Salamanders and Climate Change

I think it’s safe to say we all got a good chuckle when researchers reported that flatulent cattle were a problem in terms of climate change.

The image of gassy cows stuck in everybody’s mind, even though the smelly number is real (the livestock industry emits about 14.5% of human-associated greenhouse gases).

But now it’s time to turn our climate change spotlight from large cows to tiny salamanders. That’s because it turns out that salamanders also play a role in the global carbon cycle — but in a good way.

According to a study in the journal Ecosphere, salamanders eat mostly what are called “shredding invertebrates.” Those are bugs that spend their time ripping up and eating the leaves that have fallen to the ground. Leaf litter from deciduous trees is about 47.5% carbon. And that carbon is released into the atmosphere, along with methane, when the little bugs shred and eat them.

However, if there are plenty of salamanders around to eat the bugs, it stands to reason the leaves will remain in place, uneaten, and other leaves will cover those leaves. The anaerobic environment under those layers of leaves preserves the carbon until it can be captured by the soil. It’s a process called humification.

The researchers tested their theory in a forest in northwestern California. In a series of 16 square foot enclosures, invertebrates were free to roam. Salamanders were limited to only a few areas.

Dr. Hartwell Welsh, a herpetologist with the United States Forest Service, reports that areas with no salamanders had a significant increase in shredding insects. Conversely, the presence of salamanders created a significant decrease in shredders.

All told, the researchers calculated the salamanders eating the shredders helped to send 179 pounds of carbon per acre of forest into the soil instead of into the air. If you extrapolate those numbers to include all of the deciduous tree forests around the world, it’s enough to affect global climate.

The study raises plenty of questions of course, but it also makes you think about how even the tiny creatures have a big role to play.

— Frank Graff

Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!

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