Cerrado Sensu Stricto Area Research Articles

Allometry of some woody plant species in a Brazilian savanna after two years of a dry season fire

Studies of allometry are important in explaining effects of fire and herbivory, for estimating biomass in forests, and so on. There has been extensive research on plant allometry in temperate and tropical forests, showing that plant architecture often adjusts to the elastic similarity model, but not in Brazilian savannas (cerrado). We studied allometry of Dalbergia miscolobium, Diospyros hispida, Erythroxylum suberosum, Miconia albicans, M. ligustroides, Schefflera vinosa, and Xylopia aromatica in a cerrado sensu stricto area that was affected by a fire in August 2006. We expected that the study species would not adjust to any of the allometric models considered common for forest species ("constant stress", "elastic similarity", and "geometric growth"), and that there would be differences in allometry in burnt and unburnt patches. We sampled two species in 60 5 × 5 m contiguous plots placed in three transects, and five species in 100 5 × 5 m contiguous plots placed in five transects, where we measured the diameters at soil level (DSL) and the heights of all shoots. We used standardized major axis regressions on log-transformed data. The regression slope between the height and DSL was higher than 1.0 (p < 0.05) for four species, showing a greater height than would be expected under geometric growth, not predicted by theoretical models. We found significant differences (p < 0.05) in regression slopes and/or correlation coefficients between burnt and unburnt plots for five species, indicating that fire may influence plant allometry in the Brazilian cerrado, and that such a response is highly variable between species.

Florística da vegetação remanescente de Cerrado sensu stricto em terra indígena no noroeste de Mato Grosso, Brasil

The knowledge of the natural resources of indigenous reservations is important to evaluate the national biodiversity and to contribute for the management of these resources in the communities. In this work, we aimed at studying the shrub and tree species of the Cerrado from Terra Ind&iacute;gena Utiariti, in the municipalities of Campo Novo dos Parecis and Sapezal, in the state of Mato Grosso, evaluating its species richness and comparing with other studies conducted in different areas of Cerrado sensu stricto. We found 138 species belonging to 95 genera and 47 families in a sampling area of 2 ha. The most representative families were Leguminosae (22 species), Annonaceae and Vochysiaceae (seven species), Euphorbiaceae and Melastomataceae (six species), Arecaceae, Bignoniaceae, Myrtaceae, and Rubiaceae (five species). This area of Cerrado was characterized by the high richness and expressiveness of the Euphorbiaceae family. The literature indicates that 32.6% of the species sampled present economic potential.

Heterogeneidade do habitat, riqueza e estrutura da assembléia de besouros rola-bostas (Scarabaeidae: Scarabaeinae) em áreas de cerrado na Chapada dos Parecis, MT

Ecological theory of habitat heterogeneity and limited niche-similarity assumes that more heterogeneous environments provide a greater amount and diversity of resources than simple environments, resulting in a greater diversity of species. This study aimed to evaluate the effect of the habitat heterogeneity on the richness of dung beetles and to examine the spatial patterns of assemblage structure in relation to patterns of habitat heterogeneity. Dung beetles were collected using pitfall traps without bait in 30 points distributed in an area of cerrado sensu lato, in the region of Tangará da Serra, MT, Brazil, including areas of cerrado sensu stricto, campo sujo, cerradão and gallery forest. A total of 1,291 dung beetles were collected, distributed in 16 genera and 29 species. Overall habitat heterogeneity exerted a negative effect on patterns of dung beetles richness. Higher levels of species richness were observed in areas of cerrado campo sujo, while the areas of gallery forest were the most species poor. Regarding assembly structure, it was found that the dung beetles were separated into two major groups, one formed by the presence of specialized species in forest areas and other composed of species that occurred predominantly in cerrado. In conclusion, it was found that habitat complexity influenced the distribution of dung beetles, but the level of turnover in species composition along the heterogeneity gradient was relatively weak.

Climate and host plant characteristics effects on lepidopteran caterpillar abundance on Miconia ferruginata DC. and Miconia pohliana Cogn (Melastomataceae)

Folivore cerrado caterpillars are found on their host species in low frequencies, which vary between plants and throughout the year. We analysed the effects of climatic variation and of the characteristics of two host species (Miconia, Melastomataceae) on caterpillar abundance. The work was carried out in a cerrado sensu stricto area in Brasília, Federal District, Brazil, from May 1998 to September 1999. One hundred plants of each species were inspected monthly. All caterpillars found were collected and raised in the laboratory with Miconia leaves as food sources. Climatic data for the study area and plant characteristics such as local density, spatial distribution, foliar phenology, leaf pilosity and nutritional content were used to test the effects on caterpillar abundance. Less than 10% of the plants had larvae. Caterpillars were more frequent and abundant in M. pohliana, which was also present at higher densities than M. ferruginata. Low caterpillar frequency in host plants and an abundance peak during the dry season are consistent patterns for different cerrado Lepidoptera larvae. This abundance peak, however, is not coincident with higher leaf production in host species. We suggest that M. pohliana's higher local density and better leaf digestibility can account for the higher abundance of caterpillars in this species.

Isotopic view of vegetation and carbon and nitrogen cycles in a cerrado ecosystem, southeastern Brazil

Carbon and nitrogen biogeochemical cycles in savannas are strongly regulated by the seasonal distribution of precipitation and pulses of nutrients released during the wetting of the dry soil and are critical to the dynamics of microorganisms and vegetation. The objective of this study was to investigate the spatial and temporal variability of C and N isotope ratios as indicators of the cycling of these elements in a cerrado sensu stricto area, within a protected area in a State Park in the state of São Paulo, Brazil. The foliar δ13C and δ15N values varied from -33.6 to -24.4 ‰ and -2.5 to 4.5 ‰, respectively. The δ13C values showed a consistent relationship with canopy height, revealing the importance of structure of the canopy over the C isotopic signature of the vegetation. Carbon isotopic variations associated with the length of the dry season indicated the importance of recent fixed C to the integrated isotopic signature of the leaf organic C. The studied Cerrado species showed a depleted foliar δ15N, but a wide range of foliar Nitrogen with no difference among canopy heights. However, seasonal variability was observed, with foliar δ15N values being higher in the transition period between dry and rainy seasons. The variation of the foliar C and N isotope ratios presented here was consistent with highly diverse vegetation with high energy available but low availability of water and N.

FITOSSOCIOLOGIA DA COMUNIDADE LENHOSA DE UMA ÁREA DE CERRADO RUPESTRE NO PARQUE ESTADUAL DOS PIRENEUS, PIRENÓPOLIS, GOIÁS

This work aimed to study the floristic composition and phytosociology of an area of cerradosensu stricto located on rocky outcrops in Parque Estadual dos Pireneus, municipality of Piren&oacute;polis,Goi&aacute;s. The studied area is located between 15&ordm;47&rsquo;71&rsquo;&rsquo;S - 15o47&rsquo;77&rsquo;&rsquo;S and 48&ordm;49&ordm;&rsquo;96&rsquo;&rsquo;W - 48o50&rsquo;15&rsquo;&rsquo;W, atthe altitude of 1.355 m. Ten 20 m x 50 m plots were randomly sampled to include all woody individuals with BD(30cm) ! 5 cm. We registered 30 botanical families encompassing 45 genera and 56 species. Myrtaceae family showed the highest number of species (8), followed by Fabaceae and Melastomataceae (6 each), Malpighiaceae (4) and Clusiaceae (3). There were 507 individuals/ha, the basal area was 3.91 m2/ha , and the standing dead trees represented 9.07% of the total number of individuals. Shannon&rsquo;s (H&rsquo;) index was 3.33 nats/ind. Czekanowski similarity indices suggest that the beta diversity was high, mostly due to variation in species density between plots. The area has a characteristic flora of this region and species composition restricted to rocky outcrops adapted to shallow soils near the rocky substrate as well as generalist species of Cerrado physiognomies.

Comportamento fenológico no evento pós-queima e biologia reprodutiva de Spiranthera odoratissima A. St.-Hil. (Rutaceae)

Post-fi re phenological behavior and breeding biology of the Spiranthera odoratissima A. St.-Hil. (Rutaceae). The phenological behavior of species in response to cerrado stricken by fi re is little known. A phenological and reproductive biological study of Spiranthera odoratissima was carried out in an anthropized area of cerrado sensu stricto affected by fi re in Goiânia County, Goiás, Brazil. Phenolocial observations indicated that the indivi- duals bloomed in synchrony three months after the fi re. The phenological rhythms were associated with the seasonal pluviometric effects, a chara- cteristic pattern of shrublet species of the cerrado. The fl owers are white with a sweet odor and are grouped in panicle infl orescences. The blos- soming occurs during dusk and begins at around 16h. It offers pollen and nectar to its visitors. The species produces 32.8μl (± 3.4) of nectar with an average concentration of 16.4% (± 0.43) in equivalents of sucrose. The pollination system (phalenophily) was proposed based on an analysis of the fl ower’s characteristics. Observed visitors were bees (Apis to be merely resource thieves. It was observed that Trigona spinipes Fabr. can act as a secondary pollinator during the pilling of pollen. The results of manual pollination and the incompatibility index (ISI) indicate that the species is xenogamous and self-compatible.

Ecological aspects of lepidopteran caterpillar parasitoids from Caryocar brasiliense Camb. (Caryocaraceae) in a cerrado sensu stricto of Central Brazil

This study quantified parasitoid occurrence on five lepidopteran caterpillars species that use Caryocar brasiliense as host plant, trying to verify if there was a direct relationship between host abundance and the proportion of parasitism; if leaf shelters served as cues or protection from parasitoids; if host size influenced the proportion of parasitism, and if attacks by Diptera were more frequent than by Hymenoptera. Searches for external folivorous caterpillars were carried out in an area of cerrado sensu stricto, from July/2003 to June/2004. Caterpillars were more parasitized when occurred on mature leaves. Nola sp. (Noctuiidae) had the highest proportion of parasitism and a negative correlation between their body size and parasitoid attack. Caterpillars that constructed shelters suffered lower parasitism than those exposed. Hymenopteran parasitoids were more abundant than Dipteran parasitoids attacking caterpillars on C. brasiliense leaves. In general, parasitoid species richness and the proportion of parasitism in lepidopteran caterpillar on C. brasiliense showed associations with host population density, their life strategy, diet and leaf nutritional quality.

Similarity Between Cerrado Localities in Central and Southeastern Brazil Based on the Dry Season Bait Visitors Ant Fauna

To investigate whether similar physiognomic areas support similar faunas, the richness, similarity, and community structure of the ant fauna attracted to baits in an area of the Brazilian Cerrado sensu stricto at the core of the domain and in two Cerrado 'islands' (one of sensu stricto and another of 'cerradão') were compared. In each locality, four collecting events were performed (two during the day and two at night) capturing ants attracted to 400 sardine baits (200 in soil, 200 in vegetation). Ants of six subfamilies, 33 genera, and 121 species were identified visiting baits in the three areas (180 species estimated). The most speciose genera were Camponotus (27 species), Pheidole (13), Solenopsis (11), and Crematogaster (8). The similarity values between pair sites can be considered medium in relation to other studies. The highest value was recorded for the core area and the 'island' of Cerrado sensu stricto (Morisita-Horn = 0.57). The two Cerrado 'islands' were found to be 0.44 similar and the core area and the 'cerradão' 0.41 similar. The ordination analysis (non-metric multidimensional scaling) revealed discontinuities in species distributions between areas of Cerrado sensu stricto and 'cerradão,' and distinctive ant faunas relative to the temporal (nocturnal and diurnal) and foraging niches (ground and vegetation). The ant fauna at ground level in the 'cerradão' and Cerrado sensu stricto showed the greatest dissimilarity. The data suggest that areas of Cerrado are characterized by relatively high local ant fauna richness, and that community structure is influenced by the distance between sites and the diversity of vegetation.

Efeito de incêndios florestais na estrutura e composição florística de uma área de cerrado sensu stricto na fazenda Água Limpa-DF&lt;a name=tx&gt;&lt;/a&gt;

O objetivo desta pesquisa foi avaliar o efeito do fogo na estrutura e composição florística de uma área de 10 ha de cerrado sensu stricto, localizada na fazenda Água Limpa da Universidade de Brasília. Foram realizados dois inventários, sendo o primeiro em 1999, logo após a área ter sido totalmente queimada, devido a um incêndio criminoso, e o segundo em novembro de 2002. Quatro parcelas de 0,1 ha (20 x 50 m) foram tomadas, aleatoriamente, na área queimada. Todos os indivíduos lenhosos arbóreos vivos, com Db (diâmetro tomado a 0,30 m do solo) igual ou superior a 3 cm, foram identificados botanicamente, e seus diâmetros e alturas foram registrados. Valores de densidade, dominância, freqüência e índice de valor de cobertura foram obtidos para os dois levantamentos. A avaliação da similaridade florística entre os dois inventários foi realizada para dados qualitativos (presença e ausência de espécies), a partir do índice de Sfrensen. Os resultados mostraram que houve pouca mudança na composição florística da comunidade durante o período estudado. Entre os dois inventários houve um aumento de aproximadamente 125% na densidade por hectare. A similaridade entre os dois levantamentos foi alta (índice de Sfrensen igual a 0,68). A densidade florística, obtida a partir do índice de Shannon, foi baixa (cerca de 2,5) nas duas épocas monitoradas, quando comparada com pesquisas a longo prazo no cerrado sensu stricto da FAL (cerca de 3,5). Contudo, este valor é comum em áreas de cerrado que sofreram distúrbios. No segundo inventário, realizado três anos após o fogo, surgiram 13 espécies novas na área, o que comprova a sua recuperação e recolonização.

Fitossociologia de cerrado sensu stricto no município de Abaeté-MG

O cerrado tem sido objeto de discussão de grupos temáticos que estudam a conservação de biodiversidade no Estado de Minas Gerais. São inúmeras as áreas de conservação com vegetação de cerrado das quais não se têm informações a respeito de sua composição florística e estrutura. O objetivo deste trabalho foi avaliar florística e fitossociologicamente uma área de cerrado sensu stricto, no município de Abaeté-MG. A área de estudo é um fragmento com 2 ha de cerrado sensu stricto, preservado como área de reserva da CAF-Santa Bárbara, situada nas coordenadas 19º05'S e 44º58'W, a uma altitude de 480 m, em leve depressão próxima de uma vereda. O clima pertence ao tipo Cwa pelo sistema de Köppen, com precipitação média anual de 1.400 mm. O solo é do tipo Latossolo Vermelho distrófico. Foram instaladas 15 parcelas de 200 m² (10 x 20 m), distribuídas sistematicamente ao longo de trilhas, distanciadas 10 m entre si. Foram amostrados todos os indivíduos lenhosos vivos com circunferência do caule ao nível do solo (CAS) igual ou maior que 10 cm. O índice de Shannon foi de 3,590 e a equabilidade foi de 0,804, considerados comuns para cerrados bem conservados. Foram amostrados 1.339 indivíduos, sendo a composição florística constituída por 85 espécies, distribuídas em 44 famílias. As famílias com maior número de espécies foram Leguminosae Caesalpinioideae com sete espécies, Annonaceae com cinco, Myrtaceae, Malpighiaceae, Erythroxylaceae, Anacardiaceae, Rubiaceae e Bignoniaceae com quatro, seguidas de Vochysiaceae e Leguminosae Papilionoideae com três. As espécies que apresentaram o maior valor de importância (VI) foram Xylopia aromatica (Lam.) Mart. (22,21), Myrcia lingua Berg (18,18) Caryocar brasiliense Cambess. (17,91), Eugenia dysenterica DC. (17,58), Byrsonima intermedia A. Juss. (13,69) e Brosimum gaudichaudii Trécul (11,86).

Fitossociologia de uma área de cerrado denso na RECOR-IBGE, Brasília-DF

Foi amostrada uma área de 10ha de cerrado denso da RECOR-IBGE, Brasília-DF. Nesta foram estabelecidas parcelas experimentais de um projeto para o estudo do efeito do fogo na vegetação do cerrado com um delineamento em blocos casualizados. Este levantamento foi efetuado antes da aplicação dos tratamentos visando conhecer a composição florística e estrutura da vegetação original. Foram incluídos todos os indivíduos lenhosos e aqueles não-lenhosos pertencentes à família Velloziaceae, com diâmetro mínimo de 5cm, presentes em cinco parcelas de 1000m². Foram medidas as alturas e os diâmetros a 30cm do solo de cada indivíduo. Ao todo foram amostrados 982 indivíduos, pertencentes a 63 espécies e a 34 famílias. Cerca de 47% das famílias foram representadas por apenas uma espécie. Apenas 16 espécies foram comuns a todas as cinco parcelas. A diversidade da área foi alta (H'= 3,53) e a similaridade entre as parcelas segundo índice de Sørensen foi também alta. As espécies Sclerolobium paniculatum, Eremanthus glomerulatus, Schefflera macrocarpum, Ouratea hexasperma, Vochysia thyrsoidea, Guapira noxia, Caryocar brasiliense, Vellozia squamata, Qualea grandiflora e Emmotum nitens apresentaram os maiores valores de importância. As estimativas de densidade e de área basal por hectare foram de 1964 indivíduos e 13,28m², respectivamente. A diversidade foi equivalente a de outras áreas de cerrado sensu stricto na região, mas a densidade e a área basal foram mais elevadas.

Changes in the floristic composition of cerrado sensu stricto in Brazil over a nine-year period

Changes in floristic composition and structure in a cerrado sensu stricto area were studied over a 9-y period. A sample of 19 (20-m × 50-m) permanent plots was assessed at 3-y intervals from 1985 to 1994, when all stems ≥ 5 cm at 0.30 m above the ground level were measured. There was little change in species composition over the period. Changes in density and basal area of the whole community were in the range of 5% over the 9 y. These parameters fluctuated over the years with the greatest differences found in the comparisons of 1991, 2 y after an accidental fire reached the site, with other years. The changes in density and basal area were greater than in several tropical forests, probably due to disturbances such as fire occurring at 3 to 5-y intervals. The nearly constant density and basal area suggested a highly resilient community.

Estudo fenológico de Stryphnodendron adstringens (Mart.) Coville no cerrado sensu stricto da Fazenda Água Limpa no Distrito Federal, Brasil

Stryphnodendron adstringens, popularly known as barbatimao, is widely distributed in the cerrado bioma from Para, in the Amazon region, to the Brazilian central plateau reaching the Southeast (Minas Gerais and Sao Paulo). Its bark and fruits countain taninn and have medicinal properties. Its nutritional requirements are low and it doesn't accumulate aluminium. Flowers are hermaphrodite and pollinated by small insects, especially bees. It is one of the main woody species found in the site studied. The objective of this paper is to analyse the phenological events of this species in an area of cerrado sensu stricto in the Fazenda Agua Limpa (15°56'S and 47°46'W) from 1987 to 1991. Ten trees were observed from january/18/1987 to november/07/1991. The climate is Koppen Aw, with a well-marked seasonality. Phenological patterns were graphically analysed, by Kruskall-Wallis test at 5% and by Spearman Rank Correlation. Annual leaf change patterns were similar over the five-year period. All individuals flowered each year, except for two that did not flower in 1990, one year after an accidental burning. Flowering occurred between July to November with the peaks varying over the years. All individuals produced fruits until 1989 when they were aborted by the burning. No fruiting was observed in the following year and just half of the fruit production was observed in 1991. The phenological model is annual with flowering, fruiting, seed dispersal, peaks of senescence and leaf flushing occurring in the dry season. Fruits take about one year to ripe. Occasional dry season fires deeply affected the reproductive activities, especially fruiting.

BIODEGRADAÇÃO DE RESÍDUOS ORGÂNICOS NO SOLO

Biodegradation is a complex and multifacited process involving an enormous nmnber and variety of soil organisms. Four groups of microorganisms OCCUR during the decomposition of vegetal residues: cellutolytics, hemicellulolytics pectinolytics and ligninolytics, with exception of the anaerobics and chimiotrophics organisms, these have large energy demands. The study of biodegradation does not require complex methods, but does require long time intervals and is labor intensive . During the decomposition of leaf litther in a cerrado sensu stricto area me most frequent filamentous fungi Were: TMchoderma, AbsUBa, f usariam and CyundrodacKum. The addition of organic residue can change the litter decomposition rate.