As part of the natural world, just like every other creature with which we share the earth, we depend on the natural world for our well-being. Fortunately, the brain that allows us to adapt and cope with all types of climatic environments, also provides us with the capacity of "realization" -- we understand that there are consequences when we attempt to divorce ourselves from the constraints of the natural world.
Today, one of these "divorcements" from the natural world is taking place as we convert our farms and forests to lawns. Our love for lawns is reflected in the 2010 Chesapeake Stormwater Network study, The Clipping Point: Turf Cover Estimates for the Chesapeake Bay Watershed and Management Implications.
Although the term "turf grass," as used in the study, includes areas such as grasslands at schools, as well as in parks, cemeteries, golf courses, airports, roadsides and median strips, by far the largest component is lawns at 75 percent of the total.
According to the study, turf grass is now the Chesapeake Bay Watershed's largest "crop" with 3.8 million acres (9.5 percent) of the watershed's almost 41 million acres, versus 9.2 percent for row crops (corn, soybean, and wheat), 7.4 percent for hay/alfalfa and 7.4 percent for pasture. Estimates are that in the last 30 years the amount of turf grass has tripled.
The study goes on to explain both the environmental and economic costs (e.g., financial cost of fertilizers and pesticides and their pollution of streams) to not only the lawn owner, but the rest of us as well. One statistic that sticks in my mind is the statement by Tom Schueler, author of the study: "Summer lawn irrigation is calculated to suck nearly 7,875 cubic feet per second (cfs) of river flow to [the] Bay during summer months. To put this amount of water consumption in perspective, it is roughly five times the combined summer flow of the Choptank, James, Monacacy, Patapsco, Pamunkey, Patuxent and Rappahanock rivers in an average year."
We here in York County are not free of this natural world disconnect. Of all the Chesapeake Bay Watershed counties, we rank sixth in total acres of land in turf grass, with 110,564 acres. The only Pennsylvania county with a higher acreage amount is Lancaster County, with 119,615 acres in turf grass. (Remember this is not percentage of total area but actual number of acres.)
One cost of lawns not covered by the study is the loss of native plants in our landscape from the conversion of woodlands to lawns. The ecological cost is high to pollinators, the native plants and the animals that feed on native plants. University of Delaware Professor Dr. Doug Tallamy, who spoke here in York on June 19, has found that "more than three times as many insect species are associated with native plants as with alien plants."
He further found that native plants support "35 times more [butterfly and moth] caterpillar biomass, the preferred source of protein for most bird nestlings, than alien plants supported." Oaks, for example, support 534 species of butterflies and moths. In other words the exotic plants we landscape with do not provide the same amount of energy, as captured from the sun, to the animals further along the food chain as do native plants.
The importance of native plants to birds cannot be overemphasized, nor can the importance of birds in controlling the insects that feed upon the native plants.
Plant diversity is another component that needs to be considered in landscaping with native plants. Without the pawpaw tree, the only host for the beautiful zebra butterfly, there would be no zebra swallowtails. Likewise, without the milkweed plant there would be no monarch butterflies. The beauty of our world would be diminished.
In addition, there is a spillover effect of planting lawns with exotic species. Some of these non-native lawn plants have become invasive; they overwhelm York County's natural woodlands by out-competing native plants. On the property where we live, many plants -- Japanese barberry, privet, Norway maple to name just a few -- have escaped from the lawns where they were planted and, without control, would displace the native vegetation. Non-native plants have been freed from the constraints of animals and other organisms that kept them "under control" in their places of origin
The take-away message here is if you want a greater variety of birds and butterflies in your yard, you need native plants. You can have a beautiful yard and at the same time reconnect your lawn to the natural ecosystem upon which we all depend.
-- Rodger Waldman is a resident of Springfield Town ship.