Hunting spiders of woodland fragments and agricultural habitats in the Atlantic rain forest region of Brazil

The hunting spider communities of the Dionycha clade were studied 1986 through 1988 in fragmented woodlands and secondary agricultural habitats of the Botucatu area in São Paulo state, Brazil. The original vegetation of mainly tropical Atlantic rain forest (Mata Atlantica) was cleared already 70 years ago. In a total sample of over 1000 adult spiders, 247 species belonging to 12 families Mere determined. A decreasing frequency and diversity of spiders rc as found if forest remnants were compared with sugar cane fields and cattle pasture. The specific composition of the spider fauna as surveyed in different habitats is discussed under ecological aspects and in relation to the history of land use.

Effects of flooding regime and woody bamboos on tree community dynamics in a section of tropical semideciduous forest in South-Eastern Brazil

The influence of a population of the understorey woody bamboo Merostachys riedeliana and different flooding regimes on tree community dynamics in a section of tropical semideciduous forest in South-Eastern Brazil was examined. A forest section with an area of 1.6 ha composed of 71 adjacent plots was located on a slope ending at the river margin. The section was divided into five topographical sectors according to the mean duration of river floods. In 1991 and 1998 all trees with a diameter at the base of the trunk greater than or equal to 5 cm were measured, identified and tagged, and all live bamboo culms were counted. Annualised estimates of the rates of tree mortality and recruitment, gain and loss of tree basal area, and change in bamboo density were calculated for each of the 71 plots and five topographical sectors as well as for diameter classes and tree species. To segregate patterns arising from spatially autocorrelated events, geostatistical analyses were used prior to statistical comparisons and correlations. In general, mortality rates were not compensated by recruitment rates but there was a net increase in basal area in all sectors, suggesting that the tree community as a whole was in a building phase. Tree community dynamics of the point bar forest (Depression and Levee sectors) differed from that of the upland forest (Ridgetop, Middle Slope and Lower Slope sectors) in the extremely high rates of gain in basal area. The predominant and specialised species, Inga vera and Salix humboldtiana, are probably favoured by relaxed competition in an environment stressed by long-lasting floods. In the upland forest, mortality rates were highest at the Middle Slope, particularly for smaller trees, while recruitment rates were lowest. As bamboo clumps were concentrated in this sector, the locally higher instability in the tree community probably resulted from the direct interference of bamboos. The density of bamboo culms in the upland forest was negatively correlated with the rates of tree recruitment and gain in basal area, and positively correlated with tree mortality rates. Bamboos therefore seemed to restrict the recruitment, growth and survival of trees.

Tree population and community dynamics in a Brazilian tropical semideciduous forest

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Occurrence of hyphomycetes and actinomycetes in red-yellow latosol from a cerrado region in Brazil

A study to quantify the populations of filamentous fungi and actinomycetes was undertaken in a cerrado area, in Corumbatai county, São Paulo, at different depths of medium-textured red-yellow latosol, correlating them to humidity, organic matter, pH of the soil and climatic factors. The technique used was the serial dilution of composite soil samples (n=4), using Martin's medium with streptomycin for filamentous fungi and a starch medium for actinomycetes. The number of filamentous fungi was more abundant in the first soil layer, 0-5 cml compared to the other depths. The number of actinomycetes was higher between 5 cm and 50 cm depth. There were two-monthly variations in the number of filamentous fungi and actinomycetes. A sharp drop in fungi was found in May 1988 at all depths of the soil, when there was lower air temperature and an atypically high monthly rainfall for this period in the cerrado. Statistically significant and directly proportional correlations were obtained between the number of actinomycetes and the rainfall at depths of 0 to 5 cm and 50 to 100 cm. The results obtained in the different soil layers to 100 cm depth demonstrated the importance of the first 5 cm layer due to the heavy concentration of microorganisms, mainly the filamentous fungi, together with the highest organic matter content.

Fish community alterations due to pollution and damming in Tiete and Paranapanema rivers (Brazil)

The Tiete River crosses the metropolitan region of São Paulo (Brazil) and receives a large amount of pollution, in contrast to Paranapanema River which runs in a less populated area. In the inferior portions of the basins of these rivers, a series of reservoirs has been built for hydroelectric energy generation which improve the water quality due to the decantation of suspended soils and aeration in the water spills.Twenty-nine sampling sites were established along the two rivers and in each sampling site, two groups of eight gillnets were used with standardized sizes in two seasons: winter (dry season: June-September 1994) and summer (rainy season: December-March 1995). The fishes were measured and weighed.Twenty-five parameters related. to the water were recorded. PCA and cluster analysis helped to identify two groups of sampling sites. The first one corresponds to the rainy season samples, while the second corresponds to the dry season samples, so evidencing strong seasonal environmental variation. However, the dry season group is still divided into polluted and non-polluted sites, showing that during drought there are larger effects of pollutant concentration due to the decreased flow.A total of 415 kg of fish were caught, corresponding to 8324 individuals belonging to 64 different species, in 22 families and four orders of Teleostei. The largest catches occurred in the middle Tiete River. The catches in the reservoirs of the Tiete River, during the rainy season are superior to those of the dry season. on the other hand, sampling sites located in running water presented an inverse pattern with the largest catches in the dry-season. In river Paranapanema, catches are lower than in the Tiete River, except in Rosana Reservoir during the rainy season. Fish diversity was shown to be a good-indicator of environmental stress. In Tiete River an expressive fall in species richness was detected in the polluted stretches, with dominance of one or two species. In the intermediary stretches, the presence of rapids increases the amount of dissolved oxygen, allowing the development of the most abundant and diverse fish community of the river. Fish communities in the reservoirs of the inferior stretch of Tiete River are more diverse. on the other hand, the damming of the superior reaches of Paranapanema River provoked a decrease in diversity. 0 the whole, types of local fish communities detected, showing different compositions and specific abundances, revealed different ecological situations. A discriminant analysis revealed that the parameters of the water influencing the fish community were: dissolved oxygen, conductivity, nitrogen (nitrate, ammoniacal and albuminoid), phosphate, alkalinity, hardness and iron. Copyright (C) 2003 John Wiley Sons, Ltd.

Abiotic modulators of Podocnemis unifilis (Testudines: Podocnemididae) abundances in the Peruvian Amazon

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Microhabitat selection and daily movements of two rodents (Necromys lasiurus and Oryzomys scotti) in Brazilian Cerrado, as revealed by a spool-and-line device

Studies on patterns of habitat use by mammals are necessary for understanding the mechanisms involved in their distribution and abundance. In this study, we used the spool-and-line method to investigate habitat utilization by two sigmodontine rodents from Brazilian Cerrado, Necromys lasiurus and Oryzomys scotti. We conducted the study in a Cerrado area in central Brazil (15 degrees 56'S and e 47 degrees 56'W) where the animals were caught in an area of 7.68 ha of Cerrado sensu stricto. Captured individuals were marked, equipped with a spool-and-Line device, and released at the same capture point. The next day we followed the thread to record their daily movements and find their nests. To investigate microhabitat selection we compared habitat characteristics along traits of each studied species with general habitat characteristics of the study area. Although the mean 24-h distance was greater for N. lasiurus (mean +/- SE: 41.9 +/- 42.2 m, N=3) than for O. scotti (28.7 +/- 14.2 m, N=6) this difference was not significant (Mann-Whitney test, U=26, P>0.6). We detected significant differences among observed microhabitats variables of both species and available microhabitat characteristics as determined by discriminant analysis (Wilks's lambda F=3.001; df=14, 116; P<0.001). Both species were associated to microhabitat characteristics whose values differed markedly from the overall available habitat. Along the first canonical discriminant function of the DFA both them were associated with greater grass height than the mean height available and along the second axis N. lasiurus selected areas with higher fruit availability and more shelters than those selected by 0. scotti. For stronger inferences regarding differential patterns of habitat utilization by Cerrado rodents we suggest the simultaneous use of both spool-and-line and standard trapping methods. (c) 2005 Deutsche Geseltschaft fur Saugetierkunde. Published by Elsevier GmbH. ALL rights reserved.

Levels of persistent organic pollutants and residual pattern of DDTs in small cetaceans from the coast of São Paulo, Brazil

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

Photoacoustic spectroscopy of aromatic amino acids in proteins

This paper concerns the use of photoacoustic spectroscopy (PAS) to study the presence of aromatic amino acid in proteins. We examined the aromatic amino acids in six proteins with well-known structures using absorption spectra of near ultraviolet PAS over the wavelength range 240-320 nm. The fundamental understanding of the physical and chemical properties that govern the absorption of light and a subsequent release of heat to generate a transient pressure wave was used to test the concept of monitoring aromatic amino acids with this method. Second derivative spectroscopy in the ultraviolet region of proteins was also used to study the regions surrounding the aromatics and the percentage area in each band was related in order to determine the contribution in function of the respective molar extinction coefficients for each residue. Further investigation was conducted into the interaction between sodium dodecyl sulphate (SDS) and bothropstoxin-I (BthTx-I), with the purpose of identifying the aromatics that participate in the interaction. The clear changes in the second derivative and curve-fitting procedures suggest that initial SDS binding to the tryptophan located in the dimer interface and above 10 SDS an increased intensity between 260 and 320 nm, demonstrating that the more widespread tyrosine and phenylalanine residues contribute to the SDS/BthTx-I interactions. These results demonstrate the potential of near UV-PAS for the investigation of membrane proteins/detergent complexes in which light scattering is significant.

Biology of a catfish, Trichomycterus sp (Pisces, Siluriformes), in a pristine stream in the Morro do Diabo State Park, southeastern Brazil

The distribution, activity, diet, and reproduction of an undescribed catfish species of the genus Trichomycterus (Trichomycteridae) were studied in the Morro do Diabo State Park, an important conservation area in the Rio Paranapanema basin, State of São Paulo, southeastern Brazil. Trichomycterus sp. is a rheophilic species occurring solely in the riffle areas of the streams and hunts mostly immature aquatic insects during the day by picking them from the substrate. The population has a balanced sex ratio, but females were uncommon in the smallest and largest size classes suggesting that females demonstrate a more accelerated growth pattern. Presence of mature individuals throughout the year represents an opportunistic reproductive tactic for fishes living in fast flowing waters, where the clutches could be shifted by the current, but the high incidence of mature individuals in the wet season may be related to optimal environmental conditions for juveniles during that period. Because of the restriction of Trichomycterus sp. to riffle environments, the conservation of this species depends on the maintenance of the original characteristics of these headwaters. That demands protecting the riparian vegetation and consequently the stream from excessive siltation resulting from runoff and erosion.

Mites (Acari: Mesostigmata, Sarcoptiformes and Trombidiformes) associated to soybean in Brazil, including new records from the cerrado areas

In Brazil, soybean Glycine max (L.) Merril crops are subjected to incidence of several pests, which are mainly insect species. However, the occurrences of other pest species are growing. In this context, outbreaks of phytophagous mites are becoming more frequent. Nevertheless, records of mites in such crop are available only for Maranhao, Mato Grosso, Minas Gerais and Rio Grande do Sul states. Thus, this work gathers all information published about the diversity of mites found in soybean in Brazil, and also new records of mite species made on samplings taken from the central Cerrado area. In the whole, occurrence of 44 species of plant mites in soybean has been recorded in Brazil. Data from prior studies and the results of this work present the tetranychid Mononychellus planki (McGregor) as the mite species most frequently occurring in the Brazilian soybean crops. A large portion of Phytoseiidae species has occurred in crops from Rio Grande do Sul state. In addition, spontaneous soybean has hosted almost half of the phytoseiid species sampled in Cerrado region. High diversity of Tarsonemidae has been found in the cultivated soybean. More studies about soybean mites are needed to clarify the damage potential of phytophagous mites and the biological role of predatory mites in this crop.

Ability of different restorative materials to prevent in situ secondary caries: analysis by polarized light-microscopy and energy-dispersive X-ray

Secondary caries is the main cause of direct restoration replacement. The purpose of this study was to analyze enamel adjacent to different restorative materials after in situ cariogenic challenge using polarized-light microscopy (PLM), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDS). Twelve volunteers, with a low level of dental plaque, a low level of mutans streptococci, and normal salivary flow, wore removable palatal acrylic appliances containing enamel specimens restored with Z250 composite, Freedom composite, Fuji IX glass-ionomer cement, or Vitremer resin-modified glass-ionomer for 14 days. Volunteers dripped one drop of 20% sucrose solution (n = 10) or distilled water (control group) onto each specimen 8 times per day. Specimens were removed from the appliances and submitted to PLM for examination of the lesion area (in mm(2)), followed by dehydration, gold-sputtering, and submission to SEM and EDS. The calcium (Ca) and phosphorus (P) contents were evaluated in weight per cent (%wt). Differences were found between Z250 and Vitremer, and between Z250 and FujiIX, when analyzed using PLM. Energy-dispersive X-ray analysis results showed differences between the studied materials regarding Ca %wt. In conclusion, enamel adjacent to glass-ionomer cement presented a higher Ca %wt, but this material did not completely prevent enamel secondary caries under in situ cariogenic challenge.

Contribution of forest species to the floristic composition of a forested savanna in southeastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Habitat associations of small mammals in southern Brazil and use of regurgitated pellets of birds of prey for inventorying a local fauna

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

Impact of coal mining on water quality of three artificial lakes in Morozini River Basin (Treviso, Santa Catarina State, Brazil)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)