Monitoring the Plains Spadefoot Toad, Spea bombifrons, in Western Iowa
Jane Hey 1 & Eugenia Farrar 2
1 Biology Department, Morningside College, Sioux City, Iowa
51106.
2 Zoology and Genetics Department, Iowa State University, Ames, Iowa
50011.
The plains spadefoot toad, Spea bombifrons, has been on and off the state of Iowa threatened species list since its discovery in 1967. These animals are secretive burrowers that emerge to breed in ephemeral ponds during and after heavy rains. This behavior poses special problems for monitoring. The status assessment of this anuran is strongly influenced by the monitoring strategy used. We have been monitoring spadefoots for the past three summers by looking for individuals on the road while driving selected routes at night, listening for calls, and locating breeding sites containing tadpoles. Night driving located few individuals considering the amount of effort. Listening surveys were most successful when selected ephemeral sites were monitored during and following heavy rains. Many sites were located solely by the presence of tadpoles. We studied the natural history of breeding sites recording spadefoot breeding cycles, water chemistry, pond longevity, fairy shrimp distribution and the presence of polymorphic tadpoles. Polymorphic tadpoles present special questions for monitoring and conservation. If this species is to be successfully monitored a variety of strategies should be adopted.
Distribution and Conservation Status of Two Austroriparian Treefrogs (Hyla avivoca and Hyla cinerea) in Illinois
Michael Redmer 1, Lauren E. Brown 2 & Ronald A. Brandon 1.
1 Department of Zoology, Southern Illinois University at
Carbondale, Carbondale, Illinois 62901.
2 Department of Biological Sciences, Illinois State University,
Normal, Illinois 61790-4120.
The bird-voiced treefrog (Hyla avivoca) and the green treefrog (Hyla cinerea) reach northern limits of their ranges in southern Illinois. In 1961, H. avivoca was reported from three Illinois localities (in Alexander, Jackson, and Union counties). In 1961, H. cinerea was reported from four localities (in Alexander and Union counties). Between 1961 and 1988, H. cinerea was documented from additional localities, including records for Jackson, Johnson, and Massac counties. Since 1988, many additional localities have been found in the above counties, and in Pope, Pulaski, Randolph, and Williamson counties. New localities have been documented with voucher specimens, or are known from choruses heard in the field. At present, H. cinerea appears to have expanded its range in Illinois, and is known from over 90 localities, where it is abundant in a variety of aquatic habitats, including man-made ones at the periphery of it's Illinois range. We believe this apparent range expansion is real, and results from (1) natural colonization of formerly unoccupied and new aquatic habitats (impoundment lakes and small man-made ponds) near the original range, and (2) introduction (as tadpoles from fish hatcheries) into lakes and ponds as a by-product of fish stocking. Some localities probably escaped detection by earlier workers. Between 1961 and 1988, H. avivoca was reported from at least four additional localities in Johnson and Pulaski counties. Since 1991, our field surveys and examinations of voucher specimens have documented H. avivoca from 26 Illinois localities (in Alexander, Jackson, Johnson, Pope, Pulaski, and Union counties). Unlike H. cinerea, H. avivoca has not expanded its range in the state. Instead, it appears that most recently documented localities were overlooked by previous workers. We did not find H. avivoca at three historical localities, and all choruses were heard in remnant baldcypress-tupelo swamp communities. Large choruses were found only where the baldcypress-tupelo canopy was relatively undisturbed. While most H. avivoca localities are in the Cache River drainage on lands controlled by government or private conservation agencies, most H. avivoca habitat is fragmented and disturbed in Illinois. Because H. cinerea currently is abundant and expanding its Illinois range, it should not be listed as threatened or endangered. However, due to its small range, possible extinction of three populations, restriction to bald-cypress-tupelo swamps, and threats to remaining examples of these plant communities, H. avivoca qualifies for listing as a threatened species in Illinois.
Levels of Nonresponse Among Randomly Chosen Frog Call Routes in Illinois
Christopher A. Phillips, Jeanne M. Serb & John E. Petzing
Center for Biodiversity, Illinois Natural History Survey, Champaign, Illinois 61820.
One of the main concerns about the choice of randomly chosen frog
call routes (probability sampling) over subjectively chosen routes
(judgment sampling) is that some of the randomly chosen routes will
fail to include a sufficient quantity of potential amphibian breeding
habitat (= 10 stops in the NAAMP protocols). The number or percentage
of such failed routes in any geographic region is the level of
nonresponce. It is important to identify the level of nonresponce
before routes are assigned to volunteers for several reasons. First,
routes with no potential amphibian breeding habitat will not keep the
interest of the volunteer and participation will drop rapidly.
Second, routes without enough "stops" do not add any information
toward the goal of the survey. In other words, if a route does not
have any stops, it is analogous to "nobody home' in a door-to-door
survey. In a probability sample, nonresponse does not provide
information relevant to the goals of the survey. We field checked 65
"random routes" in Illinois according to the guidelines in the NAAMP
protocols. Three routes did not have ten qualifying "stops" within a
reasonable driving distance (30 km) and a fourth had to be terminated
before ten stops because of poor road conditions. Driving distances
varied from 8 to 30 km. The potential for implementing these routes
next spring will be discussed.
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Amphibian Diversity in the Forest Preserve District of Cook County--a Fifty Year Update
Thomas G. Anton
Forest Preserve District of Cook County, Wildlife Field Office, Elgin, Illinois 60120.
The Forest Preserve District of Cook County contains 67,000 acres of land managed for recreational use and wildlife refugia. The Forest Preserve District of Cook County's original (1940) list of 17 species is being updated during field work conducted from 1995-1996. Currently, 13 amphibian species (5 salamanders [3 families, 3 genera], 1 toad, 7 frogs [2 families, 3 genera]) are found on district property. Two species, Fowler's toad (Bufo woodhousii fowleri) and Blanchard's cricket frog (Acris crepitans) are presumed extirpated in Cook County. The mudpuppy (Necturus maculosus) is found in certain sections of Lake Michigan shoreline, but has not been found on district property. The pickerel frog (Rana palustris) was presumed to occur in Cook County, but its inclusion on subsequent faunal lists is believed to be in error. The Illinois state threatened four-toed salamander (Hemidactylium scutatum) was included on the list of amphibians found in the Chicago region based on Cook County specimens collected prior to 1932 and was not found during the 1995-1996 survey. Two species, the red-backed salamander (Plethodon cinereus) and the wood frog (Rana sylvatica) are considered rare. Bullfrogs (Rana catesbeiana) are abundant in Cook County; possible negative impacts on other frog species are being investigated. A 1,731 acre preserve in Palatine Township contains 12 amphibian species and is being compared to a site in eastern Will County showing high amphibian species richness.
Status of Frogs and Toads in Ohio
Jeffrey G. Davis 1, Scott A. Menze 1, & Stan Rullman 2
1 Cincinnati Museum of Natural History, Frederick and Amye Geier
Research and Collections Center, 1720 Gilbert Avenue, Cincinnati,
Ohio 45201.
2 The Cincinnati Zoo and Botanical Garden, 3400 Vine Street,
Cincinnati, Ohio 45220.
Fourteen species of Anurans from four families have been documented in Ohio. It has been fifty years since Charles F. Walker published their distribution. Because there has been no major attempt to update information published by Walker in 1946, we reviewed the literature, photographic records, and museum records to find additional localities to add to Walker's. Our objective was to write a new book providing updated distribution and status discussions for each Ohio species. We suspected that during the fifty year interim, a great number of localities would have been added. Our search revealed that in fact, little had been done to compliment Walker's records. We have decided that to justify an update on the distribution of Ohio's frogs and toads, a good deal of field work is necessary. Areas near universities and museums are well represented however areas far removed from them often lack a single representation in a museum collection. This paper illustrates the current distribution records for Ohio Anurans from museums, photographic records, and the literature. Likewise it demonstrates the regions of Ohio in need of field work so that a more complete understanding of the state's Anuran distribution can be known. We also suggest alternative methods for documenting Anurans when collecting may be impractical.
Effects of Pond Chemistry on Amphibian Species Richness
Jill Ogger, Treacy Ziemba, Rachel Mahns, Amanda Long & Robert Brodman
Biology Department, Saint Joseph's College, Rensslaer, Indiana 47978.
We used a frog and toad call index and time-constrained direct sampling to relatively measure breeding activity and abundance of amphibian populations in Jasper County, Indiana from 1993-1996. Amphibians were found to be non-randomly distributed among habitats. habitat characteristics and water samples were collected and analyzed from 103 ponds, 89 of which sites had at least one species of amphibian present and 31 of which had at least 4 species. Species richness significantly increased with ammonia, nitrate, sulfate, detergents, dissolved oxygen and carbon dioxide levels, surface area of the breeding pond and the presence of surrounding woodlands. Species richness significantly decreased with acidity, alkalinity, chloride/chlorine, silica, agricultural disturbance and percent of pond cover by emergent vegetation and algae. hardness, turbidity, iron and heavy metals either were not detected or were not correlates with species richness. However there was a coupled effect of low hardness and pH reducing amphibian presence at sites.
Crowding Effects on Competition Between the Larvae of Two Species of Ambystoma Salamanders
Robert Brodman
Biology Department, Saint Joseph's College, Rensslaer, Indiana 47978.
The larval stages of Ambystoma jeffersonianum and A. maculatum are known to coexist throughout much of Ohio and Indiana due to strong intraspecific competition and microhabitat shifts associated with predator avoidance. I used laboratory experiments to determine the limiting resources for each species and the effects of the smaller A. maculatum on the larger intraguild predator A. jeffersonianum. Both species experienced reduced survivorship and altered growth rates in the presence of heterospecific larvae and at high density, but only A. jeffersonianum had similar effects in treatments with artificial crowding. Experiments on larval activity indicated that A. jeffersonianum reduced activity in the presence of invertebrate prey and conspecifics, while individual spacing was farther apart than expected from random distribution. A. maculatum increased activity in the presence of invertebrate prey and conspecifics, while individual spacing was not significantly different from random distribution. In the presence of heterospecifics, A. maculatum generally moved away from A. jeffersonianum and caused the latter to have reduced predation efficiency. Interspecific interactions are a combination of intraguild predation and competition, however, the predominate interaction explaining the coexistence of these species is intraspecific competition for different limiting resources. These data are consistent with A. jeffersonianum being a space-limited sit-and-wait predator and A. maculatum being a food limited actively foraging predator.
Coexistence of Salamanders in Constructed Ponds
Spencer Cortwright
Department of Biology, Indiana University Northwest, Gary, Indiana 46408.
In many portions of the central and eastern United States, most natural wetlands have been destroyed. Pond-breeding amphibians in these areas primarily breed in constructed ponds. These ponds were designed as wildlife watering holes, not amphibian breeding sites. The means by which species coexist in such ponds will be discussed. Insights into ways to construct ponds will be offered in light of 14 years research on such habitats.