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Pig (Sus scrofa) decomposition in lotic and lentic aquatic systems as tool for determination a postmortem submersion interval in the Andean Amazon, caquetá, Colombia
No full textObjectives: Analyze the succession of insects associated with the decomposition of bodies in two aquatic ecosystems in the Andean Amazon. Scope: Provide information on the insects associated with bodies that decompose within aquatic habitats and the duration times of each decomposition phase as a tool for the determination of the post-mortem submerged interval (PMSI). Methodology: Three carcasses were placed in a stream and three in a lake, the sampling carried out every five hours, from the moment of death to its skeletonization. Main results: Total decomposition lasted for 14 days in the stream and 16 days in the lake. Six decomposition stages were observed: submerged fresh, early floating, floating decay, bloated deterioration, floating remains and sunken remains. A total of 1172 organisms were collected on the carcasses in the stream and 1585 in the lake. Trophic relationships identified were: Shredders, collectors, predators, necrophages, sarcosaprophages and incidentals. In the stream, the caddisfly shredders were the most representative organisms in the submerged fresh stage. In the lake, the mayfly shredders, and hemipterous and odonate predators, were the most representative organisms in the early floating stage. The necrophagous and sarcosaprophagous diptera were the most representative organisms in the stages exposed to the surface in both ecosystems. Conclusions: The PMSI for both carcasses was similar in the two habitats, each showing six stages of decomposition, confirming that decomposition in lotic and lentic ecosystems is different from that observed for terrestrial environments. © 2019 Universidad de Caldas
Biodiversity recovery of Neotropical secondary forests
Get PDFOld-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes. Copyright © 2019 The Authors, some rights reserved
Andean Tectonics and Mantle Dynamics as a Pervasive Influence on Amazonian Ecosystem
Get PDFThe Amazonian landscape evolution is the result of the combined effect of Andean tectonism, climate and the Earth’s interior dynamics. To reconstruct the landscape evolution and its influence on paleoenvironmental variations within Amazonia since the Oligocene, we conducted numerical experiments that incorporate different surface and geodynamic processes, reproducing many paleogeographic features as inferred from the sedimentary record. We show that the evolution of the drainage pattern gradually reduced the area of sedimentation derived from the Guiana and Brazilian shields while expanded the Andean derived deposits during the Miocene, affecting the nutrient availability. First order biotic habitats were inferred from these paleogeographical reconstructions, showing an eastward expansion of várzea and terra firme forests and consequent retraction of igapó forests, with a millennial-scale reconfiguration of a mosaic of habitats in the lowlands. We conclude that this dynamism probably guided the observed patterns of speciation in the most biodiverse biome on Earth. © 2019, The Author(s)
Light intensity affects the survival and growth of matrinxã larvae, Brycon amazonicus (Spix & Agassiz, 1829)
No full textWe evaluated the effect of light intensity on survival rate and zootechnical performance in matrinxã larvae (Brycon amazonicus) that is an important species for fish farming in the Amazon region. For this, the larvae were submitted to three experimental stages: Stage I—10–72 hr after hatching (HAH), Stage II—72–168 HAH and Stage III—168–288 HAH. The animals were submitted to three treatments of different light intensities: low (±20 lx), intermediate (±200 lx) and high (±2,000 lx). The low light intensity increased the survival rate in 24, 48, 72, 120, 168 and 288 HAH. The size of the animals was homogeneous in 72 and 168 HAH in the low and intermediate treatments. The high light intensity increased the zootechnical parameters in 288 HAH. We suggest the use of low light intensity in the initial periods of observation (24 and 48 HAH) to reduce aggressiveness and increase the survival and homogeneity of the animals. On the other hand, it is possible to suggest an increase in the light intensity in the final period of observation (288 HAH), as the increase in intensity stimulated growth and affected the survival rate of the matrinxã larvae. © 2019 John Wiley & Sons Lt
Influence of body size, topography, food availability and tree-fall gaps on space use by yellow-footed tortoises (Chelonoidis denticulatus) in Central Amazonia
Get PDFHabitat selection and extension of the area used by a given species may vary during different phases of its life and are often determined by the distribution and availability of resources throughout the landscape, such as food, breeding sites, and shelters. In this study, we assessed the influence of body size on the areas used by 21 individuals of the yellow-footed tortoises (Chelonoidis denticulatus) from January to June 2017 in a dense rain forest area in Central Amazonia. We also investigated whether individuals selected different ranges of terrain slope, elevation, areas with high food availability, or areas with treefall gaps that could be used for shelter or thermoregulation. We monitored tortoise movements using thread-bobbins, and sampled terrain characteristics, availability of potential food resources and forest gaps along the routes used by the tortoises. We also measured the same variables in plots distributed systematically throughout the study area to evaluate resource availability. Tortoises used an average area of 1.56 ha (SD = 1.51, min = 0.03, max = 6.44). The size of the area used was positively associated with the individual body size, but did not vary between sexes. Small individuals selected higher and flatter areas where the availability of fallen flowers was higher, whereas the area used by larger individuals did not differ from the natural availability of topographic traits and food in the region. Although tortoises did not select areas according to availability of tree-fall gaps, most larger tortoises were found sheltered under fallen trees (85%). Conversely, small individuals were mainly found hidden under litter (66%). Body size determined the patterns of landscape use by tortoises; larger individuals were mainly generalists, but small individuals occupied high and flat areas. The yellow-footed tortoise is endangered by hunting, illegal collection for the pet trade, habitat destruction and effects of climate change. Size-related differences in habitat selection should be taken into account in species-distribution models for the identification of suitable areas for reintroduction and the development of management plans in protected areas. © 2019 Tavares 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
Apistogramma sp. ?MIUÁ? (CICHLIFORMES: CICHLIDAE): ESTUDOS MORFOMÉTRICOS E MOLECULARES REVELAM UMA NOVA ESPÉCIE DE PEIXE NO ALTO RIO NEGRO, BACIA AMAZÔNICA
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