Soil-vegetation relationships and community structure in a "terra-firme"-white-sand vegetation gradient in Viruá National Park, northern Amazon, Brazil

Abstract

Viruá National Park encompasses a vast and complex system of hydromorphic sandy soils covered largely by the white sand vegetation ("Campinarana") ecosystem. The purpose of this study was to investigate a vegetation gradient of "terra-firme"-white sand vegetation at the Viruá National Park. Nine plots representing three physiognomic units were installed for floristic and phytosociological surveys as well as to collect composite soil samples. The data were subjected to assessments of floristic diversity and similarity, phytosociological parameters and to statistical analyses, focused on principal components (PC) and canonical correspondence analysis (CCA). The vegetation of the Campinaranas types and Forest differed in biomass and species density. Ten species, endemic to Brazil, were particularly well-represented. PC and CCA indicated a clear distinction between the studied plots, based on measured soil variables, especially base sum and clay, which were the most differentiating properties between Campinarana and Forest; For the separation of the Campinarana types, the main distinguishing variable was organic matter content and cation exchange capacity. Higher similarity of Campinaranas was associated to a monodominant species and the lower similarity of Forest was related to the high occurrence of locally rare species.

Edaphic Factors and Flooding Periodicity Determining Forest Types in a Topographic Gradient in the Northern Brazilian Amazonia

“…In this same analytical path, the concentrations of the micronutrients observed in the profile of this soil highlight the higher concentration of Fe in the first two layers (0-20 cm and 20-40 cm), being this element the main constituent of the structure of the clays [49]. This chemical characteristic was also observed in the ombrophilous forests of the Viruá National Park [23] suggesting that higher Fe contents in the ombrophilous forests of regions under the influence of treed and forested shade-loving mosaics may be due to the high presence of mineral particles (oxides of iron) derived from the organic matter deposited on the soil in litter form. This indicates that both Fe and the other micronutrients (Zn, Mn, B, Cu) have an important role in the nutrient cycling of this forest environment, but without a clearly defined role as a characterizer of forest types.…”

“…Recent works have demonstrated that the ecosystems which form the mosaic of landscapes in this region present a direct integration between the plant cover and the physical, chemical and biological attributes of the soil [23] due to essential processes related to the biogeochemical cycles, water Table outcrops, accumulation and decomposition of organic matter [16,24]. This is a strong indication that environmental conditions associated with temporal flooding, sediment drag, and nutrient leaching may have high importance in the formatting of different forest types in this peripheral region of the Amazonia [25][26][27].…”

Edaphic and Topographic Factors and their Relationship with Dendrometric Variation of Pinus Taeda L. in a High Altitude Subtropical Climate

“…Understanding the edaphic and topographic influence on forest development is essential for rational management of forest and soil. Studies relating forest development to soil conditions are common for native forests (Zhang et al, 2016;Mendonça et al, 2017;Oberhuber, 2017;Soboleski et al, 2017 ), showing the strict relationship between soil, relief, and forest, and highlighting the importance of studying these relationships at the landscape scale. However, in commercial forests, these relations are not clear, especially in rugged terrain where relationships between the landscape, soil, and plants are more complex.…”

Effect of fire under the soils on the organization of communities of three remnants of Amazonian savannas

“…Canonical correspondence analysis was used to assesses correlations between species distributions among plots and the environment (Ter Braak 1987). In this case, a primary matrix of species was built using the most abundant species in the three remnants (n ≥ 10 individuals; total of 14 species) and a secondary matrix of the variables selected by the PCA, according to the procedure used by Mendonça et al (2017). Abundance was adopted as a criterion to eliminate rare or low abundance species from the analysis since they could generate redundancies among variables (Ter Braak 1987).…”