Journal of the Iowa Academy of Science: JIAS

Volume 106 Number Article 4

1999

The Habitat and Distribution of the Stinkpot, Sternotherus odoratus, in Iowa

Kristi K. Sutton Drake University

James L. Christiansen Drake University

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Recommended Citation Sutton, Kristi K. and Christiansen, James L. (1999) "The Habitat and Distribution of the Stinkpot, Sternotherus odoratus, in Iowa," Journal of the Iowa Academy of Science: JIAS, 106(3), 63-65. Available at: https://scholarworks.uni.edu/jias/vol106/iss3/4

This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Journal of the Iowa Academy of Science: JIAS by an authorized editor of UNI ScholarWorks. For more information, please contact [email protected]. Jour. Iowa Acad. Sci. 106(3):63-65, 1999

The Habitat and Distribution of the Stinkpot, Sternotherus odoratus, in Iowa

KRISTI K. SUTTON and JAMES L. CHRISTIANSEN1

Department of Biology, Drake University, Des Moines, Iowa 50312

Twenty years of study have shown that the stinkpot, SternotheruJ odoratuJ and the Illinois mud turtle (KinoJternon j/aveJcem Jpoonert) occur in Iowa primarily in the Mississippi Alluvial Plain. Even though the turtles are found within a kilometer of each other, they are never sympatric. Illinois mud turtles are most often associated with ephemeral ponds and soils of nearly pure sand (Sparta sand and Chelsea loamy fine sand), whereas stinkpots inhabit permanent water, often fed by cold springs, and are limited to sandy, loamy soils (Aquolls and Perks sandy loam). Even though several new localities have been discovered for stinkpots, population densities are very low, and survival of the species in Iowa is tenuous.

INDEX DESCRIPTORS: Iowa kinosternids; Iowa turtle ecology; SternotheruJ odoratm; KinoJternon j/aveJcem Jpooneri; stinkpot ecology; Illinois mud turtle ecology

Iowa has only two turtles of the family Kinosternidae. The stink­ ments. It is poorly drained, containing marshes, backwater sloughs, pot, Sternotherus odoratus (Latreille), was first found in the state by ephemeral pools, and lowland timber that often floods in the spring. Dodge (1956). The Illinois mud turtle Kinosternon jlavescens spooneri Smith, was first reported in the state by Dodge and Miller (1955) METHODS although an Iowa specimen had been collected by Reeve Bailey and deposited in the Iowa State University research collection about 12 This project began in 1989 and continued through 1994. Field­ years earlier. That these animals had gone undetected in Iowa for so work was conducted primarily in May, June, and early July when long attests to their crypsis and rarity; both are now protected (Iowa both Sternotherus odoratus and Kinosternon jlavescens are active (Mah­ Natural Resources Commission 1994). The Iowa distribution and moud 1968); Christiansen et al. (1985). U.S. Geological Survey 7.5- status of the Illinois mud turtle was summarized by Christiansen et minute topographic maps were used to focus the trapping program al. (1990), but the stinkpot has received little attention since the on ponds, oxbows, and marshes where habitat appeared adequate. report of three new populations by Christiansen (1980). Soil types adjacent to pools where turtles were taken were recorded The present study was initiated to locate additional populations from Soil Conservation Service soil maps (Brown 1988, Dankert of the stinkpot and to determine its range in Iowa. We explored the 1989). Also noted were extent and permanence of interconnected habitat associations of stinkpots, including other turtles present, and pools. commented on differences between the habitat of this species and Walking surveys were conducted around the edges of pools and the Illinois mud turtle. Finally, we provided our judgment as to the rivers. Where possible, large bodies of water were surveyed for bask­ abundance of this species relative to the other turtle species in Iowa ing turtles by canoe. Modified fike-net traps (Legler 1960) baited that we have studied. with fresh fish were set in quiet water usually near basking sites with some of each trap projecting above the water surface. No more than STUDY AREA one specimen of each species was removed from each location trapped. Most turtles were released after sex was determined and The selection of the study area was influenced by 20 years of maturity judged on the basis of size, male tail development, and aquatic surveys in eastern Iowa conducted by the second author presence of oviductal eggs in females. Specimens retained were either (JLC). These surveys found Muscatine and Louisa counties, specifi­ kept alive and later released, or killed with cephalic injection of95% cally the valleys of the Cedar and Iowa Rivers, to provide the most ethyl alcohol and preserved in the Drake University Research Col­ extensive network of oxbows and riverside pools outside of the Mis­ lection. Turtles kept were preserved by the "shell and soft parts" sissippi Valley. These also were the only areas within the state that method in which shell, bones, skin, and internal organs were pre­ yielded stinkpots in the early studies. The focus of the study was served and tagged separately. This work was done under permit SC- Cone Marsh State Management Area, Pike Creek, and Cone Lake. In 00210-01 and others issued by the Iowa Department of Natural addition, we trapped suitable areas such as sloughs and floodplain Resources. pools along the entire length of the Iowa River, where it traverses Louisa County, and the Cedar River where it passes through Mus­ RESULTS catine County. The entire study area is contained within a unique geological area known as the Mississippi River Alluvial Plain (Prior Stinkpots were found at 10 previously unreported localities, all of 1991). The area is characterized by broad floodplains, terraces, and them separate pool complexes in east-central Iowa (Figure 1). In sand dunes underlain by a thick accumulation of water-sorted sedi- addition, a specimen was discovered by U.S. Fish and Wildlife Ser­ vice personnel near Lock and Dam Number 10 in the Mississippi 1 Corresponding Author River in Clayton County, far north of the other records. This locality 64 JOUR. IOWA ACAD. SCI. 106(1999)

collected serendipitously in the search for stinkpots were the painted turtle (Chrysemys picta), snapping turtle (Chelydra serpentlna), spiny softshell (Apa/one spinifera), and Blanding's turtle (Emydoidea blandin­ gii). Abundance of turtles at trapping locations yielding stinkpots is shown in Table 1. With one exception, populations of Illinois and mud turtles were •• limited to terrestrial habitats consisting of Sparta sand or Chelsea loamy fine sand. The exception was Cone Marsh where neither soil occurs. Stinkpots were much more flexible in the amount of clay and organic matter they tolerate in soils adjacent to their aquatic habi­ tats. Their soils ranged from Colo silty loam to Coland-Perks-Law­ son. Even more flexible were snapping turtles, collected in pools near soils supporting both species, as well as almost every aquatic habitat found in Iowa (Christiansen & Bailey 1988) Study of the habitats supporting stinkpots and Illinois mud turtles showed that both species were linked to somewhat sandy soils and were often associated with small bodies of water. However, even where species were found within a kilometer of each other in the LOUISA co. same valley, never were they found sympatrically. Illinois mud turtles had a strong association with ephemeral ponds, while stinkpots were strongly associated with permanent water. Even when stinkpots were taken from an ephemeral pool, permanent water was always within 75 meters.

DISCUSSION After 20 years of study, the Illinois Mud turtle has been found in only five different locations in the state and may be native to only four. While stinkpots have been found in several new localities, es­ pecially along Pike Creek and oxbows of the Iowa River, their pop­ Figure 1. Currently known localities for K. f. spooneri and S. odoratus ulation densities are extremely low. Twenty years of trapping along within the study area. Circles represent S. odoratus; diamonds denote the Mississippi River and other large S.E. Iowa rivers has failed to K. f. spooneri. Numbers refer to trapping sites in Table 1. The north­ ernmost locality for S. odoratus in Clayton County is not shown nor locate additional specimens. The new locality discoveries for stink­ are the Lee and Des Moines County localities for K. f. spooneri. pots suggest that the Cedar River/Pike Creek complex, an area over 24 km long, supports a population, in the opinion of the authors, large enough to be viable. represents the only Iowa record not in the Mississippi River Alluvial Stinkpots are much more aquatic than are Illinois mud turtles. Plain. They tend to occupy spring-fed ponds and were always in or near New localities were discovered only for stinkpots; we found no permanent water, while mud turtles are often found in ephemeral new populations for the Illinois mud turtle. However, a chance con­ pools (Christiansen et al, 1990). Their tie to permanent water was versation with a Columbus City resident provided evidence that the also observed by Smith (1961), Mahmoud (1969), Vogt (1981), Bar­ Cone Marsh population of Illinois mud turtles in northwestern Loui­ bour (1971), Ernst (1986), and Gibbons et al. (1983). The distinc­ sa County may have been introduced. Upon being shown a series of tion of the habitats of these species in Iowa is consistent with Mah­ turtle shells, this person picked out the mud turtle shell and vol­ moud's (1969) observation that the habitats of Sternotherus odoratus unteered that in the early 1950s, he picked up many (over 20) of and Kinosternon flavescens flavescens (yellow mud turtle) were separate these from the Muscatine cement plant area and released them at in Oklahoma. The narrow habitat requirements of both kinosternids Cone Marsh. The cement plant borders the largest known surviving at the northern extremes of their ranges where other factors such as population of this species at this writing and extensive trapping of temperature may be at their tolerance limit, suggest that the survival Cone Marsh has produced only two old mud turtles. Other species of the Iowa population is precarious. The fragility of all but one of

Table 1. Specimens taken at sites where Sternotherus odoratus was captured in the Mississippi Alluvial Plain. One trap per site per app. 18 hours overnight equals one trap night. Sites are represented by number in Fig. 1.

SITE 1 2 3 4 5 6 7 8 9 TOTAL % ABUN- TRAP NIGHTS 8 15 1 25 5 10 10 10 16 100 DANCE

S. odoratus 2 1 1 5 1 1 1 1 1 14 6.67 C. picta 12 23 5 29 10 30 11 25 13 158 75.23 S. serpentina 1 6 1 3 1 7 2 2 4 27 12.86 E. blandingii 0 11 0 0 0 0 0 0 0 11 5.24*

*While Blanding's turtles were of low abundance for the overall study, they were extremely abundant at site 2, a broad area of grass hummock and marsh. STERNOTHERUS DISTRIBUTION 65

the Iowa populations of the Illinois mud turtle is summarized by ulation estimates and geographic distribution of the yellow mud turtle Christiansen et al. (1990). We now believe that no Iowa stinkpot (KinoJternon flave.rcem) in Iowa. Journal of the Iowa Academy of Science population remains as dense as the endangered Big Sand Mound mud 97(3):105-108. turtle population (Christiansen et 1990). The thin population of DANKERT, W. 1989. Soil survey of Muscatine County, Iowa. Soil Conser­ al. vation Service, U.S. Department of Agriculture. stinkpots scattered through the Cedar River-Pike Creek complex DODGE, C.H. and LS. MILLER. 1955. The yellow mud turtle, KinoJternon is sufficiently precarious to continue protection of this species under flave.rcem Jpooneri Smith, in Iowa. Natural History Miscellany 42:242. Iowa law and we suggest that a small natural or man-made phenom­ DODGE, C.H. 1956. The Musk turtle in Iowa. Herpetologica 12:176. enon could extirpate stinkpots from the state. ERNST, C.H. 1986. Ecology of the turtle, SternotheruJ odoratuJ, in south­ eastern Pennsylvania. Journal of Herpetology 20(3):341-352. GIBBONS, J.W., J.L. GREEN, and J.D. CONGDON. 1983. Drought-re­ LITERATURE CITED lated responses of aquatic turtle populations. Journal of Herpetology 17(3):242-246. BARBOUR, R.W. 1971. Amphibians and reptiles of Kentucky. University IOWA NATURAL RESOURCES COMMISSION. 1994. Endangered and Press of Kentucky, Lexington Ky. Threatened animal species. Chap. 77:1-13. BROWN, M.D. 1988. Soil survey of Louisa County, Iowa. Soil Conservation LEGLER, J.M. 1960. A simple and inexpensive device for trapping aquatic Service, U.S. Department of Agriculture. turtles. Proceedings of the Utah Academy of Science, Arts and Letters CHRISTIANSEN, J.L. 1980. SternotheruJ odoratuJ, One of Iowa's rare periph­ 37:63-66. eral turtle species. Proceedings of the Iowa Academy of Science 87(1): MAHMOUD, I.Y. 1968. Feeding behavior in kinosternid turtles. Herpeto­ Abstract from 92nd Session, Simpson College. logica 24(4):300-305. CHRISTIANSEN,J.L.,J.A. COOPER,J.W. BICKHAM, B.J. GALLAWAY, MAHMOUD, I.Y. 1969. Comparative ecology of the kinosternid turtles of and M.A. SPRINGER. 1985. Aspects of the natural history of the yellow Oklahoma. Southwest. Naturalist 14(1):31-66. mud turtle, KinoJternon flave.rcem (Kinosternidae) in Iowa: a proposed en­ PRIOR, J.C. 1991. Landforms of Iowa. University of Iowa Press, Iowa City. dangered species. Southwest Naturalist 30(3):413-425. 153pp. CHRISTIANSEN, J.L., and R.M. BAILEY. 1988. The Lizards and Turtles SMITH, P.W. 1961. Amphibians and reptiles of Illinois. Illinois Natural of Iowa. Iowa D.N.R. Nongame Technical Series Special Publication (2): History Bulletin 28: 122-127. 1-19. VOGT, R.C. 1981. Natural History of Amphibians and Reptiles of Wis­ CHRISTIANSEN,J.L., B.J. GALLAWAY, andJ.W. BICKHAM. 1990. Pop- consin. Milwaukee Public Museum, 205pp.