Pathogen sharing between native and exotic plants correlates with
exotic plant impact
When comparing the change in proportional plant biomass from what was
originally planted to what was realized in plant communities, native
plants were 40% lower in proportional biomass at the end of the
experiment than at initial planting, whereas exotic plants were 60%
larger, on average. Native plant performance (relative interaction
intensity index, RII) decreased as the proportion of pathogens shared
between native and exotic plants increased (χ2=5.72,
p<0.02, Fig. 4A). In fact, the proportional native plant
biomass from the beginning to the end of the experiment was consistently
reduced in every community where exotic plants shared 30% or more of
their pathogens with them (Fig. 4A). In contrast, the correlation
between pathogen sharing and exotic plant success was not significant
(Fig. 4B); rather, exotic plants made up a greater proportion of
community biomass compared to that which they were planted in nearly
every community where they grew.