Elevated Ozone Negatively Affects the Community Characteristics and Productivity of Subtropical Grassland in India

Tropospheric ozone (O 3 ) is found to be a severe threat agriculture and natural vegetation. The present study was conducted investigate the structural functional changes in an intact seminatural grassland community when exposed elevated O (EO ; ambient + 20 parts per billion) compared (AO for years using open-top chambers. Parameters such as species richness (SR), evenness ( E ), Shannon index H ′), β-diversity (BD), concentration of dominance (Cd), similarity (SI), biomass canopy layers, productivity were evaluated. Species like Cynodon dactylon , Dichanthium annulatum Parthenium hysterophorus Digitaria sanguinalis Cyperus killinga Oplismenus burmannii Commelina benghalensis showed higher importance value (IVI), whereas Trifolium resupinatum Desmodium triflorum Melilotus officinalis Oxalis corniculata Eleusine indica rotundus Malvestrum coromandelianum Lindernia anagallis lower IVI under EO treatment AO . enhanced BD Cd, SR, ′ reduced. Biomass accumulation reduced maximally top layer bottom middle layers both forbs grasses fraction treatment. Higher reduction total aboveground indicates less carbon allocation toward root system. results clearly that exposure at level caused deleterious impact on by increasing -tolerant decreasing sensitive species, thus resulting shift composition productivity.