Lithobates Chiricahuensis Research Articles

Survival Estimates for Reintroduced Populations of the Chiricahua Leopard Frog (Lithobates chiricahuensis)

Global amphibian declines have been attributed to a number of factors including disease, invasive species, habitat degradation, and climate change. Reintroduction is one management action that is commonly used with the goal of recovering imperiled species. The success of reintroductions varies widely, and evaluating their efficacy requires estimates of population viability metrics, such as underlying vital rates and trends in abundance. Although rarely quantified, assessing vital rates for recovering populations provides a more mechanistic understanding of population growth than numerical trends in population occupancy or abundance. We used three years of capture-mark-recapture data from three breeding ponds and a Cormack-Jolly-Seber model to estimate annual apparent survival for reintroduced populations of the federally threatened Chiricahua Leopard Frog (Lithobates chiricahuensis) at the Buenos Aires National Wildlife Refuge (BANWR), in the Altar Valley, Arizona, USA. To place our results in context, we...

Spatial occupancy models for predicting metapopulation dynamics and viability following reintroduction

SummaryThe reintroduction of a species into its historic range is a critical component of conservation programmes designed to restore extirpated metapopulations. However, many reintroduction efforts fail, and the lack of rigorous monitoring programmes and statistical models have prevented a general understanding of the factors affecting metapopulation viability following reintroduction.Spatially explicit metapopulation theory provides the basis for understanding the dynamics of fragmented populations linked by dispersal, but the theory has rarely been used to guide reintroduction programmes because most spatial metapopulation models require presence–absence data from every site in the network, and they do not allow for observation error such as imperfect detection.We develop a spatial occupancy model that relaxes these restrictive assumptions and allows for inference about metapopulation extinction risk and connectivity. We demonstrate the utility of the model using six years of data on the Chiricahua leopard frogLithobates chiricahuensis, a threatened desert‐breeding amphibian that was reintroduced to a network of sites in Arizona USA in 2003.Our results indicate that the model can generate precise predictions of extinction risk and produce connectivity maps that can guide conservation efforts following reintroduction. In the case ofL. chiricahuensis, many sites were functionally isolated, and 82% of sites were characterized by intermittent water availability and high local extinction probabilities (0·84, 95% CI: 0·64–0·99). However, under the current hydrological conditions and spatial arrangement of sites, the risk of metapopulation extinction is estimated to be <3% over a 50‐year time horizon.Low metapopulation extinction risk appears to result from the high dispersal capability of the species, the high density of sites in the region and the existence of predator‐free permanent wetlands with low local extinction probabilities. Should management be required, extinction risk can be reduced by either increasing the hydroperiod of existing sites or by creating new sites to increase connectivity.Synthesis and applications. This work demonstrates how spatio‐temporal statistical models based on ecological theory can be applied to forecast the outcomes of conservation actions such as reintroduction. Our spatial occupancy model should be particularly useful when management agencies lack the funds to collect intensive individual‐level data.

Modeling Habitat Connectivity to Inform Reintroductions: A Case Study with the Chiricahua Leopard Frog

Abstract Managing species with intensive tools such as reintroduction may focus on single sites or entire landscapes. For vagile species, long-term persistence will require colonization and establishment in neighboring habitats. Therefore, both suitable colonization sites and suitable dispersal corridors between sites are required. Assessment of landscapes for both requirements can contribute to ranking and selection of reintroduction areas, thereby improving management success. Following eradication of invasive American Bullfrogs (Lithobates catesbeianus) from most of Buenos Aires National Wildlife Refuge (BANWR; Arizona, United States), larval Chiricahua Leopard Frogs (Lithobates chiricahuensis) from a private pond were reintroduced into three stock ponds. Populations became established at all three reintroduction sites followed by colonization of neighboring ponds in subsequent years. Our aim was to better understand colonization patterns by the federally threatened L. chiricahuensis which could help i...

Morphological Variation in a Polychromatic Population of Chiricahua Leopard Frogs (Lithobates chiricahuensis) from Durango, Mexico

The Chiricahua Leopard Frog (Lithobates chiricahuensis) occurs in parts of the southwestern United States and northwestern Mexico. In the United States, it is listed as a federally threatened species. Although extensive research has been conducted on populations in the United States, the status of most Mexican populations is unknown. We used mitochondrial and nuclear DNA to identify a population of L. chiricahuensis from the Mexican state of Durango. To better characterize this poorly known population, we examined morphological variation in 30 individuals that included adult males, adult females, and subadult females. Multivariate analyses of 21 size-adjusted body measurements revealed putative shifts in body dimensions associated with gender and ontogeny. Additionally, we observed notable amounts of color pattern variation in female specimens. Our field observations from 2008 suggest that this population is large and thriving. In light of this, a more comprehensive examination may yield valuable conservation insights and have implications for the management of declining L. chiricahuensis populations in the United States.

Resurrecting an extinct species: archival DNA, taxonomy, and conservation of the Vegas Valley leopard frog

Suggestions that the extinct Vegas Valley leopard frog (Rana fisheri = Lithobates fisheri) may have been synonymous with one of several declining species have complicated recovery planning for imperiled leopard frogs in southwestern United States. To address this concern, we reconstructed the phylogenetic position of R. fisheri from mitochondrial and nuclear sequence data obtained from century-old museum specimens. Analyses incorporating representative North American Rana species placed archival specimens within the clade comprising federally Threatened Chiricahua leopard frogs (Rana chiricahuensis = Lithobates chiricahuensis). Further analysis of Chiricahua leopard frogs recovered two diagnosable lineages. One lineage is composed of R. fisheri specimens and R. chiricahuensis near the Mogollon Rim in central Arizona, while the other encompasses R. chiricahuensis populations to the south and east. These findings ascribe R. chiricahuensis populations from the northwestern most portion of its range to a resurrected R. fisheri, demonstrating how phylogenetic placement of archival specimens can inform recovery and conservation plans, especially those that call for translocation, re-introduction, or population augmentation of imperiled species.

Characterization of antimicrobial peptides in skin secretions from discrete populations of Lithobates chiricahuensis (Ranidae) from central and southern Arizona

Populations of the Chiricahua leopard frog Lithobates chiricahuensis (Ranidae) occupying regions in southern Arizona (southern range) are morphologically distinct from those from the Mogollon Rim of central Arizona (northern range) and a comparison of DNA sequences of mitochondrial genes has suggested that they may represent separate species. Peptidomic analysis of norepinephrine-stimulated skin secretions has led to the identification of six peptides with antimicrobial activity in samples from specimens from both groups. The primary structure of the peptides (esculentin-2CHa, ranatuerin-2CHa, -CHb, and -CHc, and brevinin-1CHa and -CHb) isolated from both southern and northern range frogs are identical consistent with the proposal that the two populations are conspecific. However, palustrin-2CHa and the atypical brevinin-1CHc (FFPTIAG*****LTKLFCA ITKKC), containing a five amino acid residue deletion, were identified only in secretions from southern range specimens. Consequently, there is some support for the proposal that the two populations are closely related but separate species but this support is relatively weak. Esculentin-2CHa (GFSSIFRGVAKFASKGLG KDLAKLGVDLVACKISKQC) displayed the highest antimicrobial potency (MIC ≤ 10 μM) against a variety of microorganisms and was only moderately hemolytic (LC 50 = 150 μM). Cladistic analysis based upon the primary structures of brevinin-1 peptides indicates a close phylogenetic relationship between L. chiricahuensis, L. onca, and L. yavapaiensis.

Simulated potential effects of ecological factors on a hypothetical population of Chiricahua leopard frog ( Rana chiricahuensis)

Simulations provide an opportunity to examine how single or multiple perturbations may impact a specific species. The objectives of this study were to identify thresholds at which changes in stream peak flow, stream base flow, and/or chytrid fungus presence alter long-term Rana chiricahuensis populations. We used scenarios with varying peak flow mortality rates, base flow mortality rates, and chytrid fungus mortality rates. Sensitivity analysis was also conducted. Over 50 years, populations in six scenarios increased and 13 scenarios decreased. Eight scenarios resulting with fewer than 100 individuals included stochastic effects for at least two of three perturbations and the remaining scenarios included chronic effects of 30% or higher. Scenarios with population increases had either no chytrid fungus effect or chronic effects from perturbations totaling less than 30%. In the absence of chytrid fungus, populations increased and became stable. At a 10% annual death rate caused by chytrid fungus, the R. chiricahuensis population decreased 46.8%. At a 20% death rate, the population decreased 98.6%. Model scenarios were sensitive to peak flow death rates. As peak flow mortality increased to 10 and 20%, extinction rates increased to 91.7 and 99.9%, respectively. With model parameters and the no base flow mortality, R. chiricahuensis populations declined by 92% with a 3.2% extinction rate at 50 years. Models with base flow mortality rates of 10 and 20% resulted in population extinction rates of 48.7 and 96.1%, respectively. Scenario analysis of perturbations on a hypothetical R. chiricahuensis population provided a framework in which to view combined effects on a species. Analysis supports supposition that chytrid fungus is the proximate cause of many amphibian declines, but the added effect of base flow and peak flow has the potential to hasten declines.

Mitochondrial DNA Sequences Do Not Support Species Status of the Ramsey Canyon Leopard Frog (Rana subaquavocalis)

We used mitochondrial DNA sequences to investigate the phylogenetic relationship of Rana subaquavocalis and Rana chiricahuensis. We sequenced 1344 base pairs of the mitochondrial control region from 39 samples of R. subaquavocalis and 53 samples of R. chiricahuensis from localities throughout their Arizona range. In maximum-likelihood analysis, R. subaquavocalis samples were on a short branch within the southern Arizona clade of R. chiricahuensis. We also found two distinct lineages of R. chiricahuensis, one on the Mogollon Rim of central Arizona and one in southern Arizona. Our results are consistent with the hypothesis that R. chiricahuensis and R. subaquavocalis are conspecific.

Chytridiomycosis in native Arizona frogs.

Twenty-seven adult/sub-adult lowland leopard frogs (Rana yavapaiensis), two larval lowland leopard frogs, two adult Chirichahua leopard frogs (Rana chiricahuensis), and two adult canyon tree frogs (Hyla arenicolor) collected from populations experiencing mortality events at eight sites were found to have characteristic lesions of chytrid fungus infection (Batrachochytrium dendrobatidis). The mortalities occurred during December 1992 and between October and February in 1997-98 and December and February in 1998-99. Gross lesions varied from none to diffuse reddening of the skin of the abdomen, pelvic area, and legs. Microscopic lesions were characteristic of those previously reported for the disease and included diffuse epidermal hyperplasia, hyperkeratosis, and colonization of the keratinized layers of the epidermis by sporangia of the chytrid. Bacterial cultures did not yield a primary pathogenic agent. Virus isolation from frog tissues was negative. Batrachochytrium dendrobatidis was isolated from the skin of two of 10 R. yavapaiensis and one of two H. arenicolor cultured following necropsy. An additional nine of 11 clinically affected or dead R. yavapaiensis from the same locations, but not necropsied, were culture positive for B. dendrobatidis.

Helminths of Two Native Frog Species (Rana chiricahuensis, Rana yavapaiensis) and One Introduced Frog Species (Rana catesbeiana) (Ranidae) from Arizona

The gastrointestinal tracts, lungs, urinary bladders, and body cavities of Rana catesbeiana (n = 25), Rana chiricahuensis (n = 25), and Rana yavapaiensis (N = 37) from Arizona were examined for helminths. Helminths representing 9 species of trematodes: Cephalogonimus brevicirrus, Glypthelmins quieta, Gorgoderina attenuata, Haematoloechus complexus, Haematoloechus langiplexus, Megalodiscus temperatus, Alaria sp., Clinostomum sp., and an unidentified strigeid; and 4 species of nematodes: Falcaustra catesbeianae, Rhabdias ranae, Physaloptera sp., and an unidentified ascarid were found. The helminth fauna of introduced R. catesbeiana differed markedly from that of native ranids. Helminths of R. chiricahuensis and R. yavapaiensis represent new host records. Arizona is a new locality record for C. brevicirrus, G. attenuata, H. complexus, H. longiplexus, M. temperatus, and R. ranae.

Ecologically Correlated Morphological Variation in Tadpoles of the Leopard Frog, Rana chiricahuensis

Interspecific differences in tadpole morphology among leopard frogs of the Rana pipiens complex may represent adaptations to larval habitats. We documented variation in tadpole morphology among populations of R. chiricahuensis and compared intraspecific patterns of variation to those among species. Traits that exhibit similar patterns of variation in intraspecific and interspecific comparisons may represent adaptations to different larval habitats. Tadpoles of R. chiricahuensis found in streams have more contrasting melanic patterns on the tail, thicker dorsal fins, and somewhat larger tail muscles than those from ponds. Unexpected differences between tadpoles from two stream habitats might represent nonadaptive morphological variation

Allotriploidy in Natural Hybrid Frogs, Rana chiricahuensis X R. pipiens, from Arizona: Chromosomes and Electrophoretic Evidence

-In samples totalling 16 leopard frogs, R. chiricahuensis and R. pipiens, two triploid hybrids were found, both from a collection of four frogs from a sympatric locality. Analysis of the normal karyotype of R. chiricahuensis shows it to be extremely similar to that of R. pipiens. It was thus not possible to identify the three chromosome sets in the triploids cytologically. C-banding was weak, indicating that little heterochromatin was present. Electrophoretic evidence based on 21 isozyme loci indicates one hybrid to be 2 chiricahuensis, 1 pipiens and the other to be 1 chiricahuensis, 2 pipiens. The unexpectedly high occurrence of triploid hybrids may be due to higher viability of triploids relative to diploid hybrids. The many species of frogs of the Rana pipiens complex of North America are known to hybridize to varying degrees (Sage and Selander, 1979; Frost and Platz, 1983). Four species of this complex inhabit southern Arizona: R. pipiens, R. blairi, R. chiricahuensis and R. yavapiensis (Platz, 1976; Frost and Bagnara, 1977; Platz and Mecham, 1979; Platz and Frost, 1984). R. chiricahuensis, perhaps the most distinctive of these four leopard frog species in southern Arizona (Hillis et al., 1983), occurs sympatrically with R. pipiens, R. blairi and R. yavapaiensis, whose ranges are for the most part mutually allopatric. Frost and Platz (1983) have reported about 9% occurrence of natural hybrids between sympatric R. chiricahuensis and R. pipiens, with little or no backcrossing. In appearance, R. chiricahuensis is a more robust looking frog than R. pipiens, with a noticeably wider head and shorter legs and cream-colored spots on the poste3 Present address: Department of Biology, University of Windsor, Windsor, Ontario N9B 3P4, Canada. 4 Present address: Division of Hematology-Oncology, New England Medical Center, 171 Harrison Ave., Box 841, Boston, Massachusetts, USA 02111. rior thigh; it also has a different mating call (Platz and Mecham, 1979). In a collection of 16 frogs from three sites in Arizona (sympatric and allopatric R. chiricahuensis and R. pipiens), we found one triploid individual through an initial survey of karyotypes and noted that it had what appeared to be an intermediate, hybrid morphology. A ubsequent electrophoretic examination of all the specimens was undert ken to verify its suspected genotype and revealed, in addition, that another specimen we had earlier referred to R. pipiens was also a hybrid with an electrophoretic pattern again suggesting polyploidy. We report here on these findings and, with an analysis of the normal karyotype of R. chiricahuensis, discuss the possible significance of polyploidy in these wild-caught, hybrid individuals. MATERIALS AND METHODS All specimens were obtained from sites in Coconino National Forest, Coconino Co., Arizona in 1981 as follows: six allopatric R. pipiens from Fuller Tank (34040' x 111?20'), six allopatric R. chiricahuensis from New Tank (34032' x 111? 29') and three R. chiricahuensis (one later confirmed as a hybrid) and one R. pipThis content downloaded from 157.55.39.215 on Wed, 31 Aug 2016 05:06:31 UTC All use subject to http://about.jstor.org/terms D. M. GREEN AND D. M. DELISLE 41iil( ai a 4 t xx xx ..x xx A.X x 1 2 3 4 5 6 7 8 9 10 11 12 13 FIG. 1. Normal karyotype of Rana chiricahuensis (MVZ No. 176678), Baker Lake, Arizona. iens (later confirmed as a hybrid) from the sympatric locality Baker Lake (34? 27' x 111?23'). The specimens have been deposited in the Museum of Vertebrate Zoology (MVZ 176676-92). Chromosome preparations were obtained from squashes of corneal epithelium, using Bogart's (1973, 1981) methods, and of gut and testis, using the methods of Kezer and Sessions (1979). C-banding of chromosomes was attempted using Schmid's (1978) methods. Numerical analyses of karyotypes was done using the CHROMPAC system (Green et al., 1980, 1984). Starch gel electrophoresis employed methods described by Selander et al. (1971) and Clayton and Tretiak (1972).

Rana chiricahuensis, a New Species of Leopard Frog (Rana pipiens Complex) from Arizona

Rana chiricahuensis, a distinctive new species of the Rana pipens complex, ranges over much of montane central and southern Arizona, southwestern New Mexico, and part of northwestern Mexico. It may be readily distinguished from other leopard frogs on the basis of morphology, color-pattern and mating call. Sympatry has been demonstrated between the new form and several other members of the complex, and electrophoretic and morphological studies indicate that in such areas the production of F1 hybrids is low and backcross products are