Response to Comment on “Unexpected reversal of C3 versus C4 grass response to elevated CO2 during a 20-year field experiment”

Wolf and Ziska suggest that soil and species attributes can explain an unexpected 20-year reversal of C 3 -C 4 grass responses to elevated CO 2 . This is consistent with our original interpretation; however, we disagree with the assertion that such explanations somehow render our results irrelevant for questioning a long-standing paradigm of plant response to CO 2 based on C 3 -C 4 differences in photosynthetic pathway.