Anurans from a Cerrado-Atlantic Forest ecotone in Campos Gerais region , southern Brazil

Knowledge of the richness and distribution of anurans living in ecotone regions is still incipient, especially in transition zones between threatened phytogeographic areas like the Cerrado and the Atlantic Forest. This study presents a checklist of anuran amphibians in an ecotone (Cerrado-Atlantic Forest) in the Campos Gerais, Parana State, Brazil. Samplings were conducted in 66 water bodies (ponds) between October 2012 and March 2013. We identified 42 anuran species, six of them in larval stage only and eight of them in adult stage only. The anurofauna accounted for 21.05% of the species registered for the Cerrado and 9.58% of the species found in the Atlantic Forest. Four species are endemic to the Cerrado and eight to the Atlantic Forest. Our results show that this region has a rich anurofauna with species characteristic of different biomes. This study contributes to the process of knowledge production to support further research in ecology, biogeography and conservation of anurans in the Campos Gerais.


Introduction
The domains of the Cerrado and the Atlantic Forest are in the list of the world's biodiversity hotspots because they have a small representation of original areas as primary vegetation, high rates of endemism and a high degree of threat (Myers et al. 2000;Mittermeier et al. 2004).Cerrado is highly threatened by human activities, especially by agriculture and extensive livestock production (Ratter et al. 2003).Recent studies have estimated that about 55% of the 2 million km² of the original vegetation cover has been devastated (Machado et al. 2004).The Atlantic Forest, as well as the Cerrado, is threatened by human influence, and its original vegetation has been reduced, ranging from 11.4% to 16% of its original length, which was 1.5 million km² (Ribeiro et al. 2009).
The Campos Gerais suffer influence from the Atlantic Forest, but the southern limit of the Cerrado domain is also found in this region; therefore, there are some areas of savannah, which consist of a mixture of species that are characteristic of the Central Plateau of Brazil (Ritter et al. 2010).Ecotones are unique areas, with physical and biological characteristics of adjacent regions (Williams 1996).Therefore, they have a species composition derived from both areas and may have a diversity higher than that of a single biome alone (Remanamanjato et al. 2002).In this sense, disconnected remnants of different phytogeographical domains, such as of the Cerrado and the Atlantic Forest, may be important to support animal or plant species characteristic of these biomes, such as amphibians, for example.Amphibians are found in almost all types of terrestrial and freshwater habitats, and their distribution is strongly influenced by the presence of water (Duellman and Trueb 1986).Their dependence on Abstract: Knowledge of the richness and distribution of anurans living in ecotone regions is still incipient, especially in transition zones between threatened phytogeographic areas like the Cerrado and the Atlantic Forest.This study presents a checklist of anuran amphibians in an ecotone (Cerrado-Atlantic Forest) in the Campos Gerais, Paraná State, Brazil.Samplings were conducted in 66 water bodies (ponds) between October 2012 and March 2013.We identified 42 anuran species, six of them in larval stage only and eight of them in adult stage only.The anurofauna accounted for 21.05% of the species registered for the Cerrado and 9.58% of the species found in the Atlantic Forest.Four species are endemic to the Cerrado and eight to the Atlantic Forest.Our results show that this region has a rich anurofauna with species characteristic of different biomes.This study contributes to the process of knowledge production to support further research in ecology, biogeography and conservation of anurans in the Campos Gerais.the Atlantic Forest, with forest formations of Subtropical Ombrophilous Forest and Seasonal Semidecidual Forest forming mosaics of different vegetation types (Carmo et al. 2012;Moro 2012).
The region is under the influence of two climate types according to the Köeppen classification: Cfa, mesothermal subtropical climate with hot, rainy summers; and Cfb, mesothermal subtropical climate, humid, without a defined dry season and mild summers (Peel et al. 2007).The region exhibits a gently undulating relief, and altitude ranges from 800 to 1,200 m.The soil is a red-yellow oxisol and lithic neossolos, but cambisols and argisols can also occur (Melo et al. 2007).

Data collection
Fieldwork was conducted between October 2012 and March 2013 during six field trips, each lasting for six days, amounting to 36 sampling days in the region.Samplings were performed in 66 water bodies (conisting of ponds only) located in fragments of the Cerrado and ecotone regions (Atlantic Forest) with Subtropical Ombrophilous Forest and Seasonal Semidecidual Forest in Campos Gerais.The typical vegetation formations of the region may be divided into: dry fields, wetlands fields, gallery forests, mixed forests of araucaria, Cerrado relicts, seasonal semidecidual forest (Klein and Hatschbach 1971;Pillar 2000;Rodrigues 2000;Di Bitetti et al. 2003;Melo et al. 2007), pine plantations and anthropogenic grasslands.The water bodies are located in the municipalities of Sengés, Jaguariaíva, Piraí do Sul, Tibagi, Carambeí and Ponta Grossa (Figure 1, Table 1).
Tadpoles were sampled during daytime with a steel dip net with 40 cm diameter and 3 mm² mesh, dragged by the margin and inside of each water body, with sampling effort of one hour (Heyer et al. 1994).The tadpoles collected were anesthetised with 5% benzocaine, fixed and preserved in 5% formalin.Individuals were identified according to Rossa-Feres and Nomura (2006), Machado and Maltchik (2007) and Conte et al. (2007) and also by comparison with individuals deposited in other collections, using a Zeiss stereomicroscope.
Adult anurans were sampled at night, using the methods of visual and auditory search, for an hour at each sampling site (Heyer et al. 1994).All vocalising males were counted, estimating the abundance for each sampling site.Voucher individuals were collected, anesthetized with 5% lidocaine, fixed in 10% formalin and preserved in 70% alcohol.Nomenclature follows Frost (2014).All tadpoles and voucher adults collected were deposited at the Coleção Zoológica da Universidade Federal de Goiás (ZUFG), Goiânia, Goiás State, Brazil (Collection permit IAP 439.12 and ICMBIO 35767-1) (Appendix 1).
The conservation status of each species was defined based on the data available on the IUCN Red List of Threatened Species (IUCN 2013).Information about the degree of association between the species and the Cerrado and Atlantic Forest and their distribution patterns were obtained through information available in Valdujo et al. (2012) and Haddad et al. (2013).
The Abbreviations: Association = association level of the Cerrado, Distribution = distribution pattern, T = typical species, M = marginal species, E = endemic to the Cerrado, W = widely distributed, S = species with southern distribution occurring in the Cerrado, AT = species occurring in the Atlantic Forest and the Cerrado.Asterisks indicate species endemic to the Atlantic Forest.

Discussion
The species richness found herein is high compared to other areas of Cerrado (Ribeiro-Junior and Bertoluci 2009;Morais et al. 2012;Melo et al. 2013) and Atlantic Forest (Serafim et al. 2008;Cunha et al. 2010, Armstrong andConte 2010), and other areas of ecotone (Araujo et al. 2009;Bertoluci et al. 2009;Vasconcelos et al. 2011), although this study covered a larger area.According to Valdujo et al. (2011), differences in species composition between localities may stem from historical factors that contribute to the distribution of each species.The finding of a large number of species of the families Hylidae and Leptodactylidae was similar to the results of other studies and follows the pattern found in Neotropical environments (Duellman 1999;Ribeiro-Junior and Bertoluci 2009).The anurofauna corresponded to 21.05% of the recorded species for the Cerrado (Valdujo et al. 2012) and 9.58% of the species found in the Atlantic Forest (Haddad et al. 2013).There are at least 18 (42.85%)species shared with Cerrado and Atlantic Forest (e.g.Rhinella schneideri, Hypsiboas albopunctatus, Scinax fuscovarius and Leptodactylus fuscus), which reinforces the transitional nature of the sampled area.This richness also represents 30.98% of anurans registered for the Paraná State (Conte et al. 2010), which is higher than that observed for other areas of the state (Conte and Rossa-Feres 2006, 34 species;Armstrong and Conte 2010, 32 species;Cunha et al. 2010, 32 species).Moreover, this study adds nine new species for the region (D.elianae, Hypsiboas caingua, Physalaemus marmoratus, P. nattereri, Scinax aromothyella, S. fuscomarginatus, S. uruguayus, S. cf.similis and S. cf.granulatus), extending their distribution to the Paraná State.
In general, the species sampled in this study occur in more than one biome (e.g.Cerrado, Atlantic Forest sensu lato and Pampa), or even in neighbouring countries (Frost 2014).Among the recorded species, 54.8% (n = 23) are considered marginal, occurring in environments of transition between the Cerrado and other biomes, and 45.2% (n=19) are considered typical of the Cerrado (Valdujo et al. 2012).Hypsiboas jaguariaivensis is the only species endemic to the region, with restricted distribution to remnant of ′′cerrado′′ vegetation in Campos Gerais (Caramaschi et al. 2010).Six species (14.28%) presented taxonomic difficulties.The taxonomic problem is mainly due to difficulty in identifying the tadpoles, since many species have not yet had their larval stages described (Provete et al. 2012).Furthermore, larvae exhibit great morphological variation, and their body shape may change according to the environment they occupy (Michel 2011).
Most of the recorded species breed in open areas (e.g.Hypsiboas albopunctatus, Leptodactylus fuscus, Physalaemus cuvieri, Rhinella schneideri and Scinax fuscovarius), successfully colonising disturbed environments.These species do not have great specificity of breeding sites, and may be considered habitat-generalists (Brasileiro et al. 2005;Silva and Rossa-Feres 2007).Nevertheless, species such as Aplastodiscus albosignatus, Scinax rizibilis, Scinax cf.catharinae and Physalaemus lateristriga may demonstrate specificity of habitats, occurring only in forest areas (or forest edge), as previously reported in other studies (Bernarde and Machado 2001;Conte and Rossa-Feres 2007;Moraes et al. 2007).The occurrence of species in open areas in forests and forest edges reinforces the idea that the forest edge is a transition zone, where habitat generalists or specialists may eventually be found (Silva and Rossa-Feres 2007).
Although it was not tested, the high diversity of anurans recorded can be explained by the high environmental heterogeneity that has arisen from the mosaic of environments in the region (Silva et al. 2012;Melo et al. 2013), which is formed by different Cerrado physiognomies, Campos Sulinos, Subtropical Ombrophilous Forest and Seasonal Semidecidual Forest (Carmo et al. 2012;Moro 2012).Considering the large number of threatened species among amphibians in the Cerrado and the Atlantic Forest, it is imperative to create strategies and mechanisms that maximise conservation efforts, especially in regions where few data on the diversity, abundance and distribution of the species are available (Young et al. 2001;Diniz-Filho et al. 2009).In agreement to the report of Diniz-Filho et al. (2005), there are still many poorly sampled regions, mainly in the Cerrado, which suggests an underestimated number of frog species recorded to date.
Due to its ecological uniqueness, especially regarding the mosaic formed when forest and field intertwine, along with the low representativeness of protected areas, anthropogenic pressures imposed by colonisation and agricultural activities, the Campos Gerais are one of the most threatened ecosystems in Brazil (Rocha 2006).Thus, the importance and immediacy in the development of studies on the fauna of this region are evident considering that the anurofauna of the Paraná State is still poorly known (Rossa-Feres and Conte 2006;Rossa-Feres and Conte 2007;Conte et al. 2010).Studies in different types of environments favour the expansion of distribution of some taxa and discovery of new species (Caramaschi et al. 2010;Pombal et al. 2011), as well as understanding regional patterns of species richness (Valdujo et al. 2011).This work increases our knowledge about the species that may occur in marginal regions or remnants of Cerrado and ecotone regions with the Atlantic Forest in the Campos Gerais.

Figure 1 .
Figure 1.Map showing the sampled municipalities in Campos Gerais.
* Habitats sampled only for the adult stage.** Habitats sampled only for the larval stage.

Table 2 .
List of species of anurans sampled in disjoint remnants of Cerrado and ecotone (Atlantic Forest) on Campos Gerais of the Paraná, Brazil.