Leonardo Felipe Bairos Moreira

Factors influencing anuran distribution in coastal dune wetlands in southern Brazil

We investigated the potential role of hydroperiod and habitat structural complexity as explanatory factors defining richness, abundance and spatial and temporal distribution of anurans in wetlands of coastal dunes. This survey was performed in 15 wetlands along the Atlantic coastal zone of southern Brazil. We identified 10 anuran species (nine in the adult and eight in the tadpole stage) distributed in seven genera from five families. The adult richness and abundance varied among the hydroperiod classes, but without temporal variations. Both tadpole richness and abundance varied temporally and both were influenced by hydroperiod. Adult anuran composition was associated with dry months and wetland area, whereas tadpole composition was associated with emergent and floating macrophytes, wetland area and vegetation cover. This study identified the importance of habitat structural complexity and hydroperiod in spatial–temporal distribution models of anurans.

Effects of pine invasion on anurans assemblage in southern Brazil coastal ponds

The destruction of wetlands due to afforestation areas is a common activity in temperate and subtropical regions in Southern America. The expansion of pine in the Coastal Plain of Southern Brazil is out of control and its impacts on aquatic biodiversity are little known. We tested the following hypotheses: the pine occurrence diminishes the anuran richness and abundance in ponds and it changes the anuran composition; the beta-diversity between pine and native grassland matrix ponds (natural ponds) is determined mainly by nestedness. Sampling was carried out from 2007 to 2009 in five ponds in pine invasion matrix and five ponds in native grassland matrix. The natural ponds showed a greater richness of tadpoles (10 species) than pine ponds (5 species). The mean richness of adults was higher in natural ponds than pine ponds throughout the entire study. The species composition was different between natural and pine ponds, for both adults and tadpoles. Comparing natural ponds with each other and the pine ponds with each other, our results showed that neither nestedness nor turnover was determinant for beta-diversity. However, when natural ponds were compared with pine ones, we found that the contribution of nestedness was higher for the anurans beta-diversity than turnover. Increases in the nestedness mechanism indicated that the pine occurrence results in species loss in Southern Brazil ponds. Since 90% of its wetland has been already affected, the removal of Pinus in the conservation areas in southern Brazil is important to minimize their impacts on aquatic biodiversity.

CALLING PERIOD AND REPRODUCTIVE MODES IN AN ANURAN COMMUNITY OF A TEMPORARY POND IN SOUTHERN BRAZIL

Abstract The objectives of this study were to describe the calling sites and identify the reproductive modes for the anuran assemblage in a temporary pond associated to a floodplain system in a Neotropical region in Southern Brazil. In this study we analyzed the influence of temperature, rainfall and hydroperiod on the calling activity of an anuran assemblage. A total of 19 amphibian collections were carried out over a year (from September 2004 to August 2005). Seventeen anuran species of six families were identified: Bufonidae (1), Cycloramphidae (1), Hylidae (6), Leiuperidae (4), Leptodactylidae (4) and Microhylidae (1); however, only fifteen species were observed in calling activity. Three reproductive modes were observed for the community, and the habitat use was temporally and spatially partitioned. 66.7% of the species had the generalized aquatic mode. The anurans presented a prolonged calling activity, and only Chaunus fernandezae presented an explosive pattern. While rainfall for the previous 24 h, air temperature and water depth influenced the calling activity of many anuran species over the studied period, daily rainfall, rainfall for the previous 24 h and water temperature did not influence it.

Assessing patterns of nestedness and co-occurrence in coastal pond anuran assemblages

Segregated species co-occurrence and nestedness are two ecological patterns used to measure assemblage structure. We investigated species co-occurrence and nestedness patterns in assemblages of tadpoles and adult anurans in 30 coastal ponds in southern Brazil. Ponds varied in hydroperiod and were classified as temporary or permanent. We explored whether co-occurrence or nestedness varied among ponds in each hydroperiod. Species co-occurrence patterns were analyzed using the C-score index and three null models. In order to quantify nestedness, we used the nestedness metric based on overlap and decreasing fill (NODF). We found seventeen anuran species; however, only 13 species were observed in breeding activity, and 11 species were observed as tadpoles. The co-occurrence and nestedness analyses showed that anuran assemblages exhibit non-random patterns that were generally contingent on the hydroperiod and pond area. Only species in non-breeding adult anurans assemblages showed significant segregation when randomizations were weighted by pond area and the pattern was similar among hydroperiods. Tadpole assemblages of permanent ponds showed an aggregated co-occurrence in weighted-fixed model. In temporary ponds, NODF showed that anuran assemblages were significantly nestedness in all three phases of life cycle. We obtained contrasting results depending on the hydroperiod. These results support the hypothesis that habitat nestedness, due to hydroperiod, might be an important factor structuring anuran assemblages along the different phases of their life cycle.

Dynamics of the terrestrial amphibian assemblage in a flooded riparian forest fragment in a Neotropical region in the south of Brazil

The aim of this study was to analyze the richness, abundance and composition of the terrestrial amphibian assemblage in a flooded riparian forest fragment in a Neotropical region in the south of Brazil over a year (2002-2003). A total of 1,265 terrestrial amphibians were captured, representing 12 species and six families. Leiuperidae represented 41.7 and 56.3% of the total number of species and individuals captured, respectively. The amphibian richness and abundance were higher in the Spring-Summer than in the Autumn-Winter period, and these attributes did not change after the flood events. However, the floods homogeneously distributed the amphibian species over the fragment. Our study documented the terrestrial amphibians use in a riparian forest fragment associated to a floodplain system in the south of Brazil, showing the importance of these habitats as possible dispersal corridors among nearby wetlands.

Does Organic Agriculture Benefit Anuran Diversity in Rice Fields

The debate about management practices that help maintain biodiversity in cultivated areas is an ongoing controversy in conservation biology. It has been suggested that organic agriculture supports greater levels of diversity than non–organic agriculture. This study examined anuran assemblages in natural intermittent ponds and rice fields under two types of cultivation methods (conventional and organic) in southern Brazil. We tested the differences in species richness and composition among assemblages and guilds, at different stages of rice cultivation. Overall, organic fields had a different species composition than conventional fields and natural ponds. Most of the differences observed between the natural areas and the rice fields occurred during the off–season. For semi-aquatic species, richness was higher in off-season and in earlier growing stages. We found no differences in species richness of fossorial and arboreal species across the crop cycle. The differences we observed may relate to differences in dispersal abilities among guilds. Thus, the incorporation of individual traits of each species (e.g., habitat preference and reproductive mode) is fundamental to the creation of more effective conservation strategies in agroecosystems.

Amphibia, Anura, Centrolenidae, Vitreorana uranoscopa (Müller, 1924): distribution extension in the state of Rio Grande do Sul, Brazil

The glass frog Vitreorana uranoscopa (Muller, 1924) has been considered a vulnerable species for the state of Rio Grande do Sul, southern Brazil. This note recorded the presence of the species for Sao Marcos municipality, extending the species distribution towards eastern region of the state.

Intermittently Closed Estuaries and Tadpole Communities: Influence of Artificial Breaching

Naturally or mechanically opening the sand bar of intermittently closed estuaries (ICEs) plays an important role in the proper functioning of these systems. In this study, the impacts of artificial breaching of a coastal lagoon on anuran communities (composition, richness, and abundance) were investigated in the Lagoa do Peixe National Park floodplains, southern Brazil, from 2007 to 2009. The sampling period included two lagoon openings and occurred four times when the lagoon was open and four when it was closed. Artificial opening of the lagoon considerably changed the salinity and availability of temporary ponds in the estuary floodplains. Tadpole species richness and abundance were higher in areas influenced by the sand bar opening than in floodplain areas not influenced by this management. Although salinities were higher when the lagoon was open, only species that do not reproduce explosively occurred in significantly lower abundance. Multivariate analyses demonstrated that anuran species composition differed between areas affected and not affected by the lagoon opening. The composition gradient was associated with conductivity, hydroperiod, and floodplain management. These differences likely relate to individual traits of each species (e.g., habitat preference and reproductive mode). The study suggests that amphibian communities in the Peixe lagoon floodplains are resistant to oligohaline conditions when the lagoon is open. However, projected sea level rise and planned increasing drainage of freshwater wetlands could raise the salinity levels in floodplains to polyhaline or even euhaline conditions. Thus, artificially opening the sand bar for fishery management should be done with caution.

Checklist of amphibians in a rice paddy area in the Uruguayan savanna, southern Brazil

With the objective of contributing to conservation strategies for areas outside conservation areas, we present an inventory of the amphibians occurring in rice fields with different types of management (conventional and organic), in Sentinela do Sul, state of Rio Grande do Sul, Brazil, a grassland area in the Uruguayan savanna ecoregion. Between August 2010 and April 2011, we collected tadpoles in rice fields and natural ponds. We recorded 14 species of six families, and only eight of these species occurred in rice fields. Species composition differed between organic and conventional fields. Habitat features (time of flooding, presence of fish, presence of vegetation) may act synergistically with agrochemical effects on anuran species composition. Since few areas of Uruguayan savanna lie within conservation units, it is paramount to develop conservation measures that help maintain biodiversity in agroecosystems.

Daily Movement and Microhabitat Use by the Blacksmith Treefrog Hypsiboas faber (Anura: Hylidae) during the Breeding Season in a Subtemperate Forest of Southern Brazil

Abstract. We studied the patterns of daily movement and habitat use of 20 males and five females of the blacksmith treefrog, Hypsiboas faber, during the breeding season in a subtemperate forest of southern Brazil. Treefrogs were tracked with externally attached thread bobbins. There were no differences between sexes in the mean straight line distance moved (HSD) or in the effective distance moved (HDM), which ranged from 0.06–3.1 m/h and 0.4–9.8 m/h, respectively). Males showed higher site fidelity and less habitat overlap than females. Despite being an arboreal species, most of the tracked individuals used the herbaceous stratum on the ground as microhabitat, which indicates a particular microhabitat use during breeding activities. Estimates of the distance moved obtained from released thread lines revealed that animals moved distances five times greater than the distances calculated by drawing a straight line between consecutive points. Therefore, our findings suggest that the sedentary behavior attributed to some tropical and subtropical anuran species in tropical and subtropical anuran species forests might not be accurate.