Western Australian Species-Rich Kwongan (Sclerophyllous Shrubland) Affected by Drought

Abstract

Observations of responses to aseasonal water stress are reported for 238 above-ground perennial species of native vascular plants in a 20 km² area of Western Australia surveyed during the second consecutive year of below average rainfall. Eighty-six species (36%) were found with dead individuals. Both vegetative regeneration and seedling regeneration appeared to be successful means of surviving drought stress in this region. The drought affected species of the families Proteaceae and Epacridaceae more than those of other major families. There are similarities in the response of the vegetation to the two main, irregularly occurring phenomena, aseasonal drought and fire: both can affect vegetation over large areas and yet leave considerable patches within the area that are little affected. Together these two factors contribute to the production of complex and dynamic mosaic-patterns in the vegetation.