Creepy Crawlers Crucial to Grasslands

It turns out that creepy crawlers such as earthworms and beetles are crucial to the structure of grasslands, proving that things underground are just as important as those aboveground.

According to a new study, these tiny creatures help in the productivity of grasslands and how they respond to agricultural management, such as fertilization. Without them, plant species that grow in the ecosystem are altered and over plant productivity drops.

"We know these soil animals are important controls on processes which cause nutrients and carbon to cycle in ecosystems, but there was little evidence that human-induced loss of these animals has effects at the level of the whole ecosystem, on services such as agricultural yield," lead author Mark Bradford, an Associate Professor at the Yale School of Forestry & Environmental Studies, said in a statement.

"Yet that's exactly what we found."

Over the course of three years, Bradford and his colleagues simulated 16, climate-controlled Scottish sheep meadows. Each of the models included the 10 most common plant species, but the researchers introduced earthworms, slugs, and other small creatures to only some of the systems.

At first, it didn't seem like these below ground animals were making much of a difference.

"But when we ran it out through 500 days we did actually find huge changes in the ecosystem processes, including productivity of the plants," Bradford explained.

Interestingly, introducing these slugs, beetles and such improved the quality of grass yields, meaning the plants had good concentrations of proteins.

"In this case, the loss of soil animal diversity eventually changed the dominant plant species in the meadow ecosystems, and then in turn the productivity of these grasslands and how they responded to agricultural management," Bradford said. "When you next look out at a meadow or forest, remember that the tiny animals immediately beneath your feet are likely responsible for much of what you see."

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