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Fire as a tool for maintaining diversity and
influencing vegetation structure
The managementof GGRP sites
1. Protection of life
2. Protection of assets
Biomass reduction
Weed control
Biodiversity attributes
Cultural connections
Why do we burn?
Roadside burns in western Victoria maintain strategic fire breaks for human and asset protection
Burns also play an important role in preserving remnant roadside communities
Ground layer Fire response in remnant vegetation
Why do we burn GGRP sites?
• Reduce biomass and inhibit grassy dominants• Restrict undesired tree regrowth• Rejuvenate vegetation (grasses and forbs)• Allow for persistence of sub-dominants (forbs)• Maintain canopy gaps for recruitment• Cost (?)• Ease (?)• Effectiveness (?)• Competing objectives (?)
Restricting biomass and opening grassy canopy
Grass dropping seed into gaps after fire
Restricting tree regrowth
Rejuvenating vegetation
Allowing sub-dominants to persist
Opening niches for species to move to in adjoining vegetation
Issues with fire in current-day Australia
Can these goals be achieved by other means?
• Cut and bale• Slashing• Grazing
– Deferred– Rotational
• Herbicides• Combinations of the above
Grazing• Grazing can be effective in maintaining or increasing native
cover in semi-natural grasslands, but as a management tool requires good stock management skills
• Deferred (short or long term) or rotational grazing aims to graze pasture intensively (crash or cell grazing) at the point where annual grasses have raised (but not ripened) seed heads (early spring), and then remove stock over summer when natives are setting and dropping seed
• Conversely, set-stocking has been shown to have negative effects including selective grazing of native herbs, trampling, soil compaction, importation of weed seed, localised deposition and return to the soil of dung and urine
Mowing/baling
• Slashing/mowing of grass biomass (native and exotic) on public roads is a common practice due to the ready access of machinery and relatively low cost
• In native grasslands mowing is ideally followed by raking and baling to remove fallen biomass as herbage can return unwanted nutrients to soils, smother vegetation or restrict seedling recruitment
• Mowing and baling of built up grass canopy (autumn through winter) can reduce competition on wildflower species and provide recruitment gaps for seedlings
• Drawbacks of mowing include the possible introduction of weed seeds on equipment, soil compaction, and physical damage to plant structure by the tires of mowing equipment
Cut & Baling
Seed Hay
GGRP burns
Burn cues – > 70% vegetative cover
Burn cues – Dry material above 150 mm
Chepstowe
Patch burns
Hamilton
Is burning always best?
Probably not always but it is a very effective tool for grassland management in many situations