Figure legends
Figure 1 Functional group network webs in (a) Ambient, (b) Drought, (c) Nitrogen and (d) Drought * Nitrogen. Blue lines represent trophic interactions; Red lines represent biotic non-trophic interactions; Gray lines represent abiotic non-trophic interactions. The diameter of the circle under ambient is taken as the standard abundance, and the diameter of the circle under treatment changed according to the change of relative abundance (PS: plant suckers; PC: plant chewers; OM: omnivores; DE: detritivores; WS: web spiders; GH: ground hunters; VH: vegetation hunters; PA: parasite; PN: plant N content; EF: environmental factors).
Figure 2 Networks properties (connectance, interaction diversity and interaction strength) for the arthropod functional groups for ambient vs. treatment (including drought, nitrogen and their interaction) for 2 years. The Carnivores (C)-C value refer to network descriptors of the interaction of secondary consumer (a-c, horizontal interactions); C-Herbivores (H), the interaction between primary and secondary consumer (d-f, vertical interaction); H-H, the interaction of primary consumer (g-i, horizontal interactions); Total, the complete web of consumer (j-l).
Figure 3 Interaction strength of environmental factors to arthropod functional groups.
Figure 4 Response ratio of six β-diversity to N addition, drought and their interaction in grassland. The response ratio is data (treatment)/data (control), the horizontal error bars represent the 95% confidence interval. βsor: overall pairwise dissimilarity of S∅rensen, βsim: turnover, βsne: nestedness; βbc: overall pairwise dissimilarity of Bray-Curtis; βbal: balanced variation in abundance; βgra: abundance gradients. Solid squares represent significant response of β-diversity to treatments, while hollow squares represent no significant responses.