Variação diária e espectral da atividade vocal de três espécies da família Tinamidae em florestas de terra firme da Amazônia brasileira

Birds are known to share information through conspicuous acoustic signals. Acoustic signals are especially important in habitats where vegetation makes long range visual signals ineffective. However, species that share similar characteristics of acoustic signals might also experience acoustic interference. Species that are closely related phylogenetically can also overlap in ecological and behavioral characteristics, enhancing the chance of acoustic interference. In order to avoid acoustic signal overlap, there might be present behavioral adaptations such as adjusting their vocal activity to avoid syntopic congeners. In this study, we used autonomous recording units (ARUs) to sample the dawn chorus activity of three species of tinamous (Family Tinamidae) during the dry season for two consecutive years at the Biological Dynamics of Forest Fragments Project in central Amazon, Brazil. We applied a method that accounts for imperfect detection in order to estimate the time of peak vocal activity for each species, while considering effects from the sampling bias. This study investigates how the species Tinamus major, Crypturellus variegatus and C. brevirostris utilize the acoustic space in time, and evaluate the degree of overlap in spectral and temporal traits of their calls. Our results suggests that these species use the acoustic space in a similarly, broadly overlapping in relation to the timing of vocal activity. However, these species differ significantly in characteristics of their calls. Our sampling and analytical methods had a temporal and spatial resolution that few bioacoustics studies have utilized; therefore we reinforce the body of publications which make use of ARUs and the usage of detection probabilities to better understand the dynamics of the dawn chorus.As aves comunicam-se principalmente através de sinais acústicos. Sinais acústicos são especialmente importantes em ambientes como a floresta amazônica, onde sinais visuais de longe alcance são impedidos pela vegetação. Sinais acústicos de espécies de aves que apresentam características espectrais semelhantes também podem sofrer com interferência acústica. Portanto, as aves devem repartir o espaço acústico que é finito. Para evitar à sobreposição espectral e/ou temporal as espécies adaptam suas vocalizações para utilizar frequências diferentes ou emitem sinais acústicos em diferentes momentos do coro matinal. Utilizamos gravadores autônomos para gravar o coro matinal durante duas estações de seca durante os anos de 2010 e 2011 no Projeto de Dinâmica Biológica de Fragmentos Florestais (PDBFF). Usamos estimativas das probabilidades de detecção ao longo da manhã de três espécies de aves da família Tinamidae ao longo do coro matinal. Este estudo investiga como as espécies Tinamus major, Crypturellus variegatus e C.brevirostris utilizam o espaço acústico e qual o nível de sobreposição temporal e espectral das atividades vocais. Nossos resultados indicam que estas espécies utilizam o espaço acústico de forma semelhante e há sobreposição temporal entre estas espécies. Demonstramos que a sobreposição temporal é maior que esperado ao acaso e que há diferenças significativas entre os parâmetros vocais analisados. Fizemos estimativas das probabilidades de detecções das três espécies ao longo do coro matinal para demonstrar que houve diferentes intensidades de sobreposição temporal da atividade vocal entre as três espécies. Nosso método utiliza uma resolução temporal e espacial ainda pouco utilizada para estudos bioacústicos, portanto nossos resultados reforçam que a utilização de gravadores autônomos é uma excelente ferramenta para futuros estudos de bioacústica

Environmental impact assessment in Brazilian Amazonia: Challenges and prospects to assess biodiversity

Environmental Impact Assessment (EIA) has the goal of providing decision makers with an indication of the likely environmental consequences of planned actions risking environmental changes and, when necessary, allowing revision of these actions to mitigate adverse impacts. Here we provide an overview of the efficiency of EIA with emphasis on Brazilian Amazonia and discuss the problems and challenges with this type of assessment in highly diverse ecosystems. We concentrate on the methodology and performance of EIAs for three of the most recent and largest infrastructure projects in Amazonia: the Belo Monte hydroelectric dam, the BR-319 Highway, and the Juruti bauxite mine. We conclude that all of these EIAs fall short of properly assessing the expected impact of infrastructure development in situ, and that their results had little or no effect on policy decisions. To improve the reliability and usefulness of EIAs in biologically diverse ecosystems, we suggest three relatively fast and cost-effective complementary approaches for assessing biodiversity: remote sensing, reflectance spectroscopy, and DNA meta-barcoding. We discuss how these emerging cutting-edge techniques can help in identifying environmental threats and the consequences of different activities in Amazonia. The ability to monitor the state of the environment and the likely impacts of human activities on natural resources is fundamental to evidence-based decisions on development choices, to the design of appropriate management strategies, and to mitigate biological and ecological consequences. © 2017 The Author

Environmental impact assessment in Brazilian Amazonia: Challenges and prospects to assess biodiversity

Environmental Impact Assessment (EIA) has the goal of providing decision makers with an indication of the likely environmental consequences of planned actions risking environmental changes and, when necessary, allowing revision of these actions to mitigate adverse impacts. Here we provide an overview of the efficiency of EIA with emphasis on Brazilian Amazonia and discuss the problems and challenges with this type of assessment in highly diverse ecosystems. We concentrate on the methodology and performance of EIAs for three of the most recent and largest infrastructure projects in Amazonia: the Belo Monte hydroelectric dam, the BR-319 Highway, and the Juruti bauxite mine. We conclude that all of these EIAs fall short of properly assessing the expected impact of infrastructure development in situ, and that their results had little or no effect on policy decisions. To improve the reliability and usefulness of EIAs in biologically diverse ecosystems, we suggest three relatively fast and cost-effective complementary approaches for assessing biodiversity: remote sensing, reflectance spectroscopy, and DNA meta-barcoding. We discuss how these emerging cutting-edge techniques can help in identifying environmental threats and the consequences of different activities in Amazonia. The ability to monitor the state of the environment and the likely impacts of human activities on natural resources is fundamental to evidence-based decisions on development choices, to the design of appropriate management strategies, and to mitigate biological and ecological consequences. © 2017 The Author