A frequently mowed lawn, with frequent applications of weed-killers, is a biological desert. But mowing your lawn less frequently promotes a rich diversity of plants. Clovers and dandelions can thrive when mowing is less frequent. Leading to higher bee abundance. Embrace the dandelion. Jessica Damiano via AP
One of the major threats to biodiversity is the loss and degradation of favorable habitats. Like many of you, I seek to improve habitat for birds and other wildlife in my yard. Our 0.25-acre yard is modest against the tracts of natural habitat that are destroyed daily. Nevertheless, by planting plants that provide food for birds and insects, providing water, putting out nest boxes, providing shelter and, of course, providing food in bird feeders, we can improve the lot of wildlife in our yard.
I am always pleased when others try to tailor their yards to make them more plant- and animal-friendly. But my eyes were opened by reading a recent article in the journal Bioscience, written by Susannah Lerman and four colleagues. The title of the article is “Humanity for Habitat: Residential Yards as an Opportunity for Biodiversity Conservation.”
The authors begin by noting that around half a million terrestrial species are on the brink of extinction. They argue that habitat loss is the primary driver of the population declines followed by over-exploitation, climate change, pollution and invasive species.
Private residential land (our yards) represents one of the most rapidly expanding habitats on earth. I was surprised to learn that the yards of single-unit detached housing occupies 30% of U.S. land area. Compare that to the 7% of the country that is protected in national parks, national forests and conservation land. You can see that improving our yards to benefit wildlife is a huge opportunity that we should be embracing.
The authors propose a “humanity for habitat” stewardship practice for private residential yard management. This program will help restore ecological functions and provide residents with an opportunity to connect with nature.
The authors adopt the philosophy of Aldo Leopold, one of the first conservation biologists. His 1949 Sand County Almanac is a must-read for anyone interested in environmental biology. Leopold believed that stewardship of the land is the responsibility of humanity.
Lerman and her colleagues review many of the published studies showing the impacts of human management of our yards. Rural areas offer more opportunities for effective yard management. In the U.S., rural residences are sparse, averaging less than 25 per 300 acres but the average yard size is higher. Rural areas account for 72% of our private residential space.
Urban areas have dense residences, over 850 for every 300 acres and therefore the yard size is small. Despite the density of human habitation in cities, only 3% of residential yards are located in urban areas. Suburbs fall in between with intermediate lot sizes and account for the remaining 25% of residential yard space.
A frequently mowed lawn, with frequent applications of weed-killers, is a biological desert. But mowing your lawn less frequently promotes a rich diversity of plants. Clovers and dandelions can thrive when mowing is less frequent. Leading to higher bee abundance. Embrace the dandelion.
Better yet, spread the seeds of pollinator-friendly plants on your lawn and mow infrequently. Best of all, cut down on the amount of lawn you have by planting trees and shrubs.
Native plants are generally favored for planting in our yards. Those plants attract a wider diversity of insects, providing insectivores with a larger smorgasbord.
As an example, Carolina chickadees in the District of Columbia foraged more on the insects of native plants. Birds with higher access to native plants had higher nesting success.
Trees have the advantage of sequestering carbon so that it does not move into the atmosphere as carbon dioxide, producing more global warming. The evaporation of water through a tree’s leaves cools the local area by as much as 6 degrees Fahrenheit. Trees also reduce erosion from rainfall runoff.
Collaborating with abutting neighbors is a great idea but having a mosaic of habitats in your neighborhood can help promote diversity as well.
As fall wanes into winter, now is a good time to think about modifications you can make to your yard to promote biodiversity when spring arrives. Humanity for Habitat!
Herb Wilson taught ornithology and other biology courses at Colby College. He welcomes reader comments and questions at whwilson@colby.edu
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