Ecological Archives E089-041-A1

Jennifer A. Lau, Andrew C. McCall, Kendi F. Davies, John K. McKay, and Jessica W. Wright. 2008. Herbivores and edaphic factors constrain the realized niche of a native plant. Ecology 89:754–762.

Appendix A. Effects of herbivory on the survival of serpentine and non-serpentine ecotypes of Collinsia sparsiflora.

FigA1
 
   FIG. A1. Logistic regression analysis revealed a significant interaction between source population and herbivory on survival probability (chisqr < 11.05, df < 3, P < 0.01), and analyses of each source population independently indicated that herbivory tended to reduce the survival probability of the two serpentine populations (S1 and S3, solid lines) more than the two non-serpentine populations (NS1 and NS2, dashed lines) (logistic regression coefficients: S1: -0.035, chisqr = 54.86, P < 0.0001; S3: -0.020, chisqr = 16.94, P < 0.0001; NS1: -0.009, chisqr = 2.13, P = 0.14; NS2: -0.019, chisqr = 11.58, P = 0.0007). The logistic regression coefficient can be interpreted as a measure of tolerance to herbivory, where more shallow slopes indicate populations that are more tolerant of herbivory and steeper slopes indicated less tolerant populations. While the serpentine populations show higher survival probabilities than non-serpentine populations at low levels of herbivory, their fitness declines more rapidly with increasing herbivory.


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