Mountain Frogs Research Articles

Nematodes Infecting the Shield Frog <i>Adelophryne baturitensis</i> in Rainforest Enclaves of Brazilian Semiarid

Parasitological studies provide important information about host biology. However, most anuran species in mountain environments have their helminth fauna understudied. In the present study, we aimed to inventory the endoparasites associated with the shield frog Adelophryne baturitensis from an altitudinal rainforest enclave in the Brazilian semiarid region. We found 57 specimens from five nematode taxa. Perhaps, the high nematode infection on this mountain frog might be related to the host’s direct life cycle where they do not need water ponds to lay eggs and reach tadpole development. Trematodes and other endoparasite taxa are commonly reported in water-dependent frogs. Although shield frogs seem to be myrmecophagous, more studies are still needed to investigate how their feeding habits might influence parasitological infection. Our study is an important contribution to understanding the parasite-host ecological relationship in minute frogs.

First Comprehensive Tadpole Description of the Relict and Endemic Mountain Frog Chrysopaa sternosignata (Murray 1885) from Afghanistan

First Comprehensive Tadpole Description of the Relict and Endemic Mountain Frog Chrysopaa sternosignata (Murray 1885) from Afghanistan

Bioacoustic Monitoring Reveals the Calling Activity of an Endangered Mountaintop Frog (Philoria kundagungan) in Response to Environmental Conditions

Amphibians are the most endangered class of vertebrate on Earth. Knowledge of their ecology is crucial to their conservation; however, many species have received scant attention from researchers, particularly in regions that are difficult to access or when traditional monitoring methods are impractical. In recent years, technological advancements in environmental audio collection techniques and signal detection algorithms (i.e., call recognition) have created a new set of tools for examining the ecology of amphibians. This study utilises these recent technological advancements to examine the calling phenology of a poorly known Australian mountain frog (Philoria kundagungan). Audio recordings and meteorological data were collected from six localities across the species range, with recordings made every hour for ten minutes between July 2016 and March 2018. We developed an audio recognition algorithm that detected over 1.8 million P. kundagungan calls in 8760 h of audio recordings with a true positive rate of 95%. Our results suggest that calling activity was driven by substrate temperature and precipitation, which has potential consequences for the species as the climate warms and seasonal precipitation patterns shift under climate change. With this detailed knowledge of P. kundagungan calling phenology, this difficult-to-find species will now be more reliably detected, removing a barrier that has hindered efforts to study and conserve this species.

Environmental DNA and visual encounter surveys for amphibian biomonitoring in aquatic environments of the Ecuadorian Amazon.

The development of anthropogenic activities has generated a decline in aquatic fauna populations, and amphibians have been the most affected. The decline of batrachofauna is concerning, as 41% of all species worldwide are endangered. For this reason, rapid, efficient, and non-invasive biodiversity monitoring techniques are needed, and environmental DNA (eDNA) is one such tool that has been sparsely applied in Ecuador. This technique has allowed scientists generates information on species diversity and amphibian community composition from a water sample. This study applied eDNA-based biomonitoring analyses and visual encounter surveys (VES) as inventory techniques to identify the diversity of aquatic amphibians in the Tena River micro-basin (TRMB). The experimental design was divided into three components: (1) fieldwork: all amphibians were recorded by the VES technique and water samples were collected; (2) laboratory work: DNA isolation from amphibian tissue samples and eDNA-containing filters, amplification, electrophoresis, and sequencing were performed; (3) Data analysis: a local DNA reference database was constructed, and eDNA sequence data were processed for classification, taxonomic assignment, and ecological interpretation. Using both eDNA and VES, we detected 33 amphibian species (13 with eDNA only, five with VES only, and 15 with both methods). These species belonged to six amphibian families: Hylidae being the richest with 14 species (three eDNA, one VES, and 10 with both methods), followed by Strabomantidae with nine species (six eDNA, one VES, and two with both methods). All families were detected with both methods, except for the Aromobatidae, having one single record (Allobates aff. insperatus) by VES. Individually, eDNA detected 28 species and had a detection probability (DP) of 0.42 CI [0.40-0.45], while VES recorded 20 species with a DP of 0.17 CI [0.14-0.20]. Similarly, using VES, Cochranella resplendens was detected for the first time in TRMB, while with eDNA, four mountain frogs Pristimantis acerus, Pristimantis eriphus, Pristimantis mallii, and Pristimantis sp. (INABIO 15591) previously recorded at 1,518 m.a.s.l. at altitudes below 600 m.a.s.l. were detected. Results obtained in this study showed that eDNA-based detection had a greater capacity to detect amphibians in aquatic environments compared to VES. The combination of VES and eDNA improves the sensitivity of species detection and provides more reliable, robust, and detailed information. The latter is essential for developing conservation strategies in the Ecuadorian Amazon.

Microsatellite variation and population genetic structure of Anatolian mountain frogs

Anatolian mountain frogs consist of two admitted species (Rana macrocnemis and Rana tavasensis), and this group is famous for its high land distribution throughout the Anatolian mountain chain. Despite the unique features of these groups (cold-adapted and highland species), their population genetics have yet to be revealed. In this study, the allelic variation and genetic structure of Anatolian mountain frogs were investigated using six microsatellite markers across its natural distribution area in Türkiye. We evaluated 138 samples from 31 locations and clustered them based on a Structure analysis. The microsatellite markers suggested a high level of diversity in the East Anatolia cluster, while we found limited genetic diversity in the Central Taurus and West Anatolia clusters. We found a significant bottleneck in the Central Taurus cluster, with no genetic differentiation between R. macrocnemis and R. tavasensis. Our results show that the Anatolian mountain frogs exhibit underlying inbreeding signs for macro and microclimatic reasons.

Skeletal description of Pelophylax caralitanus (Anura: Ranidae): Comparison with other ranids.

A description of the skeletal development of ranids is scarce despite being well known in the family Ranidae. Herein, the description of several species of two genera representing the family Ranidae from Turkey is studied wherein the larval and adult cranial skeletons of Pelophylax caralitanus are described and compared with that of the water frog (Pelophylax bedriagae) and mountain frog (Rana macrocnemis). The data are based on cleared and double-stained specimens of 20 Gosner developmental Stages (26-46). The first element to ossify in P. caralitanus is the parasphenoid (Stage 30), followed by the exoccipitals (Stage 34) and prootics (Stage 35). The metamorphic climax commences at Stage 42 during which several modifications to the chondrocranium will unfold. In addition, ranids demonstrate remarkable differences between the water (Pelophylax sp.) and mountain (Rana sp.) frog species: (a) the ventromedial bridge between the corpora of the suprarostral cartilage in the larval upper jaw, (b) the number of processes of the central corpus in the hyobranchial skeleton, and (c) the differences in the ossification time and sequence between Pelophylax sp. and Rana sp. A detailed description of the larval osteological features of P. caralitanus conforms to the current phylogenetic position and provides a model for comparison with other ranids.

Morphological Variation and Its Environmental Correlates in the Taihangshan Swelled-Vented Frog across the Qinling Mountains.

Simple SummaryAmphibians have weak dispersal abilities and are sensitive to environmental changes, resulting in their disproportionately high risk of extinction, with many species’ populations rapidly declining. Therefore, it is critical for amphibian conservation to understand their adaptive potential by exploring how amphibians respond to environmental changes based on morphological variations. Our results showed that morphological traits of Feirana taihangnica significantly differed among ages. Along with the increase in annual mean temperature, snout-vent length showed an anti-hump trend, indicating no support for Bergmann’s rule. Mean ultraviolet-B of the highest and lowest months were positively and negatively correlated with head width, thigh length and tibia width, respectively. The present study can help understand the effects of environmental changes on morphological variations of this mountain frog species and its adaptive potential, providing important implications for species conservation.The Taihangshan swelled-vented frog (Feirana taihangnica), an endemic species to the Qinling Mountains, central China, has experienced a dramatic population decline over the last few decades. The aim of this work was to quantify morphological variation in F. taihangnica across the Qinling Mountains and examine environmental correlates of this variation of morphological traits. We implemented a hierarchical partitioning to estimate the independent contribution of each environmental variable on morphological variations. Temperature seasonality was the greatest contributor in variations of snout-vent length (SVL) and head width, and ultraviolet-B (UV-B) radiation of the lowest month was the most influential on both thigh length and tibia width. Then, we used generalized additive models to analyze the relationship between each environmental factor and morphological trait variations. Along the increasing of annual mean temperature, SVL decreased firstly and then increased, indicating no support for Bergmann’s rule. Furthermore, SVL was negatively correlated with annual precipitation, while positively with temperature seasonality. The mean UV-B of the highest and lowest months was positively and negatively correlated with head width, thigh length and tibia width, respectively. The results of this study help us to understand adaptive potential of this mountain frog species via morphological variations in the light of environmental changes.

A new species of Philoria (Anura: Limnodynastidae) from the uplands of the Gondwana Rainforests World Heritage Area of eastern Australia.

The six species of mountain frogs (Philoria: Limnodynastidae: Anura) are endemic to south-eastern Australia. Five species occur in headwater systems in mountainous north-eastern New South Wales (NSW) and south-eastern Queensland (Qld), centred on the Gondwana Rainforests of Australia World Heritage Area. A previous molecular genetic analysis identified divergent genetic lineages in the central and western McPherson Ranges region of Qld and NSW, but sampling was inadequate to test the species status of these lineages. With more comprehensive geographic sampling and examination of the nuclear genome using SNP analysis, we show that an undescribed species, P. knowlesi sp. nov., occurs in the central and western McPherson Ranges (Levers Plateau and Mount Barney complex). The new species is not phylogenetically closely related to P. loveridgei in the nuclear data but is related to one of two divergent lineages within P. loveridgei in the mtDNA data. We postulate that the discordance between the nuclear and mtDNA outcomes is due to ancient introgression of the mtDNA genome from P. loveridgei into the new species. Male advertisement calls and multivariate morphological analyses do not reliably distinguish P. knowlesi sp. nov. from any of the Philoria species in northeast NSW and southeast Qld. The genetic comparisons also enable us to define further the distributions of P. loveridgei and P. kundagungan. Samples from the Lamington Plateau, Springbrook Plateau, Wollumbin (Mt Warning National Park), and the Nightcap Range, are all P. loveridgei, and its distribution is now defined as the eastern McPherson Ranges and Tweed caldera. Philoria kundagungan is distributed from the Mistake Mountains in south-eastern Qld to the Tooloom Scrub on the Koreelah Range, southwest of Woodenbong, in NSW, with two subpopulations identified by SNP analysis. We therefore assessed the IUCN threat category of P. loveridgei and P. kundagungan and undertook new assessments for each of its two subpopulations and for the new taxon P. knowlesi sp. nov., using IUCN Red List criteria. Philoria loveridgei, P. kundagungan (entire range and northern subpopulation separately) and P. knowlesi sp. nov. each meet criteria for Endangered (EN B2(a)(b)[i, iii]). The southern subpopulation of P. kundagungan, in the Koreelah Range, meets criteria for Critically Endangered (CE B2(a)(b)[i, iii]). These taxa are all highly threatened due to the small number of known locations, the restricted nature of their breeding habitat, and direct and indirect threats from climate change, and the potential impact of the amphibian disease chytridiomycosis. Feral pigs are an emerging threat, with significant impacts now observed in Philoria breeding habitat in the Mistake Mountains.

Mountain frog species losing out to climate change around the Sichuan Basin

Amphibians are particularly vulnerable to climate changes that are expected to cause habitat fragmentation and loss and, ultimately, local extirpations. However, little is known about how the interaction between climate change and fragmentation may impede the ability of amphibians to adapt to climate change. Here, we used the iconic mountain frog Quasipaa boulengeri as an indicator species to extrapolate climate-driven shifts in its habitat availability and connectivity in central and southern China according to the minimum and maximum representative concentration pathways. The models projected an average habitat loss of 36%–71% and the in situ and ex situ climate-change refugia to be 29%–64% and 5%–18% of the present-day suitable habitats, respectively. An increase in habitat fragmentation was reflected in a 51% decrease in core patch size, a 9% increase in the mean least-cost path (LCP) length, and a 19% increase in the cost-weighted distance. These climate-driven shifts varied spatially around the Sichuan Basin, with those in the southeast of the Basin being the most pronounced habitat and connectivity losses and those along the Basin being relatively optimistic. The effectiveness of refugia may only be maintained through a narrow passageway along the southern Sichuan Basin because of the presence of LCPs over time. Our results emphasize the need to understand how climate change and connectivity will jointly affect the distribution of mountain amphibians and to accordingly adopt conservation strategies. Further, our findings highlight the importance of identifying and preserving climate-change refugia and habitat connectivity for species persistence and conservation planning.

Response of Anatolian mountain frogs (Rana macrocnemis and Rana holtzi) to freezing, anoxia, and dehydration: Glucose as a cryoprotectant

Cryoprotectants play an essential role in the survival of some amphibians in response to different stress conditions such as freezing, anoxia, and dehydration. Glucose is one of the cryoprotectants important for freeze-tolerant frogs. The aim of the present study was to investigate the survival strategies of Anatolian mountain frogs (Rana macrocnemis and Rana holtzi), which are terrestrial hibernators, by examining the changes in glucose and water content in some tissues at subzero temperatures. In the current study, animals were exposed to freezing (−2.5 °C), anoxia, and dehydration treatments. During these treatments, all frogs survived. The glucose levels in the plasma, liver, and skeletal muscle and the water content of the tissues were measured during the freezing, anoxia, and dehydration. Changes in body weight were also recorded in both species. During the freezing, a 3.3-fold increase was seen in the blood glucose level of R. macrocnemis (1.35 ± 0.25 to 4.45 ± 0.51 μmol mL−1), whereas the blood glucose level of R. holtzi exhibited a 4.5-fold increase (1.90 ± 0.25 to 8.67 ± 2.22 μmol mL−1). In the liver, a 6.7-fold increase was seen in the glucose level of R. macrocnemis (5.66 ± 0.15 to 38.27 ± 8.53 μmol g−1) and the increase in R. holtzi was approximately 6.0-fold (2.25 ± 0.46 to 13.36 ± 1.32 μmol g−1) during freezing. The liver glucose levels of both species also increased significantly in response to the anoxia and dehydration. In both species, the glucose levels of the skeletal muscle were found to be higher in dehydration than with freezing and anoxia. In conclusion, our results suggest that glucose may be identified as an important cryoprotectant that plays an important role in the survival of Anatolian mountain frogs during extreme conditions.

Genetic structure and demographic history of Indirana semipalmata, an endemic frog species of the Western Ghats, India

The evolutionary potential of a species mainly depends on the level of genetic variation in their populations. Maintenance of gene variation enables populations to adapt more quickly to environmental changes. The geographical gaps also influence the distribution and evolutionary history of many mountain frogs in the world. Hence, a sound knowledge in population genetic structure of a species will help understand its population dynamics and develop conservation strategies. In the context of facing threats to the amphibian fauna of Western Ghats due to habitat loss, we used both mitochondrial and nuclear DNA markers to investigate the genetic structure of an endemic frog species of the Western Ghats (Indirana semipalmata) with restricted distribution. The present study showed the importance of mountain gaps in shaping the species’ structuring in the Western Ghats. Though a high genetic diversity was observed for the species when considering a single unit in the southern Western Ghats, the restricted gene flow on/between either side of the Shencottah gap with genetic clustering of the sampled populations may warrant a unique management plan for the species. The habitat fragmentation of the Western Ghats through anthropogenic activities may result in severe setbacks to the survival of the species in the future.

Novel method for detection probability and estimating population size of mountain frog, Rana macrocnemis (Boulenger, 1885) at the end of its distribution range

Local amphibian populations at the edge of a species range are possibly of greater conservation concern than any other amphibians group. They experience greater demographic fluctuation than populations at the core of the range. We detected the most suitable distribution range of R. macrocnemis by maximum entropy (MaxEnt) method at the end of the southeastern edge of natural distribution range to find out which environmental variables have a significant role in determining the distribution pattern of this species in marginal populations. According to the map constructed, three important variables had a high contribution to species presence as land cover (63.4%), annual precipitation (27%), and precipitation of coldest quarter of the year (5.4%) variables. Then, we described new methods for estimating detection probability for terrestrial frogs, specifically R. macrocnemis. Finally, we estimated the population size of mountain frogs by calculated detection probability. Our repeated capture–re-capture (RCR) results suggest that the estimated detection probability for R. macrocnemis is: $$\widehat{p} = 0.052$$. Thus, the total average number of R. macrocnemis obtained from the 17 habitat sites is 982.5 adults (range: 708–1211 adults). In conclusion, the population estimates by detection probability index are generally much higher than densities reported for the Mountain frog populations than visual encounter estimation about 50.5 adults (range: 37–63 adults).

Elevational and microclimatic drivers of thermal tolerance in Andean Pristimantis frogs

AbstractAimWe analysed elevational and microclimatic drivers of thermal tolerance diversity in a tropical mountain frog clade to test three macrophysiological predictions: less spatial variation in upper than lower thermal limits (Bretts’ heat‐invariant hypothesis); narrower thermal tolerance ranges in habitats with less variation in temperature (Janzen's climatic variability hypothesis); and higher level of heat impacts at lower elevations.LocationForest and open habitats through a 4,230‐m elevational gradient across the tropical Andes of Ecuador.MethodWe examined variability in critical thermal limits (CTmax and CTmin) and thermal breadth (TB; CTmax–CTmin) in 21 species of Pristimantis frogs. Additionally, we monitored maximum and minimum temperatures at the local scale (tmax, tmin) and estimated vulnerability to acute thermal stress from heat (CTmax–tmax) and cold (tmin–CTmin), by partitioning thermal diversity into elevational and microclimatic variation.ResultsOur results were consistent with Brett's hypothesis: elevation promotes more variation in CTmin and tmin than in CTmax and tmax. Frogs inhabiting thermally variable open habitats have higher CTmax and tmax and greater TBs than species restricted to forest habitats, which show less climatic overlap across the elevational gradient (Janzen's hypothesis). Vulnerability to heat stress was higher in open than forest habitats and did not vary with elevation.Main conclusionsWe suggest a mechanistic explanation of thermal tolerance diversity in elevational gradients by including microclimatic thermal variation. We propose that the unfeasibility to buffer minimum temperatures locally may explain the rapid increase in cold tolerance (lower CTmin) with elevation. In contrast, the relative invariability in heat tolerance (CTmax) with elevation may revolve around the organisms’ habitat selection of open‐ and canopy‐buffered habitats. Secondly, on the basis of microclimatic estimates, lowland and upland species may be equally vulnerable to temperature increase, which is contrary to the pattern inferred from regional interpolated climate estimators.

Environmental stress shapes life-history variation in the swelled-vented frog (Feirana quadranus)

Understanding how environmental stress modifies life-history traits of vertebrates is highly important for their conservation and management. Amphibians, in particular, have experienced rapid declines in abundance due to their relatively low mobility and strict physiological constraints. Therefore, it is important to understand how amphibians have evolved to cope with environmental stress, and to identify the relevant life-history traits that mediate these dynamics. In this study, we quantified the variation of life-history traits (i.e., body size and age) across the distributional range for a mountain frog species, Feirana quadranus, and identified potential impacts of environmental stress on these traits. Based on the similarity of environmental variables describing bioclimatic and ultraviolet-B radiation conditions from a hierarchical cluster analysis, all populations were assigned to three distinct groups: low, intermediate and high environmental harshness regimes. We found no significant difference in age structure among environmental regimes, with 68% of individuals being between four and six years old. The average age of individuals did not differ among regimes or between sexes, but snout-vent length (SVL) and hind limb length differed significantly among both. When environmental stress was represented along the principle component axes, we found a significant correlation between environmental stress and hind limb length, but not for age or SVL. Our results help us understand potential impacts of environmental stress on life-history variation in F. quadranus covering its whole distribution range. Specifically, our findings highlight the adaptive potential of amphibians to changing environmental conditions via life-history variation as a function of environmental stress.

Inferring ecological explanations for biogeographic boundaries of parapatric Asian mountain frogs

BackgroundIdentifying and understanding the mechanisms that shape barriers to dispersal and resulting biogeographic boundaries has been a longstanding, yet challenging, goal in ecology, evolution and biogeography. Characterized by stable, adjacent ranges, without any intervening physical barriers, and limited, if any, range overlap in a narrow contact zone, parapatric species are an interesting system for studying biogeographic boundaries. The geographic ranges of two parapatric frog species, Feirana quadranus and F. taihangnica, meet in a contact zone within the Qinling Mountains, an important watershed for East Asia. To identify possible ecological determinants of the parapatric range boundaries for two closely related frog species, we quantified the extent of their niche differentiation in both geographical and environmental space combining ecological niche models with an ordination technique. We tested two alternative null hypotheses (sharp environmental gradients versus a ribbon of unsuitable habitat dividing two highly suitable regions) for biogeographic boundaries, against the null expectation that environmental variation across a given boundary is no greater than expected by chance.ResultsWe found that the niches of these two parapatric species are more similar than expected by chance, but not equivalent. No sharp environmental gradient was found, while a ribbon of unsuitable habitat did act as a barrier for F. quadranus, but not for F. taihangnica.ConclusionsIntegrating our findings with historical biogeographic information, our results suggest that at a contact zone, environmental tolerance restricted F. quadranus from dispersing further north, while interspecific competition most likely prevented the southward expansion of F. taihangnica. This study highlights the importance of both climate and competition in exploring ecological explanations for parapatric range boundaries between ecologically similar frog species, in particular under the effects of changing climate.

Phylogeny and systematics of Anatolian mountain frogs

Anatolian mountain frogs (Rana macrocnemis, Rana camerani, Rana holtzi, and Rana tavasensis) are one of the most specious amphibian groups in Turkey containing two endemic taxa (R. holtzi and R. tavasensis). The taxonomy of this group remains controversial as there are several unresolved issues.In the present study, we aimed to resolve the taxonomic uncertainty of the Anatolian mountain frogs through two mitochondrial genes (CYTB, 481 bp and COI, 743 bp) and two protein-coding nuclear genes (POMC, 401 bp and RAG1, 717 bp). The mitochondrial DNA (mtDNA) markers were found to be highly polymorphic in this group. Haplotype network analysis revealed that R. tavasensis was different for at least 33 and 52 mutational steps according to CYTB and COI gene regions, respectively. High bootstrap and posterior probability values obtained from the mtDNA genes support the idea that Anatolian mountain frogs are represented by two distinct species in Anatolia: R. macrocnemis and R. tavasensis. However, no genetic variation was detected according to nuclear DNA (nDNA) markers.The analysis of molecular variance (AMOVA) revealed no differences among the groups of R. macrocnemis, R. camerani, and R. holtzi. Despite the low genetic distance among R. macrocnemis, R. camerani, and R. holtzi species, the pairwise distances estimated from R. tavasensis were higher compared with other Anatolian mountain frog lineages.

If a frog calls in the forest: Bioacoustic monitoring reveals the breeding phenology of the endangered Richmond Range mountain frog (Philoria richmondensis)

AbstractAmphibians are the most threatened vertebrate taxon of modern times. Baseline data and affordable methods to monitor populations are absent for many Australian frog species. Furthermore, some species are visually cryptic, and detection often relies upon male advertisement calls. Imperfect detection rates impede our ability to assess the status of populations over time. Understanding the factors that influence calling is essential to inform the timing of survey effort and increase survey efficiency. Automated recording systems offer considerable potential to determine calling phenology and establish the relationship between calling and abiotic factors. The mountain frogs (Philoria Myobatrachidae) of the Gondwana rainforests are considered susceptible to climate change impacts, such as shifts in the timing of calling. In order to describe the calling phenology of Philoria richmondensis, commercially available automated recording systems were deployed at five locations, and over 5000 h of sound recordings were captured and analysed. Peak calling activity occurred during morning and evening periods in the austral spring. Ambient temperature was found to significantly contribute to the probability of a call occurring, with the highest frequency of calls recorded occurring between 15°C and 16°C, and there was a negative relationship between precipitation and calling activity. The results allow future surveys to be better targeted and provide a benchmark with which to detect changes in calling phenology over time.

Dispatches

Dispatches

First data on the helminth fauna of a locally distributed mountain frog, “Tavas frog” Rana tavasensis Baran & Atatür, 1986 (Anura: Ranidae), from the inner-west Anatolian region of Turkey

A total of 8 specimens of Rana tavasensis Baran & Atatür, 1986 (Tavas frog) were collected in Denizli Province (inner-west Anatolia, or the eastern part of the Aegean region), Turkey, in 2008 and 2009 and were examined for the first time for helminths. All 8 frogs were infected with 1 or more helminths. The helminth fauna of R. tavasensis comprised 3 species: 1 species of Digenea [Haplometra cylindracea (Zeder, 1800) Looss, 1899], 1 species of Nematoda [Cosmocerca ornata (Dujardin, 1845)], and 1 species of Acanthocephala [Acanthocephalus ranae (Schrank, 1788) Lühe, 1911)]. R. tavasensis represents a new host record for each of the observed helminth species in Turkey.

Landscape genetics of high mountain frog metapopulations

Explaining functional connectivity among occupied habitats is crucial for understanding metapopulation dynamics and species ecology. Landscape genetics has primarily focused on elucidating how ecological features between observations influence gene flow. Functional connectivity, however, may be the result of both these between-site (landscape resistance) landscape characteristics and at-site (patch quality) landscape processes that can be captured using network based models. We test hypotheses of functional connectivity that include both between-site and at-site landscape processes in metapopulations of Columbia spotted frogs (Rana luteiventris) by employing a novel justification of gravity models for landscape genetics (eight microsatellite loci, 37 sites, n = 441). Primarily used in transportation and economic geography, gravity models are a unique approach as flow (e.g. gene flow) is explained as a function of three basic components: distance between sites, production/attraction (e.g. at-site landscape process) and resistance (e.g. between-site landscape process). The study system contains a network of nutrient poor high mountain lakes where we hypothesized a short growing season and complex topography between sites limit R. luteiventris gene flow. In addition, we hypothesized production of offspring is limited by breeding site characteristics such as the introduction of predatory fish and inherent site productivity. We found that R. luteiventris connectivity was negatively correlated with distance between sites, presence of predatory fish (at-site) and topographic complexity (between-site). Conversely, site productivity (as measured by heat load index, at-site) and growing season (as measured by frost-free period between-sites) were positively correlated with gene flow. The negative effect of predation and positive effect of site productivity, in concert with bottleneck tests, support the presence of source-sink dynamics. In conclusion, gravity models provide a powerful new modelling approach for examining a wide range of both basic and applied questions in landscape genetics.