JACKSON, Wyo. — The end of October means leaves are piling up, but forgoing yard work could help support the Greater Yellowstone Ecosystem (GYE) and a number of species who rely on leaf litter for food, habitat and nesting material, in addition to the planet overall.
While Teton County provides eco-friendly ways to dispose of leaf litter, with free compostable yard waste bags available at select locations around town and a free residential waste drop-off day, the U.S. Fish and Wildlife Service (USFWS) recommends that people consider not de-leafing lawns for autumn.
According to the USFWS, this is an effort to better support wildlife who utilize the natural floor coverage, which the USFWS notes includes cardinals, chipmunks and spotted salamander.
The National Wildlife Federation (NWF) has been echoing this sentiment for years, emphasizing that additional species like toads, songbirds, mammals and invertebrates need leaves on the ground for diet and shelter.
Notably, moth and butterfly caterpillars overwinter in fallen leaves before their winged spring emergence. Lizards, birds, turtles, frogs and other insects also use fallen leaves as overwinter habitat, and the U.S. Department of Agriculture (USDA) says preserving that space for them will help keep pest numbers down around homes and increase pollination in gardens.
A 2023 peer-reviewed study suggests that leaf litter actually strengthens ecosystem biodiversity in not one but four ways: by releasing nitrogen over time through decomposition to support existing plants, by enhancing overall soil fertility, by changing soil community composition and by reducing the impact of residue-borne pathogens and pests. According to the research, the four litter-mediated mechanisms can operate simultaneously and increase the positive effects of each.
“Although leaf litter can look deceivingly stagnant, a microscopic world of activity teems beneath the foliage.”
National Geographic
“Although leaf litter can look deceivingly stagnant, a microscopic world of activity teems beneath the foliage,” National Geographic confirms.
In Wyoming, Wyoming Public Media recommends homeowners shred leaves with a mower and spread them in a thin layer, thin enough to still allow grass to photosynthesize, across a lawn to give the grass free vitamins. Remaining leaves can be piled around trees and shrubs in piles three to six inches deep.
And the USFWS suggests homeowners might even consider replacing grass lawns with planting beds that can take advantage of fallen leaves as mulch. This leaf mulch helps suppress weeds and support native plants that benefit the local ecosystem at risk of invasive weed establishment.
Composting leaves instead of throwing them away can help alleviate the pressure of sending organic matter to the landfill. As of last year, NPR reported that at least eight million tons of fallen leaves end up in landfills every year. And since organic matter can’t break down efficiently in a landfill environment, leaves will end up releasing methane, a greenhouse gas more potent than carbon dioxide that contributes majorly to global warming.
The Environmental Protection Agency confirms landfills are among the U.S.’s largest sources of methane emission due to organic waste.
“Leave the leaves!” the USDA reiterates.
In terms of yard work, the USDA suggests less might actually be more. Letting autumn leaves decay lessens the need for fertilizer, which the USDA warns can harm the ecosystem and wildlife through runoff or absorption of excessive toxins.
With regard to toxins, the University of Wyoming (UW) does note that if composting leaves, the compost should be fully mature before it’s used in a yard. Compost that has not finished the decomposition process can contain compounds that are toxic to plants, so the UW suggests composting for a minimum of 10 to 14 weeks.
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