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.