Rules of Thumb, 30x30, and the Laws of Nature

Spring Landscape (Rain), A. Krehbiel My mother had a commonplace book in which she recorded, by hand, in beautiful cursive, proverbs, sayings, and quotes that struck her as interesting, thought provoking, or wise. I also love sayings, and quotes, and mantras, but mostly I’ve collected rules of thumb, those short pithy statements that condense ways of dealing with life on earth in the same way that proverbs give advice on how to behave in prudent, trouble-avoiding ways.  Rules of thumb exist for every field of human endeavor. There are the general ones, such as the 80% rule, or Pareto Principle, that gets applied in sometimes surprising ways—"eighty percent of every thing is trash,” someone will say, or another will say that “80% of your output comes from 20% of your efforts,” for example. The 80/20 ratio is useful in all sorts of contexts. For example, in a perennial garden, the general rule (backed up by scientific evidence) is that about 75-80% of the plants should be native (lo

Leave the Leaves, Turn Out the Lights

Most people are aware of the global biodiversity crisis, the shocking declines of insects, birds, and other animals, yet many don’t connect it with life in our comfortable suburbs. Because everything is connected, what we do at home is more important than you might think. Anyone with a house and yard can take two actions that will immediately increase biodiversity by helping the creatures that share our neighborhoods: leave the leaves and turn out the lights. 

I’ve never understood why sensible people would remove autumn leaves from under their trees and bushes, only to then pay good money to add mulch and fertilizer. Fallen leaves are nature’s combination fertilizer and mulch, full of exactly the nutrients trees and shrubs need. And regarding “messiness,” nobody walks through the forest preserves in autumn wishing someone would clear out all those darn fallen leaves.

Those leaves are what make the outdoors comfortable for many animals, providing shelter, food, and habitat. Fireflies don’t go away with the summer. Their larvae spend late summer through spring among fallen leaves, hunting pest insects and waiting to emerge next year as flashing adults. Similarly, many species of butterfly and moth overwinter there, sometimes literally rolled up in a leaf. And in spring if you’ve ever watched a robin or cardinal rummaging among last year’s leaves, you’ve seen how our backyard birds need that habitat, too. It’s where they hunt the insects that both give them energy and help feed their voracious chicks.

Your yard can be naturally beautiful and biodiverse by just letting the leaves stay where they fall. Those on your grass can be raked back under bushes or into flowerbeds. And don’t forget to give instructions to your landscapers, too. 

Then for the lights. Night-time light is a boon to human civilization, but we can choose darkness when it’s bedtime. Our circadian rhythms, and our physical and mental health, depend on this. Animals also need a clear distinction between day and night. Lit-up yards, with always-on security lights or party lights strung over the deck, disrupt animals’ lives in a variety of ways. In spring and fall, migrating songbirds that depend on the stars for navigation, get confused not only by the lights in tall buildings, but across residential areas as well. Plus, resident birds—and their chicks—need to sleep at night, just as we do. Or consider the poor fireflies, just trying to mate and reproduce during their short adult lives. One reason they’re in decline is that outdoor lighting overwhelms the light pulses they use to attract mates. 

Taking these easy steps will immediately help backyard biodiversity recover: Turn out the lights, backyard and front, when you go in for the night; set a timer for the holiday lights to go off at 10 pm; evaluate how many security lights you actually need and put those on motion sensors. If even a few folks reading this made these changes, biodiversity on their block would surge. If everyone did, we’d be amazed at how many more birds, butterflies, and fireflies would grace our neighborhoods. 

This piece was originally published on October 26, 2021 in the Oak Park Wednesday Journal