Plant–soil interactions maintain biodiversity and functions of tropical forest ecosystems

Abstract

Tropical forests are characterized by high biodiversity and aboveground biomass growing on strongly weathered soils. However, the distribution of plant species and soils are highly variable even within a tropical region. This paper reviews existing and novel knowledge on soil genesis, plant and microbial physiology, and biogeochemistry. Typically, forests in Southeast Asia are dominated by dipterocarps growing on acidic Ultisols from relatively young parent material. In the Neotropics and Africa, forests contain abundant legume trees growing on Oxisols developed in the older parent materials on stable continental shields. In Southeast Asia, the removal of base cations from the surface soil due to leaching and uptake by dipterocarp trees result in intensive acidification and accumulation of exchangeable Al 3+ , which is toxic to most plants. Nutrient mining by ectomycorrhizal fungi and efficient allocation within tree organs can supply phosphorus (P) for reproduction (e.g., mast fruiting) even on P-limited soils. In the Neotropics and Africa, nitrogen (N) fixation by legume trees can ameliorate N or P limitation but excess N can promote acidification through nitrification. Biological weathering [e.g., plant silicon (Si) cycling] and leaching can lead to loss of Si from soil. The resulting accumulation of Al and Fe oxides in Oxisols that can reduce P solubility through sorption and lead to limitation of P relative to N. Thus, geographical variation in geology and plant species drives patterns of soil weathering and niche differentiation at the global scale in tropical forests.

Patterns in Soil Chemical Weathering Related to Topographic Gradients and Vegetation Structure in a High Andean Tropical Ecosystem

“…Vegetation development can be conditioned by rock-derived soil nutrient supply and soil hydrology (Hahm et al, 2014), but in its turn vegetation can adapt itself by modifying the soil physicochemical properties and soil water balance (Amundson et al, 2007;Fujii et al, 2018;Kelly et al, 1998). Enhanced cation leaching by carbonic and organic acids released by the dense and fine root' network in forests (Reich et al, 2005) can play a role in the stronger acidification and lower pool of base cations in forest soils compared to soils covered by cushion plants (Figure 9).…”

Litter Dynamics in Eucalyptus and Native Forest in the Brazilian Cerrado

“…Nutrient cycling in forest ecosystems is controlled primarily by climate, site, abiotic properties (topography, parent material), biotic communities and human activity (harvesting, fertilization) (Fonseca et al, 2018;Fujii et al, 2018;Osborne et al, 2017). In the context of sustainable production and environmental conservation, the maintenance of native forests and forest plantations is of great importance at local and global scale regulation of biogeochemical cycles (Atwell, Wuddivira, & Wilson, 2018;León & Osorio, 2014).…”

Different “metabolomic niches” of the highly diverse tree species of the French Guiana rainforests

“…Numerous mechanisms have been proposed to explain the origin and the maintenance of such high tropical tree species coexistence on local scales 3,4 . Several factors such as soil heterogeneity 2,5 , micro-site singularities 6 , gradients of soil nutrient availability 2,[7][8][9] , patchy distribution of the soil traits 10,11 , slope 12 , heterogeneity of disturbances and regeneration regimes 1 , topography 13 , or the long-term divergence of species-specific defences against herbivores 14 have been identified as promoters of species coexistence and the maintenance of tree diversity in the tropics.…”