Trait differences between exotic and native species within a long-grazed temperate grassland on the Northern Tablelands of New South Wales

Stepwise discriminant function analysis was used to compare the morphological traits of 15 exotic and 35 native herbaceous species occuring within an area of long-grazed grassland on the Northern Tablelands of New South Wales. Exotic graminoids were shorter, had less persistent litter and a shorter flowering period than native graminoids. Exotic forbs had deeper leaf litter and a longer flowering period than native forbs. Most exotic forbs had a rosette or a prostrate habit, with oblanceolate or lanceolate leaves, and undefined dispersal or pappus. For graminoids, trait differences reflected the predominance of the annual life-history within exotics, while differences between exotic and native forbs were realted to habit. There were two main groups of exotics at the site: (i) annual graminoids and (ii) forbs with a rosette or prostrate habit. Exotics possessing low growing habits and mechanisms to either avoid or tolerate nutrient and moisture stress were able to invade and persist under the grazed resource-poor conditions investigated in this study.