Nassella pulchra Survival and Water Relations Depend More on Site Productivity Than on Small-Scale Disturbance

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Address correspondence to J. S. Fehmi, email jfehmi@email.arizona.edu

Abstract

We found no significant effect (p > 0.38) of clipping surrounding non-native annuals on the performance or survival of plantings of the native Nassella pulchra. However, the preplanting productivity of the three sites had a significant effect (p < 0.001) on the demography and water relations of Nassella. Survival was 85% on the lowest productivity site and it decreased by 6% for each additional 100 kg in average aboveground productivity between 2,400 and 3,600 kg/ha. Plants experienced greater water stress in higher productivity sites. Together, these results suggest that the original habitat of N. pulchra may have been in more marginal ecological sites rather than the more fertile soils of the Central Valley.

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