Figure 4. Observed yield (D_max) of different components of particle reworking, burrow geometry and bioirrigation behaviour for species mixtures relative to species monocultures with equivalent biomass.

The observed yield indicates whether a species mixture outperforms (overyielding, D_max > 0) or underperforms (underyielding, D_max < 0) relative to the maximally performing species in monoculture, and provides an indication of how species interactions may influence species contributions to ecosystem process.