Table 1.

Significant weather variables included in the stepwise regression analysis to explain annual changes in the population index of butterfly species

++ or −−, P < 0.01; + or −, P < 0.05; (+) or (−), P < 0.10; NS (not significant), P > 0.10

F2 Second flight period; NA not applicable

t-1 represents the population index in the previous year as a measure of density dependence; R ² gives the proportion of explained variation by the regression model; % Deviation denotes the mean absolute relative difference between observed and predicted population index values over 4 years of validation

Grey-shaded cells do not apply to the species concerned