A phenotypic plasticity framework for assessing intraspecific variation in arbuscular mycorrhizal fungal traits

Statistical models of ecosystem functioning based on species traits are valuable tools for predicting how nutrient cycling will respond to global change. However, species such as arbuscular mycorrhizal fungi (AMF) have evolved high intraspecific trait variation, making trait characterization and inclusion in functional trait models difficult. We present a five-part framework based on experimental designs from the phenotypic plasticity literature to quantify AMF intraspecific trait variation in a nutrient cycling context. Framework experiments involve exposing AMF replicates to different environmental conditions and recording trait values to quantify the (i) degree of variation, (ii) reversibility of traits, (iii) relationships among traits, (iv) adaptive nature of traits and (v) potential for trait variation to evolve. We include a phenotypic trajectory analysis of a simulated data set to illustrate relationships among traits. To focus future research, we provide a synthesis of AMF traits whose evolution is particularly relevant to nutrient cycling and environmental factors that induce variation in those traits. Synthesis. Characterizing the depth and range of arbuscular mycorrhizal fungal trait variation is essential for predicting responses to natural and anthropogenic environmental changes, as well as understanding past and future fungal trait evolutionary trajectories in the Tree of Life. Characterizing the depth and range of arbuscular mycorrhizal fungal trait variation is essential for predicting responses to natural and anthropogenic environmental changes, as well as understanding past and future fungal trait evolutionary trajectories in the Tree of Life. Here, we present an experimental framework for characterizing arbuscular mycorrhizal fungal trait variation. © 2014 British Ecological Society.