Variação inter-sexual na frequência de cromossomos Bs em Corydoras aeneus (Siluriformes: Callichthyidae)

The genus Corydoras, the highest among the Siluriformes, Callichthyidae is owned by the family, consisting of 177 valid species and widely distributed in cis-Andean portion of South America How striking feature has two longitudinal series of dermal plates covering almost the entire body. Cytogenetic studies in Callichthyidae show many chromosomal rearrangements, including events of polyploidy in their evolutionary history, particularly the genus Corydoras, in which the variation is the diploid number of 2n = 40 to 2n = 134 chromosomes. The absence of information on the frequency of chromosomes in the group Bs motivated this work with the species Corydoras aeneus. A population from the Tietê River basin in Ribeirão Claro (subbasin Corumbataí - Rio Claro, SP) was sampled a total of 20 subjects (10 males and 10 females) and 30 metaphases per individual were analyzed cytogenetically. Were carried out by impregnation techniques silver (Ag-NOR). The observed modal diploid number was 2n = 60 (26m +26 sm +8 st), with the variable occurrence of 1 or 2 Bs chromosomes in males and a B chromosome in females, both acrocentric. Regarding the variation in the frequency of chromosome Bs, the occurrence of two B chromosomes is directly linked to males, because there were no female sampled with the occurrence of two chromosomes Bs The low frequency of Bs in females suggests that this event can be sporadic this sex, different from males in which this appears to be set supernumerary chromosome showing a higher frequency of 2 Bs than the actual modal number of 2n = 60. Further studies will be performed to understand the dynamics of the B chromosome in the population

Simulação de produção de sedimentos em microbacias em função de cenários de restauração florestal

In São Paulo state, deforestation and agriculture activities are increasing soil losses processes, especially in areas of susceptible soils where properties not adopt soil conservation practices. Environmental adequacy at property level regarding Permanent Protection Areas and Legal Reserves is considered a factor on reducing soil losses and considering that we assessed soil losses of different scenario of environmental adequacy. Simulations of erosive process were carried out in 15 catchments of Corumbataí river basin, according to different forest restoration scenarios, as well as the current situation of land use/land cover. The scenarios include the implementation of Permanent Preservation Areas (PPA), the reforestation of variable source areas, and two scenarios, the Legal Reserve installation in 20% of each catchment, being one of them for most critical areas in terms of erosion and the other at random. It was observed that the establishment of PPA and the reforestation of hydrologically sensitive areas, offered only a small contribution to the control of the erosive process, resulting in a reduction of 10% and 7,8%, respectively, while the legal reserve in critical areas has a significant reduction of 69,8%. The random scenario, in turn, resulted in a reduction of only 21,4%. Results show that reforestation could reduce soil losses, but previous studies of land prioritization and planning could increase significantly its efficiency at this process.

Mapeamento citogenético de sequências histônicas e ribossomais revelam conservação e divergência cromossômica em populações de peixes da espécie Astyanax bockmanni (Teleostei, Characidae)

In the present work we performed molecular cytogenetic studies in two different populations of Astyanax bockmanni from streams of Botucatu, SP: one from Capivara river, on Tietê river basin and one from Água da Madalena river, on Paranapanema river basin. The results showed that the population of Astyanax bockmanni from Capivara river have a diploid number of 50 chromosomes, with karyotype consisting of 8 methacentric, 14 submethacentric, 12 subtelocentric and 16 acrocentric, while the individuals of the population from Água da Madalena river have 50 diploid chromosomes but with karyotype organized in 8 metacentric, 14 submetacentric, 16 subtelocentric and 12 acrocentric. Also, the rDNA 18s sequences are widely dispersed throughout the genome of two populations, with intra and interindividual variations. On the other hand, the sequences for rDNA 5S and Histone H1 remained chromosomally conserved in these two samples and sites located in pairs 2 and 19 (rDNA 5S) and the pairs 2 and 15 (Histone H1). The low dispersion of structural genes and a functional dynamic independence between sequences of rDNA 5S and rDNA 18S may be related to the process of karyotype maintenance and differentiation in these populations of Astyanax bockmanni

Efeito da proximidade de estradas e da paisagem sobre a frugivoria em fragmentos florestais, utilizando frutos artificiais

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

Abordagem metalômica quantitativa de mercúrio em peixes da região amazônica

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

Variação espacial do grau de trofia e da biomassa fitoplanctônica no reservatório de Itupararanga (São Paulo, Brasil)

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

A competição interespecífica explica a distribuição espacial de macrófitas aquáticas em estuários?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A mercantilização dos bens naturais no setor elétrico: o caso da UHE Barra Grande

Pós-graduação em Geografia - FCT

The stream fish fauna from three regions of the Upper Paraná River basin

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chromium in soil organic matter and cowpea after four consecutive annual applications of composted tannery sludge

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Distribution, composition and seasonality of aquatic birds in the Nhecolandia sub-region of South Pantanal, Brazil

Despite remarkable significance of Pantanal for the conservation of aquatic birds, the status of their populations, the spatiotemporal patterns of distribution and habitat use and structure of communities are little known. Thus, we studied three aquatic environments (Negro river, bays and salines) from 2007 to 2009 in the Nhecolandia Pantanal to verify the distribution and composition of aquatic birds and also if there is significant seasonal influence on these aspects. We adopted the transect method (288 hours of sampling) and recorded 135 species (7.834 individuals). The Negro river showed the highest diversity, while the salines the lowest. The similarity of aquatic bird communities was higher between bays and salines, followed by Negro river and bays and lower between salines and Negro river. The equidistribution is more variable in the salines and more stable in the Negro river. The environments strongly differ from each other in aquatic bird composition in space (habitat use and distribution) and time (seasonal water fluctuations). The diversity of bird community in the dry season varies significantly in the salines, followed by the bays and more stable in the Negro river. The Negro river, regardless of large annual amplitude of flow, is more seasonally stable since its riparian vegetation is continuous (not isolated) and constant. These aspects provide better conditions to stay all year, contributing to decrease the seasonal nomadic tendencies of aquatic birds. Finally, all these data provide strong arguments to the preservation of all phytophysiognomies in the Nhecolandia sub-region of Pantanal, but with special attention to the salines widely used by many flocks of aquatic birds (mainly in the dry season) and migrant and/or rare species restricted to this habitat.

Areas hidrologicamente homogêneas como subsídio ao manejo de bacias hidrográficas

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Transformações da matéria orgânica em latossolo vermelho tratado com esterco bovino

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Aspectos da morfologia na relação presa/predadores de três predadores Characiformes e suas principais presas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Potencial de ocorrência de avarias ambientais em bacias hidrográficas com ocupação rural mediante análise morfométrica

The understanding of the geo-morphological characteristics allows the identification of flood areas and instability slopes among others important features for land use planning. The study of the hydrological net and the analysis of morphometric parameters help in the geomorphologic characterization, providing specific physics indicators that quantify the risks for environmental damages. The present work used Geographic Information Systems (GIS) and carried out the morphometric analysis of two watersheds in the Alto Rio Sorocaba, municipality of Ibiuna (SP). Using digitalized topographic bases in the scale 1:50,000, the main morphometric parameters were extracted and the Digital Elevation Model (DEM) was obtained. Hence the slope, ground illumination, hill orientation and relief feature maps were elaborated. The characteristics for the two watersheds were quite similar, both have low risks for floods and landslides. Therefore, the concave feature is the predominant hill shape for both watersheds. The morphometric parameters directly related to the river density of the watersheds showed some differences, because the Sorocabuçú watershed presents higher value, resulting in a higher level of relief development. Thus, with this characterization it is possible to provide subsidies for environmental planning actions to the area.