Geraldo Alves Damasceno-Junior

Inundation and Fire Shape the Structure of Riparian Forests in the Pantanal, Brazil.

Inundation and fire can affect the structure of riparian vegetation in wetlands. Our aim was to verify if there are differences in richness, abundance, basal area, composition and topographic preference of woody species in riparian forests related to the fire history, flooding duration, or the interaction between both. The study was conducted in the riparian forests of the Paraguay River some of which were burned three times between 2001 and 2011. We sampled trees with a girth of at least 5 cm at breast height in 150 5 × 10 m plots (79 burned and 71 unburned). We also measured height of the flood mark and estimated the flooding duration of each plot. We performed Generalized Linear Mixed Models to verify differences in richness, basal area, and abundance of individuals associated to interaction of fire and inundation. We used an analysis of similarity (ANOSIM) and indicator species analysis to identify differences in composition of species and the association with burned and unburned area according to different levels of inundation. Finally, we used a hierarchical set of Generalized Linear Models (GLM), the so-called HOF models, to analyse each species’ specific response to inundation based on topography and to determine their preferred optimal topographic position for both burned as well as unburned areas. Richness was positively associated with elevation only in burned areas while abundance was negatively influenced by inundation only in burned areas. Basal area was negatively associated with time of inundation independent of fire history. There were 15 species which were significant indicators for at least one combination of the studied factors. We found nine species in burned areas and 15 in unburned areas, with response curves in HOF models along the inundation gradient. From these, five species shifted their optimal position along the inundation gradient in burned areas. The interaction of fire and inundation did not appear to affect the basal area, but it did affect the richness, number of individuals, success of some species, and seemed to shape the boundary of these forests as shown by the difference in the positioning of these species along the inundation gradient.

Flora arbórea do Cerrado de Mato Grosso do Sul

The genetic diversity of 38 ecotypes of watermelon was evaluated using genetic markers and morphological traits. Analysis of variance showed a signifi cant diff erence for the studied traits. Cluster analysis using UPGMA method based on morphological traits was classifi ed studied ecotypes into four groups. Using 11 primers were obtained 89 polymorphic bands that cluster analysis of molecular data was placed 38 ecotypes into four groups. The genetic diversity structure of the watermelon accessions on the basis of ISSR data evidenced a common pattern of molecular markers. The similarity of ecotypes grouping with molecular markers and morphological traits was low and the correlation coeffi cient of the twomatrices was low (r = 0.03), revealing quite a non-signifi cant correlation between them and the efficiency of them to assays in estimating genetic diversity in watermelon is diff erent. Overall, this study demonstrated high genetic diversity among cultivated watermelon which may be attributed to their high genetic background and environmental effects.