Establishment of native grassland vegetation at Organ Pipes National Park near Melbourne, Victoria: Vegetation changes from 1989 to 2003

Abstract

Summary Native grassland establishment works undertaken on former agricultural land at Organ Pipes National Park, Victoria, during the 1980s were monitored from 1989 to 2003 to assess whether re‐introduced native plant populations had established and persisted at the site. Trends in vegetation were determined by examining the composition and cover of native and weed species in permanent transects at 2‐year intervals. The average number of native and weed species in plots changed little over 15 years, although weed species richness exhibited great variability. Of the 85 native species introduced to the grassland by seed, sods and tubestock, 33 were still present in 2003. The dominant native species, Kangaroo Grass (Themeda triandra), the native intertussock spear grasses (Austrostipa spp.), and the nationally endangered Large‐headed Groundsel (Senecio macrocarpus), have become common elements of the grassland but most other native species remain minor components. The cover of native and weed species has fluctuated dramatically over the study period in response to fire and drought. While the site remains largely weedy, the project has served to introduce native species into a secure reserve. It is clear that on‐going management (weed control, fire) and supplemental plantings will be necessary to maintain and expand the native species populations in the re‐established grassland.