Only a few species appear as introductions into Iowa in the last 30 years. The bullfrog, Rana catesbeiana, was systematically introduced along with fish stocked from hatcheries in the 1930s and this species continues to spread in northern Iowa where it poses a hazard to smaller frogs. Turtles sold as pets, primarily map turtles (Graptemys pseudogeographica and G. geographica) and red-eared turtles (Trachemys scripta) continue to be found in scattered ponds, usually rural, throughout the state. The eastern box turtle (Terrapene carolma) has been reported in or on the edge of most major Iowa cities even though no breeding population is known here. A pregnant Arizona black rattlesnake (Crotalus viridis cerberus) found in a vacant lot in southeastern Des Moines, probably escaped from a snake breeder in the area. The continued existence of a population of salamanders native to the Pacific Northwest that at least temporally established in Davis County after a lumber train derailed there in 1923, is unknown. The spread of the plains spadefoot (Spea bombifrons) throughout the loess hills since 1944 may be an example of a natural introduction. The northern movement of the plains leopard frog (Rana blairi) and the fertilizer-stimulated growth of cattails in shallow marshes that may be impacting survival of Blanding\u27s turtle (Emydoidea blandingi) may be the indirect result of human modification of the environment

Christiansen, James L.

University of Northern Iowa

Journal of the Iowa Academy of Science: JIAS Volume 108 Number Article 16 12-2001 Non-Native Amphibians and Reptiles in Iowa James L. Christiansen Drake University Let us know how access to this document benefits you Copyright © Copyright 2001 by the Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/jias  Part of the Anthropology Commons, Life Sciences Commons, Physical Sciences and Mathematics Commons, and the Science and Mathematics Education Commons Recommended Citation Christiansen, James L. (2001) "Non-Native Amphibians and Reptiles in Iowa," Journal of the Iowa Academy of Science: JIAS, 108(4), 210-211. Available at: https://scholarworks.uni.edu/jias/vol108/iss4/16 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 scholarworks@uni.edu. Jour. Iowa Acad. Sci. 108(4):210-211, 2001 Non-Native Amphibians and Reptiles in Iowa JAMES L. CHRISTIANSEN Department of Biology, Drake University, Des Moines, Iowa 50311 Only a few species appear as introductions into Iowa in the last 30 years. The bullfrog, Rana catesbeiana, was systematically introduced along with fish stocked from hatcheries in the 1930s and this species continues ro spread in northern Iowa where it poses a hazard to smaller frogs. Turtles sold as pets, primarily map turtles (Graptemys pseudogeographica and G. geographica) and red-eared turtles (Trachemys scripta) continue to be found in scattered ponds, usually rural, throughout the state. The eastern box turtle (Terrapene carolma) has been reported in or on the edge of most major Iowa cities even though no breeding population is known here. A pregnant Arizona black rattlesnake (Crotalus viridis cerberus) found in a vacant lot in southeastern Des Moines, probably escaped from a snake breeder in the area. The continued existence of a population of salamanders native to the Pacific Northwest that at least temporally established in Davis County after a lumber train derailed there in 1923, is unknown. The spread of the plains spadefoot (Spea bombifrons) throughout the loess hills since 1944 may be an example of a natural introduction. The northern movement of the plains leopard frog (Rana blairi) and the fertilizer-stimulated growth of cattails in shallow marshes that may be impacting survival of Blanding's turtle (Emydoidea blandingi) may be the indirect result of human modification of the environment. INDEX DESCRIPTORS: Iowa herpetology, introduced amphibians, introduced reptiles. The potential for an introduced species to become established de-clines as the number of limiting factors increases. The severe tem-perature swings, presence of roads around almost every square mile of the state, and agricultural and urban destruction of habitat con-ducive to wildlife make the environment of Iowa inhospitable for the vast majority if potential introductions of amphibians and rep-tiles. This paper constitutes a review of published accounts of intro-ductions and summarizes the introductions encountered in my 30 years of herpetological surveying of the state. Throughout this period telephone calls, many from county conservation board workers or other field biologists, have been received reporting obviously non-native species. Usually no record was kept of these and only rarely was it possible to examine the specimen. The accounts presented herein are those in which I have the greatest confidence. However, dates are ofren approximate and other inaccuracies are possible. ACCOUNTS OF INTRODUCED SPECIES The species found in the state in areas where they are not native are listed in Table 1. One of these that could still exist in Iowa is a salamander that was described as a new species, Ambystoma stejnegeri, by Ruthven (1912) from Bloomfield in Davis County. Several spec-imens were taken and deposited in the University of Michigan Mu-seum of Zoology. The holotype and paratypes were deposited in the US National Museum. These specimens have since been identified as the long-toed salamander (Ambystoma macrodactylum), a species na-tive to the Pacific Northwest. It is rumored that they became estab-lished in Iowa as a result of a train wreck that dumped a load of logs from Washington State. I have no evidence that suitable habitat remains in the area but the multiple specimens involved suggest that the population could have become established for a period. Two amphibians whose range changes are probably the result of natural invasion are the plains spadefoot (Spea bombifrons) and the plains leopard frog (Rana blairi). The plains spadefoot was discovered in Iowa near Council Bluffs by Huggins (1971) in 1967 approxi-mately 23 years after Bailey (1944) completed four years of extensive studies of amphibians on the region. Mabry and Christiansen (1991) found the animal to be abundant in all of the counties of the Loess Hills by 1990. The rapid expansion of the range of this species in the state seems to be a good example of a natural introduction into an ideal habitat. A second, less prominent natural range expansion involves the plains leopard frog that appears to be replacing the northern leopard frog (Rana blairi) and expanding its range to the north (Baness 1997). Bullfrogs (Rana catesbeiana) were introduced throughout the 1930s as a bonus to farmers who stocked their farm ponds with fish from the state fish hatcheries. They were an additional food source during those difficult times and the biological community was unaware of the potential damage this species does when introduced to areas where the existing community is not adapted to it. Lannoo et al. (1994) suggested that invading bullfrogs may have contributed to the decline in frogs he noted in Dickinson Co. It has been evident in my 30 years of work in the state that when the bullfrog popu-lation is high, especially in northern Iowa, it is rare to find significant numbers of other frog species sharing the pond-side habitat. Turtles, commonly kept as pets, are often released in urban ponds when their owner is tired of them. Red-eared turtles (Trachemys scripta elegans) have been reported to me several times from areas outside their range in Iowa. I have evidence, however, only of the two listed in Table 1. The false map turtle (Graptemys pseudogeographica) from Whitmer pond is another example of establishment of a released captive. It is common for travelers to pick up box turtles and bring them to Iowa. Both eastern and ornate box turtles are probably reg-ularly brought to Iowa and the list of localities of the eastern box turtle, a species not known to exist as a natural population in Iowa, shows how the specimens found tend to be associated with cities. Because of scattered natural populations, ornate box turtle introduc-tions are harder to detect. Snakes from outside Iowa are sometimes kept as pets or for other purposes. When these escape, they often receive attention. Guthrie INTRODUCED AMPHIBIANS AND REPTILES 211 Table 1. Non-native amphibians and reptiles found in Iowa. Many of the Terrapene carolina are three-toed box turtles, T. carolina triungus. Dates are often approximate because in many cases no permanent record was kept and the data are from memory. Species Ambystoma macrodactylum Spea bombifrons* Rana blairi* Rana catesbeiana Trachemys scripta elegans Trachemys scripta elegans Graptemys pseudogeographica Terrapene carolina Terrapene caroina T errapene carolina Terrapene carolina T errapene carolina Boa constrictor Python molurus C rota/us viridis cerberus Caiman crocodilus Common name Long-toed salamander Plains spadefoot Plains leopard frog Bullfrog Red-eared turtle Red-eared turtle False map turtle Eastern box turtle Eastern box turtle Eastern box turtle Eastern box turtle Eastern box turtle Central American boa Burmese python Arizona black rattlesnake Common caiman Location Bloomfield, Davis Co. Loess Hills Extending northward in S. Iowa NW 213 of Iowa Inland Clinton Co Farm Pond, S. Cedar Co. Whitmer Pond, Des Moines, Polk Co. S. Iowa City, Johnson Co. S. Muscatine, Muscatine Co. Sioux City, Woodbury Co. Council Bluffs, Pottawattamie Co. Sand Creek Wildlife Area, Dekatur Co.? grocery stores, Des Moines, Polk Co. Vacant lot, Des Moines, Polk Co. Vacant lot, Des Moines, Polk Co. Saylorville reservoir, Polk Co. Date 1912 195 2-present 1970-present 1930-present 1989 1978 1973 1990s 1971 1980s 1998 1980s 1923 1999 1991 1980s? *Natural introductions or range expansions; all others are believed to be released captives (1923) reported on Central American boas (Boa imperator = Boa con-strictor) frequently appearing in bananas shipped to local grocery stores. They, of course would not survive Iowa's winters. In 1991 a "large bullsnake" in a vacant lot in Des Moines turned out to be a 40 pound (18.14 kg) Burmese python (Python molurus). Its owner never appeared to collect the snake. The same was true for a large Arizona black rattlesnake ( C rota/us viridis cerberus) that appeared in a backyard in southeast Des Moines in 1991. Shortly after I captured the snake, it gave birth to nine young. Whether it would have sur-vived Iowa's winters is questionable unless it or its young found their way into someone's basement. "Pet alligators" appear in park ponds and sewers throughout the United States. These usually turn out to be Central American caiman (Caimen sp.) and have little chance or surviving Iowa's winters. The only record I know of in Iowa appeared in Saylorville reservoir (Table 1). CONCLUSIONS Few non-natural introductions pose a threat to Iowa's native spe-cies. With any introduction comes the risk of disease to which the native forms lack resistance. There is some evidence that some of Iowa's frogs may be in decline because of disease, but there is little evidence that the disease arrived through introduced species. The greatest damage from any herpetological introduction in Iowa ap-pears to be the local elimination of native frogs as a result of huge populations of introduced bullfrogs. Introduced red-eared and false map turtles could become established in appropriate habitats in southern Iowa and could introduce disease as well as genes that could alter the genetic makeup of natural populations. Escape of captive snakes, especially venomous or very large ones could pose a threat to humans. No elapid would survive Iowa's win-ters, but many viperids could. Whether they last that long or not, a venomous snake giving birth to young in a large city could pose a serious threat, especially to young children that may not be able to report a bite or have the report believed by an adult. Appropriate antivenom may not be available and without the exotic snake in hand, it may not be clear which or how much antivenom to use. LITERATURE CITED BAILEY, R. M. 1944. Iowa's frogs and toads. Iowa Conservationist 3(3):17-20 and 3(4):25 and 27-30. BANESS, E. 1997. The distribution and hybridization of the leopard frogs, Rana pipiens and Rana blairi in Iowa. M.S. Thesis, Drake University, Des Moines, Iowa. GUTHRIE, J. E. 1923. The banana snake, Boa imperator. Proceedings of the Iowa Academy of Science 30:189-196. HUGGINS, D. C. 1971. Scaphiopus bombifrons Cope, a species new ro Iowa. Journal of Herperology 5(3-4):216. _ LANNOO, M. J., K. LANG, T. WALTZ, and G. S. PHILLIPS. 1994. An altered amphibian assemblage: Dickinson County, Iowa, 70 years after Frank Blanchard's Survey. American Midland Naturalist 131:311-319. MABRY, C. M., and J. L. CHRISTIANSEN. 1991. The activity and breed-ing cycle of Scaphiopus bombifrons in Iowa. Journal of Herpetology 25(1): 116-119. RUTHVEN, A.G. 1912. Description of a new salamander from Iowa. Pro-ceedings of the United States National Museum. 41(1874):517-519. 

Non-Native Amphibians and Reptiles in Iowa

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Non-Native Amphibians and Reptiles in Iowa

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