Root traits and functioning: from individual plants to ecosystems

Root traits and functioning: from individual plants to ecosystemsFine roots, the most distal portions of the root system, are responsible for the uptake of water and nutrients by plants, represent the main type of plant tissue contributing to soil organic matter accrual, and are key drivers of mineral weathering and soil microbial dynamics (Bardgett et al. 2014). Despite the overwhelming importance of fine root traits for plant and plant community functioning and biogeochemical cycles, basic information about their ecology is lacking, particularly compared to the wealth of information developed for leaves and stems. Testing hypotheses on how root traits underlie these ecosystem processes has been particularly hampered due to (1) a paucity of systematically collected data and (2) the complexity of the relationships between root traits and root, plant and ecosystem functioning. Nonetheless, the development of the field of root ecology in the last two decades has been outstanding, in particular in the compilation of belowground trait datasets (Iversen et al. 2017), methodological root ecological handbooks (Freschet et al. 2021b), novel conceptual frameworks to describe root trait diversity (Bergmann et al. 2020), its connection with belowground plant and community function (Bardgett et al. 2014, Freschet et al. 2021a), species’ distributions (Laughlin et al. 2021), and scaling up traits from the individual root to the ecosystem level (McCormack et al. 2017). The papers that feature in this Special Issue on Root traits and functioning: from individual plants to ecosystems cover different climate regions, taxonomic and spatial scales, and a diversity of traits (Table 1) and form perfect examples of this upward moment of the belowground component in plant ecology.