RCAAP Repository

The Chapada Diamantina (CD) is located in Bahia State, between 11-14° S and 41-43° W, being part of the Serra do Espinhaço. The occurrence of different habitats and transition areas permits an interesting mammal fauna composition, with species from different biomes living in sympatry. Species of Didelphimorphia and Rodentia are important members of mammal communities in almost all different habitats, and morphological and cytogenetic characters are important for a correct identification of most of these species. In this work 258 specimens of small mammals from the orders Didelphimorphia (six genera and six species) and Rodentia (two families, five Sigmodontinae tribes, nine genera and 11 species) were collected during the whole field work (44 nights with traps). Chromosome preparations were obtained from 145 specimens from the species: Marmosops incanus, Gracilinanus microtarsus, Monodelphis domestica, Akodon aff. cursor, Necromys lasiurus, Cerradomys sp., Oligoryzomys fornesi, O. nigripes, O. rupestris, Calomys expulsus, Rhipidomys macrurus, Wiedomys pyrrhorhinus and Thrichomys inermis. Didelphis albiventris, Micoureus demerarae, Thylamys karymii and Nectomys sp. were identified by morphological characters. Most analyzed specimens do not show karyotype variation. However, numerical chromosomic variation was found in two individuals of Akodon aff. cursor (2n = 15) and in one individual of Cerradomys sp. (2n = 51). Structural variation in karyotype was observed in seven individuals of Cerradomys sp., showing one additional pair of metacentric chromosomes.

During the studies involving the correlation between the water temperature of the breeding site of Simulium pertinax larvae and the infection prevalence by microsporidia, developed in the Andorinhas river, Magé, RJ, weekly samples of blackfly larvae were taken within a two-year period (2001-2002 and 2003-2004), and it was noticed that the infections by Amblyospora sp. were more prevalent when compared to infections by Polydispyrenia sp. in larvae. It was also observed that the infections do not follow the same pattern, since the genus Amblyospora was recorded almost every month during the study with the exception of December, 2001. In the results of correlation between the environmental water temperature and the microsporidia infection rates, it was observed that for the first period studied, there was a high negative correlation, while during the second period there was absence correlation. On the other hand, the Amblyospora sp. infection rates prove that the correlation was high and significant in the first period, but was not significant in the second sampling period and Polydispyrenia sp. showed absence correlation in both periods.

The aim of this study was to determine the development time of embryos and to estimate the hatching rates of resting eggs of cladocerans found in the sediment of Guanabara Bay, Rio de Janeiro, Brazil, under experimental conditions. Eggs were sorted by species (Penilia avirostris - Sididae; Pleopis polyphemoides and Pseudevadne tergestina - Podonidae) and incubated at a temperature of 25 °C, salinity 35 and photoperiod 12 hours light/ 12 hours dark. Hatching rates were about 38% for Pseudevadne tergestina and 28% for Pleopis polyphemoides. Embryos of resting eggs of Penilia avirostris developed comparatively slowly (hatching after 86 days of incubation), with a hatching rate of only 5%. It was observed that development and hatching of resting eggs of marine cladocerans suggest that pulses of recruitment may exist, thus contributing to the rapid appearance and maintenance of planktonic populations of these crustaceans in Guanabara Bay.

A study of blood parasites in small wild non-flying mammals was undertaken in three areas of the Atlantic Forest in Southeastern Brazil: Serra de Itatiaia, RJ, Serra da Bocaina, SP and Serra da Fartura, SP, from June 1999 to May 2001. A total of 450 animals (15 species) were captured in traps and it was observed in 15.5% of the blood smears the presence of Haemobartonella sp. and Babesia sp. in red blood cells. There was no statistically significant difference between parasited and non-parasited specimens regarding total plasma protein, packed cell volume and body weight, which strongly suggests that these specimens might be parasite reservoirs.

Nest and or nest site reuse within and between breeding seasons was reported by the Euler's Flycatcher (Lathrotriccus euleri), the Sepia-capped Flycatcher (Leptopogon amaurocephalus) and the Gray-hooded Flycatcher (Mionectes -rufiventris) in forest fragments from southeastern Brazil. Nest and or nest site reuse between some years was frequent within a single breeding season by the Sepia-capped Flycatcher. Nest reuse, however, was not related to nesting success in the previous breeding attempt. Nest turnover rates (movement to a new site between years) were low for L. amaurocephalus, intermediate for L. euleri and high for M. rufiventris.

The objective of the study was to characterize seasonally and locally the reproduction of Pirapitinga do Sul (Brycon opalinus). The study area included three rivers (Paraibuna, Ipiranga, and Grande) in the Santa Virgínia Unit of the Serra do Mar State Park, State of São Paulo, Brazil. Breeding occurred in spring, summer, and autumn. The L50 and the L100 of this species were 16 to 18 cm and 26 to 28 cm, respectively. Spawning was total, with synchronous development in two groups. The size of mature oocytes was 1,346.4 µm, reaching a maximum of 2,570.4 µm, with a mean fecundity of 9,190.5 oocytes. This species has external fertilization, is non-migratory, and lacks parental care of the young. Preservation of the Pirapitinga do Sul depends, in great part, on maintaining water quality, preservation of the riverine forests, and access to breeding areas.

Macrobrachium amazonicum is considered a favorite Brazilian species of freshwater prawn for cultivation as a result of its quick development and because it is easy to maintain in captivity. The aim of this work is to describe the sexual cycle stages and determine maturation age of the female M. amazonicum, which was collected monthly from June, 2002 to May, 2003 in the Jaguaribe River, Itaiçaba, Ceará. A monthly sample of water was also collected to determine the following parameters: temperature, dissolved oxygen, pH and salinity. A monthly sample of females was selected among the individuals caught, to determine the total weight (W T), carapace length (L C) and abdomen+telson length (L A+T) and to register the number of non-ovigerous females (NOF) and ovigerous females (OF). Determining ovarian maturation stages of M. amazonicum was done in a laboratory by observing macroscopic characters such as coloring, size, location and appearance of ovarians examined by transparent carapace. The first maturation age was determined from the relative frequency of the total length (L T) of young and adult females. The environmental parameters of the Jaguaribe River did not hold any influence in the number of individuals collected. A total of 1,337 prawns were sampled, 513 males (38.4%) and 824 females (61.6%). The proportion between males and females in the studied population was of 1:1.6. Among the collected females, 492 (50.7%) did not carry eggs in their abdomens (NOF) and 332 (40.3%) carried eggs in their abdomens (OF). There was no record of intact females. Non-ovigerous females with mature ovaries were recorded throughout all the months of collection. The female ovaries were classified as immature (IM), rudimentary (RU), intermediary (IN) and mature (M). M. amazonicum females reach their first sexual maturity between 4.5 and 5.5 cm of total length.

Among the several fish species comercially exploited at the Pantanal of Mato Grosso do Sul, the "pacu" (Piaractus mesopotamicus) stands as one of the most important. Information regarding its exploitation level is necessary for the proper management of its stocks. Between 1996 and 1997 data on total length of the pacu were collected on a monthly basis from specimens caught by professional and sport fishers in the municipality of Corumbá. These data were used to estimate growth parameters and to assess the exploitation level for this species, applying the Beverton and Holt yield per recruit model. Length frequency analysis, carried out with the software FISAT (ELEFAN), was used to estimate growth parameters: 1996: L<FONT FACE=Symbol>¥</FONT> = 87.20 cm; K = 0.34 year-1; phi´=3.41; C = 0.74; WP = 0.81; Longevity = 8.40 years; and 1997: L<FONT FACE=Symbol>¥</FONT> = 86.50 cm; K = 0.34 year-1; phi´=3.40; C = 0.60; WP = 0.80; Longevity = 8.40 years. The value for t0is -0.363 years for mean values of L<FONT FACE=Symbol>¥</FONT> and k. The weight-length relationship, calculated from data derived from experimental fisheries carried out in 1999 and 2000, is described by the equation: W = 0.048LF2.835. Estimated mortalities and survival rates were: 1996: Z = 1.51 year-1; M = 0.62 year-1; F = 0.89 year-1; S = 21.9%; and 1997: Z = 1.65 year-1; M = 0.63 year-1; F = 1.02 year-1; S = 19.1%. The yield per recruit analysis showed the following values: F Present= 0.96 year-1; Fmax = 0.67 year-1 ; F0.1 = 0.51 year-1 (for Lc = 26.7 cm). These results suggest that the pacu is overexploited in the area, so that restrictive measures are in need to manage the pacu fisheries.

Dry forests are common, although highly threatened in the Neotropics. Their ecological processes are mostly influenced by rainfall pattern, hence their cycles exhibit contrasting phases. We studied the phenology of canopy trees in a primary dry forest in Western Brazil in the foothills of the Urucum mountain chain, in order to improve our knowledge on the functioning of these poorly-known forests. Leaf shedding started in the early dry season and was massive in the latter part of this period. Most leaf loss occurred in dry hills, while wet valleys remained evergreen. Anemochorich and autochorich species predominated in dry hills, presumably due to their tolerance to dry conditions and enhanced exposition to winds, which favour diaspores removal and dispersal. Conversely, zoochorich species dominated the wet valleys. Flowering was intense in the late dry season, the driest period of the year, while fruiting was massive just after the onset of rains, as well as flushing. Therefore, most flowering was unrelated to wet conditions, although such an abiotic factor, potentially, triggered the major fruiting episode, widely comprised by zoochorich species. Anemochorich and autochorich species flowered and fruited in the course of the long dry season. The contrasting environmental conditions present in the hills and valleys determine the arrangement of a mosaic in which patches of zoochorich and evergreen trees alternate with patches of non zoochorich and highly deciduous species. Consequently, species with such syndromes exhibited marked flowering and fruiting patterns, accordingly to the pronounced seasonality.

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Spatial and temporal variations of Cocconeis placentula var. euglypta in drift and periphyton were studied in mountain streams of the Córdoba Province (Argentina). The sampling program was conducted in study sites located on a confluence between different order streams during an annual cycle. Samples were also taken every two hours during the daylight period in high and low water conditions. The relationship between drift and cellular reproduction was evaluated by valve length biometrics analysis. C. placentula var. euglypta drift was continuous; its density was not always dependent on periphyton density in each locality. C. placentula var. euglypta drift could be related to abiotic factors such as temperature and flow during the annual cycle. There were significant differences between periphyton and drift valve lengths. Moreover, drift can be associated with cellular reproduction because density was higher when valve lengths were shorter at different hours of the day. C. placentula var. euglypta epiphytims on Cladophora glomerata also influenced drift density and size distribution, modifying the relationship between periphyton and drift during the late spring when C. placentula var. euglypta was detached from senescent mats.

The aim of this study was to understand how a stream ecosystem that flows from its fountainhead to its mouth inside a city, changes from a water resource to a point pollution source. A multidisciplinary descriptive approach was adopted, including the short-term temporal and spatial determination of physical, chemical, biological and ecotoxicological variables. Results showed that water quality rapidly decreases with increasing urbanization, leading the system to acquire raw sewage attributes even in the first hundred meters after the fountainheads. Despite the tidal circulation near the stream mouth being restricted by shallowness, some improvement of the water quality was detected in this area. The multidisciplinary evaluation showed to be useful for obtaining a more realistic understanding of the stream degradation process, and to forecast restoration and mitigation measures.

Several bromeliads species store water and organic substrates, allowing the establishment of phytotelmata and associated fauna on their leaves. In this study, we sampled 70 individuals of Vriesea sp. (Carrière) (Bromeliaceae), in rupestrian fields in the Serra de Ouro Branco-MG, Brazil. The relationships between invertebrate species richness and abundance and size of bromeliads were tested using multiple regression. We found 19 species associated with bromeliads, mainly Diptera larvae. The abundance of the phytotelmate fauna increased principally in relation to the volume of water in the bromeliad reservoir. Phytotelmata richness was affected principally by diameter of the reservoir. There was a significant relationship between the abundance and richness of invertebrates associated with leaves with diameter and height of the plant. Invertebrate richness was better explained by abundance of individuals. These results suggest that the increase of richness was attended by higher numbers of microhabitats and more space for colonization of bigger bromeliads. Additionally, there was more chance of sampling different species in locales with greater abundance of individuals.

We inventoried terrestrial small mammals in an agricultural area in southern Brazil by using trapping and prey consumed by Barn Owls (Tyto alba) and White-tailed Kites (Elanus leucurus). Small mammals were trapped in three habitat types: corn fields, uncultivated fields ("capoeiras"), and native forest fragments. A total of 1,975 small mammal specimens were trapped, another 2,062 identified from the diet of Barn Owls, and 2,066 from the diet of White-tailed Kites. Both trapping and prey in the predators' diet yielded 18 small mammal species: three marsupials (Didelphis albiventris, Gracilinanus agilis, and Monodelphis dimidiata) and 15 rodents (Akodon paranaensis, Bruceppatersonius iheringi, Calomys sp., Cavia aperea, Euryzygomatomys spinosus, Holochilus brasiliensis, Mus musculus, Necromys lasiurus, Nectomys squamipes, Oligoryzomys nigripes, Oryzomys angouya, Oxymycterus sp.1, Oxymycterus sp.2, Rattus norvegicus, and Rattus rattus (Linnaeus, 1758)). The greatest richness was found in the uncultivated habitat. We concluded that the three methods studied for inventorying small mammals (prey in the diet of Barn Owls, White-tailed Kites, and trapping) were complementary, since together, rather than separately, they produced a better picture of local richness.

Several plant characteristics, such as fruit production, nutrient reward, secondary compounds, and fruit color display, affect fruit choice by birds. On the other hand, several bird attributes affect their efficiency as dispersers. Here we investigate the ornithochoric seed dispersal of Pera glabrata Schott (Euphorbiaceae) in a cerrado fragment in southeastern Brazil. A set of bird attributes, such as frequency of visits, number of diaspores eaten, time spent foraging, methods of taking and handling the diaspores and agonistic interactions were analyzed in order to infer about the potential of each species to act as a seed disperser. Birds were the unique seed dispersers of these oil-rich diaspores. We observed 414 bird visits during 60 hours of focal observations in five trees from December 1999 to January 2000. Twenty bird species from seven families ate the diaspores of P. glabrata, but only 14 species were considered potential seed dispersers because they swallowed the diaspores, increasing the probabilities for the seeds to be defecated and/or regurgitated away from the parent trees. The main potential seed dispersers were: Turdus leucomelas (Muscicapidae), Dacnis cayana (Emberizidae), Colaptes melanochloros (Picidae) and Elaenia spp. (Tyrannidae). We did not find any significant seasonal change in the number of visits on the fruiting trees throughout the day. We also did not find any relation between the number of visits per tree and fruit production. The most effective seed dispersers of P. glabrata were generalist birds, which have a high visiting rate, high fruit consumption rate, and spend short periods on the plants. The large number of species recorded as potential seed dispersers of P. glabrata, being most of them very abundant even in Brazilian disturbed areas, may guarantee seed dispersal of this plant in small fragments and regenerating areas.

The relationships between an urban ecosystem located near the Atlantic Rainforest in southeastern Brazil and ant communities were studied with the objective of quantifying the ant richness and abundance in the household environment and its surroundings. Eighty residences were sampled, where 58 species and 28 genera pertaining to 7 sub-families were found to be present. Inside the residences, the species richness was found to be lower (26), although the abundance was greater (10,670), with the wash area and kitchen being the locales that contributed with the greatest number of hits. The opposite was true in the areas outside the residences, where 54 species and 3,747 ants were observed. Inside houses, the species known as Tramp ants were found, in the following order of importance: Solenopsis -saevissima, Tapinoma melanocephalum, Linepithema humile, Paratrechina fulva, Wasmannia -auropunctata, P. -longicornis, Pheidole megacephala, Monomorium pharaonis and M. floricola. Externally, mainly in the yards and gardens, species such as Octostruma rugifera, Heteroponera dolo, Hypoponera sp.1 and sp.6, Gnamptogenys sp. 4, G. striatula, Odontomachus meinerti, Pachycondyla constricta and P. striata were found. In general, a greater number of species and lower abundance of individuals were observed in the neighborhoods nearer the mountains than in those closer to the urban center.