Hmm. Phys.org might just have offered us an important clue about our beaver deaths. Not surprisingly the research comes from the University of Utah. Thanks BK for the lead!
Poison warmed over: Climate change may hurt animals’ ability to live on toxic plants
University of Utah lab experiments found that when temperatures get warmer, woodrats suffer a reduced ability to live on their normal diet of toxic creosote – suggesting that global warming may hurt plant-eating animals.
“This study adds to our understanding of how climate change may affect mammals, in that their ability to consume dietary toxins is impaired by warmer temperatures,” says biologist Denise Dearing, senior author of the research published online Jan. 13 in the British journal Proceedings of the Royal Society B.
“This phenomenon will result in animals changing their diets and reducing the amount of plant material they eat, relocating to cooler habitats or going extinct in local areas,” says Dearing, a distinguished professor and chair of biology at the university.
The new study’s first author, biology doctoral student Patrice Kurnath, says: “We found that desert woodrats have a harder time eating their natural diet at slightly warmer temperatures. In terms of climate changes, this study suggests that plant-eating animals all over the world may have problems dealing with their preferred food sources.”
While not all animal diets are as toxic as those of woodrats and other rodents that eat plants like creosote bushes or juniper, most mammals eat some toxins in their diet. In an ongoing evolutionary battle, plants evolve chemical defenses against being eaten and animals evolve liver enzymes or other ways to overcome or avoid plant toxins.
Dearing notes that “over 40 percent of all existing mammals eat only plants” and many more eat some plants. “Most plants produce toxins, so the majority of plant-eating mammals eat toxic compounds, and this may become more difficult to deal with as the climate warms,” she adds. Birds also might be affected, she says.
Now just sit back in your chair and think about that for a moment. Most plants contain toxins that animals have adapted to be able to digest.In normal conditions their complex systems can take out the nutrients they need and get rid of the bad stuff. And it looks like higher temperatures make that harder for them to do.
Think about the bad stuff that might be in willow (that produces the compound for aspirin) or in cottonwood (that has been studied to release chemicals to discourage insect browsing) or in Coyote Bush, which has such an acrid small that sap on pets and horses that it has been known to cause skin rashes. Think about what beavers take on every day – and not just in Martinez. And the leaves they eat are so poor in nutrients that they have to eat A LOT of them.
You know this summer in the Bay Area was record breaking hot. I’m trying to find the stats for how hot – but the reports out of the National Climate Data center say that the closes reporting station said that in June, July and August we endured 63 days over 90 degrees and in Martinez, which is usually cooled by breezes off the strait we had 34 days at or over 90. When it comes down to it, beavers are probably more affected by water temperature than air temperature, but obviously they’re related.
We aren’t the only ones who had mysterious die-offs. Think about that sick kit at Mountain View Sanitation, or the unexplained deaths of beaver in Oregon and Washington this summer. What if climate change is partly responsible for their deaths? I truly hope that’s not the case, because it’s not going to get better any time soon.
But beavers are pretty adaptable. If they can deal with nuclear fallout at Chernobyl, they can probably find a way to manage more toxins in their diet. Hmm I’m going to be thinking about this for quite a while I can see.
