Why use the same measure for each and assume it means the same thing? Why on earth would you approach children with a list of these species when you could just as easily hand them a stack of cards with photos of them and ask them to arrange them from most to least liked? Or show them a table of stuffed animals and watch which one they picked up first? Why did you decide that liking something is the same thing as being familiar with it or understanding it anyway? I may know all about my baby brother but it doesn’t mean I’m going to say I like him.

Then let’s talk about language. Are frightening things and creepy things REALLY the kind of things children avoid? I mean we all know how much children hate halloween, gummy worms and never ever tell scary stories at slumber parties, right? Sheesh, I wrote this on facebook but I’m just going to quote it again,

True story. Me and my best friend Yvette hated and were terrified of bugs, especially especially earwigs. On playdates we would spend hours turning over the rocks in my dads garden, until we found something truly horrible. Then we would scream – run into the house, slam the door, run down the hall to my room, push the door tight, throw ourselves on the bed, close our eyes shuddering…and then say breathlessly, “wanna do it again?”

You didn’t terrify yourself at slumber parties with bloody mary stories as a child because you hated religion or infanticide. You did it because being scared was an exciting feeling. Like turning in circles all those times and laying down looking up at the ceiling was an exciting feeling.

And if you want to know how kids feel about wildlife you are going to have to use a different ruler to measure them by. Something that understands being afraid of something or creeped out means you’re paying A LOT of attention to it.

Contrary to the researchers’ expectations, these patterns held fairly constant regardless of where kids lived. Though rural students, particularly those who hunted, were slightly more likely to appreciate local species, the difference was not great. “The presumed higher levels of familiarity children in more rural areas have with local wildlife is limited,” write the researchers. “Our results imply that it may not be urbanization alone that is driving the Extinction of Experience, as the disconnect with wildlife among children spans across areas of urbanization.”

Sure it could mean that all children are having an extinction of experience of wildlife at exactly the same time. OR it could mean that your methods are WRONG and the non results are telling you that you need to rethink what you’re doing. You’ve created a measure that doesn’t differentiate between two pretty different groups. Test construction theory might suggest you need to design another measure.

Other measures of asking children about their interest in wildlife? Let’s brainstorm. It depends a lot on the age group and you might have to use different methods for 4th graders than you would for 8th graders. To an older child you might ask “If some one were writing a story where the animal was the hero, which one should they chose? Think of your best friend, which of these animals would you say ne or she is most like? If you could ask one animal any a question and magically understand the answer which would you choose? How about if a magician could change you into one if these for a day, which would you pick? How questions that get to empathy too? What does this animal need?

You can see we’d have hours of fun redesigning this test. I know I feel better already.

“People tend to care about and invest in what they know. Children represent the future supporters of conservation,” they write. “ Intentionally providing children experiences in nature may be one of the most important actions conservation biologists can take.”

Finally. Something we can all agree on.

BEAVERS ARE THE WAY FORWARD

heidi08 Beavers and Nitrogen removal June 5, 2018

Jon and I spent all day joking about the nasty “invasive mergansers” – sometimes very unpleasant things stay with you for a while. Luckily for us, this morning provides an antidote. Written by Brandon Keim in the glossy magazine “Anthropocene”. Don’t you wonder what the stats would say about our single family of beavers?

The tremendous benefits provided by just one beaver family

People already know that beavers are keystone species whose activities shape landscapes in broadly beneficial ways. If such descriptions sound a bit abstract, though, consider the observations of scientists who followed the activities of a single beaver pair living in the British countryside.

In a study published in the journal Earth Surface Processes and Landforms, researchers led by hydrologist Richard Brazier of the University of Exeter describe their measurements of sediment composition and water quality in ponds built by the beavers, who were released in 2011 as part of a species reintroduction effort. Beavers were extirpated from the British Isles about 400 years ago.

The beavers’ enclosure, roughly the size of three (American) football fields and situated on a stream below a farm, originally contained one small pond. Since their arrival the beavers have built 12 more ponds. Their enclosure is now a wetland mosaic regulated by dams and canals, and the ponds are slowly filling with sediment — 101 tons of it to date, estimate Brazier’s team.

Remind me to send Dr. Brazier a thank you note. His careful research has produced such helpful results that actually benefit from the extirpation of beaver for 400 years. Come to think of it, maybe I should send a thank you note to the entire United Kingdom, since there “should we or shouldn’t we” drama has helped move the beaver conversation forward in so many ways.

Some of that sediment was generated by the beavers’ own digging. The vast majority, though, is eroded soil from the adjacent farmland. Altogether the sediments contain 16 tons of carbon — representing, were every last ounce of it sequestered permanently, the average yearly carbon emissions of six British citizens.

Carbon aside, the beavers’ wetlands also filtered out one ton of nitrogen, which becomes a pollutant when released at high concentrations into riversheds, and prevented that eroded soil from becoming lost. A 2009 report estimated that agricultural soil erosion in the United Kingdom annually costs £45 million — $60 million in U.S. dollars — in damage. Beavers might offset that, suggest Brazier and colleagues, adding yet another line to the flood-controlling, biodiversity-promoting, recreation-enhancing ledger of their services.

Given the accomplishments of just one pair observed by Brazier’s team, the landscape-scale possibilities are enormous. Beavers can “deliver significant geomorphic modifications and result in changes to nutrient and sediment fluxes,” write the researchers, “limiting negative downstream impact” of agricultural pollution. To put it another way: beavers could help clean up our messes. The same applies to the rest of Eurasia, where beavers were eradicated from much of their historical range, and also North America, where their populations are now perhaps one-tenth of pre-colonial levels.

Nice work Brandan! That’s one fine summary of some very delicious research. What a great way to start the day off right. Not only can beavers fix what ails us, they can do so cheaply and efficiently on a massive scale. You would think everyone would be fighting over who gets them first, like the last Elmo doll at a Christmas sale.

Now if you haven’t already, and you live in California, go vote! Be careful of that jungle primary too.