Ocorrências de bactérias solubilizadoras de fosfato de cálcio nas raízes de plantas na Amazônia brasileira

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

Influence of Abiotic Factors and Floral Resource Availability on Daily Foraging Activity of Bees

In this study, the daily and seasonal influences of abiotic factors and the amount of floral resources on the foraging frequency of bees were determined. The experiments were performed, during 12 consecutive months, in the main floral sources used by bees in a secondary forest fragment. The foraging frequency of each bee species on flowers of each plant was recorded for 20-min periods, every hour. To verify whether the foraging activity is influenced by abiotic factors, Pearson's correlation analysis and linear regression tests were performed for the dominant bee species. Temperature and luminosity were the two main abiotic factors regulating foraging activities of bees. A positive correlation was found between the foraging frequency of most bees and these two variables. Conversely, the foraging activity was influenced neither by the relative humidity nor by the wind speed. The activity of each species depends on a combination of factors that include not only abiotic variables, but also the amount of floral resources available during the day, body size, and behavior of each visitor. After a certain period of the day, the scarcity of floral resources produced by most plants can stimulate the bees to forage in the flowers early in subsequent days, which may occur before the period in which the abiotic conditions are really favorable.

Seedling fate across different habitats: the effects of herbivory and soil fertility

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

The Crab-eating Fox (Cerdocyon thous) as a secondary seed disperser of Eugenia umbelliflora (Myrtaceae) in a Restinga forest of southeastern Brazil

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

Hypogaeic anti epigaeic ant (Hymenoptera: Formicidae) assemblages of atlantic costal rainforest and dry mature and secondary amazon forest in Brazil: Continuums or communities

Meat, flour and sugar baits were used on the soil surface and buried to examine species composition of the ant fauna in three separate tropical forests in Brazil, and to control for the effect of the regional faunal pool. Compositional mosaic diversities were comparable among areas, bait types and foraging strata. Mosaic diversity was independent of mean assemblage size. The number of unique species per sampling unit was correlated with mean assemblage size. Canonical correspondence analysis ordered species first by foraging substrate, second by geographic location, and third by diet. The first axis was significantly correlated with mean similarity and affinity. Mean Mahanalobis distances between centroids of groups based upon foraging strata were significantly larger than between localities, indicating local ecological pressures stronger than regional species pool constraints. As most. species foraged in only one stratum in one geographical position and were not omnivorous, the response of species to environmental gradients (continuums) showed a lower coherency with these patterns than did communities, structured around guilds based upon foraging strata and diet.

A comparison of the wood anatomy of 11 species from two cerrado habitats (cerrado s.s. and adjacent gallery forest)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Structural variations in root and stem wood of Styrax (Styracaceae) from Brazilian forest and cerrado

The genus Styrax L. (Styracaceae) has a wide distribution in Brazil, occurring in diverse ecosystems. To get a better insight into the ecological adaptations of wood structure, we studied two species, S. camporum and S.ferrugineus from the cerrado, and three species, S. latifolium, S. martii and S. leprosus from the Atlantic forest. For each species, the wood of root and stem was analyzed separately and observations included qualitative as well as quantitative wood characteristics. The results show that there were significant anatomical differences between the forest and cerrado species as well as between the root and stem wood within single species. Quantitatively, the most informative features in the root wood that separated the forest from the cerrado, species were diameter, length and number of vessels, length of fibres, and width and frequency of rays. In the stem wood, length and frequency of vessels, length of fibres, and width and frequency of rays were the most informative features. In contrast to the forest species, which had larger vessel diameters in their stem wood, the cerrado species had larger vessel diameters in their root wood. The calculated vulnerability index indicates that all Sryrax species have adaptations to mesic conditions. The cerrado species had the smallest index values, which could be related to the seasonally dry condition of this environment.

Seasonal development of secondary xylem and phloem in Schizolobium parahyba (Vell.) Blake (Leguminosae : Caesalpinioideae)

The cambial activity and periodicity of secondary xylem and phloem formation have been less studied in tropical tree species than in temperate ones. This paper describes the relationship between seasonal cambial activity, xylem and phloem development, and phenology in Schizolobium parahyba, a fast growing semideciduous seasonal forest tree from southeastern Brazil. From 2002 to 2003, wood samples were collected periodically and phenology and climate were recorded monthly in the same period. S. parahyba forms annual growth increments in wood, delimited by narrow initial parenchyma bands. The reduction of the cambial activity to a minimum correlates to the dry season and leaf fall. The higher cambial activity correlates to the wet season and the presence of mature leaves. In phloem, a larger conductive region was observed in the wet season, when the trees were in full foliage. The secondary phloem did not exhibit any incremental zone marker; however, we found that the axial parenchyma tends to form irregular bands.

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.

Habitat suitability of Anopheles vector species and association with human malaria in the Atlantic Forest in south-eastern brazil

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

Chlorophyll fluorescence of tropical tree species in a semi-deciduous forest gap

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

Analysis of floristic composition and structure as an aid to monitoring protected areas of dense rain forest in southeastern Brazil

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

Feeding ecology of a selective folivore, the thin-spined porcupine (Chaetomys subspinosus) in the Atlantic forest

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

Size and lipid content of nonmyrmecochorous diaspores: Effects on the interaction with litter-foraging ants in the Atlantic rain forest of Brazil

Ants are often attracted to diaspores not adapted for dispersal by ants. These diaspores may occasionally benefit from this interaction. We selected six nonmyrmecochorous plant species (Virola oleifera, Eugenia stictosepala, Cabralea canjerana, Citharexylum myrianthum, Alchornea glandulosa and Hyeronima alchorneoides) whose diaspores differ in size and lipid content, and investigated how these features affect the outcome of ant-diaspore interactions on the floor of a lowland Atlantic forest of Southeast Brazil. A total of 23 ant species were seen interacting with diaspores on the forest floor. Ants were generally rapid at discovering and cleaning the diaspore pulp or aril. Recruitment rate and ant attendance were higher for lipid-rich diaspores than for lipid-poor ones. Removal rate and displacement distance were higher for small diaspores. The large ponerine ant Pachycondyla striata, one of the most frequent attendants to lipid-rich arillate diaspores, transported the latter into their nests and discarded clean intact seeds on refuse piles outside the nest. Germination tests with cleaned and uncleaned diaspores revealed that the removal of pulp or aril may increase germination success in Virola oleifera, Cabralea canjerana, Citharexylum myrianthum and Alchornea glandulosa. Gas chromatography analyses revealed a close similarity in the fatty acid composition of the arils of the lipid-rich diaspores and the elaiosome of a typical myrmecochorous seed (Ricinus communis), corroborating the suggestion that some arils and elaiosomes are chemically similar. Although ant-derived benefits to diaspores - secondary dispersal and/or increased germination - varied among the six plant species studied, the results enhanced the role of ant-diaspore interactions in the post-dispersal fates of nonmyrmecochorous seeds in tropical forests. The size and the lipid-content of the diaspores were shown to be major determinants of the outcome of such interactions.

Frugivory in cotingas of the Atlantic Forest of southeast Brazil

In this paper we present a list of plant species whose fruits are eaten by eight cotinga species (Carpornis cucullatus, C. melanocephalus, Laniisoma elegans, Lipaugus lanioides, Oxyruncus cristatus, Phibalura flavirostris, Procnias nudicollis, and Pyroderus scutatus) at Parque Estadual Intervales (PEI), an Atlantic Forest reserve in southeast Brazil. Besides providing a list of fruits eaten by cotingas, our goal is to allow insights into fruit use by these birds whose ecology is poorly known. From 1990 to 2001 four sites located within PEI were regularly visited. These sites form an altitudinal gradient (70-800 m a.s.l.) and also a gradient of forest disturbance (second-growth to old-growth vegetation). Feeding records were made along several trails and dirt roads that crossed the study sites. Cotingas ate a variety of fruits (99 species in 34 families) that ranged from small (< 5 mm diameter) to large (up to 37 mm) and included some non-ornithochorous ones. With the exception of P. nudicollis, cotingas exploited not only fruits typical of the forest interior but also fruits of secondary vegetation, suggesting that concerning fruit exploitation early successional vegetation does not represent a barrier for the survival of these cotingas.