Foraging efficiency of fine roots in relation to carbon dynamics in the tropical ecosystems in a changing environment: A synthesis

Abstract

Although fine roots are small-sized (2 mm to 5 mm in diameter) and a short-lived component of a plant, they play a remarkable role in the nutrient cycling in a forest ecosystem. These fine roots sustain plant survival through the acquisition of water and nutrients from the soil. Fine roots are highly dynamic, having a small life span and a frequent turn-over which contribute to significant carbon input to the soil. Despite their importance to the biogeochemical cycling of nutrients, our understanding of fine root biomass, turn-over and dynamics are still impoverished, especially in tropical forests. Therefore, the present chapter is aimed to provide an overview for fine root biomass production, turn-over and their foraging efficiency under different environmental conditions. Fine root dynamics are profoundly influenced by several environmental factors such as seasonality, soil temperature and moisture, nutrient heterogeneity, as well as temporal and spatial variations in measuring techniques. Under nutrient heterogeneity, trees adopt different foraging strategies for resource acquisition through plasticity in morphological and physiological traits of fine roots. The type of plasticity responses varies widely among species and ecosystem types and nutrient patches. Tropical forests are highly sensitive to altered climatic conditions such as CO$_2$ enrichment, and anthropogenic nitrogen deposition. The available evidence indicates that fine root increases under CO$_2$ enrichment, while a negative correlation was observed with N addition in tropical forests. Despite playing a pivotal role in global carbon (C) cycling, the contribution of fine roots to ecosystem C models is poorly represented, probably due to difficulty in quantifying its precise quantity. Therefore, to understand the function and behaviour of tropical forest ecosystems under altered environmental conditions, broadspectrum studies are needed to gain information about fine root dynamics and their nutrient exploration efficiency.

Abhishek Kumar

Senior Research Fellow

My research interests include plant ecology, restoration ecology and soil ecology.