Bell Miner Associated Dieback (BMAD) currently occurs through sclerophyll forests on public and private lands in New South Wales, Victoria and Queensland. These forests are regionally important for plant and animal conservation, water catchment management, tourism and the production of honey and timber. This form of dieback is of national significance as it is spreading through forest ecosystems in eastern Australia.
Eucalypt dieback, strongly associated with sap feeding insects called psyllids, is sometimes associated with the native Bell miner or bellbird (Manoria melanophrys) and has become common in some parts of the bird’s range. Bell miners are a natural part of some eucalypt ecosystems and normally have a functional role similar to other honeyeaters. However, increases in Bell miner populations and their distribution, in addition to other factors such as tree stress, psyllid infestation, dense forest understories, forest structure as well as weed invasion, drought, logging, pasture improvement, soil nutrient changes, frost and changing fire and grazing regimes have all been implicated in the spread of dieback. The outward expression of BMAD is generally characterised by:
Dieback occurs within wet and dry sclerophyll forest communities. The forests most susceptible to dieback are those dominated by Dunn’s white gum (Eucalyptus dunnii), Sydney blue gum (E. saligna), flooded gum (E. grandis), grey ironbark (E. siderophloia), narrow leaved White Mahogany (E. acmenoides), grey gum (E. punctata), and grey ironbark (E. paniculata). There is also evidence that some normally non-susceptible dry sclerophyll types e.g spotted gum (E. maculata) and blackbutt (E. pilularis) may be affected when they occur alongside susceptible forest types.
The potential impacts of BMAD on forest productivity and biodiversity cannot be overstated.
The actual impacts on native species has not been quantified, however the potential impacts on conservation values include: