title: Within season and carry-over effects following exposure of grassland species mixtures to increasing background ozone.
abstract: Few studies have investigated effects of increased background ozone in the absence of episodic peaks, despite a predicted increase throughout the northern hemisphere over the coming decades. In this study Leontodon hispidus was grown with Anthoxanthum odoratum or Dactylis glomerata and exposed in the UK to one of eight background ozone concentrations for 20 weeks in solardomes. Seasonal mean ozone concentrations ranged from 21.4 to 102.5 ppb. Ozone-induced senescence of L. hispidus was enhanced when grown with the more open canopy of A. odoratum compared to the denser growing D. glomerata. There was increased cover with increasing ozone exposure for both A. odoratum and D. glomerata, which resulted in an increase in the grass:Leontodon cover ratio in both community types. Carry-over effects of the ozone exposure were observed, including delayed winter die-back of L. hispidus and acceleration in the progression from flowers to seed-heads in the year following ozone exposure.
authors.affiliation: Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK. fhay@ceh.ac.uk
authors.forename: Felicity
authors.initials: F
authors.lastname: Hayes
authors.forename: Gina
authors.initials: G
authors.lastname: Mills
authors.forename: Harry
authors.initials: H
authors.lastname: Harmens
authors.forename: Kirsten
authors.initials: K
authors.lastname: Wyness
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D019659:Asteraceae / Q000187:drug effects / Q000254:growth & development; D044822:Biodiversity; D004305:Dose-Response Relationship, Drug; D010126:Ozone / Q000633:toxicity*; D006109:Poaceae / Q000187:drug effects* / Q000254:growth & development; D012621:Seasons
chemical_list: D000393:Air Pollutants; D010126:Ozone