endemic to a single nation
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (5000-200,000 square km (about 2000-80,000 square miles)) Disjunct populations in west-central and southwestern Illinois, southeastern Missouri and adjacent Arkansas (Conant and Collins 1991). See Brown and Rose (1988) for information on distribution in Illinois. See Figg (1991) for a brief account of recent survey results from southeastern Missouri.
Length: 4 cm
Catalog Number: USNM 134273
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Year Collected: 1951
Locality: Beardstown, 3 mi E of, Cass, Illinois, United States, North America
Comments: Basically terrestrial. Sand prairies and cultivated fields, open sandy areas of river lowlands. Burrows into soil using forelimbs (Tucker et al., 1995, Herpetological Review 26:32-33). Eggs and larvae develop in flooded fields, ditches, sloughs, small ponds, or other temporary bodies of water.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Migrates between breeding pools and nonbreeding terrestrial habitats.
Comments: Metamorphosed frogs eat small terrestrial arthropods obtained from ground surface or in soil. Larvae eat suspended matter, organic debris, algae, and plant tissue.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 21 - 80
Comments: Taubert et al. (no date) estimated about 394 individuals (mostly males) in their survey of 26 breeding sites in Illinois. Most populations include fewer than 20 males (Brown and Rose 1988, Herkert 1992). Locally abundant in undisturbed sand prairies in Cass and Morgan counties, Illinois (Phillips et al. 1999).
Life History and Behavior
Comments: Seldom seen except during winter-spring breeding season.
Lays clutch of up to several hundred eggs divided among many clusters. Breeds in late winter or early spring in Midwest, from as early as late January through mid-April in Arkansas. In Missouri, breeding begins in late February or early March, continues into early April (Johnson 1987). Breeds in March in Illinois (Smith 1961). Aquatic larvae metamorphose into terrestrial form in about 2 months (late spring in Illinois).
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: T3 - Vulnerable
Reasons: Restricted to Illinois, Missouri, and Arkansas; most local populations are small; suffering declines from habitat loss due largely to agricultural practices.
Intrinsic Vulnerability: Moderately vulnerable
Environmental Specificity: Narrow to moderate.
Global Short Term Trend: Decline of 10-30%
Comments: Populations likely are declining because of loss of breeding habitat.
Degree of Threat: Medium
Comments: Continued draining and clearing of bottomlands, and housing developments and other land uses, have greatly reduced the habitat in southeastern Missouri, where there also is concern over the effects of pesticides in the environment (Johnson 1987, 2000). In Illinois, habitat has been lost to drainage of breeding sites and cultivation (Brown and Rose 1988, Herkert 1992, Phillips et al. 1999). Possible threats include highway construction, water contamination, and chemical spills (Beltz 1991). Bullfrogs and fish are also threats to breeding ponds (Taubert et al., no date)
Global Protection: Few (1-3) occurrences appropriately protected and managed
Comments: Some state lands protect breeding sites in Illinois; however this protection is limited.
Illinois chorus frog
The Illinois chorus frog, Pseudacris illinoensis, is a species of chorus frog that lives in scattered, restricted habitat ecosystems in the states of Arkansas, Illinois, and Missouri. It was published by Smith in 1951. Its lifecycle is little known, its isolated populations are increasingly restricted by agricultural drainage, and it is listed as a threatened subspecies. It is often referred to as a subspecies of P. streckeri. Collins  recognized it as its own species which was followed by ASW6.0 and Amphibiaweb on the basis of its diagnosability from Pseudacris streckeri and its allopatry. The IUCNredlist 2013.2 has not incorporated this taxonomic split.
The Illinois chorus frog, a wetland amphibian, grows to a maximum length of 1.5 inches (3.7 cm). Its range is restricted to isolated sandy wetlands along the banks of the Mississippi River and a major tributary, the Illinois River.
Its lifecycle begins with the mating season beginning in late February and continuing until late April, when the small amphibian signals its aptitude with a version of the distinctive cry that gives its genus its name. The breeding call can be heard at a distance of up to 1 mile (1.6 km). The pools of spring meltwater, where they live and eat, begin to dry up as early as mid-May, and the frogs disappear into hibernation below the winter frost line. Herpetologists say that the subspecies' unique anatomy makes its members ideal candidates for a life cycle that centers on hibernation. With unusually strong forelegs for its size, the Illinois chorus frog is described as the only frog that uses a breast stroke motion to dig its sandy burrows.
The Illinois chorus frogs' preferred habitat in Arkansas includes the patch of sandy wetland soil surrounding Stuttgart, Arkansas where rice is grown. However, the invention of laser land-levelling, and its use by rice paddy operators, has eliminated 61% of the subspecies' range in this southern state.
The Illinois Department of Natural Resources carried out a field study of the Illinois chorus frog's habitat in Mason County, Illinois, in March 2011. The study hoped to develop a methodological protocol to monitor the Illinois chorus frog's threatened population.
- Jeanne Townsend Handy, "The Secret Life of the Illinois Chorus Frog", Outdoor Illinois XIX:3 (March 2011), pages 9-11.
- Collins, J. T. 1997. Standard common and current scientific names for North American amphibians and reptiles. Fourth edition. Herpetological Circular 25: 1–40.
- "Amphibian Species of the World 6.0". Retrieved 2014-06-04.
- "AmphibiaWeb". Retrieved 2014-06-04.
- "IUCNredlist 2013.2". Retrieved 2014-06-04.
- Chris Young, "Researchers listen for chorus frogs", The State Journal-Register (March 28, 2011), pages 8, 12.
Names and Taxonomy
Comments: Subspecies illinoensis was proposed as a distinct species by Collins (1991) and Collins and Taggart (2002) (without supporting data), but this taxon was listed as a subspecies of P. streckeri by Phillips et al. (1999), Johnson (2000), and Crother et al. (2000, 2003). Based on molecular data, Moriarty and Cannnatella (2004) concluded that "the question of whether streckeri and illinoensis have differentiated sufficiently in allopatry to merit status as different species deserves further study." Crother (2008) cited Moriarty and Cannatella (2004) in listing illinoensis as a species. Trauth et al. (2007) found morphological evidence of geographic (clinal) variation within P. streckeri; these data did not provide support for the taxonomic elevation of illinoensis as a distinct species. Based on these studies, Collins and Taggart (2009) regarded illinoensis as a synonym of streckeri, whereas Frost (2011) listed illinoensis as a species.
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