The Little Things Beneath our Feet

kw: book reviews, nonfiction, biogeography

After circling the globe on Beagle, Darwin spent about twenty years fussily preparing a huge tome on his findings. Upon receiving a write-up of Wallace's independent work, he rushed into print with Origin of Species, an "outline" of the larger work he never completed. During that twenty year period, and for ten years thereafter, he studied earthworms. He once stated that all the soil of England passed through her earthworms about each decade.

In Under Ground: How Creatures of Mud and Dirt Shape Our World, Yvonne Baskin presents a glimpse into the world beneath our feet. The background cover photo is labeled in the credits "200 species of mites". I suppose they were extracted from one soil sample in Canada, based on the photo credit. Doesn't surprise me. I've read that there is at least one ant colony for each living human, and at least a ton of termites to each of us. I read that there are probably ten times as many nematodes as termites in the world. The author quotes Nathan Cobb's 1914 statement: "If all the matter in the universe except nematodes were swept away, our world would still be recognizable,...its mountains, hills, vales, rivers, lakes, and oceans represented by a film of nematodes." Now it appears that more than half of all animal species are nematodes...I'd thought that was beetles! But every beetle species has at least two parasitic nematodes...

It wasn't what I expected when I began. I was hoping for a natural-historic survey of the field. That is accomplished, very briskly, in one chapter. Case histories of a number of locales make up the rest, and the focus is on what happens to the subsoil critters when people do something to it. In other words, this is an ecological manifesto. The warning is clear, if unwelcome: There are already a number of clear examples for which a large area of soil has been changed beyond recovery, even "managed recovery." Formerly forested places where trees cannot be induced to grow, for example. It is found that the subsurface fungi and microbes that could support trees have been replaced by an ecology that can't. Just one example.

A thought-provoking book. Personally, I like getting a pinch of some stuff, whether yard dirt, pond mud, or birdbath scum, and looking at it under a microscope to see what's there. Now, when I peer at tiny worms, mites, rotifers, and fungi, I'll recall that what we do to our yards can effect huge changes in which of these will flourish, which die away, and what new creatures may replace them.