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Aquatic macrophytes add structural complexity to the environment, which influences fish species. The structure of macrophytes rafts can vary depending on the hydrological cycle and space availability. Thus, the objective of the present study was to evaluate which predictors associated with environmental conditions, composition of macrophyte species and spatial factors can affect fish communities in different hydrological regimes. The study was carried out in oxbow lakes in the Amazon, in the middle Purus River, Amazonas, Brazil. Samples of fish and macrophytes were collected during the flood, receding and drought periods, and environmental variables were measured in all macrophytes rafts. Partial redundancy analysis was applied to quantify the relative contribution of environmental variables, macrophyte composition and spatial factors in the fish community. Our study revealed that environmental conditions and macrophyte species composition, and both spatially structured as well, were the main factors that explained changes in fish composition in floating meadows of oxbow lakes. Corroborating our predictions, the variations in the fish communities were explained mainly by niche-based processes, including environmental conditions and macrophyte species composition as an environmental component, which varied over the hydrological cycle. The spatial component was more important during flooding, environmental conditions during receding, and macrophyte species composition during the drought hydrological regime. However, the shared explanations that indicated a spatially structured environment, both for environmental conditions and for composition of macrophytes, were greater during all hydrological regimes, also supporting our prediction. [ABSTRACT FROM AUTHOR]

New data that seeks to fill knowledge gaps about distribution and natural history may improve our knowledge of the status of threatened species. Herein, new distributional record of the endangered species Allobates goianus is reported and information on daily activities of a population are provided using an automatic acoustic monitoring recorder. Despite the new distributional record, A. goianus has not been recorded in locations where it was previously found, we then discuss the possible causes of decline and how future efforts may help to better understand the species status. [ABSTRACT FROM AUTHOR]

The production of forest species that present seedlings with exogenous dormancy is limited by low germination rates, which can be overcome by rupturing or weakening the tegument. This study aimed to evaluate the efficiency of low-cost methods of overcoming dormancy and determine the effect of storage on the seeds of Enterolobium contortisiliquum. Four storage periods were used, freshly collected seeds (0), stored for 6, 12 and 18 months, and four methods were applied, mechanical scarification and immersion in water (EI), mechanical scarification (ES), immersion in water (IM) and control (TE). We obtained the percentage values of seedling emergence (EP) and the mean emergence time (TME). Conductivity and moisture were obtained as indicators of the physical and physiological quality of seeds, respectively. Variations in moisture content and electrical conductivity during storage did not have effect on the percentage of germination. EI treatment was more efficient for overcoming dormancy than the ES was, regardless of storage time. IM and TE treatments did not lead to germination. EI was the most efficient treatment for decreasing the TME. The results indicate that alternative and low-cost methods are efficient at overcoming exogenous dormancy and thus can be used to optimize the process of seedling production. [ABSTRACT FROM AUTHOR]

We report Pristimantis achuar, Pristimantis delius, and Pristimantis orcus as three new records from Brazil, extending their known geographic distributions from Ecuador, Colombia, and Perú. Additionally we comment on the vocalizations of Pristimantis orcus. [ABSTRACT FROM AUTHOR]

The genus Osteocephalus (Fitzinger, 1843) is represented by 23 species, of which nine occur in Brazil. Here we exntend the distribution of Osteocephalus castaneicola Moravec, Aparicio, Guerrero-Reinhard, Calderón, Jungfer & Gvoždík, 2009 and provide the first record for Acre state. We include an updated distribution map for the species. [ABSTRACT FROM AUTHOR]

During the breeding season, hundreds of anurans agglomerate at spawning sites, where a diversity of social contexts arise. In this scenario, anurans may alter their vocal repertoire according to the immediate social context, to overcome intraspecific competition. To evaluate the acoustic response of Boana goiana to successive interactions with a conspecific competitor, the present study was based on comparing the repetition rates of advertisement and aggressive calls of B. goiana focal males exposure to repeated artificial advertisement calls in 10 playback sessions. We observed that B. goiana males altered their acoustic behaviour in response to the simulated arrival of a new competitor. Males emitted less advertisement calls and more aggressive calls with the arrival of the competitors. Temperature and body condition were not important predictors of continuity of males in the experiment or the call repetition rates in the pre-playback session. However, the body condition influenced the total delta advertisement calls (differences in the call rate emission between end and the beginning of the experiment), indicating that higher values of body conditions allow males to show smaller reductions in the emission of advertisement calls over time in the presence of a competitor. [ABSTRACT FROM AUTHOR]

The article discusses the death-feigning behavior also known as thanatosis strategy observed in the Ischnocnema aff. henselii which is a nocturnal anurans. Topics include the use of selective pressures among amphibians as defensive behavior against predator interaction and the field surveys where in frogs remained motionless with belly up, arms upward and eyes closed with yellowish colour observed by researchers in Araucaria plateau in southern Brazil.

Information on bothrops moojeni from Brazil including informations related to topics like its diet, the habitat in which it is found, and its physical traits is presented.