Ecosystem functions in different physiognomies of Cerrado through the Rapid Ecosystem Function Assessment (REFA).

The assessment of ecosystem functions in Cerrado is important to implement practices of conservation. Recently, a 'rapid ecosystem function assessment' (REFA) for measuring ecosystem functions has been proposed and tested as a suitable method. Thus, this study aimed to assess the proxies of ecosystem functions of three physiognomies of Cerrado through REFA. This method was applied in three different preserved physiognomies of Cerrado from Northeastern, Brazil, namely: Campo Graminoide (CG), Cerrado Stricto Sensu (CSS), and Cerradão (CD). All proxies for the selected ecosystem functions differed between sites and seasons. The above- and belowground primary productivity and microbial biomass C were higher in CD than in CSS and CG. The above- and belowground secondary productivity and decomposition were higher and similar in CD and CSS as compared to CG. The principal component analysis explained 89.8% of the data variation and clustered the majority of ecosystem functions with CD, in both seasons and CSS in the wet season. The proxies of ecosystem functions measured through REFA showed differences between the physiognomies of Cerrado. Since each physiognomy of Cerrado presents different plant richness and diversity, and soil conditions, these characteristics contribute to influencing multiple ecosystem functions.

Structure and diversity of bacterial community in semiarid soils cultivated with prickly-pear cactus (Opuntia ficus-indica (L.) Mill.).

Studies evaluating the structure and diversity of bacterial communities in arid environments including the rhizosphere of local and adapted plant species are important. Therefore, we used a sequencing of the 16S ribosomal RNA gene for describing the structure and diversity of soil bacterial community in three zones: Agreste, Transition and Sertão. The bacterial community was clustered in 9,838 OTUs in Agreste, 8,388 OTUs in the transition, and 14,849 OTUs for Sertão. Among the most abundant phyla, Proteobacteria and Acidobacteria were abundant in Agreste and Sertão, respectively, while Actinobacteria were abundant in Transition and Sertão. Specific taxa of Proteobacteria, in Agreste, and Actinobacteria, in Sertão, exhibited differences according to biotic and abiotic conditions. Thus, the structure and diversity of bacterial community were different in these areas and were influenced by environmental and soil conditions.

Soil microbial C:N:P ratio across physiognomies of Brazilian Cerrado Soil microbial biomass across a gradient of preserved native Cerrado.

Different physiognomies across the Cerrado could influence the microbial C:N:P ratio in the soil since these physiognomies present different abundance and diversity of plant species. Thus, the aim of this study was to evaluate the microbial C:N:P ratio in soil across three different physiognomies of Cerrado in the Northeast, Brazil, namely campo graminóide (dominance of grasses), cerrado stricto sensu (dominance of grasses, shrubs, low trees, and woody stratum), and cerradão (dominance of woody stratum). Campo graminóide was characterized by lower values of total organic C, N, microbial C:P, N:P, and soil C:N. Cerrado stricto sensu presented average values for most of the measured parameters, while cerradão presented higher values of microbial C, N, P, organic C, N and soil C:P and C:N ratios. The principal component analysis showed that the samples grouped according to the sites, with a clear gradient from campo graminóide to cerradão. Therefore, the differences of vegetation across physiognomies of Cerrado influenced the soil microbial C:N:P ratio, where cerradão showed highest microbial C:N:P ratio than soil under campo graminóide.