Fabiana de Gois Aquino

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.

Nurse plant effect of Solanum lycocarpum A. St.-Hil. in area of Brazilian Savanna undergoing a process of restoration

The use of nurse plants in ecological restoration aims to reactivate succession processes to improve environmental quality and biodiversity. This study targets Solanum lycocarpum as a nurse species to promote different plant species beneath its crown by microenvironmental changes in a disturbed area in Brazilian Savanna undergoing a process of restoration. The hypothesis is that S. lycocarpum modifies the microenvironment beneath its crown and influence in order to facilitate the density and richness of different plant species. Biotic parameter as density and species-rich biota, dispersal syndromes and habit were sampled. Additionally abiotic parameters were evaluated: litter thickness, light interception, penetration resistance, moisture, soil bulk density, saturated hydraulic conductivity of soil, nutrient content, acidity and soil structure. These parameters were evaluated in ten sampling units beneath S. lycocarpum, called the area of direct influence, ten around the nurse species crown, in the area of indirect influence and ten in open fields nearby without the influence of other trees, in the control area. For the biotic factors, density and species richness were higher beneath the crown of S. lycocarpum than in other treatments, mainly due to more litter accumulation, light interception, higher nutrient content (potassium, calcium and magnesium), more moisture and lower penetration resistance. Results showed the importance of S. lycocarpum as a nurse species in a Brazilian Savanna area, because of their role in local microenvironmental changes to facilitate other plant species and promote succession processes.

Repetibilidade de características de frutos de duas populações de Hancornia speciosa da região “core” do Cerrado do Brasil

The objective of this work was to estimate the repeatability coefficients of mangaba (Hancornia speciosa) fruit traits, in order to define the number of fruit needed for an accurate selection of superior genotypes, as well as to conjecture about the nature of the phenotypic variation of these traits. Evaluations were performed for 160 fruit of 16 genotypes from two native H. speciosa populations of Goiás Velho and Padre Bernardo, in the state of Goiás, Brazil. Repeatability was estimated by the analysis of variance, principal component analyses based on covariance and on the correlation matrix, and structural analysis based on the correlation matrix. Repeatability estimates for fruit weight, diameter, and length, as well as seed number and weight, were of low magnitude, from 0.02 to 0.62, indicating low heritability. Repeatability estimates for oBrix, titratable acidity, and oBrix/acidity ratio were higher, from 0.34 to 0.91, indicating a low to potentially moderate heritability. The number of fruit for an effective selection of the best genotypes for titratable acidity, oBrix, oBrix/acidity ratio, and fruit weight is four for a 0.85 accuracy level. However, seven fruit would allow 0.90 accuracy for the same traits, and 0.85 accuracy for fruit length and diameter. The number and weight of seed per fruit are not effective for predicting the real value of a genotype.

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.

Eficiência de regenerantes como indicador de restauração ecológica no Cerrado, Brasil

The objective of this study was to evaluate the efficiency of regenerating as an ecological indicator of restoration in riparian forests in the Cerrado, DF, from January/2012 to January/2013. The restoration experiment contained six treatments with three repetitions each (T1 = Nucleation; T2 = Nucleation + perches; T3 = perches; T4 = planting in rows: lines with fast growing and good covering species and diversity lines; T5 = control with brachiaria; T6 = brachiaria suppression). The percentage of coverage of saplingwas made using the Braun-Blanquet method, and then applied the nonparametric Kruskal-Wallis test. There was a significant difference between the initial and final cover for the T1. The other treatments there was little increase in the coverage of sapling, but not significant, even as in the increase between treatments. There were no differences between treatments when analyzing only the density of sapling, which may be associated with high mortality rate of certain species. Although early, the percentage of coverage of sapling was a good indicator of the ecological restoration process, according with aspects: sensitivity, results, cost, understanding and interpretation, predictability or trend and scale. Thus, it can be concluded that the percentage of coverage of sapling demonstrated efficiency as an indicator.