Soil science[1]
tells us that prior to European occupation soil fertility was largely
maintained by the actions of macro and micro-organisms and fungi. The only
known koalas in the Bateman Bioregion[2]
survive in areas of the Five Forests, growing on the erosional Murrah Soil
Landscape that has generally low fertility.
Many of the macro species critical for maintaining soil fertility and
forest health[3], like
pademelons, bettongs and long-footed potoroos, the latter responsible for the
dispersal of various fungal species, are regionally extinct.
“Bega River Soil
Landscape: . . . Channel width in the
Bega River expanded to almost 200 metres in the 50 years following catchment
disturbance. Over 1m of sand now covers large parts of the floodplain (Brooks
1994; 1995) . . . .
Soil Limitations –
Non-cohesive stoney, erodible, highly permeable, infertile soils subject to
flood hazard, permanently high watertables, water (bedload movement) erosion
hazard with ground water pollution hazard, foundation hazard and run-on hazard. Tulau, M. 1997
The loss of species
necessary to maintain soil fertility, soil loss and disturbance from
development meant the irrevocable loss of koala habitat on cleared land.
Similarly, logging and burning has changed the tree species mix in the Five
Forests and preferred koala feed species do not grow back. Rather than
‘maintaining and improving the forests’, degraded soils mean that regrowth
forest is dominated by a species most susceptible to dieback and fire,
Silver-top Ash[4].
“The
loss of population was caused by the loss of koala habitat on the flat, fertile
soils of the district, but the data from koala fur records indicates that the
farmed region is capable of sustaining a high koala population. This is
encouragement for a replanting and restoration program such as on the fertile
soils along the Bega River.” Final NSW koala recovery plan, NSW Department of
Environment and Climate Change, November 2008.
Eleven years after the
first release of soil landscape mapping, such mapping now covers much of the
south-east, but it remains of no interest to the NSW government.
“ In both forested and agricultural lands, principles for sustainable land management will recognise soil as a fundamental and integral part of an ecosystem, identify requirements of the system and deal with them. In so doing, the precautionary principle should be observed – “if there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation (PROTEA 1991).” Tulau, M. 1997
Unfortunately, and
like soil science the precautionary principle is not considered to be a
necessary component of the NSW government’s land management policy.
[1] Tulau, M. 1997: Soil Landscapes of the Bega-Goalen Point 1:100,000
Sheet, Department of Land and Water Conservation
[2] Biolink 2008; A report to the NSW Dept of Enviroment and
Climate Change ; The utility of regularized, grid-based SAT (RGB-SAT) sampling
for the purposes of identifying areas being utilized by koalas (Phascolarctos
cinereus) in the South-east Forests of NSW- a
Pilot Study
[3] National Forest Policy
Statement, 1992: Commonwealth Government, Canberra
[4] Far South Coast Koala
Management Framework, 2007, Ecological Australia Pty Ltd