Great Basin Naturalist

Volume 53 Number 4 Article 12

12-28-1993

Distribution of the southwestern toad (Bufo microscaphus) in Arizona

Brian K. Sullivan Arizona State University West, Phoenix, Arizona

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Recommended Citation Sullivan, Brian K. (1993) "Distribution of the southwestern toad (Bufo microscaphus) in Arizona," Great Basin Naturalist: Vol. 53 : No. 4 , Article 12. Available at: https://scholarsarchive.byu.edu/gbn/vol53/iss4/12

This Note is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Great Basin Naturalist 53(4), pp. 402-406

DISTRIBUTION OF THE SOUTHWESTERN TOAD (BUFO MICROSCAPHUS) IN ARIZONA

Brian K. Sullivanl

Key words: Bufa microscaphus, southwestern toad, Arizona, distribution, amphibian decline, riparian habitat, hybridization.

The current distribution and status of pop­ adult toads were found, they were measured ulations of the southwestern toad, Bufo (snout-vent length in mm, SVL), pho­ microscaphus, are of considerable interest tographed, and released or retained as vouch­ given the suspected decline in anuran er specimens (deposited in the ASU Verte­ amphibians in the western United States brate Collection). If larvae were present, a (Blaustein and Wake 1990, Sweet 1991). This sample was collected and returned to the lab­ bufonid, typically associated with riparian oratory for rearing to allow confident identifi­ habitats in the desert Southwest, is largely cation (larvae of Bufo woodhousii and B. absent from much of its former range in microscaphus are difficult to distinguish). southern California (Sweet personal commu­ Adult hybrids between B. microscaphus nication). In Arizona and Utah, B. microsca­ and B. woodhousii were identified primarily phus is known to hybridize with a closely on the basis of morphological variation (Sulli­ related toad, B. woodhousii, and it appears van 1986). Bufo microscaphus typically lacks that B. woodhousii has replaced B. microsca­ (1) cranial crests, (2) a well-defined dorsal phus at a number of localities (Sullivan 1986). stripe, and (3) dark ventral pigmentation. In Given the interest in this species and the lack addition, given species-specific differences in of information on populations in Arizona, I vocalizations, advertisement calls were initiated a survey of the distribution of this recorded in the field and release calls were toad in Arizona in 1990. Herein I present the recorded under laboratory conditions for results of this survey and compare the historic breeding males. Cloacal temperatures were and present distributions of Bufo microsca­ recorded with a Weber Quick-recording ther­ phus microscaphus in Arizona. mometer to allow assessment of temperature effects on vocalizations (Sullivan 1992). Calls MATERIALS AND METHODS were analyzed subsequently following the methods outlined in Sullivan (1992). Historic localities were determined by examining all Bufo microscaphus present in RESULTS the following collections (abbreviations follow Edwards 1975): ASU, CAS, CM, LACM, North of the Grand Canyon, B. microsca­ MVZ, UAZ, and UMMZ. Additional historic phus has been recorded from the Virgin River localities were determined from literature at Littlefield and from Beaver Dam Wash near records through 1988 (Price and Sullivan its confluence with the Virgin River at Little­ 1988). Historic localities (Fig. 1) throughout field (Fig. 1). Bufo microscaphus has also been the state were surveyed to a limited degree in recorded from Short Creek near Colorado 1990 and more intensively in 1991 and 1992 City (route 389). In 1991 and 1992 B. (each site was visited on 1-8 occasions). All microscaphu8 were taken at Beaver Dam sites were photographed and searched for Wash, 2 km northeast of Littlefield, and in the toads and larvae during the late winter and Virgin River Gorge, 20 km northeast of Little­ spring (February through June). If juvenile or field (Fig. 1). Bufo woodhousii and hybrids

lU!C 1icicnccs Program, Box 37100, Arizona State University West. Phoenix, Aril:ona S5069-7100.

402 1993J NOTES 403

ently pure B. woodhousii were taken or heard

Virgin calling at Alamo Lake on 12 July 1991; no B, microscaphus were observed. Bufo microscaphus has been recorded from the Hassayampa River at a number of sites: immediately south of Wickenburg, at the Rin­ Little Colorado con Road crossing (3 km north of Wicken­ burg), at the box canyon approximately 5 km • northwest of Wickenburg, and near Wagoner (Fig. 1), In 1990-92 B. microscaphus was observed along the Hassayampa River approximately 5 km southeast of Wickenburg (Fig. 1). Numbers of breeding adults (12-15 Sail .,~~/ males and 3-5 females over a 200-m section of the river during 1990 and 1991) suggest a

Gila thriving population. Although B, woodhousii was recorded from this site in 1985-86 (N ~ 6 total), on the basis of morphology and vocal­

6 km ido izations, none (or possible hybrids) has heen noted since 1986. A few adult B. microscaphus (N ~ 3) were ohserved at Wagoner, along the ARIZONA upper Hassayampa in 1990. Bufo microscaphus have heen taken along Fig. 1. Historic and recent collecting localities for Bulo the Agua Fria River (mouth of Boulder Creek, microscaphl.ls in Arizona. Major drainages arc labeled. Rock Springs), upper Turkey Creek (Battleflat Solid circles (e) represent sites where B. microscaphus south of Mayer), and Cave Creek (2 km north was observed during 1991-·92; solid circles enclosed by of Cave Creek; Fig, 1), Although Sullivan squares ([!]) represent historic localities « 1990) that were not visited during the study, but likely continue to (1986) found both southwestern and Wood­ be occupied by B. microscaphtts (not all historic localities house's toads and their hybrids at the Agua are indicated). Open squares (0) represent historic sites Fria River near the mouth of Boulder Creek no longer occupied by B. microscaphus; B. woodhousii (Table Mesa road crossing) in 1984, since that was present at most ofthese sites. time only a single Bufo microscaphus has been taken (in 1992); all other individuals were also found at both sites, Suitable habitat have been B. woodhousii-like (Fig. 1). Large (i.e., riparian plant growth, water) is no longer breeding aggregations (N ~ 10-50 individu­ present at the Short Creek site. als) of apparently pure B. microscaphus were In west central Arizona, B. microscaphus observed in the spring of 1992 along the Agua has been recorded from the Big Sandy River Fria River 1 km northeast of Black Canyon (Signal, Wikieup) and its tributaries (Burro City. Creek, vicinity of the Hualapai Mountains, Bufo microscaphus have been taken from Trout Creek); the Santa Maria River (route 93 Granite Creek Uust north of Prescott), Oak crossing) and its tributaries (Kirkland Creek); Creek (Sedona), Webber Creek (10 km east of and the Bill Williams proper (Alamo Crossing, Pine), and the Verde River proper at 1950; Fig. 1). In 1991 B. microscaphus was Perkinsville and the Verde Valley (mouth of observed and/or taken on the Big Sandy Wet Beaver Creek; Fig. 1), A single adult B. (route 93 crossing), Burro Creek (route 93 microscaphus was observed along Webber crossing), Santa Maria River (crossings at Creek (10 km east of Pine) in 1990. A single routes 93 and 96), and Kirkland Creek (route toad was observed on the Simmons-Camp 96 crossing; Fig. 1). Breeding aggregations at Wood road (northwest of Prescott) during the Burro Creek (N ~ 1.5 calling males, N ~ 3 spring of 1991 (Howland personal communi­ ovipositing females) and the Santa Maria cation). A breeding aggregation of B. micro­ River (N ~ 10 calling males estimated at scaphus (N ~ 12 males) was observed at route 93 crossing) on 22 February 1991 indi­ Granite Creek Oust east of the route 89 cross­ cate thriving populations. Numerous appar- ing, 2 km northeast of Prescott) on 7 May 404 GREAT BASIN NATURALIST [Volume 53

TWL8 L Localities where Bufo microscaphus was present in 1991-92: T = township, R = range, S = section. Site County Locality data (T, R. 5) I Coconino East Clear Creek at Jones Crossing (T13N, RIDE. SID) 2 Gila Cedar Creek at rle 73 crossing (T, R. and S unavailable) 3 Gila Tonlo Creek at rie 260 crossing (TUN. R12E. 821) 4 Gila Creek north ofSan Carlos on road to Sawmill (T, R. and S unavailable) 5 Graham Bonita Creek north ofconfluence wit.h Gila River (T6S. R28E, 816) 6 Greenlee Upper Eagle Creek northwest of rie 666 on road to Honeymoon CTlS. R28E, 520) 7 Greenlee Blue River southeast ofrte 666, neu town afBIue (T3N, R31E, 822) 6 Maricopa Hassayampa River, southeast ofWickenburg mN, R4W. 820) 9 Mohave Beaver Dam Wash (T40N. RlSW, S5) 10 Mohave Big Sandy Wash at rte 93 crossing (T15N. R13W, 51) 11 Mohave Burro Creek at rte 93 crossing (T14N. RllW, 819) 12 Mohave Virgin River, Virgin River Gorge Campground (T41N, RI4W, SI5) 13 Yavapai Agua Fria River, Black Canyon City (T9N, R2E, 535) 14 Yavapai Agua Fria River at Table Mesa Road crossing (17N, R2E, 86) 15 Yavapai Agua Fria River at rte 169 cros:.;ng (TI3N, RIE. 52) 16 Yavapai. Big Bug Creek. vicinity of Mayer (T12N, RIE, 528) 17 Yavapai Black Canyon Greek. north ofBlack Canyon Gily (T9N. R2E. 528) 18 Yavapai Granite Greek. northeast ofPresooll (T14N, R2W, 526) 19 Yavapai Hassayampa River, vicinity orWagoner (TlON, R3W, 514) 20 Yavapai Kirkland Creek at rte 96 crossing (TI3N, R6W, 59) 21 Yaw.pai Santa Maria River at rte 93 crossing (TI2N, R9W, 815) 22 Yavapai Santa Maria River at rte 96 crossing (TI3N, R8W, 817)

1991; larvae and adults were found near immediately downstream from the Blue Mayer and Dewey, respectively, in 1992. Bufo Ridge Reservoir on East Clear Creek in May woodhousii occurs sympatrically with B. of 1990; larvae were abundant at Jones Cross­ microscaphu8 in the vicinity of Prescott and ing ofEast Clear Creek on 17 July 1991. Dewey, and there is evidence ofhybridization In central and east central Arizona, B. m. near the latter site. microscaphus have been taken near Tonto No B. microscaphus were observed at a Creek (route 260), Cherry Creek (vicinity of number of points along the Verde River: near Young), near Sawmill (Sawmill Canyon, 17 !an Paulden (1 visit in 1991), approximately 3 km east of route 71), the vicinity of Point of Pines north of Clarkdale (1 visit in 1991), at the (12 km north of the Black River), and the mouths of Wet Beaver and West Clear creeks vicinity of Maverick (near Pacheta Creek; Fig. (total of3 visits in 1990-91), or along the East 1). One adult B. microscaphus was taken at Verde River at the route 87 crossing and 10 the route 260 crossing ofTonto Creek (17 July km east of the route 87 crossing (3 visits in 1991). Two recently metamorphosed juveniles 1990-91). Similarly, no B. microscaphus were «25 mm SVL) were observed al Dove tank, apparent along Oak Creek (south of Sedona) near Cottonwood Creek, southwest of Show on three visits in 1990-91. Habitats at most of Low (route 60), on 12 August 1991. Larvae of these locations (e.g., lentic aquatic sites) may B. microscaphus (verified by lab rearing) were favor B. woodhousi~ which has been recorded abundant at Cedar Creek (route 73 crossing) from the Verde Valley since at least the 1950s. on 1 July 1991, and approximately 13 km A number of larvae and/or adult B. wood­ north of San Carlos (route 170) on 26 July housii were taken at the Verde River (3 km 1991. north of Clarkdale), along Oak Creek (near Bufo microscaphus have been taken from Cornville), and along Wet Beaver Creek (in Eagle Creek (13 !an west of Clifton), the San the vicinity of Lake Montezuma) in 1990 and Francisco River (northeast of Clifton), and the 1991. Blue River (southeast of Alpine; Fig. 1). Lar­ Bufo microscaphus have been taken along vae of B. mic,.oscaphus (verified by lab rear­ East Clear Creek Oones Crossing) and Silver ing) were abundant on Eagle Creek, 40 miles Creek (5 km southeast of Show Low) from the northwest of Clifton, on 12 June 1991, and on late 1970s through the mid-1980s (Fig. 1). the Blue River, southeasl ofAlpine, on 2 July Juvenile B. microscaphus were observed 1991. 1993J NOTES 405

TABLE 2. Localities where Bufo microscaphus was absent in 1991-92; T =: township, R =: range, S =: section.

Site County Locality data (T, R, S) 1 Gila East Fork Verde River, east rte 87 (T, R, and S unavailable) 2 Gila Sycamore Creek near Sunflower (T6N, R9E, 517) 3 Gila Reynolds Creek at rte 288 crossing (T6N, R14E, S18) 4 Graham Gila River southwest ofmouth ofBonita Creek (T6S, R28E, 829) 5 La Paz Alamo Reservoir, Bill Williams River (TION, R13W, 82) 6 Maricopa Cave Creek (T6N, R4E, 59) 7 Mohave Short Creek at rte 389 crossing, Colorado City (T42N, R6W, 56) 8 Yavapai Agua Fria River, south of Black Canyon City (T8N, ME, 89) 9 Yavapai Verde River, northwest ofClarkdale (T16N, R2E, 533) 10 Yavapai West Clear C,eek (rl3N, R5E, S13) 11 Yavapai Wet Beaver Creek at Lake Montezuma (T14N, R5E, 51) 12 Yavapai Beaver Creek near confluence with Verde River (T14N, R5E, 517) 13 Yavapai Oak Creek in vicinity of Cornville (T16N, R4E, 526)

DISCUSSION upstream from Lake Pleasant proper (Table Mesa road crossing), With the documentation Populations of B. microscaphus in west of vigorous reproductive activity by B. micro­ central Arizona appear to be thriving. Howev­ scaphus at Black Canyon City in 1992, it er, it is critical to note that demographic data seems reasonable to conclude that without aHowing an adequate evaluation of the status additional habitat alteration, B. woodhousii of these (or any other) populations are will be unable to move further upstream from unavailable. During 1990-91, adults, juve­ the Table Mesa Road site. The expansion of niles, and larvae were noted at most of the Waddell Dam should provide an excellent historic localities (Bill Williams and Has­ opportunity for testing this hypothesis. sayampa drainages). Over most of this area The Verde River VaHey (Clarkdale to Camp there is no immediate threat from hybridiza­ Verde) is one area in which historic collec­ tion with B. woodhousii. However, documen­ tions (all prior to 1960) documented Bufo tation of B. woodhousii at Alamo Lake sug­ microscaphus, but where only B. woodhousii gests that areas of hybridization immediately are present today. The increase in lentic habi­ upstream and downstream from the impound­ tats associated with agricultural activities in ment may bave been initiated recently foHow­ the Verde Valley presumably has favored tbe ing establisbment of lentic babitats preferred establishment of populations of B, wood­ for breeding by B. woodhousii (SuHivan 1986). housii, It is reasonable to conclude that pure It is difficult to predict the outcome of such populations of B. microscaphus remain intact interactions, but in the absence of further along the relatively undisturbed and inacces­ modification of the riparian corridor it is rea­ sible sections of the Verde River (e,g., Per­ sonable to anticipate that B, woodhousii wiH kinsville) and its tributaries (e.g" Sycamore remain confined to the general vicinity of Creek), For example, a "pure" breeding aggre­ Alamo Lake. It should be noted that in con­ gation of B. microscaphus was observed at trast to the report ofJones (1981), no B. wood­ PerkinsviHe on the Verde River on 22 May housii were found in 1990-92 on any of tbe 1989, However, the extent to which B. wood­ tributaries of the Bill Williams River. housii has gained access to the major tribu­ Although most of the sites visited were rela­ taries of the Verde (e,g" Wet Beaver Creek, tively disturbed (human recreational activity, West Clear Creek, Oak Creek) remains cattle and burro grazing), other than at Alamo unclear; B. woodhousii is currently present in Lake, lotic habitats preferred by B. microsca­ the lower reacbes of all of these streams, phus for breeding predominated, The .abundance of larvae at Cedar, Eagle, With respect to the south central portion of and Bonita creeks, as weH as the Blue River, the state, B. microscaphus is apparently no indicates that populations of B, microscaphus longer present on the lower reaches of the occur throughout the historic range in this Agua Fria River or Cave Creek. Along the part of the state. Bufo woodhousii occurs in Agua Fria River, it appears that B. woodhousii the Gila River proper and is thought to has replaced B. microscaphus to a point just hybridize with B, microscaphu8 near the 406 GREAT BASIN NATURALIST (Volume 53 mouths of both Bonita and Eagle creeks (Sul­ LITERATURE CITED livan 1986, Minckley personal communica­ tion). The present results suggest that B. BLAUSTEIN. A. R.. AND D. B. WAKE. 1990. Declining amphibian populations: a globaJ phenomenon? tVoodhousii has not moved further upstream Trends in Ecology and Evolution 5: 203-204. into the tributaries ofthe Gila River, but addi­ EDWARDS, S. R., £0. 1975. Collections of preserved tional study will be necessary to adequately amphibians and reptiles in the United States. Mis­ assess the extent of hybridization in this cellaneous Publications, Society for the Study of region. Amphibians and Reptiles 3: 1-22. JONf::S, K. B. 1981. Distribution, ecology, and habitat In swnmary, B. microscaphus is present at management of the reptiles and amphibians of the a number of historic localities, but absent Hualapai.Aquarius planning area, Mohave and from those where the riparian corridor has Yavapai counties, Arizona. USDI, BLM, Technical been altered dramatically through the con­ Note 353. 134 pp. PRICE, A., ''"0 B. K. SULLIVAN. 1988. Bufo microscaplws, struction of impoundments. Unfortunately, the southwestern toad. Species account. Catalog of only anecdotal data are available on the status American Amphibians and Reptiles 415; 1-3. of extant populations. Additional study will be SULLlYAN, B. K. 1986. Hybridization between the toads necessary to adequately assess population Bu/a microscaphus and Bufo woodhousei in Arizona; dynamics of this toad across its present distri­ morphological variation. Journal of Herpetology 20; 11-21. bution. __~. 1992. Sexual selection and calling behavior in the American toad (Bulo americanus). Copeia 1992: 1-7. ACKNOWLEDGMENTS SWEET, S. S. 1991. Initial reportoD the ecology and status of the arroyo toad (Bufo microscaphus californicw) on the Los Padres National Fore.~t of southern Cali­ I thank 1,. Allison, R. W Bowker, M. Dem­ fornia, with management recommendations. USDA long, E. Gergus, S. H. Hinshaw, J. Howland, contract report, Forest Sen'ice, Goleta, California. T. R. Jones, M. Loeb,]. O'Reilly, and M. Sredl 198 pp. for assistance with locality data. Rob Bowker, M. Demlong, and E. Gergus helped with some observations. This work was supported Receiood 21 January 1993 in part by a Faculty Grant-in-Aid and a Sum­ Accepted 15 April 1993 mer Research Grant from Arizona State Uni­ versity, and Contract GlO048A from the Ari­ zona Game and Fish Department.