Figure 1. Implications of intraspecific variation in root
traits for an interspecific Root Economics Space (RES). The graph shows
a conceptual diagram of the interspecific RES with the collaboration
gradient on the x-axis which ranges from species that rely on their own
roots (i.e., the do-it-yourself strategy) to species that depend on
mycorrhizal symbiosis (i.e., the outsourcing strategy) for soil resource
uptake. The y-axis represents the conservation gradient separating
species with root traits that permit poor to strong conservation of
plant resources. These two axes are further explained in the main text.
Each dot with a black outline represents a given species positioned in
the RES depending on its root trait expressions (RD , root
diameter; SRL , specific root length; MF %, mycorrhizal
colonization rate; RN , root nitrogen concentration; RTD ,
root tissue density). Dots with the same color but without the black
outline represent the same species after it shifted positions within the
RES due to intraspecific variation in the corresponding root traits.
Numbers in the graph refer to the hypothesized underlying cause of this
shift further outlined in the main text.