|Scientific Name:||Spermophilus franklinii|
|Species Authority:||(Sabine, 1822)|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Pergams, O., Nyberg, D. & NatureServe (Hammerson, G.)|
|Reviewer(s):||Amori, G. & Hafner, D.J. (Small Non-volant Mammal Red List Authority)|
Listed as Least Concern because it is very widespread, although there have been declines in area of occupancy and extent of occurrence of more than 30% in some parts of its range, overall the loss of habitat throughout its range is less than that. In some states this species is of conservation concern but in others it is quite secure.
|Range Description:||This species occurs in the United States and Canada: from Kansas, Missouri, and Illinois northward to Alberta, Saskatchewan, and Manitoba. This includes parts of North Dakota, South Dakota, Nebraska, Indiana, Wisconsin, Minnesota, and Ontario; and all of Iowa. Eastern (Illinois, Indiana, Wisconsin, Ontario) and southern (Kansas, Missouri) parts of its range seem to be shrinking rapidly with few populations (often estimated to be less than 10 per state or province) known to remain extant. Populations in Alberta, Manitoba, and Saskatchewan still seem to be relatively common.|
Native:Canada (Alberta, Manitoba, Ontario, Saskatchewan); United States (Illinois, Indiana, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota, Wisconsin)
|Range Map:||Click here to open the map viewer and explore range.|
It is thought to be very rare in Illinois, Indiana, Wisconsin, Ontario, Kansas, Iowa, and Missouri; scarce in Nebraska, Minnesota, South Dakota, and North Dakota; and relatively common in Alberta, Manitoba, and Saskatchewan. In most of the United States the S. franklinii population is highly fragmented into small, often linear habitats. In much of Canada, even though fire suppression has resulted in the succession of prairie to aspen parkland, large contiguous tracts have been preserved, and S. franklinii seems to be faring better.
However, in view of extensive loss of prairie habitats, together with available data that document declines in both area of occupancy and extent of occurrence, it is likely that S. franklinii has declined to the level of rarity in the USA. On the other hand, while there has been some additional loss of prairies in the last 10 years, it is probable that in recent years more acres of prairie have been restored than have been lost. In addition, S. franklinii is not exclusively associated with prairie vegetation. Under these circumstances, it is unclear why populations of S. franklinii are still declining.
|Habitat and Ecology:||
This species has a strong affinity for tall grass and mid-grass prairies. It also uses riparian areas (marsh edges), forest-field edges, fields, hedgerows, and unmowed strips along railroad rights-of-way and roadsides. It generally avoids short grass habitats. Nests are in underground burrows. It is primarily diurnal, but less conspicuous than other ground squirrels. Less than 10% of its time is spent above ground (Sowls 1948). It begins hibernation by late September.
It is not colonial, but lives in loose colonies. Densities of 10-20/ha have been recorded (Banfield 1974). Populations appear cyclic and peak every 4-6 years. During peak years it may occur in densities of 30/acre (74/ha) (Schwartz and Schwartz 1981). In central South Dakota, the annual home range was 25 ha for males, 9 ha for females (Choromanski-Norris et al. 1989).
The breeding period is immediately after hibernation in early spring. Gestation lasts 28 days, with young being born in May or June. Litter size is 5-11 (average 7); with one litter per year. Young are weaned in 40 days.
Although prairie habitats may be stable or increasing, other Franklin’s Ground Squirrel habitats may be declining. The availability of suitable cover and soil structure for burrows contribute to limiting their distribution. Burrows must be deep to be insulated from heat and cold, and must be well drained. This species seems to prefer to burrow in embankments (river and ditch banks; Kennicott 1855) or berms (highway and railroad rights-of-way; Ellis 1982). This may be because:
1) there is better drainage;
2) embankments and berms often consist of less tightly packed soil, allowing easier digging; or
3) tunnels need to be shorter.
Elevated railroad right-of-way beds seem to provide acceptable habitats, as well as dispersal corridors. In fact, in states for which data exist, populations of S. franklinii have become largely restricted to railroad rights-of-way, and to some lesser extent prairie fragments. Ellis (1982) points out that such rights-of-way usually have a diversity of dicotyledonous plants and a mixture of weedy and native species. Occasionally populations are also found in road rights-of-way, prairie cemeteries, forest/grassland edges, fencerows, and fallow fields and pastures. While prairies are no longer declining dramatically in acreage, railroad right-of-way habitats are being lost to changing management techniques and abandonment. Encroachment by woody vegetation on abandoned rights-of-way may provide less suitable conditions for S. franklinii. It requires adequate vegetative cover, and are not found in areas with short grasses resulting from frequent mowing (more than once a year) or herbicide treatments (Benjamin 1991, Lewis and Rongstad 1992, Hofmann 1999). It is possible that right-of-ways are more often mowed or treated with herbicide by railroad maintenance crews than in the past.
Threats in decreasing order of severity are: 1). Loss and fragmentation of primary habitat: tall- and midgrass prairie; 2). Extermination by man as a supposed agricultural pest and acknowledged predator of duck eggs; 3). Frequent mowing and herbicide of railroad rights-of-way; and 4). Loss of railroad rights-of-way to other uses.
The historical distribution of S. franklinii is from Kansas, Missouri, and Illinois northward to Alberta, Saskatchewan, and Manitoba, coinciding with former mid- and tallgrass prairie habitats. Such habitats have been greatly reduced, with 82.6–99.9% declines in the extent of tallgrass prairies in 12 states and one Canadian province since European settlement (Bowles et al. 1998). Prairie mammals, such as the Prairie Deer Mouse (Peromyscus maniculatus bairdii), Prairie Vole (Microtus ochrogaster), and Franklin’s Ground Squirrel have suffered as a result (Bowles et al. 1998, Pergams and Nyberg 2001).
In the eastern part of its range, S. franklinii is found primarily in small linear habitats. The continuing decline could be the result of the difficulty of dispersing individuals finding a suitable unoccupied habitat. It is known that male juveniles disperse (Ellis 1982, Benjamin 1991), but it is unknown for what distance. Perhaps juvenile mortality has increased so much (automobiles and trains are obvious potential sources) that they rarely find suitable habitats during dispersal.
Population fragmentation and isolation may also have longer-term effects through declines in vigour due to loss of genetic variability. Occupation of small, isolated habitat patches, as is the case in the USA, may hamper successful dispersal and promote inbreeding. It seems to be faring appreciably better in Canada (perhaps suitable habitat patches are larger and less isolated), although Canadian populations are also apparently declining. Habitat changes in Canada may be less detrimental. For example, in Canada, fire suppression has resulted in the succession of prairie to aspen parkland, where S. franklinii continues to be found. Although the habitat has changed, large contiguous tracts have been preserved, whereas in the USA only smaller prairie fragments and rights-of-way continue to provide habitat for S. franklinii.
It opportunistically eats the seeds, fruits, and foliage of a great variety of plants, but vegetation probably does not comprise the majority of its diet. It has been thought to be an agricultural pest, and has at times been systematically exterminated. Millions of S. franklinii were killed for bounties ranging 1–10¢ per skin in the late 1800s (Bailey 1893). However, there is little evidence that they cause much crop damage. Spermophilus franklinii may be the least herbivorous of the ground squirrels, eating as much or more insect and other animal matter as vegetation (Bailey 1893, Ellis 1982, Hofmann 1999). There is, in fact, some evidence that they avoid row crops, and are only occasionally found in cover crops (Benjamin 1991). On the other hand, there is good evidence that S. franklinii opportunistically preys on waterfowl eggs, and there has been some extermination of the species for that reason (Sowls 1948, Balser et al.1968, Lynch 1972).
"Poison peanuts" (pelleted peanuts and zinc phosphide) are often ploughed into the ground by highway departments to control plains pocket gophers (Geomys bursarius); this probably affects S. franklinii in areas with both species. Pesticide use has played, and may still play, a role in the decline of this species. Scott et al. (1959) describe "virtually annihilative losses" of S. franklinii in areas treated with dieldrin, a pesticide banned in 1974. Deleterious effects from other pesticides still in use are possible.
Internal parasites known to infest S. franklinii are the protozoans Eimeria franklinii and Trypanosoma hixsoni, the cestode Hymenolepsis diminuta, and the nematodes Capillaria chandleri, Citellinema bifurcatum, Physaloptera masino, Rictularia citelli, and Weinlandia citelli (Jackson 1961, p. 142).
Spermophilus franklinii is listed as S2 (Imperiled) in Indiana, Kansas, Missouri, Ontario, and Wisconsin; and as S3 (Rare) in Iowa. Thus S. franklinii has listed status in 6 out of 14 states and provinces of its historical range. However, many of the S4 (Apparently Secure) and S5 (Secure) rankings seem to be based on insubstantial data. Some exceptions are Alberta, Manitoba, and Saskatchewan, where populations still seem to be relatively common. Spermophilus franklinii is unranked in Minnesota and North Dakota. There are no individuals of S. franklinii in captivity listed in the International Species Information System database (ISIS 2003).
There have been at least two introductions of S. franklinii, both in Illinois and both were failures. The first attempt (van Petten and Schramm 1972) succeeded for a number of years and was reportedly doing well in the late 1980s (Hoffmeister 1989: 163-164), but when the site was surveyed in 2001 by Martin et al. (2002), no squirrels were caught. The second attempt (Panzer and Schipp 1986) may have failed because of lack of dispersal possibilities from a small, urban site (Martin et al. 2002).
Recent literature and conversations indicate populations of S. franklinii exist in the following protected areas. Alberta: Dry Island Buffalo Jump Provincial Park (Alberta ERM), Lakeland Provincial Park (Alberta ERM), Long Lake Provincial Park (Alberta ERM), Sir Winston Churchill Provincial Park (Alberta ERM); Illinois: Barnhart Grove Prairie Restoration (Champaign County Soil and Water Conservation District); Indiana: Clark and Pine Nature Preserve (Indiana DNR), Gibson Woods/Shell Oil Nature Preserve (Lake County Parks Dept.); Manitoba: Belair Provincial Forest (Manitoba ERM), Grand Beach Provincial Park (Manitoba ERM), Riding Mountain National Park (Canadian Wildlife Service), St. Ambroise Provincial Park (Manitoba ERM), Spruce Woods Provincial Park (Manitoba ERM), Winnipeg Beach Provincial Park (Manitoba ERM); Saskatchewan: Douglas Provincial Park (Saskatchewan ERM), Duck Mountain Provincial Park (Saskatchewan ERM), Good Spirit Provincial Park (Saskatchewan ERM), Moose Mountain Provincial Park (Saskatchewan ERM), St. Denis National Wildlife Area (Canadian Wildlife Service); Wisconsin: Chiwaukee Prairie (Wisconsin DNR/The Nature Conservancy).
1. Initiate metapopulation study to determine rates and distances of S. franklinii colonization events. Study factors that influence colonization and extinction rates.
2. Initiate genetic studies to determine genetic diversity and structure of S. franklinii metapopulations.
3. Initiate studies of stable populations to help understand basis for population size change.
4. Acquire and preserve other lands inhabited by S. franklinii.
5. Improve census information in all 14 states and provinces.
6. Improve knowledge of vegetation and soil required by this species.
7. Initiate cooperative agreements with railroads for management of rights-of-way inhabited by S. franklinii populations (e.g., stop frequent mowing and treating with herbicide).
8. Acquire for preservation abandoned railroad rights-of-way inhabited by S. franklinii populations, especially those connecting larger preserves.
9. Identify extent to which S. franklinii is controlled by farmers and ranchers. Design a program compatible with conservation of S. franklinii and economic needs of farmers and ranchers.
10. Assess effect of "poison peanuts" on S. franklinii. If S. franklinii is impacted, modify control program to mitigate effect on S. franklinii.
11. Assess effect of pesticides on S. franklinii. If S. franklinii is impacted, modify pesticide program to mitigate effect on S. franklinii.
12. Initiate a public education program about S. franklinii.
13. Initiate captive breeding and translocation program reintroducing animals to suitable habitats.
|Citation:||Pergams, O., Nyberg, D. & NatureServe (Hammerson, G.) 2008. Spermophilus franklinii. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 28 May 2015.|
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