A couple of days ago, I was flipping some cow pads to see what kinds of dung beetle activity we have on the ranch. I found Aphodius fimetarius, which is a European dung beetle that was brought over to North America by the settlers presumably.
There are about 2000 species of Aphodius and 46 of them can be found in California. “However, the most common and conspicuous of these species are those accidentally introduced from Europe.” (Evans and Hogue, 2006)
Aphodius species are dwellers and therefore do not bury much dung underground. Aerating the dung reduces pathogens and prepares the pad for microbial breakdown. However, some of the nutrient cycling is lost through oxidation due to lack of burying. It would seem that while Aphodius provides some ecosystem services, other species might furnish greater advantages.
The ecosystem services that dung beetles provide are important for improving available forage, removing the cow pads, and breaking the pest cycle. Dung beetles can break down cow pads to assist in nutrient cycling over a wider area for improved soil structure leading to healthier pasture and increased soil organic carbon. Of particular importance to our climate, dung beetles break up the pad to provide faster decomposition by microbes and microarthoropods so that the pad is not suppressing growth underneath it. The enhanced decomposition also reduces the amount of rank herbage around the pads that cows don’t want to eat. Generally, cow pads can take up to 3 years to decompose when there is little moisture. These pads continue to oxidize in the sun losing valuable nutrients like nitrogen and carbon.
I’m going to keep digging through the dung. Maybe we’ll find some Canthon simplex (tumblebugs) or some other dung beetles working out in the pasture. That would be pretty cool.