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at Oriners recently, including Sicklepod (Senna obtusifolia), Grader grass (Themeda
quadrivalis) and other unidentified burr species. Neldner et al. (1997) noted that Sicklepod
was the most serious exotic weed threatening grassland communities on Cape York, while
Grader grass was also rapidly invading roadsides and other areas disturbed by clearing or
overgrazing.
It is most likely that increased vehicle traffic associated with station access, pig hunting, new
road construction, road maintenance and grading, and tourism have increased the spread of
weeds onto Oriners and Sefton Stations. For example, at Oriners Station observations of
Sicklepod, Grader grass, and other herbaceous weeds immediately around the homestead
have been brought in by vehicles and equipment used by both Indigenous and European
people. New weeds have also been recently observed along the newly bulldozed and
enlarged road through Oriners. Additional weed dispersal also can occur down river and
stream channels from upstream source areas, especially during flood. Feral animals such as
pig and wild cattle are also known to spread weed species across Cape York.
Undoubtable, the new road and increased traffic through Oriners generally means that
weeds may require more significant management action in the future to prevent invasion and
spread. Local weed surveys on Oriners and Sefton Stations are critically needed to plan for
future management and address critical weed hotspots.
3.3.4 Fire timing, frequency, and distribution
Fire regimes are defined by the magnitude, frequency, duration, timing, and spatial patterns
of fires through vegetation of grasslands and woodlands. Since European settlement and the
introduction of cattle grazing on Cape York, traditional Indigenous fire regimes have been
replaced by regimes that are tailored toward the production of cattle (Crowley 1995; Neldner,
Stanton et al. 1997; Crowley and Garnett 1998; Crowley and Garnett 2000). These regimes
either reduce fire frequency by restricting burning, focus on burning fire breaks in the earlydry
season to protect remaining feed and control cattle movement, and/or burn in the earlywet
season (storm burns) to clear out old vegetation and residual weed biomass (Crowley
1995; Crowley and Garnett 2000) . These fire regimes are different than those traditionally
used by Indigenous people of Cape York, who utilized fire year round in a mosaic pattern
across the landscape for game and vegetation management, but focused their fire burning
efforts across large areas in the early dry season or winter periods (Fensham 1997; Crowley
and Garnett 2000).
On nearby cattle stations to the east of Oriners and Sefton (Artemis, Dixie, Musgrave, etc.)
on central Cape York, Crowley and Garnett (Crowley and Garnett 1998; Crowley and Garnett
2000) documented that changes in fire regimes or reduced burning between the 1960s and
1990s resulted in woodland thickening as Melaleuca viridiflora (ti-tree) invaded previously
open grasslands of wet meadows. Cattle grazing also shifted the dominance of grass
species from preferred kangaroo grass (Themeda triandra) to black spear grass
(Heteropogon contortus), along with other changes to preferred native grasses and invasion
of exotic grasses and weeds. The combined influence of fire regime changes and intensive
grazing pressure on grass species dominance and fuel load resulted in a net reduction
grassland area by 10% between the 1960s and 1990s. The degree that similar changes have
occurred at Oriners and Sefton is unknown, but both currently and historically cattle numbers
were less on Oriners and Sefton compared to stations further east and west.
At Oriners and Sefton Stations, the current fire regime for the last 15 years has been
dominated by frequent fires at least every other year (Figure 75) and hot late-dry season fires
between September and December (Figure 76). The ignition source of these fires is
unknown, but many appear to be unmanaged fires from either lightening strikes in the latedry
season onto high fuel loads in largely un-grazed county, or fires mistakenly or
deliberately lit by people living or travelling through the area for various reasons (e.g., pig
hunters). This area is somewhat anomalous compared to the rest of Cape York, where fire is
managed more intensively in the late-dry season to eliminate fire completely or control fire
using fire breaks or grazing management of fuel loads. Undoubtedly this fire regime is
different than a traditional Indigenous regime that would have utilized early-dry season fires
Working Knowledge at Oriners Station, Cape York
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