The relationship between leafy spurge cover, plant species richness and forage production. The relationship between leafy spurge and total species richness are shown for the intensive local survey (a) and the multi-site survey (b). Forage production was assessed for graminoid biomass for the single (c) and multi-site (d) surveys and as graminoid phosphorus content, but only for the multi-site survey. Management actions are colour-coded as per figure legends. There were no significant relationships between leafy spurge abundance and graminoid nitrogen content in either survey (not shown). Leafy spurge abundance was typically assessed as proportional cover, except leafy spurge stem density was a better predictor of graminoid biomass in the single-site survey (c). Plots are partial residual plots and fitted lines show the results of quadratic (a–c) or linear (d–e) regressions with 95% confidence intervals.