Endangered Species Handbook

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Projects

Lawns

Project Summary
Many biologists and conservationists are now questioning the use of green lawns in yards, in front of public buildings and along highways.  In general, green lawns have to be maintained through use of chemicals that can pollute the groundwater and kill beneficial plants and insects; use noisy, gas-guzzling mowers and leaf-blowers; and fail to preserve native plants.  This project involves examination of the effects of these lawns on the environment and human health, as well as the use of energy and water to maintain them.
 
Background
Most biologists consider grass lawns to be ecological deserts because of their lack of diversity.  In many areas, grass lawns cover a large percentage of land in villages and suburbs.  Golf courses are increasing in number.  Lawns are replacing natural habitats, such as woodlands, grasslands, shrub and desert and, in the process, wildlife and natural landscapes retreat.  The Eastern Box Turtle has lost a large percentage of its original long grass, shrubby habitat to green lawns, and the species has declined dramatically.  These slow-moving reptiles are also badly injured or killed by lawn mowers, which smash their shells (see Stevens 1994).  Migratory birds and butterflies return in the spring to find their natural habitats converted to green lawns, depriving them of feeding and breeding sites.  In general, lawns provide little or no habitat for wildlife.
 
To keep them green, herbicides, pesticides and chemical fertilizers are sprayed or spread in vast quantities.  More than 67 million pounds of chemicals are placed on US lawns annually (see Wasowski 2001).  These chemicals kill useful native animals, such as pollinating insects, birds that disperse seeds and consume insects, burrowing rodents, and earthworms that aerate the soil.  They also contaminate the groundwater.  Some of these poisons are so powerful that they have caused sickness and death in humans. Early in 2001, the city of Halifax, Nova Scotia, Canada, became the first in North America to order a ban on all insecticides, herbicides and fungicides used on lawns.  The ban was primarily intended to protect human health, especially children who are most vulnerable to pesticides (see Nickerson 2001).  Fifty-five other communities across Canada are considering similar bans.  Opposition to grass lawns and frequent mowing along public highways is also growing.  One citizen of Orleans, Massachusetts, objected to the The Boston Globe when mowers destroyed carefully planted native wildflowers growing along a major highway in this Cape Cod area.  The flowers, planted by volunteers (one as old as 85), of the New England Wild Flower Society, had been clearly posted not to be mowed.
 
Green lawns require constant care and use enormous amounts of energy for mowing, edging and removing leaves.  Most lawn mowers and leaf blowers consume gasoline and pollute the air with fumes, while also creating noise pollution.  Mowers also damage tree trunks or kill above-ground tree roots, especially of old trees, and frequently-applied fertilizer can harm older trees, which need slow-release enrichment of the soil (see Stocker 2001).  For these reasons, gardeners recommend that no large tree be within 2 feet of a lawn.  Another threat to trees is lawn watering during droughts; an insufficient amount of water reaches the tree roots, while the lawn absorbs most of the water (see Stocker 2001). 
 
Lawns are also extremely costly. The American Nursery and Landscape Association estimated that Americans spent $17.4 billion on their lawns in 1999 (see Schembari 2001).  The Lawn Institute, based in Illinois, estimates that the lawn care industry for North America is worth more than $25 billion (see Nickerson 2001).  By planting perennial native grasses, shrubs, trees and flowers, homeowners could save literally billions of dollars. 
 
The grass used for lawns in the United States is composed of various European turf species, which, unlike most native American grasses, require large amounts of water, often as much as a third of local water supplies.  Householders use 40 to 60 percent of their water on their lawns in the summer.  Erroneously called "Kentucky Blue Grass," this and other commercially distributed grass seed needs cool, damp climates for healthy growth.  The grass quickly turns brown in the heat of summer or when not watered enough.  In dry seasons, many towns mandate water rationing because lawn watering has depleted local supplies.  The average lawn will use up to 10,000 gallons of water of a summer and 10 times the amount of pesticides as an acre of farmland (see Egan 2001). 
 
Communities being built in dry areas, such as southwestern deserts, tend to plant green lawns because their owners have come from areas where they were typically used.  In desert areas, green lawns can only be maintained through diversion of water that dries up rivers or alters the ecology of these regions.  In Arizona, for example, several rivers have been reduced to dry beds by diversion for the burgeoning developments surrounding Phoenix and Tucson.  Cities of the Southwest and California use enormous amounts of their water supplies to water green lawns.  In the process, several pairs of endangered Bald Eagles that nested on one of these rivers, along with thousands of other forms of life, disappeared.  One new resident of Phoenix, an architect, planted native plants in his garden instead of grass, defying local developers, who remove all native vegetation and cover the land with gravel.  His yard was soon filled with wild marigolds, creosote bushes and other plants that seeded themselves in his beautiful, no-maintenance back yard. In Glendale, Arizona, homeowners receive a $100 rebate for converting 50 percent or more of their grass to shrubs or plants.  Studies from Las Vegas found that a city could save 40 percent of its water by converting to non-grass alternatives.  With the world facing increasing water shortages, the grass lawn, especially of non-native species of grasses, has become a luxury that is wasting this precious resource.
 
Green lawns can be grown with native grasses that do not require artificial watering and chemicals, and by using the cut grass as mulch.  Fertilizers and herbicides are not necessary for these lawns, which can be mowed with electric or old-fashioned, human-powered mowers.  Also, smaller areas can be planted. Instead of dominating the yard, lawns can become a minor part.  Planting native vegetation, including wildflowers, shrubs and trees, in back yards and city lots is a preferable alternative to the green lawn.  In shady, moist areas, mosses can be planted that never require mowing and stay green year-round (see reference list below).  Perennial plants do not need replanting each year and require almost no maintenance.  Trees provide shade, erosion control and habitat for wildlife.  Planting a garden with native American plants can also aid in the conservation of ecosystems and rare species.  By not using chemicals, groundwater and wildlife are protected. 
 
Activities
Consult the books listed below before beginning the following project:
 
o  Select two small land plots (each about 200 square feet) each distanced from one another by at least 100 feet.  Prior to planting, take samples of soil and examine them under a microscope to determine the diversity of plants and animals, whether there are earthworms to aerate the soil, and other life forms.  Measure the acidity.  Describe the soil's texture, whether rich loam, clay or sand, and whether it is dry and crumbly or moist.  Are there birds that feed in the grass or evidence of small mammals, such as tunnels?  In one half of the plot, plant non-native grass and use the chemicals recommended by the grass seed company.  Water and mow the lawn, if needed.  On the other half of the lawn, dig up the soil and spread natural compost from leaves and other vegetation throughout, to a level of 2 feet.  Sow seeds of native grasses, such as buffalograss (sold in many nurseries).  Water this portion until the seeds are established, but not afterward.  Do not apply any artificial fertilizers or other chemicals.  Mow with electric or hand mower only.  After one month, take soil samples from both areas and examine them under a microscope to determine the diversity of microbes and the moisture content in the two soil samples.  Note whether the organic wildlife area has above-ground evidence of wildlife such as butterflies, small mammals, reptiles, amphibians and birds.  Identify them by species.  Did the organic grass survive without artificial watering?  Compare the two soils, their moisture content, invertebrate species diversity, water usage, environmental effects and the cost to maintain each one.  A third alternative is described in the next project, “Living with Nature,” focusing on conversion of the lawn to native wildflowers, bushes and trees, which requires even less water and labor.
 
o  As a study project, select a suburban area of approximately one city block and measure the acreage in green lawns, calculating the cost in use of chemicals, as well as gasoline for lawn mowers and leaf blowers.  Estimate water consumption and the percentage of this that must be artificially applied through hosing or sprinklers.  What is the water source?  Ask the local water department how much water is used in your area for watering lawns each year.  Contact the Environmental Protection Agency in Washington, DC, for information on contamination of groundwater by lawn chemicals and their effects on wildlife and human health.
 
Books and Publications
Egan, T. 2001. Grass is Gone on Other Side of these Fences. The New York Times, May 5.
Eschbacher, K. 2000. Cape Officials, residents ask for cut in Route 6
  mowing. The Boston Globe, Aug, 20.
Forster, R. Roy and Alex M. Downie. 1999. The Woodland Garden: Planting in
  Harmony with Nature. Firefly Press, Buffalo, NY.
Nickerson, C. 2001. A grass-roots drive for purity. Pesticide ban sparks
  turf war in Canada. The Boston Globe, Sept. 3.
Raver, A. 2001. In the Desert's Warm Embrace. The New York Times, April 5.
Schembari, J. 2001. Personal Business. Why the Grass Must be Greener. The New
  York Times, Aug. 26.
Schultz, Warren. 1996. The Chemical-Free Lawn. The Newest Varieties and
 Techniques to Grow Lush, Hardy Grass. Rodale Press, Emmaus, PA.
Stein, Sara. 1993. Noah's Garden. Restoring the Ecology of Our Own Back Yards.
  Houghton Mifflin Co., Boston, MA.
Stein, Sara. 1997. Planting Noah's Garden; Further Adventures in Backyard
  Ecology. Houghton Mifflin Co., Boston, MA.
Stevens, W.K. 1994. American Box Turtles Decline, Perishing Cruelly in
  Foreign Lands. The New York Times, May 10.
Stocker, C. 2001. When to give up on a dying tree. Gardening. The New York
  Times, May 3.
Wasowski, A. 2001. Dawn of a New Lawn. Audubon, May-June.


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