Global Change Impacts on Forest Soils: Linkage Between Soil Biota and Carbon-Nitrogen-Phosphorus Stoichiometry

Nadia I Maaroufi,Jonathan R De Long

doi:10.3389/ffgc.2020.00016

Abstract

Forest ecosystems are subjected to global change drivers worldwide, such as increasing temperature, atmospheric carbon dioxide, nutrient pollution, as well as changes in fire and precipitation regimes. These global change drivers have greatly modified the biogeochemical cycles of carbon (C), nitrogen (N), and phosphorus (P), which has an impact on primary productivity in forest ecosystems and in turn, affect the quality and quantity of resources entering the soil food web. However, C, N, and P soil dynamics have been mostly studied without considering their coupling effects on soil organisms. This is of critical interest because changes in nutrient stoichiometry may have a strong effect on soil biota and the ecosystem functions they drive. Further, most studies have focused on global change effects on bacteria and fungi and their C:N:P stoichiometry, while neglecting other soil organisms at higher trophic levels. This has led to an incomplete understanding of how the entire soil food web drives ecosystem processes involved in organic matter turnover and nutrient cycling. Here, we review studies that investigated how global change drivers impact C:N:P stoichiometry of soil organisms at different trophic levels in forest ecosystems and identify important knowledge gaps. We propose future directions for research on global change impacts on the linkages between soil biota and C:N:P stoichiometry.

Highlights

In forests around the world, soil biota play a critical role in regulating ecosystem processes involved in plant litter decomposition, soil organic matter turnover, and associated nutrient mineralization (Nielsen et al, 2011; Bardgett and van der Putten, 2014)
We provide suggestions for future research that will close critical knowledge gaps in C-N-P coupling in forest soil biota and, thereby, improve our ability to anticipate the implications of global change (GC) drivers in forest ecosystems
Nutrient limitation, N and P, typically varies based on whether northern boreal and temperate forests vs. tropical forests are considered, respectively (Xu et al, 2017). Such contrasts in nutrient limitation are likely to interact differently with increasing global temperatures, which will likely lead to different effects on soil biota stoichiometry that is specific to forest type and latitude

Summary

INTRODUCTION

In forests around the world, soil biota play a critical role in regulating ecosystem processes involved in plant litter decomposition, soil organic matter turnover, and associated nutrient mineralization (Nielsen et al, 2011; Bardgett and van der Putten, 2014). Temperature had contrasting effects on the feeding behavior of the two millipede species, with one species consuming more and the other consuming less leaf litter, which may be due to differences in their metabolic requirements to maintain elemental homeostasis These findings raise more questions than they answer about what species-specific temperature responses might mean in the long-term for nutrient cycling and plant productivity in forests, if the N budget of the entire soil food web were to be considered in tandem. Nutrient limitation, N and P, typically varies based on whether northern boreal and temperate forests vs tropical forests are considered, respectively (Xu et al, 2017) Such contrasts in nutrient limitation are likely to interact differently with increasing global temperatures, which will likely lead to different effects on soil biota stoichiometry that is specific to forest type and latitude

AND FLOODING

Drying and Rewetting Cycles

ELEVATED ATMOSPHERIC CARBON DIOXIDE

CHANGES TO FIRE REGIMES

NUTRIENT ENRICHMENT