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Why short tussock grasslands are highly predisposed to vegetation change
At a Conservation Workshop held in September 1996, Dr Rose presented information on the susceptability of short tussock grasslands to vegetation change and weed invasion. Reasons given for them being predisposed to invasion by Hieracium or woody species were:
- They occur in an environment which is also suited to many exotic grassland and woody species.
- Short tussock grasslands have had a long history of disturbance, which has created a vegetation with low resistance to invasion in terms of its vegetation structure and composition
- Present day disturbance has little influence on the rate and extent of spread of Hieracium.
- Low rates of disturbance will encourage invasion by native woody species and snow tussocks
- The long history of disturbance has created a vegetation cover with low resistance to invasion. These attributes include:
- short vegetation
- low canopy cover
- abundant canopy gaps
- abundant establishment sites, including bare ground and low growing intertussock species
- The following attributes promote weed seedling establishment:
- the tussock microclimate
- shallow layer of litter
- Tussocks are poorly adapted to the impacts of grazing, trampling or burning.
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