Ecological Archives E093-157-A5

James O. Eckberg, Brigitte Tenhumberg, and Svata M. Louda. 2012. Insect herbivory and propagule pressure influence Cirsium vulgare invasiveness across the landscape. Ecology 93:1787–1794.

Appendix E (Fig. E1). Observed proportion of Cirsium vulgare subplots (1 m2, N = 666 subplots) with no seedling establishment (failed invasion) at the end of the growing season in relation to propagule input (7 levels) and herbivory treatment (insecticide vs. water only). The means represent eight sites and two annual seed cohorts. Control and insecticide points overlap at seed density 350. Linear regression was performed on the means: seed density (P = 0.006), insecticide (P = 0.009), seed density × insecticide (P = 0.112) and adjusted R2 = 0.653. Line equations (S = seed density): Proportion failed plots (control) = 0.176 - 4.6-4S; proportion failed plots (insecticide) = 0.0387 - 1.3-4S.

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