Anuran Diversity Research Articles

Better desiccated than eaten by fish: Distribution of anurans among habitats with different risks to offspring

Abstract Freshwater species with complex life cycles face a trade‐off between the risks of offspring mortality due to desiccation in temporary habitats and due to predators common in long‐duration habitats, especially fish. In real‐world conditions, intermediate‐gradient areas that are highly suitable for some ecological specialists are often limited. I examined the relative significance of drivers of the permanence–predation gradient in habitat selection by pond‐breeding anurans. Anuran oviposition was investigated at the community level in fish pond landscapes with only three types of habitat, permanent fish‐containing ponds and highly desiccation‐prone pools, either fishless or recently emptied of fish and with fish odour (fish cue). Altogether, 65 ponds/pools, interspersed in four clusters, were examined for the presence of egg masses. Bufo bufo was the only species preferring permanent ponds. Egg masses of Rana sp. (Rana arvalis/Rana temporaria) occurred in all fishless pools, and less frequently in the ponds. Bufotes viridis and long larval period species Pelobates fuscus and Hyla orientalis oviposited almost exclusively in fishless pools. Fish‐cue pools were avoided by all species. Anuran richness was higher in fishless pools than in permanent ponds. Species distribution between the two habitats was nested, with both common and rare species occurring in fishless pools. The results indicate the primacy of offspring predation risk over hydroperiod constraints in oviposition decision‐making by fish‐intolerant anurans. The absence of some species from ponds and pools with fish or fish cues shows that non‐consumptive interactions may better explain the scarcity of anuran larvae in waters dominated by fish than actual consumption. The strict avoidance of fish habitats despite their proximity to fishless patches indicates fine‐scale assessment of predation risk. However, rigid habitat selection against fish predation on offspring may prove maladaptive if habitats with high desiccation risk are the main alternative and are indiscriminately preferred. Maintenance of fishless wetlands with a hydroperiod sufficient to allow completion of metamorphosis should be a conservation priority for anuran diversity in areas where fishless habitats are limited.

Something is not quite right: Effects of two land uses on anuran diversity in subtropical grasslands

AbstractAlthough habitat modification is considered one of the main causes of biodiversity loss, the relative contribution of different rural land uses to biodiversity conservation is far less known. Additionally, the realization of the multidimensionality of biodiversity demands studies integrating variation of functional traits and phylogenetic information as complements to address the effects of land use on the structure of animal communities. Herein, we investigated the effects of land use (i.e., intensive agricultural and extensive livestock rearing) on functional and phylogenetic diversity of anuran communities in farmland ponds from the Uruguayan savanna ecoregion, while considering the effects of local factors (i.e., water depth) on species composition. We surveyed adults and tadpoles in 22 ponds and quantified five traits related to tadpole feeding, habitat use, and predator avoidance. Tadpole identification was corroborated by DNA barcoding based on a fragment of the mitochondrial 16S rRNA gene. We observed a decline in phylogenetic mean nearest taxon distance associated with increase of surrounding agricultural land use. While land use intensification did not affect richness (functional or phylogenetic), ponds in livestock ranches hosted about four times more tadpoles than agricultural ponds. Functional evenness decreased with water depth, although such relationship disappeared when considering phylogenetic non‐independence. Our results indicated that specific anuran clades were more sensitive to intensification in land use, reinforcing a recent view of phylogenetic homogenization following habitat conversion. Additionally, our study suggests that extensive cattle grazing over wide native pastures may provide an alternative more compatible with conservation than short‐term crops in subtropical grasslands.Abstract in Portuguese is available with online material.

Tolerant and avoiders in an urban landscape: anuran species richness and functional groups responses in the Yungas’ forest of NW Argentina

Urbanization is one of the most important causes of ecological changes and biodiversity loss worldwide, and forests in Latin America provide valuable scenarios to understand the ecological effects of this human-driven phenomenon due to its high urbanization rate. Our aim was to investigate how urbanization shapes species richness (SR) and composition of anuran communities in NW Argentina, and to determine which suite of life history traits are related to anuran tolerance to urban development. We classified anuran species in Functional Groups (FG) based on a series of ecological traits and recognized them as urban-tolerant or urban-avoiders. We constructed an urbanization composite index (UI) through an exploratory factor analysis based on measures of artificial light intensity, noise pollution, land use types, and mean values of LTS, NDMI, and NDVI. We tested the response of SR, FG and species occurrence to UI with Generalized Linear Models and a variation partitioning analysis. Our results showed the negative influence of urbanization on anuran diversity and suggested that the loss of anuran species is not random, pointing to the presence of environmental filters. Only terrestrial frogs that build aquatic foam nests were not affected by an increase in urbanization, so they may be considered as urban--tolerant. Further, our results highlighted the important role of dispersal capacity in structuring the urban anuran assemblages. As ecologists working in urban habitats, we emphasize the need of a more comprehensive and generalized understanding of ecological and life history traits associated with urban tolerant anurans.

Extinctions of Threatened Frogs may Impact Ecosystems in a Global Hotspot of Anuran Diversity

Human activity is accelerating rates of extinction around the world, and there is therefore an urgent need to understand the potential consequences of species loss on functional diversity and ecosystem functioning. It is frequently assumed that the extinction of threatened species, which are usually rare species, may have limited effects on ecosystem functioning, especially within highly diverse regions, given the low abundance of individuals of each species and the potentially high functional redundancy among them. However, these rare species may contribute unique and irreplaceable functional roles, and therefore their extinction could have disproportionate impacts on ecosystems. We assess the functional importance of highly threatened anurans (frogs and toads) and then explore how the loss of these threatened species would impact spatial patterns of β-diversity in Ecuador, a hotspot of anuran biodiversity and endemism. We found that highly threatened species are, on average, more functionally distinct at an assemblage level than are less threatened anurans. We then show that the potential extinction of these highly endangered species would drive the taxonomic, phylogenetic, and, especially, functional homogenization of anuran assemblages across the Ecuadorian Andes. We suggest this could lead to profound alterations in the stability of local ecosystem functioning. Finally, we highlight the limited scope of the existing network of protected areas in Ecuador to effectively cover anuran assemblages predicted to become increasingly functionally homogenous. Our study underscores the potential losses of functional diversity that accompany species extinctions and the importance of considering the many facets of biodiversity in conservation decision-making.

Threats to aquatic taxa in an arid landscape: Knowledge gaps and areas of understanding for amphibians of the American Southwest

AbstractThe American Southwest is a dryland region with variable, seasonal precipitation, and a wide range of freshwater habitats. Amphibians are among the diverse freshwater taxa that rely on aquatic habitats of the southwest, yet the state‐of‐the‐science regarding vulnerability of the region’s amphibians to threats recognized globally is unclear. To address this knowledge gap, we reviewed 81 publications and 341 species:threat relationships to assess coverage in the peer‐reviewed literature of potential threats to 35 amphibians native to the region. We classified threats into three major categories: climate change, biological, and land use. Using a new trait database for anurans (frogs and toads) of the United States, we evaluated these threats in the context of life history diversity of the region's anurans. We found high coverage for hydrological alteration and introduced species as well as changes to community dynamics, land use, and precipitation. Other potential threats—particularly those linked to climate change such as changes in seasonality and fire—had comparatively low coverage. Coverage varied widely among species, with the number of reported species:threat relationships ranging from 37 (the lowland leopard frog, Lithobates yavapaiensis) to no coverage for some species—including some of conservation concern (e.g., Sacramento Mountains salamander, Aneides hardii). Our findings support leveraging available information to test hypothesized linkages between amphibian life histories and risk and response to threats; using high coverage species and threats to inform simulations and experiments exploring species:threat relationships and efficacy of management strategies; and addressing knowledge gaps for species and threats with no proxies through on‐the‐ground natural history efforts.This article is categorized under: Water and Life > Stresses and Pressures on Ecosystems > Conservation, Management, and Awareness Science of Water > Water and Environmental Change

Responses of anuran diversity to wetland characteristics and surrounding landscape in the Southern Andean Yungas, Argentina

AbstractModification and loss of natural habitats caused by human activities are among the main drivers of biodiversity decline worldwide. To evaluate how land‐use changes affect species diversity at different spatial scales, amphibians represent an excellent group given that their complex life cycle requires both aquatic and terrestrial habitats.In this study, the influence of wetland characteristics and surrounding landscape features on richness and functional diversity of anurans was investigated in 26 natural wetlands in a human‐modified landscape within the Southern Andean Yungas.The analysis was performed at two spatial scales: wetland scale (the breeding pond structure) and the surrounding landscape scale. The classification of the landscape was limited to land uses modified by human activities within concentric circular buffers (radius = 0.1, 0.2, 0.5, and 1 km) centred on each breeding pond.Generalized linear models were applied to investigate the relationship between environmental variables measured at different scales and anuran species richness and functional diversity, respectively.Pond area best explained the observed variation in both diversity measures, which is consistent with other studies on anuran diversity in disturbed landscapes. In contrast to regression models including landscape scale variables only, integrated models (which included variables on both scales) highly improved model fit.Conservation strategies for anuran species diversity in these altered Andean Yungas forests should include efforts to maintain or restore aquatic habitats (e.g. breeding ponds) placed within suitable landscapes.Successful long‐term management will require an understanding of relationships between habitat characteristics at different spatial scales to identify variables that relate to species diversity in such heterogeneous habitats.

The Diversity of Anuran Species in Urban Forest in Selangor

This study aimed at determining anuran diversity in Compartment 12 and 13 of Ayer Hitam Forest Reserve (AHFR), Puchong, Selangor. The study determining species diversity, richness and evenness, analyzing correlation between the anuran species with the microclimate and updating anuran species status. Fieldwork was carried out from October 2016 to February 2017 investing six person of sampling effort. Fifteen of 300 m nocturnal transect lines have been constructed in this inventory at three different study areas; walking trails, streams, and swampy. A total of 119 individuals belonging to 18 species came from five anuran families were recorded. Most abundant species recorded were Fejervarya cancrivora, Leptobrachium hendricksoni, and Pulchrana laterimaculata. Compartment 12 found to have the highest species diversity and evenness compared to Compartment 13. Stream has the highest species composition with Ingerophrynus parvus and Leptobrachium hendricksoni each with eight individuals respectively. Most anuran species recorded were highly associated with temperature such as Limnonectes malesianus, Amnirana nicobariensis, Limnonectes plicatellus, and Fejervarya limnocharis. This study also recorded Amnirana nicobariensis, Kalophrynus pleurostigma, and Pulchrana laterimaculata for the first time for AHFR. Therefore, this further research is needed by increasing forest coverage for the anuran diversity study as a reference for future study.

Native and invasive alien anuran species in urbanized areas in Davao City, Philippines, with preliminary study of feeding biology

This article presents the anuran species in urbanized areas, diet overlaps between native and invasive alien anuran species, and its implications on conservation and ecological health in urban environment. Visual encounter technique following the road as a transect was done to determine the diversity of anurans, and stomach content extraction was employed to analyze its diet composition. Results revealed a very low anuran diversity (Shannon-Weiner; 1.165), which is dominated by invasive alien anuran species. Jackknife 1 species richness estimator indicated that 77-100% of the anuran species in the area were already detected which includes three invasive; Rhinella marina (Linnaeus, 1758), Kaloula pulchra Gray, 1831, Hoplobatrachus rugulosus (Wiegmann, 1834), and two natives; Polypedates leucomystax (Gravenhorst, 1829), Limnonectes leytensis (Boettger, 1893). Additionally, assessing the diet of 33 randomly selected anuran samples revealed that Formicidae dominated their food item. Invasive anurans also showed more diverse diet composition compared to native frogs, in which diet overlaps were observed. In conclusion, the study supports the idea that urbanization decreases anuran diversity and supports the dominance of invasive anurans which compete for food with their native and endemic counterparts. Additionally, it is important to manage invasive anurans that dominates urban ecosystem which might affect the native and endemic species in the area and possibly in nearby pristine environment.

Multilocus phylogeny of Paratelmatobiinae (Anura: Leptodactylidae) reveals strong spatial structure and previously unknown diversity in the Atlantic Forest hotspot

The Brazilian Atlantic Forest harbors high levels of anuran diversity and endemism, including several taxa restricted to small geographic ranges. Here, we provide a multilocus phylogeny for Paratelmatobiinae, a leptodactylid subfamily composed of small-ranged species distributed in the Brazilian Atlantic Forest and in the campo rupestre ecosystem. We performed Bayesian inference and maximum likelihood analyses using three mitochondrial and five nuclear markers, and a matrix comprising a broad taxonomic sampling. We then delimitated independently evolving lineages within the group. We recovered Paratelmatobiinae and each of its four genera as monophyletic and robustly supported. Five putatively new species included in our analyses were unambiguously supported in the phylogenetic trees and delimitation analyses. We also recovered other deeply divergent and geographically structured lineages within the four genera of Paratelmatobiinae. Our estimation of divergence times indicates that diversification in the subfamily began in the Eocene and continued until the Pleistocene. We discuss possible scenarios of diversification for the four genera of Paratelmatobiinae, and outline the implications of our findings for taxonomy and conservation.

Two New Cryptic Endemic Toads of Bufo Discovered in Central Nevada, Western United States (Amphibia: Bufonidae: Bufo [Anaxyrus

We describe two new cryptic species of Bufo within the subgenus Anaxyrus discovered in Central Nevada of the western United States. Our analyses revealed that these two localized endemic toads are genetically divergent and morphologically distinct, yet were concealed under the range of the broadly distributed western toad (Bufo boreas), which occurs throughout Nevada. The newly discovered species are close in geographic proximity to each other (albeit, in different hydrological basins) but have evolved unique morphological characters that are distinct from each other and distinctive from all allied taxa within the B. boreas species complex. The delimiting of these two rare toads emphasizes the link between taxonomic crypsis and inadequate conservation as these newly described species are vulnerable to extinction due to severely restricted geographic ranges, unknown population sizes, and dependency on rare, fragile wetland habitat, which is a limited resource within Nevada, the primary state that makes up the arid Great Basin. These two endemics join the Great Basin B. boreas species complex as imperiled new members, and our study demonstrates that our knowledge of anuran diversity is incomplete and that new discoveries can still be made, even in unlikely settings.

Surveying frogs from the bellies of their parasites: Invertebrate-derived DNA as a novel survey method for frogs

Biodiversity conservation is reliant on thorough species occurrence data. However, the collection of such data is often difficult for species with poor detectability. Recently, invertebrate-derived DNA (iDNA) has emerged as a potentially powerful survey method to increase the detectability of terrestrial vertebrates. Parasitic invertebrates are effective samplers of some vertebrate diversity and can be used to detect and identify their host species by sequencing the DNA contained in their meals. Among taxa that can be very difficult to detect using traditional survey methods are many frog species, which are often of a high conservation priority. However, the potential for frog-specific iDNA surveys has not been explored; most iDNA surveys have targeted mammals. We carried out traditional audio-visual and iDNA frog surveys in eastern Australia to determine whether frog-biting midges (Corethrella and Sycorax spp.) can be used as an effective survey method for frogs. The frog species detected through each method differed. Five species were detected only during traditional surveys, three by both methods, and one exclusively via iDNA. We demonstrate for the first time that iDNA can be used in targeted surveys of frog diversity and that it may increase the detectability of some species compared to traditional surveys. iDNA holds particular promise in the search for rare species, including those that are missing, feared extinct, and may also be useful in biosecurity, detecting invasive species.

No Net Loss of Species Diversity After Prescribed Fires in the Brazilian Savanna

Although savannas are fire-adapted ecosystems, prescribing fire for biodiversity conservation remains controversial at least in some regions where savannas occur. Faced with uncertainty, many decision makers and even scientists are still reluctant to prescribe fire for conservation purposes in fire-prone ecosystems, invoking the precautionary principle. Knowledge gaps on the ideal fire regime, such as how and when to burn, and especially the fear of biodiversity losses, are among the main arguments against fire management applied to remnants of native savanna vegetation. To inform this debate, we assessed the impact of prescribed fires on diversity of plants (different growth forms), ants, frogs, lizards, birds, and small mammals, in savannas and grasslands of the Brazilian Cerrado. We assessed the existing species richness, composition, and abundance in areas subjected to long periods of fire suppression and compared to that observed over a short period after prescribed dry-season fires, within each group of plants and animals. Whenever possible, we carried out separate analyses for grassland and savanna. Burning did not significantly reduce species richness of any of the groups analyzed, but had a positive effect on richness of graminoids in grassland. When analyzed at the species level, abundance of most animal groups did not show consistent responses to fire, except for a decrease in some frog populations in grasslands. Forbs, graminoids and subshrubs increased in abundance after fire in grassland areas, though in savanna areas, abundance of forbs and subshrubs tended to decline after fire. Species composition changed little in response to fire as indicated by low levels of dissimilarity between burned and unburned areas. These results confirm the high resilience of Cerrado biota to fire, as expected for savanna ecosystems in general. Besides, we demonstrate here that the risk of biodiversity losses cannot justify the objections to the use of prescribed fire for conservation purposes in the Cerrado.

The Effects of Habitat Alteration on Anuran Diversity and Assemblages on Mount Mulanje, Malawi

Anthropogenic disturbance and increased environmental degradation often lead to losses in species diversity. As continuous forests become increasingly limited, it is important to determine conservation and biodiversity values of intact forests and surrounding landscapes. Currently, there is little data on how anuran communities react to the alarming growth of habitat degradation in tropical East Africa, nor on the value of remnant forests. This study evaluated the alpha, beta and gamma diversity of frogs in an altered landscape on Mount Mulanje, Malawi, East Africa, and assessed the impact of habitat degradation and diversity of a landscape matrix of various habitat types. Nine sites were sampled: three intact miombo forests, three eucalyptus plantations, and three secondary forests. Twenty-nine species were found throughout these landscapes. Intact miombo forests contained significantly more frog species than the other habitats. The degree of canopy cover and area size appeared to determine species diversity across all three landscapes. Although eucalyptus plantations were impoverished, naturally regenerating secondary forests can help relieve the effects of habitat alteration. Nevertheless, degraded habitats cannot substitute for continuous blocks of forest; therefore understanding these differences is crucial for maintaining the biodiversity value in the long term.

Is there an association between the ecological characteristics of anurans from the Brazilian Atlantic Forest and their extinction risk?

Extinctions of anuran amphibians are more alarming compared to all other vertebrates. Several reports of declines come from Atlantic Forest, which currently holds only 1.62% of natural vegetation under full protection. However, despite this degradation, the Atlantic Forest still shelters a great diversity of anurans with a high diversity of specific ecological characteristics. Thus, our objective was to identify which ecological characteristics of anurans from the Atlantic Forest can be associated to this extinction risk, in order to understand how these characteristics can promote the species persistence against environmental disturbance. For each species, we gathered biological/ecological characteristics from literature, as well the extinction risk based on the National List of Endangered Species of Wildlife. In 2015, 547 anuran species had been assigned to the Atlantic Forest, of which 406 had their extinction risk defined. However, we considered only 295 species in our analyses due to the availability of biological/ecological information. We observed that the clutch size and the altitudinal distribution are related to the extinction risk of anurans. Threatened species had a small clutch size and were distributed in low or high areas, whereas non-threatened species had a larger clutch size and were distributed in intermediate altitude areas. Studies that investigate ecological characteristics that determine the extinction risk of species can be useful to assist conservation actions, concentrating efforts to species more sensitive to environmental alterations, besides highlighting the importance of natural history and the ecology of organisms in conservation decisions.

Anurans of Sete Cidades National Park, Piauí state, northeastern Brazil

Abstract The Sete Cidades National Park is located in the Brazilian municipalities of Piracuruca and Brasileira, Piauí state, in a transitional zone between the Caatinga and Cerrado biomes. Studies on its herpetofauna were limited to anuran distribution notes and a snake checklist. Thus, here we present an unpublished species list of anurans from Sete Cidades National Park, Piauí state, northeastern Brazil. We recorded one of the two highest species richness for all northeastern National Parks, and also increased the geographic distribution of one species in the state of Piauí. Most species observed are common of both Caatinga and Cerrado biomes or have wide distribution in Brazil. The anuran assemblage of Sete Cidades National Park is more similar to those registered at the Delta do Parnaíba Environmental Protection Area, Ceará, Piauí and Maranhão states, and Ubajara National Park, Ceará state. These results increase our knowledge on anuran diversity in northeastern Brazil, providing basic information for management and conservation actions of an important Brazilian National Park.

Comparison of frog diversity between paddy fields with chemical and non-chemical use in Nong Khai province, Thailand

Comparison of frog diversity between paddy fields with chemical and non-chemical use in Nong Khai province, Thailand

Comparison of frog diversity between paddy fields with chemical and non-chemical use in Nong Khai province, Thailand

Comparison of frog diversity between paddy fields with chemical and non-chemical use in Nong Khai province, Thailand

Keanekaragaman katak dan kodok (Amphibia: Anura) di Suaka Margasatwa Paliyan, Gunungkidul, Yogyakarta

Frogs and toads commonly found by human. Frogs and toads could become a bio-indicator of anenvironment. Paliyan Wildlife Sanctuary is a forest area which posses several animal to protect and it’slocated in Gunungkidul Regency, Province of DIY. The diversity of frogs and toads in this wildlifesanctuary is not yet recorded and published. The aim of this research is to understand the diversity of frogsand toads in the area of Paliyan Wildlife Sanctuary. The results there were 9 species of frogs and toads, i.e.,Duttaphrynus melanostictus, Ingerophrynus biporcatus, Fejervarya limnocharis, Kaloula baleata,Occidozyga lima, Occidozyga sumatrana, Microhyla orientalis, Microhyla palmipes and Polypedatesleucomystax. The diversity of frogs and toads in the wildlife sanctuary is moderate according to theShannon-Wiener Index with value: 1,43. Area of Paliyan Wildlife Sanctuary is a suitable habitat for frogsand toads due to its location with dense forest, bushes, rivers, lakes and pools as well as least humanactivities.

Monitoring the Diversity of Frogs and Toads (Amphibia: Anura) along Code River Province of Daerah Istimewa Yogyakarta

The research about frogs and toads diversity in the Code River, Province of Daerah Istimewa Yogyakarta (DIY) had been done in 2012 (Yudha et al, 2013). Now, after five years passed, we conduct monitoring activities to updating its diversity and distribution. After five years, we consider that there are many changes along the river that influenced habitat condition for frogs and toads which live along and near the river. Some of the changes are unused land became human settlement or paddy fields and waste land. The purpose of this research is to monitor the diversity of frogs and toads after five years along Code River. The method used was line transect combine with visual encounter surveys (VES) and river bank cruising. Results show that the species number of frogs and toads found in 2012 were slightly higher compare to 2017. The frogs and toads on upstream part were diverse in 2017 compare to 2012 due to natural restoration of riparian vegetation occur on upstream. The frogs and toads on midstream part were less diverse in 2017 compare to 2012 due to increasing human activities near the river and less riparian vegetation. The frogs and toads on downstream part were also less diverse in 2017 compare to 2012 due to increasing human activities near the river and more household waste stuck on riparian vegetation. There was variation of anurans diversity after five years due to changing on physical condition of the river and human activities near the river.

Acoustic niche partitioning in an anuran community from the municipality of Floriano, Piauí, Brazil.

Vocalizations are an important trait for the identification of cryptic and/or closely related amphibian species. Different vocalizations also contribute to partitioning of the acoustic space by sympatric species. This study aimed to describe the advertisement calls of anurans in a pond of the municipality of Floriano, State of Piauí, Brazil, and infer the acoustic niche partitioning of amphibians. Euclidean distance was used in a cluster analysis approach to infer the acoustic similarities among species. Thirteen species were analysed: Boana raniceps, Dendropsophus nanus, D. rubicundulus , D. minutus, Leptodactylus fuscus, L. troglodytes, L. vastus, Pithecopus nordestinus , Physalaemus cuvieri, P. nattereri, Pleurodema diplolister, Proceratophrys cristiceps and Scinax ruber. From these, six showed more than 90% of acoustic overlap: P. nattereri , P. cuvieri, L. fuscus and L. vastus (Leptodactylidae); and, D. nanus and D. rubicundulus (Hylidae). Despite the acoustic similarities among these six species, the acoustic interference was reduced due to the small number of sympatric species and to distinct features on carrier frequency such as dominant frequency and the degree of modulation in the frequency. Environmental factors limit the periods and sites of reproduction respectively, which may maintain the low anuran diversity and consequently reduce acoustic overlap.