If it weren't for our country's love affair with the lawn, conflicts between people and moles would almost never happen.
For reasons buried deep in our psyches, Americans have long demanded landscapes dominated by open expanses of fastidiously tended greenery, requiring excessive trimming, water, and chemicals to maintain. Literally billions of dollars are spent every year to manicure nature to such perfection. Only recently have the negative environmental effects of this obsession come to the public's attention, including pesticide, herbicide, and fertilizer runoff, toxic effects on birds, and, of course, the loss of habitat for many species.
One animal who does tolerate—and perhaps even benefit from—the lawns people create is the mole. Moles impact lawns by tunneling, pushing up mounds of earth and (occasionally and then only temporarily) undermining the root systems of growing plants. Suffice it to say that the damage caused by moles is almost entirely cosmetic. On the other hand, moles provide benefits by turning soil, mixing soil nutrients, and improving soil aeration.
The Dirt on Moles
Although often mistaken for rodents, moles are actually members of the taxonomic order Insectivora, as are shrews. Unlike rodents, moles have naked snouts, eyes often hidden in fur, no external ears, and distinctive paddle-shaped forelegs that clearly distinguish them. Moles are also insectivores, with a dietary preference for worms, grubs, and other insects found underground. Seven species occur in North America, with eastern (Scalopus aquaticus) and star-nosed (Condylura cristata) moles the most widely distributed. Moles are not found throughout most of the Great Plains, Great Basin, and Rocky Mountain areas of the West.
Moles are fossorial, meaning that they spend most of their lives underground. They prefer moist, loose soils of the sort favored by their main source of food—grubs and earthworms. Not all mole tunneling leads to plant damage—even when evidence would seem to suggest it. Some plant damage may be caused by rodents (mice and voles) who use the moles' tunnels.
Holey Moley
Moles, in fact, are often blamed for damage caused by other species. The evidence of moles in your yard is easy to detect—sometimes as easy as tripping over one of their excavations, whether a small mound of earth that results from deep tunneling (molehills) or a shallow surface run or tunnel that collapses underfoot. Damage to lawns can occur when the raised turf over the surface tunnels is hit by mower blades—but only when the lawn is being clipped very short. Or it can occur when you simply step on a shallow run and create a hole in your lawn.
The HSUS doesn't advise any direct efforts to control moles or their habitat, except in extreme cases. (In those extreme cases, habitat management and exclusion should be used.)
For the average homeowner, however, problems with moles usually can be managed with minimal effort and persistence. Flattening mole runs by foot or with a lawn roller will solve the problem of a mower hitting the mounds of earth. Be aware that over-watering lawns can keep earthworms and other mole prey near the surface, and result in increased surface tunneling. Encouraging native plants to establish in the lawn and keeping lawn size to a minimum whenever possible are also effective approaches to dealing with mole problems.
Better yet, sowing "natural" lawns (composed of native grasses and forbs) not only minimize conflicts with moles and other wildlife, but are environmentally friendly and low maintenance.
Barriers can be erected around flower or garden plots by burying hardware cloth a foot deep in an L shape, and at least eight inches out to keep animals from burrowing under it. Concrete edges buried eight to 12 inches underground, or similar barriers used to keep weeds from spreading into flower beds, may also repel tunneling moles. However, these approaches are costly and labor-intensive, and are recommended only for exceptional situations.
One method to deal with moles requires no money and no physical energy. It's a change of attitude. After all, no other ornamental landscape element on this planet receives as much fuss and attention as the lawn. Until our attitude toward that ubiquitous green turf changes, some people will undoubtedly continue battling moles over the appearance of their grass.
Updated Sept. 9, 2006.
