Spermophilus washingtoni

This species is not complete.

September 5, 2009 by Josh Lawler

Author(s) Expertise:

Login or register to post comments
Print species as a PDF

Sensitivity Factor	Sensitivity Help 1 - 7 (one being least sensitive, seven being most sensitive)	Confidence Help 1 - 5 (one being least sensitive, five being most sensitive)
Generalist/Specialist	3 Medium	1 Very Poor
Physiology	4 Medium-High
Life History	5 High
Habitat
Dispersal Ability	4 Medium-High
Disturbance Regimes	3 Medium
Ecology
Non-Climatic
Other (weight)

Sensitivity Score Help: 31 Medium

Sensitivity Score

100 * [(0.5 *(Dispersal Distance + Dispersal Barriers) + Disturbance Regimes + (0.5 * Generalist/Specialist) + Physiology + (0.5 * Life History) + Sensitive Habitats + Ecology + Non-Climatic Stressors + (Other * Weight) / 49 + (7 * Weight)]

Note: if Sensitive Habitats are identified, this factor automatically gets a value of seven, otherwise it remains zero.

Confidence Score Help: 0

Confidence Score

The Confidence Score is an average of the Confidence column above.

Overall User Ranking: 5 High

Common Name:

Washington Ground Squirrel

Is this Species completed:

Taxonomy

This is a description of the whole group

Scientific Name:

Spermophilus washingtoni

Realm:

Terrestrial

Kingdom:

Animal

Phylum:

Craniata

Class:

Mammalia

Order:

Rodentia

Family:

Sciuridae

Genus:

Spermophilus

Global Rank:

G2 (2006)

Rounded Global Rank:

G2 - Imperiled

IUCN:

Near Threatened ver 3.1 - 2008

US Endangered Species Act Code:

Not Listed

TGTID:

101353000

Species Element Code:

AMAFB05020

Generalist/Specialist

Broadly, where does this species fall on the spectrum of generalist to specialist? :

Confidence in your assessment of the degree to which the species is a generalist or specialist:

1 Very Poor

Please further describe the relationships that make the species more of a specialist:

No dependencies on other species are known.

Comments:

Washington ground squirrels inhabit a number of habitat subtypes within shrub-steppe and grassland, including human-modified habitats such as lawns, degraded weedy locations, edges of crop fields, and highway rights-of-way. They also have a relatively broad diet of mainly grasses, forbs, and seeds, with at least 100 species of plant known to be eaten.

Citations:

1) Betts, B. J. 1990. Geographic distribution and habitat preferences of Washington ground squirrels (Spermophilus washingtoni). Northwestern Naturalist 71:27-37. 2) Greene, E. 1999. Abundance and habitat associations of Washington ground squirrels in north-central Oregon. M.S. thesis, Oregon State University, Corvallis, Oregon.

Physiology

Species' physiological sensitivity:

Please specify whether or not this species is physiologically sensitive to one or more of the following:

Please describe any specific physiological sensitivities:

Washington ground squirrels hibernate for 7-8 months of the year and require adequate body fat reserves to survive hibernation. Long-term declines in rainfall or increases in temperature could potentially affect plant growth patterns (through premature drying) in the squirrel's preferred habitats. This may in turn reduce the species' ability to gather adequate forage for accumulating body fat, which could reduce overwinter survival and harm populations.

Life History

Species' reproductive strategy:

Is the species polycyclic, iteroparous, or semelparous?:

Polycyclic (reproduces intermittently throughout a lifespan)

Average length of time to reproductive maturity:

365 days

How many surviving young can an individual produce during a single reproductive event under optimal conditions?:

10-11 per litter

How many reproductive events can an individual undergo in a single year under optimal conditions?:

Comments:

Scheffer (1941) reported an average of 8 fetuses (range = 5-11) in pregnant females, as determined through counts of embryos and placental scars. Bailey (1936) listed litter size at birth as ranging from 5-10 young.

Citations:

1) Bailey, V. 1936. The mammals and life zones of Oregon. North American Fauna 55:1-416; 2) Scheffer, T. H. 1941. Ground squirrel studies of the four-rivers country, Washington. Journal of Mammalogy 22:270-279.

Sensitive Habitats

Comments:

Washington ground squirrels inhabit a number habitat subtypes within shrub-steppe and grassland, including human-modified habitats such as lawns, degraded weedy locations, edges of crop fields, and highway rights-of-way.

Citations:

Dispersal Ability

Maximum annual dispersal distance:

1-5km

Within the context of dispersal distance above, do barriers to dispersal exist?:

Specific dispersal distance (if known), and dispersal type (juvenile, adult, etc.):

Dispersal distances among juvenile males average about 1 km, with 90% of individuals moving from 300 m to 2.2 km. Maximum recorded distance is 3.5 km. Juvenile females are also known to disperse, but evidence suggests that they move much shorter distances (perhaps a maximum of 300 m) and do so much less frequently than males.

Please select the types of barriers relevant to dispersal:

Agriculture

Industrial or Urban Development

Please enter any known specific restrictions to dispersal:

Wheat fields and other large-scale croplands are one of the most important barriers.

Citations:

1) Carlson, L., G. Geupel, J. Kjelmyr, J. MacIvor, M. Morton, and N. Shishido. 1980. Geographic range, habitat requirements and a preliminary population study of Spermophilus washingtoni. Final Technical Report Grant Number SMI 5350, National Science Foundation Student-Originated Studies Program, Arlington, Virginia. 2) Klein, K. J. 2005. Dispersal patterns of Washington ground squirrels in Oregon. M.S. thesis, Oregon State University, Corvallis, Oregon. 3) Sherman, P. W. and J. Shellman Sherman. 2005. Distribution, demography, and behavioral ecology of Washington ground squirrels (Spermophilus washingtoni) in central Washington: results of the 2005 field season and future research. Unpublished report, Cornell University, Ithaca, New York. 4) Sherman, P. W. and J. Shellman Sherman. 2006. Distribution, demography, and behavioral ecology of Washington ground squirrels (Spermophilus washingtoni) in central Washington: results of the 2006 field season and future research. Unpublished report, Cornell University, Ithaca, New York.

Disturbance Regimes

How sensitive is this species to one or more disturbance regimes:

3 somewhat sensitive

Comments:

Responses to disturbance are poorly documented and it is not known to what extent the species as benefits from disturbance. However, it can coexist well with minor to moderate amounts of livestock grazing, which may open up dense shrub cover and make predators easier to detect. Also, there is speculation that Washington ground squirrels sometimes respond well to small-scale fires.

Overall User Ranking

In your opinion, how would you rank the overall sensitivity of this species to climate change?:

Comments:

Climate change could potentially affect this species through two processes. First, a significant increase in fire occurrence could degrade habitat and reduce the availability of food and cover. Second, as already noted, long-term declines in rainfall or increases in temperature could potentially affect plant growth patterns in the squirrel's preferred habitats through premature drying. This may reduce the species' ability to gather adequate forage and to gain adequate body fat before hibernation, which could reduce overwinter survival and harm populations.

Login or register to post comments
Print species as a PDF

Authorship

Submitted by root on Wed, 2009-09-23 18:45.

Information originally entered by wilesgjw

Climate Change Sensitivity Database

Spermophilus washingtoni

Sensitivity Score

Confidence Score

Authorship