Figure legends
Figure 1 Global distribution of S. chamaejasme based on previously published records (Liu, Long & Yao 2004; Wang 2004; Wang & Gilbert 2007; Zhang, Volis & Sun 2010; Zhao et al. 2010), primarily including southern Russia, North Korea, Mongolia, Nepal, and northern and southwestern China.
Figure 2 Plants, flowers, and landscapes of the toxic weed (S. chamaejasme ). (A): plants of S. chamaejasme in an alpine grassland; (B): plants of S. chamaejasme in a typical grassland; (C): S. chamaejasme outside the fence; (D): white flower of S. chamaejasme ; (E): landscape of S. chamaejasmein an alpine grassland; (F): landscape pattern of S. chamaejasmein a desert grassland taken by an unmanned aerial vehicle.
Figure 3 Conceptual graph of the adaptive strategies of toxic weeds for environmental stress (yellow background), competition from other plants (blue background), and animal disturbance (orange background). Fine dotted arrow = impacts of environmental conditions; Thick blue dotted arrow = intraspecific and interspecific relationships; Thick orange dotted arrow = interactions between plant and animals.
Figure 4 The potential ecological effects of toxic weeds on grassland ecosystems (purple background), soil (yellow background), and co-existing plants (green background).
Figure 5 The processes of grassland succession. ① Grassland degrades as a result of climate change and human activities; ② Toxic weeds invade as a consequence of their many adaptations to disturbed environments; ③ Degraded grassland recovers under the protection of toxic weeds from excessive destruction; ④ Livestock and rats destroy degraded grasslands by the excessive removal of toxic weeds; ⑤ The grassland ecosystem collapses and desertification occurs as a consequence of the excessive damage. Red solid arrows indicate the positive feedback loop with toxic weeds. Yellow dotted arrows indicate the negative feedback direction that occurs in the absence of toxic weeds.