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This study aims to contribute toward a better understanding of the current biodiversity patterns existing in the Atlantic Forest of the state of Rio de Janeiro from a paleo-ecological approach. Three soil profiles, each formed from distinct source materials under varied climate and vegetation conditions were selected from the coastal regions of Rio de Janeiro, Brazil. Soil horizon samples for chemical and physical characterization were collected from 10 cm-interval depths, and the total organic carbon was determined in addition to performing isotype and phytolithic analyses. The phytolithic analysis associated with the isotopic techniques (δ 13 C) permitted the characterization of three stages of paleo-environmental evolution for the studied soils, presenting valid trends that indicate small variations within the phytosociological structure of the vegetation along a Spodosols line in the studied areas. These stages indicated that the phytolithic assemblage was formed from a vegetation profile containing more trees, adapted to conditions colder than the existing vegetation, although no environmental changes were detected using the isotopic data. The milder temperature conditions may have favored the pedogenetic processes of the spodic B horizon formation as well as the maintenance of the organic matter contained in the soil. This study serves as the first draft for the paleo-environmental association among the regions where the analyzed profiles are found. [ABSTRACT FROM AUTHOR]

• Multiproxy approach indicates different pedogenesis processes in the soils. • In the Mantiqueira Range at the Espírito Santo State, soils are polygenetic. • Variations in the pedological cover highlight the relationship of the soil formation. • Phytoliths are used as indicators of pedogenesis and paleoenvironmental changes. Soils can preserve numerous proxies that provide highly useful data on ancient climates or environments. In this study we hypothesized that analysis of the pedological cover combining soil phytolith assemblages and pedological, geochemical and isotopic analyses (δ13C and 14C) allows the reconstruction of events associated with the soil-landscape relationship at a toposequence scale. Soil profiles were collected from a toposequence in the upper montane environment of Mantiqueira Range, Espírito Santo State, in the Southeastern region of Brazil. Samples were collected by horizon/layer for pedological and geochemical analysis, and by depth, at 10-cm intervals, for phytolith and carbon (C) isotope (14C and δ13C) analysis. The soils are characterized by high organic matter contents, favored by the cold and humid climate, which is typical of the upland mountainous environments of Mantiqueira Range. The multiproxy approach provided important information about the paleoenvironmental conditions during the pedogenesis process, allowing to establish pedochronostratigraphic correlations, that improved the understanding of soil-landscape relationships in these environments. Soil-preserved phytolith assemblages, isotopic composition (δ13C) and organic matter dating (14C) indicated variations in the type of plant communities in the studied soils, suggesting climatic changes that influenced the soil formation and evolution. The soils experienced different pedogenesis conditions during the Late Holocene, and are, therefore, considered polygenetic soils. In summary, 3 environmental moments were identified by multiproxy analysis: Phase I (before −2330 cal. yr BP), hotter and drier than the current period; Phase II (from −2330 to −2063 cal. yr BP), colder and wetter than the current period; Phase III (after −2063 cal. yr BP), during which the current climate conditions were established. [ABSTRACT FROM AUTHOR]

In addition to being an important reservoir of carbon and water, Histosols are used as archives of palaeoenvironmental changes. This study aimed to reconstruct the evolutionary trajectory of the formation of Histosols in a mountain environment in the State of Espírito Santo, southeastern region of Brazil. This information was used in a multiproxy approach to palaeoenvironmental reconstruction. Our analysis of the profile indicated that the Histosol initially formed in a peatland. Multiproxy records indicate significant environmental changes in the formation of the peatland, which constituted the Histosol parent material. Slope position contributed to the formation of a hydromorphic environment, with low oxygen availability that prevent organic matter degradation. Organic deposits was initially caused by the process of terrestrialization at the beginning of the Late Holocene (~2.814 ± 28 cal BP) in a lacustrine environment, rich in Pediastrum and Botryoccocus colonies. This lacustrine environment would have formed when the climate was colder and humid, which favored the establishment of forested vegetation. The paludization process occurred after the lake filled (~771 ± 24 cal BP), with a transition to warmer weather and more open vegetation, similar to that of today. Applying palaeoenvironmental reconstruction techniques with multiple proxies facilitates the investigation of Histosol genesis. This approach allows results to be obtained beyond those classically used in pedology. • Histosols contain paleoenvironmental records used to evaluate landscapes evolution. • Histosols genesis were studied using palaeoenvironmental reconstruction approaches. • The palynofacies and phytolithic analysis and the isotopic techniques δ13C were used. • Three environmental moments indicating changes during the peatland formation. [ABSTRACT FROM AUTHOR]