Abstract
Tropospheric ozone (O 3 ) is found to be a severe threat to agriculture and natural vegetation. The present study was conducted to investigate the structural and functional changes in an intact seminatural grassland community when exposed to elevated O 3 (EO 3 ; ambient + 20 parts per billion) compared to ambient O 3 (AO 3 ) for 3 years using open-top chambers. Parameters such as species richness (SR), evenness ( E ), Shannon index ( H ′), β-diversity (BD), concentration of dominance (Cd), similarity index (SI), biomass in canopy layers, and community productivity were evaluated. Species like Cynodon dactylon , Dichanthium annulatum , Parthenium hysterophorus , Digitaria sanguinalis , Cyperus killinga , Oplismenus burmannii , and Commelina benghalensis showed higher importance value index (IVI), whereas Trifolium resupinatum , Desmodium triflorum , Melilotus officinalis , Oxalis corniculata , Eleusine indica , Cyperus rotundus , Malvestrum coromandelianum , and Lindernia anagallis showed lower IVI under EO 3 treatment compared to AO 3 . EO 3 enhanced BD and Cd, whereas SR, E , and H ′ in the community reduced. Biomass accumulation reduced maximally in top layer compared to bottom and middle canopy layers in both forbs and grasses fraction under EO 3 treatment. Higher reduction in total biomass compared to aboveground biomass indicates less carbon allocation toward root system. The results of the present study clearly indicates that 3 years of exposure at EO 3 level caused deleterious impact on grassland community by increasing O 3 -tolerant and decreasing sensitive species, thus resulting in a shift in species composition and community productivity.
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Claims 8
Claim · model-written summary
Seven listed grassland species had higher importance values under elevated ozone.
- Taxon
- Cynodon dactylon
Cynodon dactylone0 - Treatment
- EO 3 treatmente0
- Outcome
- importance value index (IVI)e0
- Direction
- highere0
- Comparator
- AO 3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Species like Cynodon dactylon , Dichanthium annulatum , Parthenium hysterophorus , Digitaria sanguinalis , Cyperus killinga , Oplismenus burmannii , and Commelina benghalensis showed higher importance value index (IVI), whereas Trifolium resupinatum , Desmodium triflorum , Melilotus officinalis , Oxalis corniculata , Eleusine indica , Cyperus rotundus , Malvestrum coromandelianum , and Lindernia anagallis showed lower IVI under EO 3 treatment compared to AO 3”
Claim · model-written summary
Eight listed grassland species had lower importance values under elevated ozone.
- Taxon
- Trifolium resupinatum
Trifolium resupinatume0 - Treatment
- EO 3 treatmente0
- Outcome
- IVIe0
- Direction
- lowere0
- Comparator
- AO 3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Trifolium resupinatum , Desmodium triflorum , Melilotus officinalis , Oxalis corniculata , Eleusine indica , Cyperus rotundus , Malvestrum coromandelianum , and Lindernia anagallis showed lower IVI under EO 3 treatment compared to AO 3”
Claim · model-written summary
Elevated ozone enhanced beta diversity and concentration of dominance.
Not reportedComparator
Verbatim
e0“EO 3 enhanced BD and Cd, whereas SR, E , and H ′ in the community reduced”
Claim · model-written summary
Elevated ozone reduced species richness, evenness and Shannon index.
Not reportedComparator
Verbatim
e0“EO 3 enhanced BD and Cd, whereas SR, E , and H ′ in the community reduced”
Claim · model-written summary
Elevated ozone reduced biomass accumulation most in the top canopy layer.
Verbatim
e0“Biomass accumulation reduced maximally in top layer compared to bottom and middle canopy layers in both forbs and grasses fraction under EO 3 treatment”
Claim · model-written summary
Total biomass declined more than aboveground biomass under elevated ozone.
Not reportedTreatment
Verbatim
e0“Higher reduction in total biomass compared to aboveground biomass indicates less carbon allocation toward root system”
Claim · model-written summary
The authors infer less carbon allocation to roots from the relative biomass declines.
Verbatim
e0“Higher reduction in total biomass compared to aboveground biomass indicates less carbon allocation toward root system”
Claim · model-written summary
Three years of elevated ozone shifted grassland species composition toward tolerant species and away from sensitive species.
- Taxon
- grassland communitye0
- Treatment
- 3 years of exposure at EO 3 levele0
- Outcome
- species composition and community productivitye0
- Direction
- a shifte0
Not reportedComparator
Verbatim
e0“3 years of exposure at EO 3 level caused deleterious impact on grassland community by increasing O 3 -tolerant and decreasing sensitive species, thus resulting in a shift in species composition and community productivity”