Methane concentrations and fluxes in agricultural and preserved tropical headwater streams.

Tropical streams have been intensively impacted by agricultural activities. Among the most important agricultural activities in Brazil, sugarcane production represents a large impact for economic development and for environmental conditions. Permeating sugarcane fields, several headwater streams can be affected by sugarcane cultivation, in special, aquatic biogeochemical cycles because of the deforestation, fertilization, crop residues and higher temperatures in the tropics. In this study, we analyzed the effects of sugarcane cultivation on methane fluxes and concentrations, assuming that carbon cycles are influenced by agricultural activities in headwater streams. Our study aimed to (1) measure methane fluxes and concentrations in tropical streams located in Southeastern Brazil, (2) Analyze whether seasonal cycles influence methane fluxes and concentrations, (3) Evaluate the influence of sugarcane cultivation on methane fluxes and (4) Analyze the association between water chemistry in the methane concentrations in tropical streams. We found mean fluxes of CH4 of 0.280 mmol m-2 d-1, with higher fluxes during the summer and in streams draining preserved catchments. The average CH4 concentrations were 0.695 µmol L-1, with higher values during the summer and in streams draining preserved catchments. Methane concentrations in the studied streams was influenced by dissolved oxygen (negatively), dissolved organic carbon (negatively), water velocity (positively) and conductivity (negatively). Methane concentrations were significantly higher than concentrations found in Temperate Grasslands, Savannas & Shrublands and similar to concentrations found in other tropical biomes (excluding Tropical & Subtropical Moist Broadleaf Forests which receives large amounts of organic inputs). We conclude that sugarcane influence methane concentrations and fluxes in tropical streams by reducing the organic matter availability provided by the native vegetation in soil and water.

ATLANTIC AMPHIBIANS: a data set of amphibian communities from the Atlantic Forests of South America.

Amphibians are among the most threatened vertebrates in the world and this is also true for those inhabiting the Atlantic Forest hotspot, living in ecosystems that are highly degraded and threatened by anthropogenic activities. We present a data set containing information about amphibian communities sampled throughout the Atlantic Forest Biome in South America. The data were extracted from 389 bibliographic references (articles, books, theses, and dissertations) representing inventories of amphibian communities from 1940 to 2017. The data set includes 17,619 records of 528 species with taxonomic certainty, from 1,163 study sites. Of all the records, 14,450 (82%) were classified using the criterion of endemism; of those, 7,787 (44%) were considered endemic and 6,663 (38%) were not. Historically, multiple sampling methods were used to survey amphibians, the most representative methods being active surveys (82.1%), surveys at breeding sites (20%), pitfall traps (15.3%), and occasional encounters (14.5%). Species richness averaged 15.2 ± 11.3 (mean ± SD), ranging from 1 to 80 species per site. We found a low dominance in the communities, with 10 species occurring in about 26% of communities: Physalaemus cuvieri (4.1%), Dendropsophus minutus (3.8%), Boana faber (3.1%), Scinax fuscovarius (2.8%), Leptodactylus latrans (2.7%), Leptodactylus fuscus (2.6%), Boana albopunctata (2.3%), Dendropsophus nanus (1.6%), Rhinella ornata (1.6%), and Leptodactylus mystacinus (1.6%). This data set represents a major effort to compile inventories of amphibian communities for the Neotropical region, filling a large gap in the data on the Atlantic Forest hotspot. We hope this data set can be used as a credible tool in the proposal of new studies on amphibian sampling and even in the development of conservation planning for these taxa. This information also has great relevance for macroecological studies, being foundational for both conservation and restoration strategies in this biodiversity hotspot. No copyright or proprietary restrictions are associated with the use of this data set. Please cite this data paper when the data are used in publications or teaching events.

Anuros do cerrado da Estação Ecológica e da Floresta Estadual de Assis, sudeste do Brasil / Anurans of the cerrado of the Estação Ecológica and the Floresta Estadual de Assis, southeastern Brazil

O cerrado brasileiro é um dos 25 "hotspots" da Terra, áreas caracterizadas pela concentração de espécies endêmicas e por experimentar excepcional perda de hábitat. São conhecidas cerca de 150 espécies de anfíbios no Cerrado brasileiro, e aproximadamente 28% dessas espécies são endêmicas. Trabalhos com comunidades de anuros do cerrado ainda são escassos, e a forte pressão antrópica, o alto grau de endemismo e o declínio de populações de anuros registrados nesse bioma reforçam a importância de estudos relacionados à anurofauna. O presente trabalho apresenta um inventário de espécies de anuros em duas unidades de conservação no cerrado da cidade de Assis, sudoeste do Estado de São Paulo: Estação Ecológica de Assis e Floresta Estadual de Assis. Durante o estudo, foram registradas 23 espécies distribuídas em 13 gêneros e seis famílias. A fauna de anuros do cerrado de Assis é fortemente dominada pelas famílias Hylidae (oito espécies) e Leptodactylidae (seis espécies), um padrão comumente encontrado em localidades da região Neotropical. A riqueza de espécies e a representatividade das famílias foram similares às encontradas em outras áreas de cerrado do Brasil e de formações vegetais antropizadas com perda de área florestal e aumento de áreas abertas. A taxocenose de anuros da localidade de estudo é composta por espécies amplamente distribuídas em ambientes abertos do complexo Cerrado-Caatinga-Chaco.

The Brazilian cerrado is a hotspot of biodiversity, areas with many endemic species subjected to severe habitat loss. About 150 amphibian species are known to the Brazilian cerrado, and 28% of them are endemic. Studies focusing cerrado anuran communities are rare. Here we provide a commented list of anurans of two conservation unities of the municipality of Assis, southeastern Brazil: the Estação Ecológica de Assis and the Floresta Estadual de Assis. Twenty three anuran species were recorded, and these belong to 13 genera and six families. The anuran fauna of the cerrado of Assis is dominated by the families Hylidae (eight species) and Leptodactylidae (six species), a pattern commonly found in neotropical sites. Species richness and taxonomic composition at the family level were similar to those of other Brazilian cerrados and perturbed areas characterized by deforestation and increase of open areas. The taxocenosis contains species widespread in open formations of the Cerrado-Caatinga-Chaco complex.