Cerrado Vegetation Of Central Brazil Research Articles

Two new species of Sticta (Peltigeraceae subfam. Lobarioideae) from the Brazilian Cerrado (Brazilian savanna)

Sticta, the most diverse genus of the Lobarioideae (Ascomycota: Peltigeraceae), contains species easily recognized by the presence of genuine cyphellae on the lower cortex of the thallus. Two new species collected in typical cerrado vegetation in Central Brazil are described as S. cerradensis and S. porella, including morphological, anatomical, and molecular analyses based on the ITS region. The two new taxa belong to one of the major Sticta clades, which contains mostly New World species. This work shows that the cerrado, a global biodiversity hotspot located in the center of South America, could contain a great diversity of new species of lichenized fungi.

Arbuscular Mycorrhizal Fungi Associated with Bamboo Under Cerrado Brazilian Vegetation

Most studies on bamboo have evaluated their commercial use but few have investigated their associated arbuscular mycorrhizal fungi (AMF). These symbiont fungi are fundamental on plant growth, nutrient cycling, biodiversity maintenance, etc., particularly on acidic/dystrophic soils as those of the Brazilian Cerrado. This study aimed to characterize the community composition and ecological interactions of AMF associated with the bamboo species Actinocladum verticillatum and Bambusa vulgaris vittata, under Cerrado vegetation in central Brazil. Roots and rhizospheric soil samples of A. verticillatum and B. vulgaris vittata were collected on 12 plots in the Gurupi (Tocantis state) and Porangatu (Goias state) microregions. The roots’ mycorrhizal colonization rate, rhizospheric soil’ spore density, and the associated AMF genera were evaluated. There were no differences in the radical mycorrhizal colonization rates among the two bamboo species, although B. vulgaris vittata showed higher spore density than A. verticillatum. The genera Acaulospora, Claroideglomus, Diversispora, Scutellospora, Glomus, and Gigaspora were identified in both bamboo species, while Sclerocystis was present only on A. verticillatum. The genera Acaulospora, Diversispora, and Glomus were frequently found together. This study may be a first step to future AMF-based bamboo micro-propagation efforts in the Cerrado Brazilian vegetation.

New record of <i>Pantophthalmus pictus</i> (Wiedemann, 1821) (Diptera, Pantophthalmidae) in the Cerrado vegetation of central Brazil

Abstract Pantophthalmus pictus (Wiedemann, 1821) (Diptera, Pantophthalmidae) has been reported to occur in south and southeastern Brazil, Paraguay and Argentina. Here we report the first occurrence of these rare flies in the Cerrado vegetation of central Brazil. We also provide an updated list of the geographical distribution of the 20 species of the genus Opetiops Enderlein, 1921 (1 species) and Pantophthalmus Thunberg, 1919 (19 species) in the Neotropical region.

Birds nesting survival in disturbed and protected Neotropical savannas

Fragmentation and other habitat disturbances are long known to negatively affect birds, in large part by decreasing nest success due to high nest predation rates. The factors, however, that cause this decrease in nest success are still poorly understood and may vary among regions or species. Here, we show that nest survival is also lower in a disturbed landscape versus a protected cerrado (savanna-like) Neotropical landscape. Also, we tested the importance of garbage in the nest, brood parasitism, microhabitat and bird family in nest survival, controlling for temporal effects. We monitored 144 birds’ nests in a disturbed landscape and 150 nests in a natural reserve of cerrado vegetation in central Brazil, between September and December 2006. We used Program MARK to estimate nest survival probabilities and evaluate the effect of covariates in nest success in the disturbed area. Nest daily survival rate (DSR) was higher in the reserve (survival probability = 29.4%) than in the disturbed landscape (survival probability = 16.6%). Nest daily survival rate (DSR) was smaller in nests with garbage (survival probability = 9.3%) than in nests without garbage (survival probability = 19.5%) in the disturbed landscape. Effects of habitat disturbance on nest survival differed among bird families, with finches and tanagers being more affected mostly due to high nest predation rates. Conservation and management of birds in disturbed landscapes should include actions to decrease nest predation. In poor rural or suburban areas in developing countries, such as Brazil, actions like better garbage treatment may help conserve birds in disturbed landscapes.

A new species of Argiope (Araneae: Araneidae) from Brazil

A new species of Argiope Audouin, 1826 is described. This is a large Argiope from South America and is found mainly in cerrado vegetation in central Brazil. Argiope legionis sp. nov. is most similar to A. ericae LEVI, 2004 but differs from this species by the coloration and epigynum in the female and the median apophysis and embolus of the palpus in the male palp.

Influence of environmental variables and anthropogenic perturbations on stream fish assemblages, Upper Paraná River, Central Brazil

The Ouvidor River, a tributary of the Upper Paraná River, drains areas covered by cerrado vegetation in Central Brazil. We collected data for environmental variables (water temperature, dissolved oxygen, pH, conductivity, turbidity, water velocity, luminosity, channel substrate and width) and anthropogenic perturbations (industry, reservoirs, urban areas) that may structure the fish assemblage in ten stream sites of the Ouvidor River basin. In each stream we delimited one 50 m long site where fish were captured by electrofishing and abiotic data were collected every two month between August 2004 and June 2005. Co-inertia analysis indicated that pH, water velocity, channel width and water temperature most strongly structured the fish assemblages. The interactions of water velocity and channel width with the fish assemblage were not directly affected by wet and dry seasons but the opposite was true for pH and water temperature.

A Synopsis of the Genus Cyrtopodium (Catasetinae: Orchidaceae)

ABSTRACT A synopsis is presented for the Neotropical genus Cyrtopodium. Type data, taxonomic status, geographical distribution, and nomenclatural and taxonomic notes are presented for each species. A total of 116 names have been proposed in the genus, of which 50 are accepted here (47 species and three subspecific taxa). The identity of five species in the list is unclear. Forty names are synonyms in the genus, five are nomina nuda, and 21 belong in other genera including Eulophia, Koellensteinia, Otostylis, Eriopsis, Tetramicra, and Oncidium. Brazil, with 39 species, is the country with the highest number of species, followed by Bolivia and Venezuela, with nine species each. The main center of diversity of the genus is the cerrado vegetation of central Brazil, were 29 taxa are found. Field and taxonomic research on the genus in the last 15 years has led to the description of 19 new and accepted species, most from central Brazil. Eight lectotypifications and one new synonym are proposed. Cyrtopodium flavu...

A New Species of Cyrtopodium (orchidaceae) from the Cerrado of Central Brazil

Cyrtopodium macedoi, a new species (Orchidaceae, Cymbidieae, Cyrtopodiinae) from the cerrado vegetation of central Brazil, is described and illustrated. The species was first collected in 1951 but was subsequently misidentified as C. vernum. The principal distinctive character for C. macedoi is the basal portion of the corolla lip and the region between the lateral lobes, which is strongly deflexed and almost parallel to the lip midlobe. Cyrtopodium macedoi appears to be rare and so far known only from two sites in the Triângulo Mineiro region of the western part of the state of Minas Gerais in southeastern Brazil.

Diversity, floristic and structural patterns of cerrado vegetation in Central Brazil

The cerrado has been identified as one of the richest and most threatened biomes of the world, but few phytogeographical studies have been undertaken in the region. A total of 70 land systems based on climate, landscape and soils have been identified in the region, but it remains to be seen if the distribution and structure of the plant communities support these divisions. The aim of this work was to compare the floristic and structural similarity of cerrado sensu stricto within and between three physiographic units, named Pratinha, Veadeiros and Sao Francisco, which contain six land systems in central Brazil and cover 10 degrees of latitude and five degrees of longitude. The woody vegetation of 15 selected sites of the cerrado sensu stricto physiognomy was surveyed under a standardized methodology. The number of species per site varied from 55 to 97, with most sites having around 60 to 70 species, and Shannon´s diversity indices ranged from 3.44 to 3.73, with most sites around 3.5 suggesting high alpha diversity. Sorensen´s floristic similarity index was high, with all Figures above 0.5 between the sites in the same land system in each physiographic unit but low between sites in different land systems in the Veadeiros. Czekanowski similarity indices were lower than Sorensen’s in the comparisons due to a high structural differentiation between the sites. There is a large overlap in species occurrence in the sites but the size of their populations is very different at each site. Therefore, the high beta diversity is mostly due to differences in abundance of species between sites. The sites were separated by physiographic units, considering the first three divisions of TWINSPAN classification. The first axis of DCA ordination showed a gradient going from the cerrado on deep soils in Pratinha, through to those on sandy soils in Sao Francisco and ending on the shallower soils of the Veadeiros. Land systems conformed well with the floristic and structural variations of the vegetation, indicating their potential use in designing a network of conservation areas in the cerrado region and as a basis for decision-making on management.

Sintopy of two Tropidurus lizard species (Squamata: Tropiduridae) in a rocky Cerrado habitat in Central Brazil

We studied the ecology of Tropidurus itambere and T. oreadicus that occur syntopically in rocky habitats of Cerrado vegetation in central Brazil during the dry season (April to September 2000). The two species are ecologically similar, but somewhat differentiated in vertical microhabitat use. The two species preferred rocky surface microhabitat. Both species demonstrated a unimodal activity pattern, with a peak between 10 and 15 h. Their diets were similar in composition and prey size. The most frequent item used by both species was ants, whereas the most important preys volumetrically were termites and ants. Small morphological differences observed between the two Tropidurus species could explain minor microhabitat divergence: T. itambere is slightly smaller, heavier, and more robust, and uses lower perches. T. oreadicus is larger, lankier, with longer extremities (tail, fore- and hindlegs), and uses a larger vertical microhabitat range. These ecological differences are slight, when compared with those observed between sympatric species of Tropidurus in spatially more heterogeneous landscapes. Considering the slight ecomorphological divergence between the two Tropidurus species and their high abundance in outcrops, we suggest that interspecific territoriality is the mechanism of coexistence.

Effects of Fire on the Abundance of Xenarthrans in Mato Grosso, Brazil

Abstract Fire is an important ecological factor in Cerrado vegetation of central Brazil, and in other savanna ecosystems. The effect of fire on the abundance of some Xenarthran mammal species Priodontes maximus Kerr, 1792 (giant armadillo), Euphractus sexcinctus Linnaeus, 1758 (yellow armadillo) and Myrmecophaga tridactyla Linnaeus, 1758 (giant anteater)) was studied at Reserva Xavante do Rio das Mortes, a 329 000 ha Xavante Indian reserve in the Cerrado of Mato Grosso, Brazil. Track counts were used to compare the abundance of these mammals along seven burned and seven unburned transects, on seven occasions between August 1995 and August 1996. The number of tracks in burned and unburned areas did not differ. Xenarthrans probably use burned areas to obtain food resources, basically termites and ants. Xavante traditional fire hunts may reduce fuel accumulation and function as a mechanism to prevent more destructive fires. Fire management at Reserva Xavante is recommended because the burning system of Brazilian farmers is already influencing the Xavante community. Xavante traditional knowledge about fire could be an important instrument for this management.

Alteração no potencial osmótico e teor de carboidratos solúveis em plantas jovens de lobeira (Solanum lycocarpum St.-Hil.) em resposta ao estresse hídrico

Solanum lycocarpum is a typical species from the cerrado vegetation in Central Brazil and has shown drought resistance under environmental conditions. Osmotic adjustment refers to a decrease in osmotic potential caused by accumulation of solutes and the continuous accumulation of solutes must occur in tissues to maintain the water potential gradient necessary for cell enlargement and turgor maintenance. The influence of water stress on osmotic potential and soluble carbohydrate levels was investigated in this research. The analyses of the results showed a decrease in osmotic potential in response to water stress. An increase in the carbohydrate levels was observed in plants under stress conditions in greenhouse. Reducing sugars were the major contributors to soluble carbohydrates levels detected in leaves and roots. These results suggested that Solanum lycocarpum plants showed a mechanism of adaptation to survival in water stress conditions.

Reproductive biology of woody plants in a cerrado community of Central Brazil

The flowering phenology, pollination biology and breeding systems of tree and shrub species were studied in a 40 h area of cerrado vegetation in Central Brazil. The cerrados are Neotropical savanna plant formations in Central Brazil. They represent the second most important vegetation province in Brazil and are nowadays the main agricultural frontier which has resulted in deforestation rates much higher than those occurring in lowland tropical forests. Despite the marked winter/dry − summer/wet seasonality, different species were encountered in flower throughout the year, although with a peak at the end of the dry season. Seven pollination guilds were identified, ranging from very small insects (body size less than 5 mm) to bats, but bee pollination was predominant, and overall pollination biology of the cerrado community was similar to that reported for evergreen neotropical forests. Most species were outbreeding in that self-pollinations yielded very few fruits, but heteromorphic and homomorphic self-incompatibility were rare and control of selfing was commonly exercised by ill-defined post-zygotic mechanisms. The results indicated that the reproductive biology of woody cerrado species is not markedly different from other tropical forest communities and suggested the adaptation to seasonal habitats did not always lead to simplification or changes in breeding features of the cerrado species.

Dioecy in the Cerrado vegetation of Central Brazil

Summary Occurrence of dioecy in Cerrado, Neotropical savanna region in Central Brazil, is analyzed here. Frequency of dioecious species and their phenological and morphological characteristics were studied for a cerrado woody community near Brasilia, and a broader comparative survey was done using phytosociological data for different cerrado areas and vegetation physiognomies. Nine dioecious species were found in the studied community (15% of the species in the area), most with simple open flowers visited by small insects. Flowering phenology differed from species to species including long, sparse flowering and comucopian strategies. Distance between flowering individuals varied from 13 to 70 m. Gender related differences in spatial distribution and in height or circumference were tested for three of the species and significant departure from random was found only for Rapanea guianensis . The regional survey showed frequencies of dioecy higher in denser woodlands and forest than in open cerrado areas. Most species presented small promiscuous flowers, probably associated to pollination by small insects, and fleshy fruits. Among the species occurring in the cerrado areas one could separate a group of dioecious shrubs and treelets really adapted to cerrado environment and another group of evergreen forest species which occur only in denser woodlands, the cerradao. Differences in the frequency of dioecy seems to be related to the occurrence of this latter group and the appearance of cerradao.

Arthropogon rupestris (Poaceae: Arthropogoneae) a new species from the Brazilian cerrado vegetation and a revised key for the genus.

Arthropogon rupestris sp. nov., a new panicoid grass species from the cerrado vegetation of central Brazil is described, illustrated and compared to A. scaber and A. bolivianus. A key to the eight species of the genus is given as well as their known distribution.

Response of the ground layer community of a cerrado vegetation in central Brazil to liming and irrigation

A split plot design with irrigation as the main plot treatment and liming as subplot treatment was utilized to determine the response of the ground layer community of a cerrado vegetation on a dystrophic dark red latosol (Haplustox) in central Brazil to liming and irrigation. Aerial live biomass of the grasses and nongrasses of the ground layer and their nutrient concentrations were determined over a period of 18 months. As liming rate increased from 0 to 8.4 t ha-1 the soil pH increased from 5.2 to 5.8. The availability of Ca increased from 0.24 to 6.91 cmol (+) kg-1 dry soil and that of Mg from 0.10 to 0.17 cmol(+)kg-1 dry soil. Liming decreased the exchangeable Al from 0.66 to 0.24 cmol (+) kg-1 dry soil. There was an increase of up to 70% in the biomass concentration of Ca in grasses and 87% in nongrasses as a result of liming up to 8.4 t ha-1. Concentrations of Mn decreased by 37% in grasses and by 33% in nongrasses. However, liming did not result in any increase in the primary production of either grasses or nongrasses. Irrigation during the dry season did not alter soil pH, nutrient availability in the soil or foliar concentrations of nutrients in grasses and nongrasses. Irrigation during the dry season increased the live aerial biomass of grasses by an average of 41% over the experimental period but not that of the nongrasses.

Pollination ecology ofCaryocar brasiliense(Caryocaraceae) in Central Brazil cerrado vegetation

ABSTRACTThe floral biology, breeding system and pollination ofCaryocar brasiliensewere studied in the cerrado vegetation of Central Brazil. The large, yellowish-cream, brush-like flowers are pollinated mainly by glossophagine bats (Glossophaga soricinaandAnoura geoffroyi). Three non-glossophagine bats (Phyllostomus discolor, Vampyrops lineatusandCarollia perspicillata) and two short probosisced hawk moths (Erinyis elloandPseudosphinx tetrio) may also act as occasional pollinators.Caryocar brasilienseis self-compatible although it sets significantly more fruits when crossed than when selfed. The natural fruit set (fruit/flower ratio) and seed set (seed/ovule ratio) are 3.1% and 1.0% respectively. Most of the fruits and seeds are formed through the action of the flower visitors, despite the fact that about 20% of the non-visited flowers receive self pollen on at least one stigma.

Nest Density of some Social Wasp Species in Cerrado Vegetation of Central Brazil (Hymenoptera: Vespidae)

Nest Density of some Social Wasp Species in Cerrado Vegetation of Central Brazil (Hymenoptera: Vespidae)

Pollination and Breeding System of Vellozia squamata (Liliales: Velloziaceae): A Species of the Brazilian Cerrados

AbstractThe pollination biology and breeding system of Vellozia squamata (Velloziaceae), a species of cerrado vegetation in Central Brazil, were studied. V. squamata is unusual in being pollinated by a few, generalist bee species despite having very large flowers, and having a distinctive pulsed flowering phenology. The species is self‐incompatible but with a late‐acting, post‐fertilization rejection mechanism.

Semiquantitative estimates of Al and other cations in the leaf tissues of some Al-accumulating species using electron probe microanalysis

Electron probe microanalysis of transverse sections was used to provide semiquantitative estimates of Al and other cations in the leaf tissues of some Al-accumulating plants of the cerrado vegetation of central Brazil. Concentrations of Al were generally higher than those of other cations in the phloem elements of these plants growing on dystrophic as well as fertile acid soils. When one of the Al-accumulating species,Vochysia thyrsoidea, was grown in a calcareous soil, the concentration of Al in the phloem elements of leaves was lower than that of Ca and K though the cotyledons showed higher concentrations of Al than those of other cations.