Western red-backed vole
|Western red-backed vole|
The western red-backed vole (Myodes californicus) is a species of vole in the family Cricetidae. It is found in California and Oregon in the United States and lives mainly in coniferous forest. The body color is chestnut brown, or brown mixed with a considerable quantity of black hair gradually lightening on the sides and grading into a buffy-gray belly, with an indistinct reddish stripe on the back and a bicolored tail about half as long as the head and body. Average length is between 2.5–5.65 inches (65–137 mm), with height between 0.75–0.87 inches (18–21 mm).
The species is closely related to the southern red-backed vole (Myodes gapperi), which lives to the north and east of the range of this species, and is redder, with a more sharply bicolored tail.
The species breeds between February and November on the slopes of the Cascade Range in north Oregon, as well as all year to the west of the Cascade Range, with 2–7 young per litter and a gestation period of around 18 days.
The western red-backed vole lives largely underground in an extensive system of burrows. It feeds preferentially on the fruiting bodies of the mycorrhizal fungi which are the symbionts of the forest trees around it. Rhizopogon vinicolor is one such which is associated with the Douglas-fir (Pseudotsuga spp.). Fruiting of the fungus takes place in well decayed timber when the nutrients are becoming exhausted. Because the fruiting bodies are underground, the spores are not liberated into the air as in most fungal species. However, the spores are found in the vole's droppings and are deposited throughout its burrows, thus enabling the fungus to spread and form associations with uninfected trees. It has been found that in a clear-cut forest where all the dead wood and trimmings are removed, the mycorrhiza stops fruiting, the vole population dies out and newly planted trees fail to thrive. This is an example of a three way symbiosis. The vole gains food from the fungus and spreads its spores. The fungus gains photosynthetic products from the tree which benefits from the nutrients produced by the fungus.
In areas where vole populations live in close proximity to industrial areas, voles are used as a sentinel organism to monitor environmental contamination, especially persistent organic pollutants such as PCBs which build up in the vole's fatty tissues.
- Linzey, A.V. & NatureServe (Hammerson, G.) (2008). Myodes californicus. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 30 June 2009. Database entry includes a brief justification of why this species is of least concern.
- Don E. Wilson; DeeAnn M. Reeder (2005). Mammal Species of the World: A Taxonomic and Geographic Reference. JHU Press. pp. 1022–. ISBN 978-0-8018-8221-0.
- Schultz, Stewart T. The Northwest Coast: A Natural History. (1990) Timber Press, Inc. Portland, Oregon. pp. 275–276 ISBN 0881924180.