The Ecological Effects of Ozone Exposure on Upland Semi-Natural Vegetation of the Yorkshire Dales National Park

Tropospheric ozone is a pollutant which has been shown to cause significant effects on crop species, but its impact on semi-natural vegetation remains uncertain. This study aimed to evaiuate the impact of ozone on communities of conservation importance within one area of the UK - the Yorkshire Dales National Park; an upland area was selected because ozone exposure in upland areas is predicted to be higher and increase more rapidly than in lowland areas. Individual plant species and woodland mesocosms taken from the study area were exposed to ozone under controlled environmental conditions. The results suggest that species and ecotypes of limestone communities were relatively insensitive to ozone, but that characteristic species of woodland ground flora communities could be adversely affected. The study also identified subtle morphological changes in grassland species and a greater impact on root compared with shoot biomass. The results highlight adverse effects on ecological fitness caused by ozone exposure and the results are placed in the wider context of woodland ecology. Keywords: ozone, woodlands, uplands, mesocosms, conservation, ground flora.