Incidence of ozone symptoms on vegetation within a National Wildlife Refuge in New Jersey, USA

During 1993–1996 and 2001–2003, we evaluated the percentage of plants (incidence) exhibiting ozone-induced foliar symptoms on vegetation within a National Wildlife Refuge located along the Atlantic Ocean coast of New Jersey, USA. Incidence varied among plant species and years. Bioindicator plants most sensitive to ozone, across all years, included native common milkweed ( Asclepias syriaca) and wild grape ( Vitis spp.), as well as introduced tree-of-heaven ( Ailanthus altissima). Less sensitive bioindicators included Virginia creeper ( Parthenocissus quinquefolia) and winged sumac ( Rhus coppolina). Black cherry ( Prunus serotina) and sassafras ( Sassafras albidum) were least sensitive. The greatest incidence of ozone symptoms, across all plant species, occurred in 1996, followed by 2001 > 1995 > 1994 > 1993 > 2003 > 2002. A model was developed that showed a statistically significant relationship between incidence of ozone symptoms and the following parameters: plant species, Palmer Drought Severity Index, and the interaction of W126 × N100 measures of ambient ozone. Vegetation in a National Wildlife Refuge containing a Class I wilderness area exhibits foliar symptoms from ambient ozone.