Estimativa da diversidade genética de Queixadas (Tayassu pecari) da região do Taboco (Corguinho, MS)

The Brazilian fauna has been constantly threatened by deforestation and forest fragmentation. As a result, many populations become isolated and small which negatively impacts their genetic diversity, putting them at a higher risk of extinction than large and stable populations. The aim of this work was to estimate the genetic diversity of white-lipped peccaries (Tayassu pecari) in the region of Taboco (Corguinho, MS), a fragmented area; and to compare these estimates with that obtained previously for two populations from Brazilian Pantanal, which is considered a relatively well-preserved biome and where the species is not threatened. A total of 18 blood and 72 hair samples of white-lipped peccaries had their DNA extracted and amplified for five polymorphic microsatellite loci. With the individuals identified, genetic diversity indicators (such as number of alleles, allelic richness, expected end and observed) and the inbreeding coefficient FIS were calculated. In addition, to verify if the population suffered a recent population bottleneck, we used the tests implemented in the program Bottleneck. The population of Taboco showed no evidence of recent population bottleneck (p > 0.05) or inbreeding (FIS = 0.008; p > 0.022). In addition, the levels of genetic diversity in this population (mean number of alleles = 2.60; mean allelic richness = 2.56 mean observed and expected heterozygosities = 0.45 and 0.47, respectively) were statistically similar to those found previously for the two populations from Pantanal (p > 0,05); although the region of Taboco is more impacted than the Pantanal. Even though we showed no evidence of loss of genetic diversity, it does not mean that the population is not suffering with fragmentation; but that there was not sufficient time to evidence the genetic changes. In addition, may be occurring gene flow with populations of nearby fragments, which is maintaining... (Complete abstract click electronic access below)

Phytoplankton composition, dominance and abundance as indicators of environmental compartmentalization in Jurumirim Reservoir (Paranapanema River), São Paulo, Brazil

Patterns in the spatial and temporal composition, dominance and abundance of the phytoplankton community of the Jurumirim Reservoir (Brazil) were studied during one year at ten different sampling stations. The main phytoplankton associations were characterized by diatoms and blue-green algae, in distinctive patterns of dominance. The main species were Microcystis aeruginosa Kuetz, Anabaena circinalis Rabenhorst, A. spiroides Kleb., A. solitaria Kleb., Aulacoseira cf. italica Grunow and A. granulata (Ehr.) Simon. A high growth of Aulacoseira was observed in the upstream zones of the reservoir in spring, at the beginning of the seasonal rainy period. This growth was a response to increased flow rates and input of fresh nutrients by the main feeder rivers. A high concentration of blue-green algae, especially Anabaena circinalis and A. spiroides, was observed in winter (dry season) in the lacustrine part of the reservoir, towards the dam. These algae benefitted from the longer water retention times and greater internal circulation of nutrients in the absence of a thermocline at this time of the year. Among the Cyanophyceae, there was an alternation between M. aeruginosa, more abundant in summer, and Anabaena, dominant in autumn and winter. A conspicuous growth of Anabaena occurred in a diverticle of the reservoir, sheltered from the main advective processes that predominate in the central channel. Higher phytoplankton diversity was associated with the contact zone between riverine and lacustrine systems.

Diversity of Epigeal Ants (Hymenoptera: Formicidae) in Urban Areas of Alto Tiete

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Stability Predicts Genetic Diversity in the Brazilian Atlantic Forest Hotspot

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Environmental heterogeneity: Anuran diversity in homogeneous environments

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Lower Permian stems as fluvial paleocurrent indicators of the Parnaíba Basin, northern Brazil

A comprehensive biostratinomic study was carried out with abundant stems from the Lower Permian Motuca Formation of the intracratonic Parnaíba Basin, central-north Brazil. The fossils represent a rare tropical to subtropical paleofloristic record in north Gondwana. Tree ferns dominate the assemblages (mainly Tietea, secondarily Psaronius), followed by gymnosperms, sphenophytes, other ferns and rare lycophytes. They are silica-permineralized, commonly reach 4 m length (exceptionally more than 10 m), lie loosely on the ground or are embedded in the original sandstone or siltstone matrix, and attract particular attention because of their frequent parallel attitudes. Many tree fern stems present the original straight cylindrical to slightly conical forms, other are somewhat flattened, and the gymnosperm stems are usually more irregular. Measurements of stem orientations and dimensions were made in three sites approximately aligned in a W-E direction in a distance of 27.3 km at the conservation unit Tocantins Fossil Trees Natural Monument In the eastern site, rose diagrams for 54 stems indicate a relatively narrow azimuthal range to SE. These stems commonly present attached basal bulbous root mantles and thin cylindrical sandstone envelopes, which sometimes hold, almost adjacent to the lateral stem surface, permineralized fern pinnae and other small plant fragments. In the more central site, 82 measured stems are preferentially oriented in the SW-NE direction, the proportion of gymnosperms is higher and cross-stratification sets of sandstones indicate paleocurrents mainly to NE and secondarily to SE. In the western site, most of the 42 measured stems lie in E-W positions. The predominantly sandy succession, where the fossil stems are best represented, evidences a braided fluvial system under semiarid conditions. The low plant diversity, some xeromorphic features and the supposedly almost syndepositional silica impregnation of the plants are coherent with marked dry seasons. Thick mudstones and some coquinites below and above the sandy interval may represent lacustrine facies formed in probably more humid conditions. The taphonomic history of the preserved plants began with exceptional storms that caused fast-flowing high water in channels and far into the floodplains. In the eastern site region, many tree ferns only fell, thus sometimes covering and protecting plant litter and leaves from further fragmentation. Assemblages of the central and western sites suggest that the trees were uprooted and transported in suspension (floating) parallel to the flow. Heavier ends of stems (according to their form or because of attached basal bulbous root mantle or large apical fronds) were oriented to upstream because of inertial forces. During falling water stage, the stems were stranded on riverbanks, usually maintaining the previous transport orientation, and were slightly buried. The perpendicular or oblique positions of some stems may have been caused by interference with other stems or shallow bars. Rare observed stems were apparently waterlogged before the final depositional process and transported as bedload. The differences of interpreted channel orientations between the three sites are expected in a braided fluvial system, considering the very low gradients of the basin and the work scale in the order of tens of kilometers. The mean direction of the drainage probably was to east and the flows apparently became weaker downstream. This study seems to provide reliable data for paleocurrent interpretations, especially considering areas with scarce preserved sedimentary structures. © 2013 Elsevier Ltd.

Computer intensive methods for controlling bias in a generalized species diversity index

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)