Open AccessEdaphic Factors and Flooding Periodicity Determining Forest Types in a Topographic Gradient in the Northern Brazilian Amazonia
Author(s) -
Luis Antonio Beltrán Alemán,
R. I. Barbosa,
I. Montero Fernández,
Lidiany Camila da Silva Carvalho,
Paulo Eduardo Barni,
Rodrigo Leonardo Costa de Oliveira,
José Frutuoso do Vale,
Stephen Maldonado,
Nataly Perez
Publication year - 2019
Publication title -
international journal of plant and soil science
Language(s) - English
Resource type - Journals
ISSN - 2320-7035
DOI - 10.9734/ijpss/2019/v28i630127
Subject(s) - edaphic , amazon rainforest , flooding (psychology) , altitude (triangle) , geography , ecology , transect , environmental science , soil water , forestry , hydrology (agriculture) , physical geography , geology , biology , psychology , psychotherapist , geotechnical engineering , geometry , mathematics
The Brazilian Amazonia is a region covered by an extensive mosaic of tropical forests conditioned by different topographical and hydro-edaphic features. Although studies relating environmental determinants of structure and floristic composition are systematically evolving in the region, there is no doubt that there are still information gaps due to the lack of research in peripheric areas of the Amazonia. The seasonally flooded areas of the state of Roraima situated on rio Branco-rio Negro basin, northern Brazilian Amazonia, still are deprived of such information. In this way, this work had as objective determine the physical and soil chemical attributes, and the flooding periodicity that characterize different forest types dispersed in a topographic gradient located in an area on the north of rio Branco-rio Negro basin. Soil samples (0-60 cm) were collected along a 2.7 km transect (31.1-64.8 m a.s.l.) crossing three different forest types: (i) mosaic between treed and forested shade-loving (La+Ld), (ii) area of ecological tension between forested shade-loving and open ombrophilous forest (LO) and (iii) open ombrophilous forest (Ab+As). The results indicated different soil classes and flooding periodicity for each forest type observed: Entisols Fluvents (La+Ld, 3-4 months flooded), Entisols Quartzipsamments (LO, 1-2 months) and Yellow Ultisols (Ab+As, no flooding). All analyzed soils were defined as nutrient-poor areas, especially those located on low altitude, characterized for higher hydrological restrictions (seasonal flooding) aggregating forest types of lower structural patterns (e.g. La+Ld). Soils on low altitude were also characterized as those with the highest percentage of fine sand and silt, while soil free of seasonal flooding (Yellow Ultisols) presented the highest levels of clay and coarse sand, always associated with the ombrophilous forests (higher structural patterns). These results improve our understanding of the environmental factors conditioning different forest types in this peripheral region of Amazonia, suggesting that ecosystems with higher hydro-edaphic restrictions are a strong indicator of forest types with lower structural patterns.