Mark Hodson

And B, the soil can't hold water either.

So it's going to be another nail in the coffin of plant growth.

What's more, because the water can't get through the soil, it's not going to be filtered.

So as water percolates through soil, it's often filtered and some chemicals get removed.

It helps clean the water up.

And there's a sort of multiple whammy.

Soil erosion is probably going to get worse as well.

So soil grows at about the speed that your fingernails grow.

it can erode up to 10 times more quickly than that.

And earthworms help reduce soil erosion because earthworms mean you've got more roots, that holds the soil together.

So we're losing soil as well.

We need soil to grow plants, to feed ourselves.

In a sense, we've done this experiment in reverse.

After the last glaciation ice age in America about 10 or 20,000 years ago, all the soil was scraped off.

So North America doesn't have a significant native earthworm population.

But there are lots of European earthworms, and they came over with the colonizers or invaders.

The earthworms can consume like 10 centimeters depth of leaves in a year.

So that thickness of leaves is essentially gone.

That changes the plants which can germinate.

You get fewer plants germinating and growing and fewer plants for the deer to eat.