Pest and weed incursionPest and weed incursion

Pest and weed incursion

The 2019–20 bushfires were followed by three years of above average rainfall which resulted in a significant increase in feral herbivore populations and range expansions for feral pigs and deer. These conditions also resulted in significant growth of perennial weeds within the Wollemi Pine catchment area, including blackberry (Rubus fruticosus agg.), tree of heaven (Ailanthus altissima) and Madeira vine (Anredera cordifolia). While restricted populations of a range of pests and weeds existed within the catchment before 2019, expansion of pest and weed populations following ideal growing conditions requires significantly more effort to manage potential risks.

Previous recovery plans did not identify pest incursion as a threat to the Wollemi Pine. Additionally, changing climate and increased storm severity (per climate change projections) has seen stream bank damage and disturbance that provides ideal growing conditions for a range of weed species that may not have been a threat until recently.

Feral deer and pigs, while not yet detected in the wild stands, are present in the immediate catchment area. These species are vectors for weeds and soil pathogens, and funded control is essential to ensuring populations do not increase significantly and directly impact the Wollemi Pine.