Time filter

Source Type

Santos-Fischer C.B.D.,Federal University of Rio Grande do Sul | Correa I.C.S.,Federal University of Rio Grande do Sul | Weschenfelder J.,Federal University of Rio Grande do Sul | Torgan L.C.,Museu de Ciencias Naturais da Fundacao Zoobotanica do Rio Grande do Sul | Stone J.R.,Indiana State University
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2016

Diatom assemblages provide a strong basis for detailed interpretations of paleoceanography and diatom paleoecology of the southern Brazilian coast. Nine cores obtained in the coastal plain, shelf and continental slope and thirteen surface sediment samples of the Patos Lagoon, provide an excellent opportunity to use a paleoecological approach to study detailed Quaternary environmental changes in the southern coasts. In the interval studied, the basin sedimentation occurred in a marine-dominated environment related to humid periods prior to 43,500 year BP. Abundant diatom taxa are highlighted as excellent indicators of environmental changes, including salinity, sediment composition and transport by incised-valleys, providing additional insights into coastal evolution. Paralia sulcata is dominant in all analyzed cores, occurring continuously from Late Pleistocene to Holocene, but is rare in the modern sediments. Non-marine diatom assemblages occurred continuously, but in very low densities in periods before and after the Last Glacial Maximum. Abrupt changes in sedimentation have been recorded related to shifts from marine-dominated to shallow-estuarine deposition. During the Holocene, sea-level rose rapidly which is responsible for the progressive coastal flooding prior to 8420-7930. year. BP. The Holocene barrier system became more continuous and Patos Lagoon developed. Consequently, the secondary former inlets from the Jacuí and Camaquã rivers are closed and only one single inlet (Rio Grande channel) remains active. The spatial distribution of modern assemblages is controlled by salinity gradient, wind action, and climate forcing. The bottom sediments of Patos Lagoon are dominated by freshwater diatom Aulacoseira veraluciae, Aulacoseira sp. 2 and marine-estuarine species of Cyclotella litoralis. © 2016 Elsevier B.V. Source

Favero E.R.,University of Campinas | Veiga-Menoncello A.C.P.,University of Campinas | Rossa-Feres D.C.,Sao Paulo State University | Strussmann C.,Federal University of Mato Grosso | And 4 more authors.
Zoological Studies | Year: 2011

Herein, we report karyological data for Pseudopaludicola frogs, with the main objective to investigate the confusing taxonomic identification of these anurans. The samples analyzed included topotypes of P. falcipes and P. ameghini (currently considered a synonym of P. mystacalis) in addition to specimens of P. mystacalis and P. ternetzi and of 8 additional populations of Pseudopaludicola from several regions of Brazil. Interspecific variations in the chromosome number, location of the nucleolar organizer region (NOR), and banding patterns were observed. The karyotype of P. falcipes consisted of 2n = 22 chromosomes, whereas P. ameghini (sensu Cope 1887) and P. ternetzi had 2n = 20 and P. mystacalis had 2n = 16 chromosomes. The chromosome number 2n = 16 was also found in specimens of populations from Santa Fé do Sul, Vitória Brazil, Icém, Palestina (southeastern Brazil), Barreirinhas, Urbano Santos (northeastern Brazil), Poconé, and Santa Terezinha (west-central Brazil). Nevertheless, in some individuals from Icém and Poconé, we found 2n = 20 and 2n = 22 chromosomes, respectively. This variation in chromosome number indicates diverse taxa coexisting in sympatry. The karyotypic patterns of 2n = 20 in P. ameghini (sensu Cope 1887) and 2n = 16 in P. mystacalis are clearly indicative of 2 distinct taxonomic units. Therefore, our data corroborate the removal of P. ameghini from synonymy with P. mystacalis as previously suggested. We define the karyotype of P. falcipes as 2n = 22 and of P. ternetzi as 2n = 20 and reinforce the need for a taxonomic revision of this genus. Source

Kaffer M.I.,Museu de Ciencias Naturais da Fundacao Zoobotanica do Rio Grande do Sul | De Azevedo Martins S.M.,Museu de Ciencias Naturais da Fundacao Zoobotanica do Rio Grande do Sul
Bosque | Year: 2014

Environmental Protection Areas (EPA) are of extreme importance for species conservation and establishment. We investigated different areas of riparian forests in the Environmental Protection Area of Ibirapuitã, southern Brazil. We analyzed the environmental quality of these areas by studying the lichen community and using the index of atmospheric purity (IAP) with the environmental classification factor (ECF) as the correction factor. The lichen community was analyzed in 12 riparian forest stands located in the southern region of EPA. Lichens were registered on 60 tree barks, from 50 cm to 150 cm above the ground, on both north and south sides. A cluster analysis was used to test whether there were changes in lichen species similarity among communities from each forest vegetation stands. A total of 193 lichen species were registered. The stands were classified into poor-lichen, transition zone, and normal for lichen development. The cluster analysis showed distinct groups, demonstrating differences in species composition among the stands. Indicator lichen species were registered in 80% of the studied stands. In the most conserved areas, higher species richness and a greater number of fruticose species were registered, besides the presence of key species such as the genus Lobaria. The conservation of forest areas in environmental protection areas is essential for biodiversity conservation. Our results confirm the usage of the index of atmospheric purity with ECF to evaluate environmental quality of forest areas. © 2014, Universidad Austral de Chile. All Rights reserved. Source

Kaffer M.I.,Federal University of Rio Grande do Sul | Alves C.,Museu de Ciencias Naturais da Fundacao Zoobotanica do Rio Grande do Sul | Caceres M.E.S.,Federal University of Sergipe | Martins S.M.A.,Museu de Ciencias Naturais da Fundacao Zoobotanica do Rio Grande do Sul | Vargas V.M.F.,Federal University of Rio Grande do Sul
Acta Botanica Brasilica | Year: 2011

Lichens are symbiotic organisms found in a variety of habitats; however, in urban areas the lichen community can be altered due to the influence of anthropogenic factors. This study aimed to analyze the corticolous lichen community composition in Porto Alegre and adjacent areas, as well as to investigate the frequency, coverage and importance value of the reported taxa. A key to the urban species is also provided. Three hundred phorophytes distributed in 30 sampling stations, divided among 33 city districts, were analyzed. One hundred and forty-four taxa of lichenized fungi were recorded with three probable new citations for Brazil and two new records for Rio Grande do Sul State. The most important species in the community were Canoparmelia texana (Tuck.) Elix & Hale and Dirinaria picta (Sw.) Schaer. ex Clem, which showed the highest values of importance, frequency and coverage. The high number of taxa found in the studied areas represents a significant contribution to lichenological research, mainly for use in air quality monitoring programs and to evaluate forest ecosystem structure. Source

Benatti M.N.,Institute Botanica | Kaffer M.I.,Museu de Ciencias Naturais da Fundacao Zoobotanica do Rio Grande do Sul | De Azevedo Martins S.M.,Museu de Ciencias Naturais da Fundacao Zoobotanica do Rio Grande do Sul | De Lemos A.B.,Prefeitura de Eldorado Do sul
Cryptogamie, Mycologie | Year: 2015

Bulbothrix bulbillosa is recorded for the first time in Brazil, Rio Grande do Sul State. The species was described recently from the Galapagos Islands, Ecuador and known only from the type locality. All specimens found belong to the gyrophoric acid chemotype, whereas material from Galapagos contains either gyrophoric or lecanoric acid. © 2015 Adac. Tous droits reserves. Source

Discover hidden collaborations