Meadow Vole (Microtus pennsylvanicus)

County List:

Rule:

Mixed Forested/Nonforested or Nonforested Landscapes

      Grass
      or Upland Brush
      or Savanna
      or Small Grains/Forage Crops
      or Fields/Pasture

Habitat List:

view size class definitions

Literature:

It is one of the most common small mammals in our region. The meadow vole prefers moist, grassy fields and also frequents marshes and bogs thick with grasses, sedges, and rushes. Even though dispersing individuals sometimes venture into forested habitats, resident populations seldom exist in such sites.

This animal literally lives surrounded by its food, because grasses and sedges dominate the diet. It eats sprouting shoots in spring, goes after tender tips and seeds in summer and autumn, and munches the green basal portions and roots in winter. During warm-weather months, clover, plantain, dandelion, goldenrod, yarrow, and other herbs contribute to the diet. At times of high population density or cold weather, a meadow vole resorts to bark for food and often girdles small trees in the process. Fungi and insects, particularly caterpillars, are eaten in small amounts.

Habitat: Fields, pastures, orchards, freshwater and saltwater marshes and meadows, borders of streams and lakes, open and wooded swamps, bogs; less commonly in open woods and clearcuts.

Special Habitat Requirements: Herbaceous vegetation, loose organic soils.

Habitat Preferences: The meadow vole is a grassland species, preferring moist, open grass-herb vegetation. In fallow agricultural areas in Michigan, Beckwith found the meadow vole became the prominent small mammal in the community when the vegetative succession moved from the annual-biennial stage to the perennial grass stage. Nevertheless, overhead grassy cover seems essential for optimum habitat, serving to provide both seclusion and food. In Michigan, meadow voles have been studied in a deer yard containing even-age saplings with rank herbaceous ground cover in Alger and Schoolcraft counties; in grassy bogs and beaver meadows in Marquette and Baraga counties; in meadow and white cedar swamp in Marquette County; in meadow, sedge, black ash swamp, white cedar swamp, leather leaf and sphagnum bogs, and black spruce-tamarack bog in Gogebic and Ontonagon counties; in sedge, rush, grass, sphagnum tamarack, black spruce, and white cedar bogs, in aspen and second-growth hardwoods, and in cultivated fields in Charlevoix County; in sedges bordering a brook and a beaver meadow in Montmorency County; in timothy and other grasses in Washtenaw County; in grass and cultivated areas and in old beaver meadows in Washtenaw County; in old field and grass sedge marsh in Washtenaw County; in grass, clover and alfalfa, and in winter under deep snow in upland brush or coniferous plantings in Kalamazoo County; in bluegrass association in Livingston County; in grassy areas along roads and adjacent to swamps in Missaukee County; in cultivated fields in winter, grass-herb areas and infrequently in woods in Clinton County; in old field habitat in Ingham County; along railroad tracks in Ingham County; and in orchards, conifer plantations, nurseries, parks, landscaped areas, and cultivated fields containing field-shocked grain.

Distribution in Correlation with Vegetative Succession. - Much of presettlement Michigan was forested. Rodents chiefly adapted for open lands were restricted to streamside growth, swamp and marsh edges, beach, beaver meadows, forest openings, including natural ones like those found in southwestern Michigan, and other areas in various stages of second growth after forest disturbance caused by fires, wind storms, and clearing. Although the meadow vole appears to have resided in Michigan since postglacial times, this author suspects (without adequate data) that the southern bog lemming, which today plays only a minor role as a grass-eating rodent, may originally have been the dominant microtine in suitable Michigan habitat. During settlement, pronounced changes resulted from forest clearing, intensive farming and the spread and introduction of numerous herbaceous plants including bluegrass, quack grass, and brome. These changes provided abundant and attractive habitat and food for grass-eating microtines. The meadow vole then presumably increased in these environments. In discussing the meadow vole in Washtenaw County, Wood wrote that the species "was formerly found in beaver meadows, but with the clearing of the forests it has extended its range to the fields of grass and grain and has become the most numerous of all the mammals of the county." In short, the meadow vole thrived as a result of these environmental changes, possibly to the detriment of the southern bog lemming. The success of the meadow vole in adapting to human land-use is well illustrated by its highly successful occupation of isolated strips of grassy vegetation, some no more than five meters wide, on the right-of-ways bordering roads, railroad tracks, and more recently, pipe lines and power lines. The meadow vole's ability to respond to agricultural operations was documented in a study done in a Wisconsin alfalfa field where the animal's major habitat was shown to be the edge environment around the field. However, as the alfalfa increased in height, the vole spread into the field; when the crop was mowed, the animals used only the edge. The meadow vole's dominant position in Michigan's open lands today depends on the presence of proper grassy seral stages in the ecological succession of plant growth.

Behavior: Meadow voles construct nests in clumps of grass, along surface runways, under boards or rocks, underground in shallow burrows, in bird nests, or in winter in surface locations protected by a blanket of snow.

Food Habits: Meadow voles primarily eat herbaceous vegetation, the leaves and other growing parts of grasses, sedges, forbs, and other plants. They also will eat seeds, fruits, insects, snails, and other invertebrates, and various small vertebrates including, on occasion, each other.

Ecology: This vole is often restricted to moister habitats when sympatric with M. ochrogaster or M. montanus, and excludes Clethrionomys gapperi, Peromyscus leucopus, and P. maniculatus from grasslands.

Habitat selection may be influenced by relative ground cover of grasses and herbs, soil moisture, soil sodium levels, surface temperature and humidity, and inter-specific competition. Woodland populations have a lower reproductive success and lower adult survival rates than do grassland populations.

Meadow voles preferred partially cut softwoods and the Rubus stage compared to uncut softwoods. The sapling stage was used less than uncut softwoods, and partially cut softwoods more than slash or sapling stages. Meadow vole activity was greater in the Rubus stage than in slash or sapling stages, and uncut or partially cut hardwoods. Relatively more meadow voles were trapped in partially cut softwoods than in uncut or partially cut hardwoods. Use of partially cut hardwoods was greater than in the sapling stage.

Softwood - 3 treatments; uncut, partially cut, and clearcut (slash - rubus - sapling)

Hardwood - 2 treatments; uncut, partially cut

Before harvest, upland sites supported mature stands of black spruce with a small component of jack pine, paper-birch, and aspen. Dry knolls supported mixed stands of aspen, paper-birch, white spruce, and balsam fir, while wet lowland sites supported stands of black spruce with a small component of white cedar.

Meadow voles were taken only on clearcuts at least 1 year old and varied in numbers among the areas sampled. Micro-distribution of meadow voles has been reported to correlate with moisture and graminoid vegetation cover. It is likely, therefore, that they appear on clearcuts once sufficient cover has been established and in densities proportional to the amount of moist, graminoid cover present.

Clearcutting of upland black spruce forest in northern Ontario altered the environment so that clearcut sites were less desirable than uncut sites for red-backed voles, rock voles, and bog lemmings, although the opposite was true for deer mice, meadow voles, heather voles, and least chipmunks.

ABSTRACT - Three meadow voles were among 195 small mammals collected on two forest clearcuts in Cumberland Co., Pennsylvania, during 39 nights of removal sampling from 22 September to 21 November 1987. All three (one male; two females) were subadults and were judged to have been dispersing when collected. Each of the capture localities was at least 2.6 km from the nearest appreciable suitable habitat for this species. Such apparent long-distance dispersal in M. pennsylvanicus may represent an evolutionary adaptation to conditions that existed in eastern North America prior to European colonization, when unbroken forests dominated the landscape and herbaceous habitats were small and widely scattered. Given the ephemeral nature of many of these habitats, natural selection may have favored long-distance dispersal in M. pennsylvanicus as a means of reaching and exploiting newly-created herbaceous habitats or sites from which resident populations had been extirpated.

The meadow vole, a common grassland species whose geographic distribution is the largest of any North American representative of the genus Microtus and encompasses temperate grassland, deciduous and coniferous forest, and tundra biomes.

Microtus pennsylvanicus typically inhabits grassland habitats characterized by relatively dense herbaceous cover and seems to prefer moister sites, which would be characterized by more rank vegetation. Although M. pennsylvanicus frequently exploits recent clearcuttings in the Adirondack Mountains of northern New York and the higher elevations of central West Virginia, such areas generally support luxuriant herbaceous vegetation. In contrast, recent clearcuts in southcentral Pennsylvania are conspicuously drier with herbaceous cover being confined to small isolated patches and lack resident populations of meadow voles.