Fire is an important ecological factor that structures savannas, such as the cerrado, by selecting plant species and altering soil nutrient content. In Emas National Park, central Brazil, we compared soils under three different fire regimes and their relationship to the cerrado species they support. We collected 25 soil and vegetation samples at each site. We found differences in soil characteristics (p<0.05), with fertility and fire frequency positively related: in the annually burned site we found higher values of organic matter, nitrogen, and clay, whereas in the protected site we detected lower values of pH and higher values of aluminum. We also observed differences in plant community structure, with distinct floristic compositions in each site. Floristic composition was more related to sand proportion (intra-set correlation=0.834). Different fire frequencies increase environmental heterogeneity and beta diversity in the Brazilian cerrado.

Plants have traits against herbivory that may occur together and increase defense efficiency. We tested whether there are defense syndromes in a cerrado community and, if so, whether there is a phylogenetic signal in them. We measured nine defense traits from a woodland cerrado community in southeastern Brazil. We tested the correlation between all pairs of traits and grouped the species into defense syndromes according to their traits. Most pairwise correlations of traits were complementary. Plants with lower specific leaf area also presented tougher leaves, with low nitrogen, more trichomes, and tannins. We found five syndromes: two with low defenses and high nutritional quality, two with high defenses and low nutritional quality, and one with traits compensating each other. There were two predominant strategies against herbivory in cerrado: ''tolerance'' and ''low nutritional quality'' syndromes. Phylogeny did not determine the suite of traits species presented. We argue that herbivory exerts significant selection pressure on these plant defense traits.

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Background: Plant community assemblage is influenced by many factors, including soil characteristics and the arrival of diaspores from surrounding areas. These factors may be especially important in transition areas, leading to spatial gradients in the plant community. Methods: This study was performed in the understorey of an abandoned Eucalyptus grandis W. Hill ex Maiden plantation between a savanna and a forest, 490 m apart, in south-eastern Brazil. This study assessed whether the spatial variation in several variables related to the understorey's structure and composition is best described by linear or non-linear (quadratic) models. The linear model would indicate a gradient between the two vegetation types, whereas the quadratic model would indicate a stronger effect of the plantation's edges. Results: There was a gradient in species composition between the two edges of the plantation. Mean vegetation height was greatest at the savanna edge and lowest in the centre of the plantation. The total number of individuals per plot and the phylogenetic diversity decreased with distance from the savanna edge. Different patterns were observed for different dispersal syndromes, with animal dispersal being more common at the savanna edge, wind dispersal in the centre of the plantation and self dispersal at the forest edge. Conclusions: The greater number of individuals at the savanna edge may indicate that dispersal and arrival of diaspores are the most important factors influencing community structure and composition of the understorey of this abandoned E. grandis plantation, with most propagules coming from the savanna area. The smaller vegetation height in the centre of the fragment may also indicate older colonisation at the edges. Therefore, in addition to highlighting the recovery potential of undergrowth beneath abandoned Eucalyptus spp. plantations, these results show that this recovery is spatially heterogeneous and that dispersal plays a large role in it. This should be taken into account in restoration projects. The authors recommend careful consideration before removing regenerating Eucalyptus spp. trees as part of the site restoration. Instead the focus should be on the recovery potential of the undergrowth, with gradual removal of Eucalyptus trees, if necessary.

The originality of a species is how much that species contributes to the rarity of traits in a community. Here we tested the relation between abundance and both phylogenetic and phenotypic originality. We measured nine traits associated with defence against herbivory, as well as phylogenetic information and abundance for woody plant species in a woodland cerrado in southeastern Brazil. About 90% of the species accounted for about 50% of the phylogenetic and phenotypic originality: most woody species had low originality. Abundance was related to tougher leaves, lower specific leaf area and lower originality based on nutritional quality. Our results suggest that herbivory may reduce the abundance of species with low resistance to herbivory and with different nutritional quality. Nevertheless, abundance was not related to either phylogenetic or phenotypic originality, so extinction of rare species may not endanger overall community function as long as more abundant species are retained.We argue that this is a consequence of the low complementarity of a large number of woody species.