Eastern meadow vole
The eastern meadow vole (Microtus pennsylvanicus),[2] sometimes called the field mouse or meadow mouse, is a North American vole found in eastern Canada and the United States. Its range extends farther south along the Atlantic coast.
The western meadow vole, Florida salt marsh vole, and beach vole were formerly considered regional variants or subspecies of M. pennsylvanicus, but have all since been designated as distinct species.
The eastern meadow vole is active year-round, usually at night. It also digs burrows, where it stores food for the winter and females give birth to their young. Although these animals tend to live close together, they are aggressive towards one another. This is particularly evident in males during the breeding season. They can cause damage to fruit trees, garden plants, and commercial grain crops.
Taxonomy[edit]
The species was formerly grouped with the western meadow vole (M. drummondii) and the Florida salt marsh vole (M. dukecampbelli) as a single species with a very large range, but genetic evidence indicates that these are all distinct species.[3]
Distribution[edit]
The eastern meadow vole is found throughout eastern North America. It ranges from Labrador and New Brunswick south to South Carolina and extreme northeastern Georgia; west through Tennessee to Ohio. West of Ohio, it is replaced by the western meadow vole.[4][5] Several subspecies are found on eastern islands, including the beach vole (M. p. breweri) and the extinct Gull Island vole.[3]
Plant communities[edit]
Eastern meadow voles are most commonly found in grasslands, preferring moister areas, but are also found in wooded areas.[5]
In east-central Ohio, eastern meadow voles were captured in reconstructed common cattail (Typha latifolia) wetlands.[6] In Virginia, eastern meadow voles were least abundant in eastern red cedar (Juniperus virginiana) glades and most abundant in fields with dense grass cover.[7]
Habits[edit]
Eastern meadow voles are active year-round[8][9] and day or night, with no clear 24-hour rhythm in many areas.[10] Most changes in activity are imposed by season, habitat, cover, temperature, and other factors. Eastern meadow voles have to eat frequently, and their active periods (every two to three hours) are associated with food digestion.[8][9] In Canada, eastern meadow voles are active the first few hours after dawn and during the two- to four-hour period before sunset. Most of the inactive period is spent in the nest.[9]
Cover requirements[edit]
Nests are used as nurseries, resting areas, and as protection against weather. They are constructed of woven grass; they are usually subterranean or are constructed under boards, rocks, logs, brush piles, hay bales, fenceposts, or in grassy tussocks. Eastern meadow voles dig shallow burrows,[9] and in burrows, nests are constructed in enlarged chambers. In winter, nests are often constructed on the ground surface under a covering of snow, usually against some natural formation such as a rock or log.[8][9]
Eastern meadow voles form runways or paths in dense grasses.[8][9]
Diets[edit]
Eastern meadow voles eat most available species of grasses, sedges, and forbs, including many agricultural plant species.[5][9] In summer and fall, grasses are cut into match-length sections to reach the succulent portions of the leaves and seedheads. Leaves, flowers, and fruits of forbs are also typical components of the summer diet. Fungi, primarily endogones (Endogone spp.), have been reported in eastern meadow vole diets. They occasionally consume insects and snails, and occasionally scavenge on animal remains; cannibalism is frequent in periods of high population density. Eastern meadow voles may damage woody vegetation by girdling when population density is high.[5]
In winter, eastern meadow voles consume green basal portions of grass plants, often hidden under snow. Other winter diet components include seeds, roots, and bulbs. They occasionally strip the bark from woody plants. Seeds and tubers are stored in nests and burrows.[8][9] Evidence of coprophagy is sparse, but thought to occur.[9]
In an old-field community in Quebec, plants preferred by eastern meadow voles included quackgrass (Elytrigia repens), sedges, fescues (Festuca spp.), wild strawberry (Fragaria virginiana), timothy (Phleum pratense), bluegrasses (Poa spp.), and bird vetch (Vicia cracca).[24]
Predators[edit]
Eastern meadow voles are important prey for many hawks, owls, and mammalian carnivores, and are also taken by some snakes.[5] Almost all species of raptors take microtine (Microtus spp.) rodents as prey. Birds not usually considered predators of mice do take voles; examples include gulls (Larus spp.), northern shrike (Larius borealis), common raven (Corvus corax), American crow (C. brachyrhynchos), great blue heron (Ardea herodias), and American bittern (Botaurus lentiginosus).[9] In Ohio, eastern meadow voles comprised 90% of the individual prey remains in long-eared owl (Asio otus) pellets on a relict wet prairie,[25] and in Wisconsin, eastern meadow voles comprised 95% of short-eared owl (A. flammeus) prey.[26] Most mammalian predators take microtine prey.[9] The American short-tailed shrew (Blarina brevicauda) is a major predator; eastern meadow voles avoid areas frequented by short-tailed shrews.[5] Other major mammalian predators include the badger (Taxidea taxus), striped skunk (Mephitis mephitis), weasels (Mustela spp.), marten (Martes americana), domestic dog (Canis familiaris), domestic cat (Felis catus) and mountain lion. Other animals reported to have ingested voles include trout (Salmo spp.) and garter snake (Thamnophis spp.).[9]
Management[edit]
Eastern meadow voles are abundant in agricultural habitats. The list of crops damaged by eastern meadow voles includes root and stem crops (asparagus, kohlrabi), tubers, leaf and leafstalks, immature inflorescent vegetables (artichoke, broccoli), low-growing fruits (beans, squash), the bark of fruit trees, pasture, grassland, hay, and grains.[9] Eastern meadow voles are listed as pests on forest plantations.[27] In central New York, colonization of old fields by trees and shrubs was reduced due to seedling predation by eastern meadow voles, particularly under the herb canopy.[28]
Management of eastern meadow vole populations in agricultural areas includes reduction of habitat in waste places such as roadsides and fencerows by mowing, plowing, and herbicide application. Predators, particularly raptors, should be protected to keep eastern meadow vole populations in check. Direct control methods include trapping, fencing, and poisoning; trapping and fencing are of limited effectiveness. Poisons are efficient. Repellents are largely ineffective at present.[9] Plastic mesh cylinders were effective in preventing seedling damage by eastern meadow voles and other rodents.[29] Properly timed cultivation and controlled fires are at least partially effective in reducing populations.
Ecto- and endoparasites have been reported to include trematodes, cestodes, nematodes, acanthocephalans, lice (Anoplura), fleas (Siphonaptera), Diptera, and ticks and mites (Acari).[5][9]
Human diseases transmitted by microtine rodents include cystic hydatid disease, tularemia, bubonic plague, babesiosis, giardiasis[9] and the Lyme disease spirochete Borrelia burgdorferi.[30]
Ecological importance[edit]
As with many other small mammal species, M. pennsylvanicus plays important ecological roles.[31] The eastern meadow vole is an important food source for many predators, and disperses mycorrhizal fungi. It is a major consumer of grass and disperses grass nutrients in its feces.[31] After disruptive site disturbances such as forest or meadow fires, the meadow vole's activities contribute to habitat restoration.[31] It prefers open, nonforest habitats and colonizes such open areas created by fire or other clearing disturbances. Very few eastern meadow voles are found in forest or woodland areas. In newly opened areas, it is quite abundant.[31] In these new open areas, the vole quickly becomes a food source for predators.[32]
Threats[edit]
While it is a common and wide-ranging species throughout eastern North America, insular populations on the eastern periphery of the species' range are at risk from invasive species, with the extinction of the Gull Island vole being a notable example of this. In addition, due to its dependence on mesic habitats, populations of the species on the mainland periphery of its range in the Southeastern United States may be at potential risk from climate change-induced aridification.[3]