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throughout March and April. The voles require green vegetation for reproduction so the timing of peak gestation corresponds with plant emergence in the spring and is partially controlled by timing of first rainfall. Gestation in this subspecies lasts 21 days, with the offspring (usually 4-5 young) being weaned 14 days after that. Females experience an estrus cycle immediately after giving birth that makes them especially receptive to postpartum copulations and allows them to have many successive litters. Sexual maturity is reached by young females very early; they can have litters when they are as young as 3 weeks old. Males become sexually mature at just 6 weeks. The third molars erupt after 22 days and this, along with molt patterns, can be used to age individuals.
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throughout non-breeding season. Especially during peak breeding season in March and April, males tend to be territorial and make an effort to exclude other males from their home ranges. Male and female home ranges, however, may overlap. Daily ranges of these animals is substantially smaller, with individuals traveling only 16–17 feet (4.9–5.2 m) from the burrow entrance to meet most of its life history needs. Daily movements and home range sizes vary somewhat with the environment and population density. Voles disperse throughout their lifetime, but dispersal is often limited by fragmentation of their habitat.
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social system. They can found living in burrows in family groups of up to one male, several females, and their offspring. The female home range averages 0.02 acres (81 m) and the male home range averages 0.03 acres (120 m), although the females generally travel longer distances than males
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The
Amargosa vole has a life span of around one year. Several factors allow them to have very high reproductive success with huge numbers of litters produced, despite their short life spans. The Amargosa vole possesses the ability to reproduce year-round, but highest rates of pregnancy are usually
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make up the majority of the
Amargosa vole's diet, but they may also rely on roots and seeds throughout certain times of the year. When harvesting the seed heads from grasses and forbs, individuals will often stand on their hind feet and chew off the herbaceous stem, causing the seeds to fall into
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between the river and marshes. This has also increased fragmentation in the landscape, making dispersal between suitable habitats a challenge. Many of the
Amargosa vole metapopulations are already reliant on flooding events to not become completely isolated, and increasing the fragmentation will
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One major threat to the
Amargosa vole is destruction of habitat. In the past, the marsh habitat has been intentionally destroyed for development or creating new grazing land for livestock. Other actions, such as building roads and railroads, have indirectly affected the vital marsh habitat by
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Other potential threats to the vole are groundwater pumping and development and implementation of water diversion structures, which alter the flow and hydrology of the marshes and reduce the amount of available surface water that feeds that marshes on which the
Amargosa voles rely.
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The
Amargosa vole is recognized by the characteristic long, low profile of all voles. It has gray feet and whiskers, and its back is covered by dark, blackish fur. This subspecies has a bicolored tail that exhibits black on the top and gray on the underside. They are a
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Critical habitat was designated for the subspecies in 1984, when it was first federally listed. Although its habitat is naturally fragmented, human disturbance does not help the situation. If the suitable habitat patches become too isolated,
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in 1976, it was rediscovered three years later when 21 individuals were captured during sampling of potential habitat. Today, the population is thought to consist of only 67 individuals based on the most recent sampling efforts.
448:), changes the vegetative community and the hydrology of the marsh. It has the potential to use so much water that it changes or even eliminates the standing water from the vole habitat. Two other introduced species,
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in size. Their habitat is unique; the landscape is a matrix of spring-fed marshes and tributaries that are naturally fragmented and isolated by inhospitable desert terrain. This subspecies requires permanent
456:, do not alter the ecosystem but directly impact the vole. House cats are known predators of the vole, but the relationship between the Amargosa vole and house mice is not as well understood.
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and its associated tributaries and marshes. Although their historic range is not fully understood, it is thought they have always had a very small range, limited by life history requirements.
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exacerbate the issue. Because of population isolation, there are genetic issues associated with the conservation efforts, with the potential for inbreeding and genetic homogeneity to occur.
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stops occurring, and the subspecies could be even more threatened. One conservation priority is to maintain habitat between marsh patches in order to promote gene flow and preserve
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Amargosa voles have very specific habitat requirements. They live only along the
Amargosa River in its associated tributary and marsh ecosystems on land with less than a 20 percent
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their reach. Around dusk and dawn is when they are usually most active, but during extremely hot, dry weather, they adjust their foraging strategy to occur mostly at night.
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Lidicker, W. Z., Jr. 1973. Regulation of numbers in an island population of
California vole, a problem in community dynamics. Ecological Monographs 43:271–302.
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381:). It is estimated that there is only 247 acres (1.00 km) of land that meets the habitat requirements of the Amargosa vole within their range.
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742:. Pp. 626–628 in The Smithsonian book of North American mammals (D. E. Wilson and S. Ruff, eds.). Smithsonian Institution Press, Washington, D.C.
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341:), however, other plant species are also frequently found in ecosystems where Amargosa voles are known to live, including
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Neuwald, J. L. 2010. Population isolation exacerbates conservation genetic concerns in the endangered
Amargosa vole,
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One benefit to conservation of this subspecies is that most of the
Amargosa vole's range is on land owned by the
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McClenaghan, L. R., and S. J. Montgomery. 1998. Draft Report: Distribution and abundance of the Amargosa Vole (
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516:, which prevents many of the actions that continue to threaten the subspecies, including burning and grazing.
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Laboratory in Infectious Disease Ecology. School of Veterinary Medicine, University of California, Davis.
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Introduction of invasive species is also a threat to the Amargosa vole. One extremely aggressive plant,
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and medium to dense vegetation. It is evident that the dominant plant preferred by this subspecies is
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species, in which the males are longer and heavier than the females of the subspecies. The
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540:. Gland, Switzerland and Cambridge, UK: IUCN/SSC Rodent Specialist Group. p. 91.
313:. Their current range is mostly contained along a 10-mile (16 km) stretch of the
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in each of the upper and lower quadrants. They are characterized by an opening in the
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Amargosa voles are a subspecies that is active year-round; they have no period of
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Portland, Oregon: U.S. Fish and Wildlife Service, Region One. September 1997.
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Amargosa voles have a very small range, limited only to certain parts of
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Hafner, David J.; Yensen, Eric; Kirkland, Gordon L. Jr., eds. (1998).
729:) species profile. Draft. U.S. Fish and Wildlife Service. March 2012.
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Ventura, California: Ventura Fish and Wildlife Office. January 2009.
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Greenwald, G. S. 1956. The reproductive cycle of the field mouse,
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North American Rodents. Status Survey and Conservation Action Plan
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Heske, E. J., and W. Z. Lidicker, Jr. 1999. California vole:
324:. The marshes in which they reside are typically one to five
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NatureServe Explorer. Version 7.1. Accessed 23 June 2017.
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North American Fauna, U.S. Department of Agriculture.
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476:. Additionally, it is listed as vulnerable by the
472:in the state of California and federally by the
478:International Union for Conservation of Nature
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707:) 5-year review: summary and evaluation.
633:Revision of American voles of the genus
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474:United States Fish and Wildlife Service
514:Area of Critical Environmental Concern
512:. This land has been set aside as an
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946:Endemic rodents of the United States
791:Amargosa Vole Conservation Efforts.
767:. Journal of Mammalogy 37: 213-222.
305:. They are endemic to parts of the
956:Species endangered by habitat loss
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510:California State Lands Commission
226:) is one of 17 subspecies of the
817:Microtus californicus scirpensis
783:Microtus californicus scirpensis
727:Microtus californicus scirpensis
675:Microtus californicus scirpensis
655:Microtus californicus scirpensis
577:Microtus californicus scirpensis
223:Microtus californicus scirpensis
203:Microtus californicus scirpensis
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705:Microtus californicus scipensis
468:The Amargosa vole is listed as
941:Endangered fauna of California
622:Mammalian Species 42: 230-243.
293:directly behind the incisors.
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725:USFWS. 2012. Amargosa Vole (
951:Endemic fauna of California
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385:Diet and foraging strategy
502:Bureau of Land Management
236:M. californicus vallicola
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70:Scientific classification
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297:Distribution and habitat
620:(Rodentia: Cricetidae).
273:, meaning there is one
931:ESA endangered species
797:Amargosa Vole Project.
506:The Nature Conservancy
480:. Originally declared
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765:Microtus californicus
740:Microtus californicus
618:Microtus californicus
262:of Amargosa voles is
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185:M. c. scirpensis
398:Population structure
371:Phragmites australis
363:Atriplex lentiformis
171:M. californicus
16:Subspecies of rodent
780:NatureServe. 2017.
40:Conservation status
379:Distichlis spicata
256:sexually dimorphic
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809:Taxon identifiers
631:Bailey, V. 1900.
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890:NatureServe
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404:hibernation
311:Inyo County
242:Description
147:Arvicolinae
143:Subfamily:
925:Categories
520:References
508:, and the
470:endangered
454:house mice
450:house cats
408:polygynous
303:California
137:Cricetidae
55:Endangered
832:Q16974097
491:gene flow
431:hydrology
375:saltgrass
359:quailbush
351:arrowweed
283:premolars
165:Species:
93:Kingdom:
87:Eukaryota
936:Microtus
895:2.101942
826:Wikidata
635:Microtus
439:tamarisk
343:seepweed
158:Microtus
133:Family:
127:Rodentia
117:Mammalia
107:Chordata
103:Phylum:
97:Animalia
83:Domain:
856:6163547
482:extinct
443:Tamarix
424:Decline
373:), and
335:bulrush
279:canines
275:incisor
269:1.0.0.3
266:1.0.0.3
153:Genus:
123:Order:
113:Class:
58: (
908:717895
882:202375
869:237264
840:ECOS:
544:
287:molars
391:forbs
326:acres
322:grade
903:NCBI
877:ITIS
851:GBIF
843:7963
542:ISBN
452:and
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216:The
365:),
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281:or
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
