Data from: A growth-defense trade-off is general across native and exotic grasses

High-resource environments typically favor quick-growing, poorly-defended
plants, while resource-poor environments typically favor slow-growing,
well-defended plants. The prevailing hypothesis explaining this pattern
states that, as resource availability increases, well-defended,
slow-growing species are replaced by poorly defended, fast-growing
species. A second hypothesis states that greater resource availability
increases allocation to growth at the expense of defense, within species.
Regardless of mechanism, if exotic species are released from enemies
relative to natives, shifts in allocation to growth and defense both
within and among species could differ by geographic provenance. To test
whether resource availability alters growth or defense, within and among
species, and whether any such effects differ between natives and exotics,
we manipulated soil nutrient supply and access of aboveground insect
herbivores and fungal pathogens under field conditions to individuals of
six native and six exotic grass species that co-occurred in a North
Carolina old field. The prevailing hypothesis’ prediction—that
species-level enemy impact increases with species’ nutrient
responsiveness—was confirmed. Moreover, this relationship did not differ
between native and exotic species. The second hypothesis’ prediction—that
individual-level enemy impact increases with nutrient supply, after
accounting for species-level variation in performance—was not supported.
Together, these results support the idea, across native and exotic
species, that plant species turnover is the primary mechanism underlying
effects of nutrient enrichment on allocation to growth and defense in
plant communities.