Variação temporal na predação de ninhos de jacaré-açu (Melanosuchus niger, Alligatoridae) na Amazônia Central, Brasil

In the Amazon floodplain, the nesting period of the black caiman (Melanosuchus niger) occurs in the dry season, when land areas are available. The incubation period can extend up to 90 days. The main threats to the success of nesting of black caiman are flooding and predation of nests. The main predators of black caiman eggs are jaguars (Panthera onca), tegu lizards (Tupinambis teguixim), capuchin monkeys (Sapajus macrocephalus) and humans (Homo sapiens). In this study, we investigated the relationship between predator attacks on nests and incubation period, and evaluated the influence of initial predation on subsequent predation in the Mamirauá Sustainable Development Reserve. We also evaluated the influence of presence of females near the nests and manipulation of nests on the occurrence of attacks. We compared results from data obtained with camera traps and vestiges left by predators on estimates of rates of predation by different predators. Egg predation was recorded in 32% of the 658 black caiman nests monitored for two years. Our results suggest that the probability of predation on black caiman eggs is relatively constant throughout the incubation period and that predation on eggs was lower when adults, presumably females, were present. The opening of nests and handling of eggs did not increase the number of attacks on black caiman nests. Nest opening by a predator appeared to increase the chances of a subsequent attack because most of the attacks on nests occurred soon after a predator first opened the nest. However, attacks by another species of predator do not appear tobe necessary to initiate attacks by any of the species of predator. Results based on camera traps and vestiges were generally similar, but of vestiges underestimates the number of species that attacked the nest in more than one predation event. This making the method ineffective for studies that seek information on all species of predators involved.Na várzea amazônica, o período de nidificação do jacaré-açu (Melanosuchus niger) ocorre na época da seca, quando áreas terrestres ficam disponíveis. O período de incubação pode durar até 90 dias. As principais ameaças ao sucesso da nidificação do jacaré-açu são a inundação e a predação dos ninhos. Os principais predadores de ninhos de jacaré-açu são a onça pintada (Panthera onca), o lagarto jacuraru (Tupinambis teguixim), o macaco prego (Sapajus macrocephalus) e o homem (Homo sapiens). Neste estudo, foi investigada a relação entre os ataques de predadores aos ninhos e o período de incubação e avaliou-se a influência da predação inicial na predação subsequente na Reserva de Desenvolvimento Sustentável de Mamirauá. Também foi avaliada a influência da presença de fêmeas perto dos ninhos e da manipulação de ninhos na ocorrência de ataques. Os resultados de dados obtidos com armadilhas de câmeras e de vestígios deixados por predadores foram comparados em estimativas de taxas de predação por diferentes predadores. A predação de ovos foi registrada em 32% dos 658 ninhos monitorados por dois anos. Os resultados sugerem que a probabilidade de predação em ovos de jacaré-açu é relativamente constante ao longo do período de incubação e que a predação nos ovos foi menor quando adultos, presumivelmente fêmeas, estavam presentes. A abertura dos ninhos e o manejo dos ovos não aumentaram o número de ataques aos ninhos. A abertura do ninho por um predador pareceu aumentar as possibilidades de um ataque subsequente, porque a maioria dos ataques aos ninhos ocorreu logo depois que um predador abriu primeiramente o ninho. No entanto, os ataques de outra espécie de predador não parecem ser necessários parainiciar ataques de qualquer espécie de predador. Os resultados baseados em armadilhas fotográficas e vestígios foram semelhantes, porém os dados de vestígios subestimam o número de espécies que atacaram quando o ninho teve mais de um evento de predação. Isso torna o método ineficaz para os estudos que procuram informações sobre todas as espécies de predadores envolvidos

Novo registro de ocorrência da perereca-franjada, Cruziohyla craspedopus (Anura: phyllomedusidae) estende o limite oriental de sua distribuição

The fringed leaf frog, Cruziohyla craspedopus is rarely sampled in the Brazilian Amazon, probably due to low detection probability associated with its arboreal habit. The knowledge about the species’ distribution stems from successive additions of occasional occurrence records, which indicate that the species is widely distributed throughout Amazonia. We present new occurrence records to update the geographic range of the species, which is hereby extended 224 km to the northeast. We also present morphological data from collected specimens and discuss the updated range from the geographic and ecological points of view. We show that the range of the leaf frog crosses several main tributaries along the southern bank of the Amazonas River, although the species occurrence is apparently limited by a minimum tree cover of 70%. © 2019, Instituto Nacional de Pesquisas da Amazonia. All rights reserved

Temporal variation in black-caiman-nest predation in varzea of central Brazilian amazonia

On the Amazon floodplain, the main predators of black caiman (Melanosuchus niger) eggs are jaguars (Panthera onca), tegu lizards (Tupinambis teguixim), capuchin monkeys (Sapajus macrocephalus) and humans (Homo sapiens). In this study, we investigated the relationship between predator attacks on nests and incubation period, and evaluated the influence of initial predation on subsequent predation in the Mamirauá Sustainable Development Reserve. We also evaluated the influence of presence of females near the nests and manipulation of nests on the occurrence of attacks. We compared results from data obtained with camera traps and vestiges left by predators on estimates of rates of predation by different predators. Egg predation was recorded in 32% of the 658 black caiman nests monitored during two years. Our results suggest that the probability of predation on black caiman eggs is relatively constant throughout the incubation period and that predation on eggs was lower when adults, presumably females, were present. Careful opening of nests and handling of eggs did not increase the number of attacks on black caiman nests. Nest opening by a predator appeared to increase the chances of a subsequent attack because most of the attacks on nests occurred soon after a predator first opened the nest. However, attacks by another species of predator do not appear to be necessary to initiate attacks by any other species of predator. Results based on camera traps and vestiges differed, but use of vestiges was adequate for identifying the principal predators on eggs in black caiman nests and, in many circumstances, the vestiges may be better for estimating predation by humans. In this study, opening nests and handling eggs did not increase the number of attacks on black caiman nests. © 2017 Torralvo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Tool use by Amazonian capuchin monkeys during predation on caiman nests in a high-productivity forest

Descriptions of new tool-use events are important for understanding how ecological context may drive the evolution of tool use among primate traditions. Here, we report a possible case of the first record of tool use by wild Amazonian capuchin monkeys (Sapajus macrocephalus). The record was made by a camera trap, while we were monitoring caiman nest predation at Mamirauá Reserve in Central Amazonia. An adult individual was registered in a bipedal posture, apparently using a branch as a shovel to dig eggs out of a nest. Caiman eggs are frequently depredated by opportunistic animals, such as the capuchin monkeys. As the Mamirauá Reserve is covered by a high-productivity forest, and caiman eggs are a high-quality food resource seasonally available on the ground, we believe that tool use by capuchins is more likely to be opportunity driven, rather than necessity driven, in our study site. © 2017, Japan Monkey Centre and Springer Japan

Number and proportion of predators that attacked black caiman nests monitored by vestiges (n = 595) and monitored by cameras (n = 63) in the years 2013 and 2014.

<p>Number and proportion of predators that attacked black caiman nests monitored by vestiges (n = 595) and monitored by cameras (n = 63) in the years 2013 and 2014.</p

Relationship between the times to first and second predation events in black caiman nests monitored in the years 2013 and 2014.

<p>Relationship between the times to first and second predation events in black caiman nests monitored in the years 2013 and 2014.</p

Number and proportion of nests attack by only one predator other than humans monitored by vestiges (n = 74) and monitored by cameras (n = 14) in the years 2013 and 2014.

<p>Number and proportion of nests attack by only one predator other than humans monitored by vestiges (n = 74) and monitored by cameras (n = 14) in the years 2013 and 2014.</p

Location of the study area.

<p>Red lines show the limits of the Mamiraua Sustainable Development Reserve–MSDR. The green line on the inset indicates the limits of the Amazon basin. Map created by Jefferson Ferreira Ferreira.</p

Diverse anthropogenic disturbances shift Amazon forests along a structural spectrum

Amazon forests are being degraded by myriad anthropogenic disturbances, altering ecosystem and climate function. We analyzed the effects of a range of land-use and climate-change disturbances on fine-scale canopy structure using a large database of profiling canopy lidar collected from disturbed and mature Amazon forest plots. At most of the disturbed sites, surveys were conducted 10–30 years after disturbance, with many exhibiting signs of recovery. Structural impacts differed in magnitude more than in character among disturbance types, producing a gradient of impacts. Structural changes were highly coordinated in a manner consistent across disturbance types, indicating commonalities in regeneration pathways. At the most severely affected site – burned igapó (seasonally flooded forest) – no signs of canopy regeneration were observed, indicating a sustained alteration of microclimates and consequently greater vulnerability to transitioning to a more open-canopy, savanna-like state. Notably, disturbances rarely shifted forests beyond the natural background of structural variation within mature plots, highlighting the similarities between anthropogenic and natural disturbance regimes, and indicating a degree of resilience among Amazon forests. Studying diverse disturbance types within an integrated analytical framework builds capacity to predict the risk of degradation-driven forest transitions.ISSN:1540-9295ISSN:1540-930

Diverse anthropogenic disturbances shift Amazon forests along a structural spectrum

Amazon forests are being degraded by myriad anthropogenic disturbances, altering ecosystem and climate function. We analyzed the effects of a range of land-use and climate-change disturbances on fine-scale canopy structure using a large database of profiling canopy lidar collected from disturbed and mature Amazon forest plots. At most of the disturbed sites, surveys were conducted 10–30 years after disturbance, with many exhibiting signs of recovery. Structural impacts differed in magnitude more than in character among disturbance types, producing a gradient of impacts. Structural changes were highly coordinated in a manner consistent across disturbance types, indicating commonalities in regeneration pathways. At the most severely affected site – burned igapó (seasonally flooded forest) – no signs of canopy regeneration were observed, indicating a sustained alteration of microclimates and consequently greater vulnerability to transitioning to a more open-canopy, savanna-like state. Notably, disturbances rarely shifted forests beyond the natural background of structural variation within mature plots, highlighting the similarities between anthropogenic and natural disturbance regimes, and indicating a degree of resilience among Amazon forests. Studying diverse disturbance types within an integrated analytical framework builds capacity to predict the risk of degradation-driven forest transitions.Fil: Smith, Marielle N.. Bangor University; Reino Unido. Michigan State University; Estados UnidosFil: Stark, Scott C.. Michigan State University; Estados UnidosFil: Taylor, Tyeen C.. University of Michigan; Estados UnidosFil: Schietti, Juliana. Universidade Federal Do Amazonas; Brasil. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: de Almeida, Danilo Roberti Alves. Universidade de Sao Paulo; BrasilFil: Aragón, Susan. Universidade Federal Do Oeste Do Pará; BrasilFil: Torralvo, Kelly. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Lima, Albertina P.. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: de Oliveira, Gabriel. University Of South Alabama; Estados UnidosFil: de Assis, Rafael Leandro. University of Oslo; Noruega. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Leitold, Veronika. University of Maryland; Estados UnidosFil: Pontes-Lopes, Aline. Instituto Nacional de Pesquisas Espaciais; BrasilFil: Scoles, Ricardo. Universidade Federal Do Oeste Do Pará; BrasilFil: de Sousa Vieira, Luciana Cristina. Instituto Nacional de Pesquisas Espaciais; BrasilFil: Resende, Angelica Faria. Universidade de Sao Paulo; BrasilFil: Coppola, Alysha I.. ETH Zurich. Geological Institute Biogeosciences; SuizaFil: Brandão, Diego Oliveira. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: de Athaydes Silva Junior, João. Universidade Federal do Pará; BrasilFil: Lobato, Laura F.. Universidade Federal Do Oeste Do Pará; BrasilFil: Freitas, Wagner. Universidade Federal Do Oeste Do Pará; BrasilFil: Almeida, Daniel. Universidade Federal Do Oeste Do Pará; BrasilFil: Souza, Mendell S.. Universidade Federal Do Oeste Do Pará; BrasilFil: Minor, David M.. University of Maryland; Estados UnidosFil: Villegas, Juan Camilo. Universidad de Antioquia; ColombiaFil: Law, Darin J.. University of Arizona; Estados UnidosFil: Gonçalves, Nathan. Michigan State University; Estados UnidosFil: da Rocha, Daniel Gomes. The Mamirauá Sustainable Development Institute; Brasil. University of California at Davis; Estados UnidosFil: Guedes, Marcelino Carneiro. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Tonini, Hélio. Embrapa Pecuária Sul; BrasilFil: da Silva, Kátia Emídio. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: van Haren, Joost. University of Arizona; Estados UnidosFil: Rosa, Diogo Martins. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: do Valle, Dalton Freitas. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Cordeiro, Carlos Leandro. Instituto Internacional Para Sustentabilidade; BrasilFil: de Lima, Nicolas Zaslavsky. Universidade Federal Do Oeste Do Pará; BrasilFil: Shao, Gang. Michigan State University; Estados Unidos. Purdue University Libraries And School Of Information Studies; Estados UnidosFil: Menor, Imma Oliveras. University of Oxford; Reino UnidoFil: Conti, Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Florentino, Ana Paula. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Montti, Lía. Universidad Nacional de Mar del Plata; ArgentinaFil: Aragão, Luiz. Instituto Nacional de Pesquisas Espaciais; BrasilFil: McMahon, Sean M.. Smithsonian Environmental Research Center; Estados UnidosFil: Parker, Geoffrey G.. Smithsonian Environmental Research Center; Estados UnidosFil: Breshears, David D.. University of Arizona; Estados UnidosFil: Da Costa, Antonio Carlos Lola. Universidade Federal do Pará; BrasilFil: Magnusson, William E.. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Mesquita, Rita. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: Camargo, José Luís C.. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; BrasilFil: de Oliveira, Raimundo C.. Embrapa Amazônia Oriental; BrasilFil: de Camargo, Plinio B.. Universidade de Sao Paulo; BrasilFil: Saleska, Scott R.. University of Arizona; Estados UnidosFil: Nelson, Bruce Walker. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; Brasi