Bruno Machado Teles Walter

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 São 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. Sørensen´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 Sørensen’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 São 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.

Fitossociologia de dois trechos inundáveis de Matas de Galeria no Distrito Federal, Brasil

ABSTRACT – (Phytosociology of two swamped portions of gallery forests in Distrito Federal, Brazil). Gallery forests in the Cerradobiome possess physiognomic and floristic peculiarities that allow its division in two subtypes: “non-swamp” located in well drainedsoils; and “swamp” the less studied subtype, located in badly drained soils. The present study aimed to characterize the structure andthe flora of two swamped portions in the gallery forests of the Acampamento stream (15°35’S; 48°10’W) and the Riacho Fundo stream(15°55’S and 48°02’W), both in Distrito Federal (DF). In each forest it was allocated a grid of 160×50 m (0.8 ha), composed by 40 plotsof 10×20 m (200 m 2 ). All the individuals with DBH ≥ 3.0 cm were surveyed, including the standing dead plants. It was sampled 6,078individuals, being 3,030 in the swamped portion of Acampamento stream (33 families, 49 genera and 60 species) and 3,048 in the RiachoFund portion (30 families, 41 genera, 53 species). The basal area (dominance) and the diversity (H’) for the studied portions were47.96€m

Impacto da invasão e do manejo do capim-gordura (Melinis minutiflora) sobre a riqueza e biomassa da flora nativa do Cerrado sentido restrito

No Brasil, varias especies de gramineas sao citadas como invasoras em Unidades de Conservacao. Contudo, ainda se conhece muito pouco sobre o impacto do estabelecimento e da colonizacao dessas especies nas areas protegidas. Entre as gramineas exoticas introduzidas no bioma Cerrado merece destaque a especie africana Melinis minutiflora P. Beauv., o capim-gordura. O presente estudo objetivou avaliar o impacto desta invasora na biomassa e na riqueza da comunidade nativa em uma area de Cerrado Ralo invadido, como tambem estudar a dinâmica da vegetacao do estrato rasteiro submetida a aplicacao de diferentes tecnicas de manejo para o controle do capim-gordura. Os resultados mostraram que, na area experimental, onde o capim-gordura representa cerca 62% da biomassa total do estrato rasteiro, o numero de especies nativas encontradas foi alto. Nas areas onde o capim-gordura apresentou alto indice de colonizacao (> 98%), sua biomassa alcancou cerca de duas vezes a biomassa do estrato rasteiro registrada para o Cerrado. A realizacao de uma queimada nao foi suficiente para controlar o capim-gordura, porque apos tres anos a sua biomassa se aproximou aos valores encontrados inicialmente. Por outro lado, no tratamento manejo integrado (maio ou setembro) a reducao de mais de 99,9% na sua presenca favoreceu a expansao da vegetacao nativa, configurando-se, assim, uma estrategia promissora para a recuperacao ambiental das areas invadidas pelo capim-gordura no Cerrado.

Dinâmica de populações de espécies lenhosas de Cerrado, Balsas, Maranhão

The objective of the present study was to evaluate the population dynamics of 12 woody species. This study was conducted in two fragments of Cerrado stricto sensu in the Gerais de Balsas Colonization Project, located in Southern Maranhao, Brazil, between 1995 and 2002. The frequency distribution in diameter classes showed the reverse J-shape curve for the majority of species studied. The high recruitment rates were registered for Byrsonima coccolobifolia, Sclerolobium paniculatum e Vochysia rufa, in fragment 1, and B. coccolobifolia, Byrsonima crassa, Davilla elliptica and Qualea parviflora, in fragment 2. The high growth rates were registered for B. crassa, Q. parviflora, S. paniculatum and V. rufa, to both fragments. The species that presented high recruitment and high growth rates, probably, will remain as the principal species in the community structure. On the other hand, the populations of Connarus suberosus, D. elliptica, Hirtella ciliata and Erythroxylum deciduum, in fragment 1, and Salvertia convallariaeodora, in fragment 2, did not present high recruitment rates, in this manner, if the tendencies persist these populations will probably have their survival compromised in the future.

Comparação do método de parcelas com o "levantamento rápido" para amostragem da vegetação arbórea do Cerrado sentido restrito

The Cerrado biome has lost much of its area through human activity, and its degradation has been increasing since the 1960s. With the aim of gathering botanical information as efficiently as possible, research projects in the region have been using a fast sampling method called the rapid survey, but these methods are still the target of much academic criticism. Our aim was to compare the rapid survey with the plot method most commonly used in Central Brazil. The study was carried out in a section of Cerrado s. str. vegetation in the Federal District, Brazil, using the rapid survey along three lines (L1, L2 and L3). Walking along each line, the presence of previously unrecorded species was noted at 5-minute intervals to produce a species×time curve. L1 was divided into sample plots (11 plots of 20×50 m, surveying trees with stem diameter over 5 cm at 0.3 m above soil level), allowing for a direct comparison. Forty minutes was the longest time necessary to flatten a species×time curve (L2), and the sum of the three lines totaled 67 species, 53 genera and 32 families. In the plots 1,132 individuals were sampled over 8 hours and 17 minutes, belonging to 58 species, 45 genera and 27 families. Although exactly the same structurally homogeneous area was sampled, the floristic results from L1 and from the plots revealed differences that were analyzed in the light of the characteristics of each method. The rapid survey, which calls for participants with broad field identification experience, was a reliable way of determining the richness of the Cerrado area studied, and was more efficient than the plot method. However, it does not supply structural information about the vegetation, and the information on relative species abundance appears to be precarious, based on subjective estimates. Nevertheless, because of speed and ease of application plus low cost and minimum time spent in the field, the rapid survey should be seriously considered when urgent surveys of large areas are required. It is a valuable support tool for Cerrado conservation.

Richness pattern and phytogeography of the Cerrado herb–shrub flora and implications for conservation

Aims The herb–shrub flora has been widely neglected in science and conservation policy throughout the world, so that this biodiversity component remains largely unknown. The objective of this study was to elucidate the spatial patterns of species richness and phytogeographic regions of the Cerrado herb–shrub flora, and to estimate the percentage of areas with high species richness that is still covered by natural vegetation and is located in protected areas or priority areas for conservation. Location Central Brazil and surrounding territories. Methods To estimate the pattern of species richness we produced species distribution models (SDMs) for 5362 species using botanical records combined with 17 least correlated environmental variables. All SDMs were tested against a bias-corrected null model and the 5039 significant SDMs were stacked to generate the pattern of botanical richness. The resulting presence–absence matrix was subjected to a partitioning around medoids (PAM) cluster analysis to delineate phytogeographic regions. Results The pattern of species richness indicated that highest levels of richness are in the central–south and west parts of the Cerrado. The study recognized two floristically distinct clusters at the core of the Cerrado region, and seven additional regions that share floristic elements with the two core clusters. Many areas with high levels of modelled species richness are located outside protected and priority areas for conservation. Conclusions We recognized patterns of regional variation, reflected in the phytogeographic division. Furthermore, we show that the current protected areas in Brazil do not effectively protect high richness areas of the herb–shrub flora.

Vascular Flora of the Tocantins River Middle Basin, Brazil

This study provides a checklist of the phanerogams and pteridophytes of the Tocantins river middle basin, in northern Goias state and southern Tocantins state, Brazil. Herbarium samples were collected from 2000 to 2009 and this floristic survey recorded 1572 species from 135 families. The most species-rich families were Fabaceae (217), Poaceae (116), Asteraceae (88), Euphorbiaceae (65), Orchidaceae (58) and Malpighiaceae (56). Furthermore, 14 endangered species and 31 rare species were recorded, mainly associated with the campos rupestres in the Veadeiros Plateau region. The flora mainly from the phytophyisiognomies cerrado stricto sensu , campo rupestre (“rocky fields”), mata de galeria (“gallery forest”), mata ciliar (“riverine forest”) and semi-deciduous seasonal forest comprised typical species of the mid-western Cerrado floristic province, such as the most widely known woody plants Anadenanthera colubrina (Vell.) Brenan (popular name angico ), Aspidosperma subincanum Mart. ex A. DC. ( guatambu ), Astronium fraxinifolium Schott ex Spreng. ( goncalo-alves ), Callisthene fasciculata Mart. ( pau-jacare ), Dipteryx alata Vogel ( baru ), Guazuma ulmifolia Lam. ( mutamba ) and Magonia pubescens A. St.-Hil. ( tingui ). This study is the first to record a wide floristic list of this important region of central Brazil.

Tree diversity and above-ground biomass in the South America Cerrado biome and their conservation implications

Less than half of the original two million square kilometers of the Cerrado vegetation remains standing, and there are still many uncertainties as to how to conserve and prioritize remaining areas effectively. A key limitation is the continuing lack of geographically-extensive evaluation of ecosystem-level properties across the biome. Here we sought to address this gap by comparing the woody vegetation of the typical cerrado of the Cerrado–Amazonia Transition with that of the core area of the Cerrado in terms of both tree diversity and vegetation biomass. We used 21 one-hectare plots in the transition and 18 in the core to compare key structural parameters (tree height, basal area, and above-ground biomass), and diversity metrics between the regions. We also evaluated the effects of temperature and precipitation on biomass, as well as explored the species diversity versus biomass relationship. We found, for the first time, both that the typical cerrado at the transition holds substantially more biomass than at the core, and that higher temperature and greater precipitation can explain this difference. By contrast, plot-level alpha diversity was almost identical in the two regions. Finally, contrary to some theoretical expectations, we found no positive relationship between species diversity and biomass for the Cerrado woody vegetation. This has implications for the development of effective conservation measures, given that areas with high biomass and importance for the compensation of greenhouse gas emissions are often not those with the greatest diversity.

Floristic and structural comparisons between woody communities of two seasonal forest fragments in the Tocantins river basin and other remnants of this forest physiognomy in Brazil

This work describes the woody layer composition and structure in two seasonal forest fragments in the Tocantins river basin and compares them to other remnants of this forest physiognomy in Brazil. The survey was carried out by using 17 plot samples (20 × 50 m) located in Palmeiropolis, state of Tocantins, and in Minacu, state of Goias. All woody individuals showing diameters > 5 cm, at 1.30 cm above ground level, were recorded. The higher floristic similarity of these forest remnants compared with other closer seasonal forests did not show a distinct pattern. The floristic composition was more similar to that of a deciduous seasonal forest in the Parana valley, and more dissimilar to other forests in this same valley. This result and a higher dissimilarity related to the southern forests in Goias suggest that the forest fragments showed a floristic composition and structure typical of lowland seasonal forests in the Tocantins river basin. The results also indicated that the forest fragments have distinct floristic compositions with a relatively similar structure and diversity.