Figure 2 Radar maps of biodiversity under N addition rates in ICNs (left panel) and TCNs (right panel) from 2008 to 2020. The radius is a measure of biodiversity, and the N addition rate is expressed in shades of colour from red (0 g N m-2year-1) to blue (50 g N m-2year-1). The points represent the average number of species under different N addition rates in each year. The value zero means that the diversity at this time was no longer regulated by the network structure.