Campbell Hill Pioneer Reserve

Toolijooa managed Campbell Hill Pioneer Reserve continuously from 2003 to 2009. Pre-European vegetation within the site consists predominately of Shale Plains Woodland, with small pockets of Cooks River / Castlereagh Ironbark Forest and Alluvial Woodland lining the creek and river banks (Cumberland Plain Vegetation Mapping Project, DEC). All these communities are listed as ‘endangered ecological communities’ under the NSW Threatened Species Conservation Act 1995.

The site is of particular interest because of the variety of techniques being implemented to reinstate local vegetation communities.

Brush-cutters are used extensively throughout this large site and have been highly effective in favouring native perennial grass growth and spread at the expense of exotic annual species. Brush-cutting exotic annual species on a regular basis has facilitated patch dominance of native grasses and forbs, reducing establishment opportunities for exotic annual species and the requirement for regular herbicide applications.

Brush-cutting has also been used as a replacement to herbicides within a heavily exotic annual-dominated area that had historically been managed through herbicide suppression of these species. This management regime facilitated no native species regeneration, resulting in an erosive bare ground area that was being managed solely to suppress exotic annual growth. Following cessation of herbicide applications and replacement of exotic annual suppression by brush-cutting native pioneer species began to colonise the area, followed by colonising native perennial grasses such as Microlaena stipoides and Austrodanthonia tenuior It is possible that overuse of herbicides in the past may have led to a 'sterilisation' effect on the soil. Leaving live plants rooted in the ground facilitated a regeneration of soil flora, carbon and condition, and formed regeneration catchments for colonising native species. The area has subsequently been supplemented by low density native perennial species diversity plantings and has now established close to 50% native cover.

Campbell Hill Pioneer Reserve also contains large areas of cleared ex-agricultural land. Biomass harvesting of heavy exotic perennial grass growth has been initiated over recent years to assist the restoration of these fields. It is hoped that biomass harvesting will gradually reduce soil macro-nutrient levels, disadvantaging exotic annual species in the long-term. Harvesting also provides a duel benefit of assisting in locating native species patches and facilitating treatment of exotic perennial grasses (Briza subaristata, Cynodon dactylon, Eragrostis curvula, Paspalum dilatatum, Pennisetum clandestinum, Sporobolus africanus).

Fire has also played an ongoing role in the natural regeneration of indigenous communities, with arson a regular occurrence within the restoration areas of the reserve. Low intensity patch burns within areas of high exotic species cover have facilitated expansion of native perennial grasses, in particular Microlaena stipoides, Austrodanthonia tenuior and Themeda australis, at the expense of prevalent exotic annual species such as Bidens pilosa, Sida rhombifolia and Setaria gracilis. With the assistance of low level post-burn maintenance weeding burnt patches have generally become dominated by a good diversity of native grass and forb species, often within the period of just one year.

Bridal Creeper Asparagus asparagoides infestations have been significantly reduced through the majority of the reserve over the past 5 years through a combination of herbicide treatment during flowering and prevention of seed set through ripping of above ground material when and where herbicide application was not possible. Campbell Hill Reserve still contains heavy infestations of Bridal Creeper Asparagus asparagoides and Asparagus Fern Asparagus aethiopicus within its northern remnant. Patches of this remnant where these species have been removed are exhibiting excellent native species regeneration and their ongoing removal remains a high priority.