The Loss of Massive Mammals Means We Lose Their Poop and Their Nutrients

When we lose large animals to extinction, we may be disrupting the entire globe's nutrient cycle. Scientists have found that the loss of whales and oversized land mammals may cause our planet to be less fertile.

Before now, animals weren't thought to play an important role in nutrient movement. However, it seems as if that's not the case. On land, for example, large animals carry nutrients away from concentrated "hotspots." Animals act as a crucial "distribution pump," transporting masses of fecal matter to fertilize many places that would otherwise we less productive.

Before humans hunted large animals to extinction, there were elephant-like gompotheres the size of a backhoe, deer with twelve-foot-wide antlers, and bison herds to the horizon. All of these animals played a crucial role in accelerating the release of nutrients through digestion and carrying these nutrients away from feeding areas to higher ground through their deposit of feces, urine and decomposing bodies.

Now, researchers have found that this animal-powered, planetary pump may have dropped to just six percent of its former capacity to spread nutrients away from concentrated sources on both land and sea.

For example, whale densities are estimated to have declined by between 66 percent and 90 percent over the last three centuries due to commercial hunting. In fact, an estimated 350,000 blue whales are estimated to have once inhabited the oceans around the globe. Now, only a few thousand remain.

With that said, this doesn't mean the time of large mammals has ceased. Populations are already recovering.

"But recover is possible and important," said Joe Roman, one of the researchers, in a news release. "That's achievable. It might be a challenge policy-wise, but it's certainly within our power to bring back herds of bison to North America. That's one way we could restore an essential nutrient pathway."

The findings are published in the journal Proceedings of the National Academy of Sciences.

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