Landcare Revegetation

Rehabilitation is the process of reclaiming land for economical or
conservation purposes. This process usually involves
re-vegetation. The main aim in rehabilitation is to either return the
land to a self-sustaining ecosystem or prepare the land for human
use, i.e. crops, pastures and plantations. Rehabilitation should take
place at a rate that is significantly higher than natural succession.
Several principles are implemented for successful rehabilitation. Of
these principles includes the need for preventing disasters and
anticipating problems before they arise, if this is taken to
consideration then rehabilitation will be less costly and trouble
free. When rehabilitating a site, all the components making up the
ecosystem need to be looked at individually. They include soil,
climate, vegetation, time and animals. These components need to
interact at certain rates in order for the desired effect to be
achieved and so might need to be altered. There are other
principles of rehabilitation, which will be discussed, in greater
detail.

There are many methods and strategies involved in rehabilitation
which, are specific to a site. In this case, surface mine reclamation
and farmland will be looked at. A step by step illustration of the
processes involved will be covered. When rehabilitating mine land,
it is important to first prepare a plan before mining takes place.
Researching and obtaining data on the floral and faunal elements
of the ecosystem by conducting surveys of the upper, mid and
under-story species present. If the aim is to restore the land to its
original ecological balance and to conserve the species present,
then further studies should be conducted on the ecology of the
native species, i.e. seed biology of all species. Propagation
techniques and the order of re-establishing species should be
studied. When rehabilitation work was conducted on the bauxite
mines in the southwest of W.A., special research was conducted
on the germination requirements of sown seed.

The aim in this case was to re-establish a self-sustaining forest,
which maintains water, timber and all the valued qualities of forest.
The timing component was carefully considered when removing
topsoil in summer to ensure maximum seed store this was achieved
when the forest was cleared after seed set took place. Hand
seeding was done soon after ripping in order to ensured that the
seeds other propagules were well established before germination.
When conducting mining operations it is generally desirable that
rehabilitation work takes place at the same rate as mining occurs.

The soil component in this case needs to be removed in layers
(topsoil and overburden) and stock piled during the mining
process. The topsoil is very important because is contains most of
the seed, propagules and micro-organisms which are needed for
successful revegetation. Topsoil is often treated with fertiliser after
being reapplied as it is already nutrient poor and would not be able
to support new plant growth. A major purpose for rehabilitation is
to reduce of soil erosion. This also a problem that occurs during
the early stage of revegetation. Young seedlings cannot provide
enough protection for the soil as wind and rain move soil particles.
It would also be unwise to plant too many small shrubs, i.e.
legumes to help combat the problem as they will compete with
other seedlings. Before replacing soil it is important to ensure that
the land is reshaped so to resemble the original landscape.
Adequate drainage is necessary and can be achieved by deep
ripping the soil. This also ensures that the soil is not compacted,
well aerated and root penetration is better achieved. Before
returning soil to a site, it should be thoroughly tested for toxicity.
It is extremely important to treat affected soil overburden before it
is returned. When the aim of a rehabilitation project is to return the
land to a self-sustaining ecosystem, then a sound understanding
of the nutrient cycle is required.

The least abundant and most limiting nutrients in Australian soils
are phosphorus and nitrogen. Nitrogen is mostly present in
organic matter and is accumulated in the roots of nitrogen fixing
plants i.e. legumes. Most phosphorus can be added as fertiliser.
This will aid the initial growth of vegetation but will not sustain the
ecosystem’s needs. The addition of mycorrhizal fungi in this case
would be most appropriate.

Mine site rehabilitation is probably the most involved of all the
types. Before any rehabilitation or research is conducted, it is
necessary that the post-mined land use be agreed upon. It would
be at the best interest of the mining company to reduce costs. A
significant cost reduction strategy is rehabilitating an area in a way
that it would require minimum post-mining management. This
means that the area will have to be self-sustaining environment.
Management can be time consuming and very expensive