PROCEEDINGS OF THE OKLAHOMA ACADEMY OF SCIENCE Volume 81—2001

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Distribution and Relative Abundance of the Oklahoma Salamander (Eurycea tynerensis)

George R. Cline¹ and Renn Tumlison²

Oklahoma Cooperative Fish and Wildlife Research Unit and Department of Zoology, Oklahoma State University, Stillwater, OK 74078

¹Current address: Department of Biology, Jacksonville State University, Jacksonville, AL 36265

²Current address: Department of Biology, Henderson State University, Arkadelphia, AR 71999

The Oklahoma salamander (Eurycea tynerensis) occurs in the western Springfield Plateau of the Ozark Mountains of Arkansas, Oklahoma, and Missouri. Our survey of distribution examined 213 sites, 50 of which produced salamanders at the time of sampling, with several new records of distribution documented. Most sites at which salamanders were found were clumped along a few drainages. Potential threats to the species include graveling operations, siltation, and permanent flooding from damming of streams. Notes are provided about the conditions of habitat at new as well as historic sites. ©2001 Oklahoma Academy of Science

INTRODUCTION

The Oklahoma salamander, Eurycea tynerensis, is a small neotenic salamander endemic to gravel-bottomed streams located along the western slopes of the Ozark Mountains of Oklahoma, Missouri, and Arkansas (1-3). The Springfield Plateau is a unique subregion of the Ozarks due to the presence of deep cherty limestone deposits and to the presence of E. tynerensis.

Oklahoma salamanders have been collected from 28 localities in five Oklahoma counties — Adair, Cherokee, Delaware, Mayes, Ottawa — with specimens deposited in the Oklahoma State University Museum of Zoology (OSU) and University of Michigan Museum of Zoology (UMMZ) (2,4-6). In Arkansas, animals were collected at eight sites in Benton County,[Carnegie Museum of Natural History] (7,8); and in Missouri at 40 sites in Barry, McDonald, Newton, Stone, and Taney counties (3,9,10).

Museum records at OSU and UMMZ indicated high population densities at some Oklahoma and Missouri sites. Dundee (2) reported population densities ranging from 2.3-24.2 salamanders per ft² (0.09 m²) at Pineville, Missouri, yet recent status surveys conducted in Missouri (10) and Arkansas (8) indicated lower densities. Both reports suggested that the species is threatened by habitat loss caused by siltation and gravelling operations. Oklahoma salamanders are considered rare or endangered species in all three states (11-13; T. Johnson, personal communication); however, no current data exist concerning the status of the Oklahoma salamander in Oklahoma.

This study was conducted to achieve an extensive survey of the status of the Oklahoma salamander in Oklahoma and a less extensive survey of sites in Missouri and Arkansas. We report relative abundance and conditions supporting populations of Oklahoma salamanders in the areas surveyed.

Potential survey sites were determined from historic records and 7.5 min U.S. Geological Survey quadrangle maps. Details of the 213 specific locations visited are provided in the final report submitted to the U.S. Fish and Wildlife Service (14) and marked on quadrangle maps housed at the Tulsa Field Office. Previous authors (8,10) suggested that the salamanders typically were found in streams bounded by narrow valleys, so we sampled 213 such sites intensively from 1

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March through 10 October, but primarily during June and July of 1988. Salamanders were collected by turning submerged stones and catching exposed individuals in aquarium nets. All sites were sampled during daylight for 30 min by two researchers, i.e., 1 work-hour. We surveyed seven microhabitats in each stream: pools, pool edges, riffles, riffle edges, runs, run edges, and isolated pools. Runs were defined as flowing water that was not mixed as violently as riffles. We attempted to invest equal time and intensity while sampling each microhabitat. Three sites in Oklahoma were visited more than once to ascertain within-site variation in density and to gain insight about daytime versus night-time activity. These were: Tyner Creek (the type locality), 4 visits; Peavine Creek, an historic location subject to disturbance by gravel operations (2), 6 visits; and Rock Creek at Camp Egan, a site with historically high population densities based on museum records at OSU, 18 visits. Multiple visits were not included in this analysis, and results of those studies will be reported elsewhere.

Sites were coded for presence/absence and the number of salamanders observed. Relative population density was estimated as the number of salamanders observed per work-hour. Wet channel width (water only; m), dry channel width (total width of the streambed; m), and average water depth (cm) were recorded. Water temperature was measured to 0.2°C with a rapid register thermometer. Flow was measured with a Teledyne Gurley pygmy current meter. Substrate size was coded by use of a modified Wentworth scale (15). Embeddedness is a measure of the accumulation of particles <2 mm diameter that were found filling interstitial spaces under the surface layer of rocks. Aquatic and shoreline vegetation and local landform was recorded for each site. Stream order was determined from 1:500,000 scale water resources maps.

Two hundred thirteen sites were examined in the three-state area (14; Appendix 1). Voucher specimens of E. tynerensis collected from the new locations were deposited in the Oklahoma State University Museum of Zoology. Two sites in Arkansas, one in Missouri, and 25 in Oklahoma were new records of distribution. Salamanders were present at 50 (23.5%) of the surveyed sites and absent at 82 (38.5%). The remaining 81 (38.0%) sites were dry at the time of survey. Salamanders occupied 37.9% of the sites that had surface flow. Salamanders were found at 43.5% of 92 Oklahoma sites with water at the time of survey, 17.8% of 28 Arkansas sites, and 21.7% of 23 Missouri sites. Missouri and Arkansas sites were examined in early July when water levels were dropping and many streams were dry, thus comparison among states probably is biased.

Salamanders were observed at 50% of the historic sites in Oklahoma. Three historic sites in Oklahoma (Turkey Ford, Marvin Springs, MacSpadden Falls) were not surveyed because of active gravel operations, denial of access by the landowner, heavy embeddedness, or lack of surface water at the site. Nearby available habitat was sampled in each of these cases, i.e., Council Creek, Tyner Creek, Steeley Springs. Five historic Oklahoma sites could not be located (unnamed creek 9.1 mi W of Colcord, Stansberry-January Cave, Hendron Spring, 0.5 mi E Tahlequah, Moody Township). Three historic sites were dry (Boudinott Springs, Northeastern State University, Turkey Ford), one was heavily embedded (Marvin Springs), and one was flooded (3 mi. S of Salina). E. tynerensis historically has not been collected at the spring off Cloud Creek (16), but we collected specimens in Cloud Creek. We were unable to enter Little Spring Creek at the OK Hwy 82 bridge, but we collected salamanders at two other sites on Spring Creek. Museum specimens at OSU and UMMZ collected at Pipe Springs and identified as E. tynerensis were actually Typhlotriton spelaeus. Historic sites in Missouri were identifiable only by the stream name and the quadrangle map; thus our sample sites were chosen based on easy access.

Salamanders were found in the Baron Fork, Illinois, Spavinaw, Honey, Saline, Spring, Grand, Elk, and White River drainages (Fig. 1). Geologically, their distribution is restricted to the southwestern portion of

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the Springfield Plateau, bounded on the west by the Grand River and the Osage Plains, and on the south by the Boston Mountains. To the northeast their distribution abuts the western edge of the Salem Plateau, but there was no obvious geological barrier to the north or east.

The stream bed at positive sites had a mean depth of 9.9 cm (range = 1-48 cm). Wet channel width averaged 5.0 m (range = 1-14 m), and dry channel width averaged 11.9 m (range = 1.5-48 m). Average flow rate was 19 cm/s (range = 0.2-75 cm/s). Water temperature averaged 18.9°C (range = 14-23°C). Substrate size was between categories 3 and 4 (particles 16-64 mm and 65-256 mm, respectively). Embeddedness was between categories 3 and 4 (25-50% and 50-75%, respectively). Shorelines comprised riparian forests, fields, and cliffs. Dominant tree species in riparian forests included sycamore (Platanus occidentalis), willows (Salix spp.), American elm (Ulmus americana), and oaks (Quercus sp.). Water willow (Justicea americana) was the most common emergent aquatic macrophyte. A few sites had attached filamentous algae.

Salamanders were found in creeks in broad or narrow valleys. Positive sites often were bordered by cliffs on one side. When cattle pastures bordered creeks, narrow riparian zones usually were present. Salamanders were found in first- (e.g., Rock, Black Fox Hollow, and Dog Hollow creeks), second- (e.g., Tyner, Saline, and Summerfield creeks), and third-order (Spavinaw creek) streams. Extensive field observations indicated that larger streams seldom supported higher densities of salamanders. Salamanders were found in slow moving, shal-

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low water along pools, runs, and riffles, and in isolated pools (17). Salamander populations were clumped along major drainages; the greatest concentration of positive sites occurred along the Illinois River northeast of Tahlequah, Oklahoma (Fig. 1).

Densities ranged from 1-28 salamanders/work-h. Rock Creek had high densities of salamanders ranging from15 salamanders/work-h, during one daytime survey, to 92 salamanders/work-h during a night observation, indicating appreciable variation was possible within sites. Twenty salamanders were counted in a 1-m long stretch in 20 min at Camp Egan. Densities appeared to be low at Peavine Creek, an historic site subjected to periodic gravelling operations. Repeated surveys there produced no more than 5 salamanders work-h.

DISCUSSION

We expanded the known range of E. tynerensis approximately 3 km west with the discovery of the Spring Creek site. The population of salamanders at Off Davis Hollow in Barry County, Missouri, represents a 1 km range extension, pending identification of several salamanders collected in Christian County, Missouri (T. Johnson, personal communication).

In general, populations appear to be viable at most locations, with a few notable exceptions. The site 4.8 km south of Salina (5) was flooded sometime after the completion of Lake Hudson Dam in 1964. Although likely extirpated from this site, salamanders may exist further upstream from the site, but this area was not surveyed. Dundee's (2) Turkey Ford site was dry and a major gravel operation was in progress. We collected Oklahoma salamanders under the bridge of OK Hwy 10 approximately 1.3 km downstream from Dundee's site, but our site is threatened by flooding from Grand Lake. Damming of creeks on private land for watering of cattle and recreational use also threatens many sites.

Salamanders were present at Peavine Creek, but the density appeared to be much lower than literature and museum records indicated. Dundee (2) noted that gravel operations began at Peavine Creek in 1954. Observations made by Cline over the previous 6 y and during this study suggest that this site continues to be disturbed by gravelling. The long-term movement and removal of gravel may have resulted in a negative effect on the salamander population. Salamanders were present at other sites where small gravel operations occurred, so this species apparently can withstand some habitat alteration. However, there appears to be an increase in gravelling throughout the region, and more sites are being modified to provide recreational areas, increasing the threat to salamander populations. Care must be taken when comparing our density results with historic records because equivalent collecting techniques were not used. Long-term monitoring of several sites on relatively undisturbed and heavily impacted streams to determine the effect of gravelling on salamander populations is warranted.

Siltation appears to be a bigger problem in Missouri and Arkansas than in Oklahoma. Streams in those states tended to have smaller riparian zones, were surrounded by fields for cattle grazing, and tended to have deeper soils than comparable Oklahoma sites. Interstitial spaces among gravel particles were filled with silt at many of these sites. Becker (10) and Polechla (8) suggested that increased siltation clogged the gills of salamanders and affected their ability to respire. E. tynerensis has reduced gills and probably relies on cutaneous respiration for much of its gaseous exchange, thus siltation may not inhibit branchial respiration for the salamanders. However, siltation fills spaces among stones and inhibits movement of the salamander through the substrate to avoid predation and dessication. Furthermore, it may suffocate eggs, and it may increase the biological oxygen demand, reducing the amount of dissolved oxygen that is available for the animals.

ACKNOWLEDGMENTS

This research was conducted under the auspices of the U.S. National Biological Survey, Oklahoma Cooperative Fish and Wildlife Research Unit; Oklahoma Department of Wildlife Conservation, U.S. Fish and Wild-

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life Service, Oklahoma State University, and Wildlife Management Institute, cooperating.

REFERENCES

1.   Dowling HA. Geographic relations of Ozarkian amphibians and reptiles. Southwest Nat 1956;1:174-189.

2.   Dundee HA. Habitat selection by aquatic plethodontid salamanders of the Ozarks, with studies on their life histories [Ph.D. dissertation] Ann Arbor(MI): University of Michigan; 1958. 185 p. Available from University Microfilms.

3.   Johnson TR. The amphibians and reptiles of Missouri. Jefferson City, MO: Missouri Department of Conservation; 1987. 369 p.

4.   Bragg AN. The amphibia of Cherokee County, Oklahoma.Herpetologica 1955;11:25-30.

5.   Dundee HA. Notes on salamanders collected in Oklahoma. Copeia 1947; 1947:117-120.

6.   Dundee HA. Eurycea tynerensis. Cat Am Amphib Reptiles, ASIH, Ken-sington, MD 1965;22:22.1-22.2.

7.   Bonati RL. The amphibians and reptiles of northwestern Arkansas: a report on their abundance and distribution [M.S. thesis] Fayetteville (AR): University of Arkansas; 1980. 155 p. Available from University Microfilms.

8.   Polechla PJ Jr. Distribution of the Oklahoma salamander (Eurycea tynerensis) in Arkansas. Final report to the Arkansas Natural Heritage Commission; 1987. 18 p.

9.   Anderson P. A second list of new herpetological records for Missouri. Nat Hist Misc 1957;161:1-5.

10.   Becker DR. Oklahoma salamander survey - Final report to the Missouri Department of Conservation; 1986. 13 p. Available from Missouri Department of Conservation.

11.   Reagan DP. Threatened native amphibians of Arkansas. In: Arkansas natural area plan. Little Rock: Arkansas Department of Planning; 1974. p 93-99.

12.   Glass BP. Mammals, reptiles and amphibians. In: Rare and endangered vertebrates and plants of Oklahoma. Rare and Endangered Species of Oklahoma Committee and U.S. Department of Agriculture, Soil Conservation Service; 1975. 35 p.

13.   Ashton RE Jr. Threatened and endangered amphibians and reptiles of the United States. SSAR Herp Circ 1976;5:1-65.

14.   Cline GR, Tumlison R, Zwank P. Report of the study of the Oklahoma salamander, (Eurycea tynerensis). Final report to the U.S. Fish and Wildlife Service; 1988.143 p.

15.   Bain MB, Finn JT, Brooke HE. Quantifying stream substrate for habitat analysis studies. N Am J Fish Manag 1985;5:499-500.

16.   Rudolph DC. Aspects of the ecology of five plethodontid salamanders of the western Ozarks. Am Midl Nat 1978; 100:141-159.

17.   Tumlison R, Cline GR, Zwank P. Surface habitat associations of the Oklahoma salamander (Eurycea tynerensis). Herpetologica 1990;46:169-175.

Received: November 20, 2000; Accepted: June 12, 2001

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Appendix 1. Localities visited during the survey of distribution of the Oklahoma salamander (Eurycea tynerensis). Comments either describe the site at the time of visit if no E. tynerensis was found, or gives the number of individuals found in what appeared to be good habitat (several or many were qualitative assessments of numbers seen). Most sites were roadside locations with sampling at the spring or along the creek above and below the bridge.

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