Agenda - Council - 10/22/2002 - Laserfiche WebLink

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332 BL.~q-DING'S TURTLE Emydoidea blandingii (Holbrook) I I I I I I I I i I I. I I I I I I ~>L988, S~te of Minnesota, Vcra Ming Wont OFFICIA. L STATUS: Threatened B>~S[5 FOR STATUs: Although formert? more widespread, the Brand- ing's turtle is now restricted to a small number of states and provinces in the Upper Midwest. stretching from Nebraska eastward to Michigan. On- tario, and Quebec..4. smaller remnar{t population, spanning potions oi" a few New England states, as well az a number of scattered populations throughout the Northeast, testify' to the turtle's more espanded range in earlier times. Mi_nnesota lies on the northwest periphery of the Species' range. An extensive area of. sand dunes and marshes along thc Mississippi River, south of the town of Kellogg, is recognized as a major concentration~ area for the turtle and may be one of the tartest breeding populations in its entire range. Elsewhere in the state, the Bland[rig's turtle has a more spoFy distribution, following the ~ississippi and St. Croix rivers north- ward into east-central Minnesota and thg Minnesota River westward into thc south-central portions of the state. Two recent records from P~pestone County also confirm the species' presence in the Missouri River drainage of extreme southwestern Minnesota. As a marsh inhabitant the recent destruction Of wetland habitats bS' d. rai~: age and/or inundation for agricultural purposes, river channelization, and. water impoundme.nt has greatly decreased av:iilable h~ibitat for the species. Like other' turtles, the Blanding's turde is also vuineraNe to collecting as a desirable pet ~pecies (.545 for a 15 to 20 centimeter tm-de); it is easily cot- letted in areas where it is abundiant, especially during the nesting season.. Thc species' life history also-makes this turtle particularly susceptible to human disturbances, as evidenced by a long term and in. tens[ye study of' the population inhabiting the Kellogg Dunes (Pappas, personal communi- cation). Some features contributing to this susceptibility are late mature- don, tow reproductive potential (one clutch/season), tong-tired adults, and high mortality of eggs and juveniles. Population and reproductive dy- . nam[cs suggest viable pOpulations of Blanding's turtles are dependent on large numbers of animals and adequate areas.of undisturbed' habitat. PREFERRED HABITAT: The preferred habitat of the Bland[rig's turtle includes calm, shallow water, rich, aquatic vegetation and sandy uplands for nesting. Studies by Congdon'ct al. (1983) in Michigan and by Linck (personal communication) in Massachusert~ have shown th~t nesting ma[es may travel considerable distances (200 to 400 meters) to a nesting area, pressing cnroutc what appears to be suitable nesting habitat immedi- ately adjacent to the marsh in which they reside. AID TO IDENTIFICATION: Blanding~s turtle is medium-sized, averag-- lng. IS'to 25 centimeters in: length. The species' most diagnostic field char-' acteristics are its smooth, domed upper shell, or carapace, and irs bright yellow neck, throat, and chin. The carapace usually appears bluish black. with numerous specks of yellow throughout. The lower shell, or plastron, xs-b~g~t',V~!l:o.w'w~m"%Iack'~atches ~h:. ~e Ou~i.dc margin. In general', the adult male can be dist!nguisged. {'rom the fei'flair, by its slightly indented plastron a.nd longer tail. T~e mokt distinct feature of the plastron is thc hinge, which allows ihe turde td raise the plastron upward and provide more protection to the soft extremities that it has pu[le~ inside thc shell. For this reason the species is'often referred to as a ~semibox" turtle. RECOiVI~fEND~TIONS: Efforts to identify., protect, and presen'e pre- ferred habitats of this species should be continued, particularly where populations are locally abundant. Additional information on. the species' ' local distribution and. abundance should also be collected to allow an act curare assessment of its current status and to aid in protection efforts. SELECTED REFERENCES: Breckenridge 19~; Conant 1975: Con- gdon et al. 1983; Ewer[ 1982; Graham and Doyle 1977; McCoy [973: Vogt 1981. "7- Bland.[rig's Tunic: adult viewed ~'rom above {top) and below Ibonorn): side view shown in silhouette. -37~-