just as birds stop chirping and go into hiding before a storm and ants begin to march before it starts pouring, some plant species can warn of possible environmental damage
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/uprooting-pollution
[2] http://admin.indiaenvironmentportal.org.in/category/author/vibha-varshney
[3] http://admin.indiaenvironmentportal.org.in/category/newspaper/down-earth
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment-impact-assessment-eia
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/plant-diseases
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/research
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/india