We investigated the paradox of why Amazonian manatees Trichechus inunguis undergo seasonal migrations to a habitat where they apparently fast. Ten males were tracked using VHF telemetry between 1994 and 2006 in the Mamirau´a and Amana˜Sustainable Development Reserves, constituting the only long-term dataset on Amazonian manatee movements in the wild. Their habitat was characterized by analysing aquatic space and macrophyte coverage dynamics associated with the annual flood-pulse cycle of the River Solimo˜es. Habitat information came from fieldwork, two hydrographs, a three-dimensional model of the water bodies and classifications of Landsat-TM/ETM + images. We show that during high-water season (mid-May to end-June), males stay in várzea lakes in association with macrophytes, which they select. We then show that, during lowwater (October-November), the drastic reduction in aquatic space in the várzea leads to the risk of their habitat drying out and increases the manatees' vulnerability to predators such as caimans, jaguars and humans. This explains why males migrate to Ria Amana˜. Based on data on illegal hunting, we argue that this habitat variability influences females to migrate too. We then use published knowledge of the environment's dynamics to argue that when water levels are high, the habitats that can support the largest manatee populations are the várzeas of white-water rivers, and we conjecture that rias are the species' main low-water refuges throughout Western Amazonia. Finally, we warn that the species may be at greater risk than previously thought, because migration and low-water levels make manatees particularly vulnerable to hunters. Moreover, because the flooding regime of Amazonian rivers is strongly related to large-scale climatic phenomena, there might be a perilous connection between climate change and the future prospects for the species. Our experience reveals that the success of research and conservation of wild Amazonian manatees depends on close working relationships with local inhabitants.

Information on macrophyte distribution in space and time is very important for tropical reservoir management. Macrophyte stands are major sinks/ sources of methane and the knowledge of their spatial and temporal variation in biomass is useful for improving the assessment of the role of reservoirs in the carbon cycle. Moreover, macrophyte stands are a driving force in insect-induced diseases such as malaria. In this paper we examine the relationship between macrophyte stand variables such as above-ground biomass, stand average height and moisture, and radar backscatter at C and L bands. The study was carried out in TucuruÌ reservoir, where ground data were available concurrently to JERS-1 and RADARSAT overpasses. The results showed that C band is much more sensitive to macrophyte leaf shape than L band. However, L band proved to be more sensitive to above-ground biomass and stand height. Results support the integration of L and C band images to discriminate among the three main genera found in TucuruÌ: T ypha, Ciperacea and Eicchornia.

In a particular region within western Amazonia, Amazonian manatees (Trichechus inunguis) live in a floodplain environment that becomes inhospitable for them during the annual low-water season. To flee from it, they undergo a dangerous migration to a refuge while water levels are dropping fast. Our aim was to better understand the role of depth variation in this migratory process. We analyzed the sole tracking data on wild manatees (n=10 males), 30 years of Landsat images, a 14-year hydrograph and a 3-D bathymetric model. Migratory routes contained shallower segments, here called 'migratory bottlenecks', which dried out at the end of most lowering-water seasons, blocking the passage to the refuge. Manatees began migrating just in time to traverse the bottlenecks furthest away, suggesting they fine-tuned their departure so as to maximize time within the foraging home range without compromising safety. They apparently achieved this by estimating depth at the bottlenecks. Moreover, a bottleneck was created in >15 years, illustrating the environment's dynamism and the challenge this imposes upon manatees. Our results are probably generalizable to most of the species' range. We contend manatees possess an updatable cognitive map of their environment and are behaviorally plastic. Current dam-building plans, if implemented, would create more bottlenecks and make flooding less predictable, increasing manatee mortality from unsuccessful migrations. It would also partition the species into small populations, each prone to short-term extinction. The natural outcome would be the second species-level collapse. Economic growth should not come at the expense of the extinction of the iconic manatee. KEYWORDS: Sirenia, behavioral plasticity, Mamirauá, Amazon development Gargalos na rota migratória do peixe-boi amazônico e a ameaça das barragens hidrelétricas RESUMO Em uma região particular da Amazônia ocidental, peixes-boi amazônicos (Trichechus inunguis) vivem em um ambiente que se torna inóspito para eles durante a água-baixa anual. Para fugir dele, realizam uma migração perigosa para o refúgio enquanto o nível da água desce rapidamente. Nosso objetivo foi compreender melhor o papel da variação da profundidade neste processo migratório. Analisamos os únicos dados de rastreamento de peixes-boi selvagens (n=10 machos), 30 anos de imagens Landsat, 14 anos de hidrógrafa e um modelo batimétrico 3-D. As rotas migratórias possuíam trechos mais rasos, denominados gargalos migratórios, que secaram no final da maioria das vazantes, bloqueando o acesso ao refúgio. Os peixes-boi começaram a migração em tempo justo para atravessar os gargalos mais distantes, sugerindo que a sintonizaram para maximizar o período se alimentando sem comprometer a segurança. Para tal, parecem ter estimado a profundidade nos gargalos. Adicionalmente, um gargalo foi criado em <15 anos, ilustrando o dinamismo do ambiente e o desafio que isto impõe aos peixes-boi. Esses resultados provavelmente valem para boa parte da área de distribuição da espécie. Argume...

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non‐detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non‐governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer‐reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non‐detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio‐temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large‐scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data.

RESUMOObjetivou-se com o presente estudo monitorar o comportamento do uso territorial de um macho de onça parda, capturado no Parque Estadual da Serra do Brigadeiro (PESB), por meio da telemetria, usando colar de GPS via Satélite Globalstar. O monitoramento de doze meses resultou na transmissão via satélite de 328 localizações, as quais sugerem que a área utilizada por esse felino seja de aproximadamente 610km 2 , sendo esta a maior área já descrita para a espécie. Foi possível observar que apenas 20% das localizações ocorreram dentro da área do PESB. O comportamento territorial observado neste trabalho mostra a vulnerabilidade do animal a ações antrópicas, como a caça, atropelamentos e o contato com patógenos entre animais silvestres e domésticos. Observou-se também que duas rodovias configuram barreiras artificiais para o deslocamento do animal, possivelmente impedindo o fluxo gênico entre o PESB e dois outros importantes parques. Com os dados levantados é possível a sugestão de ações de manejo, como a criação de uma conectividade efetiva entre o PESB, o Parque Estadual do Rio Doce e o Parque Nacional do Caparaó, o que poderia contribuir para o intercâmbio genético entre as populações e, dessa forma, favorecer a conservação não somente da onça parda.