Fig. 4

Effects of environmental change on the invasion process of Solidago canadensis. Linear regression models were fitted to determine the effect of invasion degree on growth parameters as well as on the competitiveness of S. canadensis. Data that did not fit a linear regression model (non-linear response to invasion levels) were analyzed using locally estimated scatterplot smoothing (LOESS) regression, and connected by modified Bezier curve. A total of seven environmental treatments were imposed: CK (control), N5 (N addition 5 g m^-2 yr^-1), N12 (N addition 12 g m^-2 yr^-1), T1 (temperature increase of 1.15 °C), T1N5 (combined 1.15 °C temperature increase and N addition of 5 g m^-2 yr^-1), T2 (temperature increase of 1.86 °C) and T2N12 (combined 1.86 °C temperature increase and N addition of 12 g m^-2 yr^-1). Error bars represent the SEs of the means (N=10)