beavers and Amphibians

Beavers are the boyscouts of the animal kingdom. Why they’re practically helping old ladies across the street, and literally making new habitat for all. Now there’s some new research underlining the fact that they also play a very important role for amphibians.

Trends in Rocky Mountain amphibians and the role of beaver as a keystone species

Blake R. Hossacka, William R. Gouldb, Debra A. Patlac, Erin Muthsd, Rob Daleye, Kristin Legge, Paul Stephen Corna t

We used explicit dynamics models to estimate variation in annual occupancy, extinction, and colonization of wetlands according to summer drought and several biophysical characteristics (e.g., wetland size, elevation), including the influence of North American beaver (Castor canadensis). Although beaver were uncommon, their creation or modification of wetlands was associated with higher colonization rates for 4 of 5 amphibian species, producing a 34% increase in occupancy in beaver-influenced wetlands compared to wetlands without beaver influence. Also, colonization rates and occupancy of boreal toads (Anaxyrus boreas) and Columbia spotted frogs (Rana luteiventris) were ⩾2 times higher in beaver-influenced wetlands.

These strong relationships suggest management for beaver that fosters amphibian recovery could counter declines in some areasand demonstrate the close ecological association between beaver and wetland-dependent species.

The study discusses the grim fate of frogs in general, especially the drying species not lucky to live near a beaver dam. I’m pretty sure that if we cared as a nation about our frogs, (or our salmon) we’d protect beavers as the key player they are. Maybe even issue a frog-fine to folks who remove dams. We could use those monies to have a national scholarship for flow devices fund. Am I dreaming?

Another part of that big tree near the bank fell across the creek this week. turning our urban setting into a scene from the amazon. No piranhas but plenty of happy beavers making their way around the new food source. There were lots of visitors of the bipedal variety too last night, including a photographer from Bay Area News Group. Let’s hope beavers smile in the paper soon.

We counted at least four sampling the new tree, which wasn’t brought down by beaver, at least directly. Sometimes we saw several at once coming and going in every direction. No kits though, yet. Although I have to think they’re going to find this playpen pretty irresistible. The adults certainly did. Here’s nice glimpse of a beaver shaking himself as if to see if he’s dreaming at his crazy good fortune.

I think THIS windfall will take several days to finish, which means great photo ops for us in the meantime! In Napa last night Rusty was finally able to capture the two kits in a single shot, which confirms my earlier suspicion that one of the kits probably has the most adorable birth defect of all time. Either it will self correct or he’ll grow to be a very unique adult.

a tail study

And if you can’t spot the difference dramatically enough there’s always this guide. I think I’m going to call this image the “GREEN EYED SNAKE TAIL”.

Back in that other millennium, when I worked at day care, one of my favorite things to read in the afternoon on a swim day when 30 children flopped onto the floor for quiet time was “Frog and Toad are friends”. The series used very nice illustrations to tell great stories of ‘Frog’, (who was free-spirited and easily social), and the more inaccessible ‘Toad’, who was kind of asperger’s-y and harder to love. They were “friends” and had lots of adventures together, but with this article from the Oregonian we may need to tell a new story.

Study finds a steady decline in territory occupied by amphibians in the United States

Herpetologist Michael Adams was the lead author on a groundbreaking study that found a steady decline in the territory occupied by amphibians in the United States. The decline stretched across all regions, and into relatively unspoiled national parks and wildlife refuges.

Instead of focusing on individual populations, Adams and his colleagues analyzed “occupancy” – whether a spot is occupied by a particular amphibian or not. That’s a blunter gauge than individual population counts, but less variable, simpler and a clear way to track how fast creatures are disappearing from places where they’re known to live.

The researchers also developed a statistical model to account for false negatives — the chances that field workers missed a stray amphibian when declaring a spot unoccupied.

Their estimates “quantify amphibian declines to an extent that really hasn’t been possible,” says Michael Lannoo, a professor at Indiana University School of Medicine and the United States’ representative on IUCN’s Amphibian Specialist Group. Lannoo was among the peer reviewers of the study.“We’ve known about amphibian population declines for a long time, but the problem may be worse than we thought,” Adams says. “We need to be careful.”

The article is a nice look at complex ecoscience, with stunning photos that make you feel like you’re outdoors on a early summer day in the sierras and just found a private creek of your very own. Go check it out. Apparently the ozone layer isn’t killing as many amphibians at the moment but there may be lots of other things that are, like fungus and predators and habitat.