999 resultados para South Brazil
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Aquatic macrophyte community distribution along the eastern shoreline of the Itaipu Reservoir (one of the South America's largest impoundments) is described in relation to limnological and sedimentological factors. The central body of the reservoir is mesotrophic, while the arms (flooded influent river valleys) along the eastern shore may be oligo-mesotrophic to eutrophic, depending on time of year and sub-catchment characteristics. Macrophyte community composition and species cover were surveyed at 30 sites in four arms, in relation to sediment total P and organic matter; underwater light regime; and water total P and Kjeldahl N concentration, alkalinity, conductivity, depth and pH. Seventeen euhydrophyte and six emergent macrophyte species were recorded. Large stands of Egeria najas dominated the euhydrophyte vegetation, together with free-floating weed species (Pistia stratiotes Linn., Salvinia auriculata Aublet and Eichhornia crassipes (Mart.) Solms.). Canonical Correspondence Analysis of the data showed that two sets of variables were important predictors of aquatic macrophyte community structure. Floating macrophyte assemblage was closely related to concentration of nutrients in both water and sediment, while light penetration was the strongest predictor of submerged species occurrence. Although a large number of potential nuisance species were present, dense growths were restricted to shallower areas of the Itaipu Reservoir, causing localised problems. The possibility of increasing interference by these plants with fisheries, recreational use, transport and hydroelectricity generation suggests a need for continued monitoring of weed distribution and abundance, and investigation of appropriate management measures.
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Seasonal variation in gross primary production (GPP) of Utricularia foliosa Linnaeus, Egeria densa Planchon and Cabomba furcata Schult & Schult.f. in rivers of the coastal plain of the state of São Paulo, Brazil was examined in relation to water physico-chemistry. These three species do not affect the multiple uses of the streams and are present throughout the year. The most productive was U. foliosa (maximum production 24.7 mgO(2) g(-1) DW h(-1)), while C. furcata had an intermediate GPP (maximum production 17.5 mgO(2) g(-1) DW h(-1)) and E. densa was lowest at 5.6 mgO(2) g(-1) DW h(-1). Despite the low amplitude of seasonal variation in this south tropical area, the three species showed seasonal variation in the primary production: GPP was positively correlated with photosynthetic active radiation for U. foliosa and E. densa, and there was a negative correlation for C. furcata. For U. foliosa, GPP was positively correlated with temperature and dissolved inorganic carbon and the GPP of C. jurcata was positively correlated with dissolved inorganic carbon.
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Analysis of 141 seats of maned wolf Chrysocyon brachyurus collected in a region of upland forest and meadows of south-eastern Brazil yielded 351 food items in the wet season (60 seats) and 407 in the dry season (81 seats). Scarabaeidae and rodents were the most frequent animal food in both seasons, complemented by birds in the wet season and unidentified mammals in the dry season. Seeds revealed Solanum lycocarpum to be the most frequent plant food in the dry season and an Annonaceae and a Cactaceae the most frequent in the wet season. A total of 33 seed morphospecies were retrieved. Although our results reveal some shared and some divergent trends from dietary studies undertaken in savanna ('cerrado') areas, we found a very high frequency of potentially harmful tourists' garbage. This highlights the necessity for better environmental education and confirms that the maned wolf is a generalist and opportunist omnivore.
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Gobies of the genus Elacatinus are regarded as the most specialised cleaner fishes in the western tropical Atlantic, yet there are no studies on these cleaners in the southern portion of West Atlantic. We studied the diversity of clients and the daily cleaning activity of the barber goby, Elacatinus figaro, on rocky reefs in southeastern Brazil (23-24 degrees S). A total of 34 fish client species in 16 families were recorded over 484 cleaning events. The most frequent clients were damselfishes, Pomacentridae (37.9% of cleaning events) and grunts, Haemulidae (16.9%). Planktivores were the most frequently attended trophic category, and two species in that category accounted for about a half (44%) of the total cleaning events. Size of clients ranged 4.5-55 cm and most individuals were medium-sized (12-30 cm); as the barber goby ranged 2-4.5 cm, clients were 1.5 to 15 times larger than the cleaner was. Cleaning activity started at dawn and ended shortly before nightfall, the highest frequency of interactions occurring at early morning (nocturnal clients) and mid-afternoon (diurnal clients). By midday the frequency of cleaning events decreased and their duration increased. A total of 109 +/- 3 cleaning events and 30 +/- 1 min of cleaning activity were estimated per cleaning station per day, both figures low when compared to those recorded for cleaner fishes in tropical areas of the western Atlantic and Indo-Pacific.
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A new species of leptodactylid frog is described from Parque das Mangabeiras, in Belo Horizonte, Minas Gerais, south-eastern Brazil. The new species is a member of the Hylodes lateristrigatus group, and is characterized by medium size, snout rounded in dorsal view and protruding in lateral view, presence of vocal slits and sacs, upper surface of finger and toe discs with well-developed scutes, a weakly developed stripe on the upper lip, dorsum, arm, leg, and foot dark brown with small irregular brown and black dots, and absence of red and yellow spots in live specimens. The descriptions of the tadpoles and vocalizations, and information on natural history are provided. Hylodes perplicatus (Miranda-Ribeiro), previously considered a member of the H. nasus species group, is transferred to the H. lateristrigatus species group.
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Apesar do grande número de estudos realizados com a herpetofauna do Estado de São Paulo, que a caracteriza como a mais conhecida no país, ainda existem vazios amostrais dentro de biomas considerados mundialmente como prioritários para a conservação pelo elevado grau de endemismo e pressão antrópica, como é o caso da Mata Atlântica. Como resultado de pressões políticas e históricas, o bioma foi reduzido a menos de 12% de sua extensão original e apesar de sua importância para a conservação da biodiversidade mundial, apenas uma porcentagem mínima de sua cobertura vegetal original (1%) encontra-se protegida sob alguma forma legal de proteção. Este é o caso do Parque Estadual Turístico do Alto Ribeira (PETAR) que juntamente com o Parque Estadual de Intervales, Parque Estadual Carlos Botelho e Mosaico de Unidades de Conservação de Jacupiranga formam um extenso contínuo ecológico de 360 mil ha de floresta ombrófila no sul do estado. O presente estudo apresenta a lista de anfíbios e répteis do PETAR, com informações sobre a distribuição local e uso de hábitat destas espécies. O inventário foi realizado de outubro a dezembro 2009, totalizando 15 dias de amostragens que foram realizadas por meio de quatro métodos complementares de amostragem ativa: procura visual, procura auditiva, procura de carro e encontro ocasional. Foram registradas no total 91 espécies pertencentes a 53 gêneros e 24 famílias. Esta alta diversidade pode ser atribuída à existência de uma grande variedade de hábitats e microhábitats nesta localidade, como os diversos sítios aquáticos utilizados por várias das espécies de anfíbios anuros amostradas. Além disso, o PETAR apresenta um amplo gradiente altitudinal (80 - 1.160 m) que confere uma grande heterogeneidade climática, geológica e hidrológica a área. Neste sentido, este inventário é uma importante contribuição para a ampliação do conhecimento destas taxocenoses de floresta ombrófila presentes na porção mais ao sul da Serra de Paranapiacaba, fornecendo subsídios para a adoção de medidas visando à conservação dessas taxocenoses no Estado de São Paulo.
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A maioria dos peixes da família Rivulidae são popularmente conhecidos como anuais por completarem todo seu ciclo biológico em pequenos corpos de água temporários que secam obrigatoriamente em determinados períodos do ano causando a morte dos indivíduos adultos. Possuem características biológicas peculiares como pequeno porte, maturação sexual precoce, reprodução contínua, um elaborado padrão de corte e uma grande capacidade reprodutiva entre os peixes. Os rivulídeos se encontram amplamente distribuídos nas Américas do Norte, Central e Sul. Este trabalho analisou a dieta e a biologia reprodutiva de Cynopoecilus melanotaenia. Foram coletados 263 exemplares e a análise de 233 conteúdos gastrointestinais revelou uma dieta invertívora composta principalmente por microcrustáceos (Cladocera, Amphipoda e Ostracoda) e insetos imaturos (Chaoboridae, Culicidae, Syrphidae, mas principalmente larvas de Chironomidae). Foi registrada a lepidofagia na dieta dos machos. A fecundidade foi estimada pela análise de 59 pares de ovários maduros e variou entre 2 a 157 ovócitos (média, 19 ± 26[DP]). A espécie apresentou desova parcelada, uma estratégia para aumentar a chance de sobrevivência a depleções prolongadas. Este trabalho apresenta a primeira investigação sobre a biologia reprodutiva de C. melanotaenia. Os resultados encontrados sugerem a estratégia reprodutiva oportunista de C. melanotaenia e fornecem novas informações biológicas que podem contribuir para pesquisas de conservação e manutenção da espécie em seu ambiente natural.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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We describe a new species of Ischnocnema from Santa Teresa, in the Atlantic Rainforest of the State of Espirito Santo, Brazil. Ischnocnema abdita sp. nov. is a member of the Ischnocnema lactea species series; it differs from other Ischnocnema mainly by presenting small size (adult male SVL 15.7 [plus or minus] 0.49 mm; range 15.0-16.8 mm); small discs on fingers I and II, and elliptical, wider than long, moderate sized discs on fingers III and IV; and finger I slightly smaller than finger II. The new species closely resembles Ischnocnema bolbodactyla, differing from it by presenting upper and lower margins of iris red in life; inguinal region with many yellow blotches in life; posterior region of belly and ventral surfaces of thighs, shanks, and feet roughly marbled with large pale yellow blotches; and hidden dorsal area of thighs dark brown with few large pale yellow blotches.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Há uma grande lacuna no conhecimento da biologia e corologia de Nyctinomops aurispinosus. Nesta comunicação, nós apresentamos o registro mais austral deste molossídeo, realizado na cidade de Curitiba (25° 25' S e 49° 15' W, 920 m), estado do Paraná, Brasil, e sumarizamos a distribuição geográfica conhecida para a espécie na América do Sul.
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This paper reports twelve acarine species belonging to eleven genera in five families, associated with Bambusa sp. (Poaceae), in a woody area from São Paulo State, Brazil. Four species of Tetranychidae (Monoceronychus bambusicola, sp.n.. Oligonychus santoantoniensis, sp.n.. Schizotetranychus longirostris, sp.n. and S. paraelymus, sp.n.) are regarded as new. The genus Cheletomimus Oudemans, 1904 (Cheyletidae) is recorded for the first time to South America.
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Phylogeographic trends in Batrachospermum macrosporum Mont. were investigated using the mitochondrial intergenic spacer between the cytochrome oxidase subunit 2 and 3 genes (cox2-3). A total of 11 stream segments were sampled with seven in the coastal plain of North America and four in tropical areas of South America. Fifteen thalli were sampled from seven streams, 14 thalli from two streams, and eight thalli from two streams. There were 16 haplotypes detected using 149 individuals. of the eight haplotypes from locations in North America, all were 334 base pairs (bp) in length, and of those from South America, five were 344 bp, and three were 348 bp. Two individual networks were produced: one for the haplotypes from North America and another for those from South America, and these could not be joined due to the large number of base pair differences. This split between haplotypes from North and South America was confirmed with sequence data of the rbcL gene. There was very little genetic variation among the haplotypes from the North American locations, leading us to hypothesize that these are fairly recent colonization events along the coastal plain. In contrast, there was high variation among haplotypes from South America, and it would appear that the Amazon serves as a center of diversity. We detected considerable variation in haplotypes among streams, but frequently, a single haplotype in an individual stream segment, which is consistent with data from previous studies of other batrachospermalean taxa, may suggest a single colonization event per stream.
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Hemigrammus parana is described from the upper rio Parana system, in the area of influence of the Ilha Solteira reservoir in states of Mato Grosso do Sul, Minas Gerais and São Paulo, southeastern Brazil. The new species differs from all congeners by the combination of the following characters: absence of humeral spot; presence of a roughly triangular or rectangular conspicuous black caudal spot, extending from base to tip of middle caudal-fin rays, its greatest depth at base of caudal-fin rays; and anal-fin rays iii-iv, 18-23.