||Black Hill Conservation Park contains vegetation associations of excellent quality (indicative of pre-European Mount Lofty Ranges vegetation) and of degraded and modified land. Land clearance, logging, development of market gardens, orchards, grazing, quarrying and residential development resulted in widespread pest plant invasion and loss of species diversity within the Mount Lofty Ranges. The Vegetation Management Plan for Black Hill Conservation Park (Paul 2001) identifies 309 native species, 79 of which have rated conservation significance. The plan also identifies 81 pest plant species. Units 1, 2, 3 and 4 in the Torrens Gorge area of the Park, are identified as areas of relatively high priority due to the presence of species and vegetation associations of rated conservation significance, their uniqueness and integrity and the threats to plant species and associations. The Vegetation Management Plan for Black Hill Conservation Park indicates management units 1, 2 and 3 have an association of Allocasuarina verticillata over Trymalium wayae and Melaleuca lanceolata. This is the only occurrence of its type in the Mount Lofty Ranges. An association of Eucalyptus porosa, Eucalyptus leucoxylon, Eucalyptus camaldulensis woodland over native and exotic grasses and herbs is in the Torrens Gorge area, near the Main Ridge Track. Despite past pressures of grazing and clearing with invasion of exotic grasses and woody weeds, native understorey species survive in patches throughout the community. According to Neagle (1992) Eucalyptus porosa woodlands have a high conservation status (priority 5 poorly conserved or not conserved interstate or only in South Australia). Significant plant species include Logania saxitilis, Phyllanthus saxosus, Cymbopogon ambiguus and Cymbopogon obtectus. In terms of understorey species, Unit 1 has 10 species of rated conservation significance, Unit 2 contains 13 species of rated conservation significance and Unit 3 contains 6 species of rated conservation significance.