The falling autumn leaves are drifting by my window now, fluttering to the floor of the beautiful woods behind my home in Decatur.
When they land, they become part of the leaf litter, the layer of leaves, twigs and other castoff matter from trees, shrubs and other plants that covers the ground.
In woods and forests, the leaf litter is essential to ecological health. It provides nesting material for birds and squirrels, hiding places for small turtles and salamanders and protected spots for seeds. Numerous songbirds forage in the leaf litter.
Within the layer of leaves, nature’s recycling is a marvel of efficiency. Countless tiny creatures known as detritivores — beetles, woodlice, millipedes, centipedes, slugs, maggots, earthworms and others — shred and break up the fallen leaves into tiny pieces for food and other purposes.
Then, mind-boggling numbers of fungi, bacteria and other microbes living in the soil (a teaspoon of topsoil may harbor tens of millions of them) take over. Using enzymes, they reduce the remaining bits of plant matter to basic nutrients and molecules, such as ammonium, phosphate and calcium. The substances will enrich the soil and nourish trees, wildflowers and other plants for next spring’s growth.
The leaf litter is also crucial for next year’s new generations of numerous moth and butterfly species. It is where the insects’ larvae overwinter and pupate in cocoons and chrysalises. For instance, in autumn, the caterpillar of the Eastern tiger swallowtail, Georgia’s state butterfly, forms a brown chrysalis that blends in with the leaf litter. The dead leaves hide the chrysalis and insulate it from cold temperatures. From the chrysalis a butterfly will emerge in spring.
Fallen leaves also can benefit our yards in the same way they help forests — if we can resist raking them up or blasting them away with noisy leaf blowers.
IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The North Taurid meteor shower peaks at 15 meteors per hour this weekend — in the east after dark. Last weekend was the peak of the South Taurid meteor shower.
The moon will be new on Monday. Mercury is low in the west just after sunset. Venus rises in the east a few hours before sunrise. Jupiter rises in the east at sunset. Saturn is in the south just after dark. Mars is not easily seen now.
Charles Seabrook can be reached at charles.seabrook@yahoo.com.
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