This study aimed to generate knowledge about transition areas between phytophysiognomies for the understanding and conservation of these unique environments. Thus, the existence of different floristic groups was analyzed in a spatial gradient of an ecotone in the municipality of São Desidério, state of Bahia, Brazil. To this end, a transect of approximately 4.7 km, with orientation from Northeast to Southwest, was established along a spatial gradient. Twelve (12) 10x50 m sampling plots (500 m² each) were distributed throughout this transect. The following methodology was employed: First, the floristic similarity between the sampling plots was measured. These sampling plots were then grouped and the data were graphically presented in a dendrogram (Cluster analysis) and an ordering diagram (nMDS). Finally, the phytosociological parameters by ordered group were obtained. The results showed the presence of three floristic groups: Groups I, II and III, classified as wooded savannah, seasonal deciduous forest, and forested savannah, respectively. The floristic groups were formed gradually along the spatial gradient, and transition between phytophysiognomies does not occur abruptly, since the ordering by groups is more due to the difference between the abundance of species than to their presence and/or absence. The distribution pattern of the phytophysiognomies along the spatial gradient indicates association with abiotic factors, such as the pedological characteristics and the relief found along the transect, possibly creating an environmental gradient.

This study aimed to evaluate the biomass and chemical composition of the forest floor litter in three remnants of Submontane Dense Ombrophilous Forest located in the Guaricica Natural Reserve in the municipality of Antonina, state of Paraná, Brazil. The areas selected for this study are at different stages of secondary succession, here named initial stage (INI), intermediate stage (INT), and advanced stage (ADV). The litter was collected in different seasons of the year (summer and winter of 2013 and 2014) and sorted into fractions: whole leaves (WL), leaves under some stage of decomposition (DL), miscellaneous litter (ML), and branches (B). After sorting, the litter was oven-dried, weighed, and had the contents of C, N, P, K, Ca, and Mg measured. After that, the accumulated amount of each nutrient in the different litter fractions was estimated. Accumulation of biomass in the INI was lower than that in the ADV. The DL fraction showed the highest level of biomass accumulation among all fractions. The average concentration of macronutrients in the litter showed the following sequence: C>N>Ca>Mg>K>P. The C/N ratio was higher in the INI and INT compared with that in the ADV. Higher levels of macronutrients were frequently observed in the ADV. Inputs of C and of most nutrients increased from the INI to the ADV, except for Ca, whose input varied little throughout the different successional stages.