The main aim in rehabilitation is to either return theland to a self-sustaining ecosystem or prepare the land for humanuse, i. e. crops, pastures and plantations. Rehabilitation should takeplace at a rate that is significantly higher than natural succession. Several principles are implemented for successful rehabilitation.
Ofthese principles includes the need for preventing disasters andanticipating problems before they arise, if this is taken toconsideration then rehabilitation will be less costly and troublefree. When rehabilitating a site, all the components making up theecosystem need to be looked at individually. They include soil,climate, vegetation, time and animals. These components need tointeract at certain rates in order for the desired effect to beachieved and so might need to be altered. There are otherprinciples of rehabilitation, which will be discussed, in greaterdetail.
There are many methods and strategies involved in rehabilitationwhich, are specific to a site. In this case, surface mine reclamationand farmland will be looked at. A step by step illustration of theprocesses 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 elementsof the ecosystem by conducting surveys of the upper, mid andunder-story species present.
If the aim is to restore the land to itsoriginal ecological balance and to conserve the species present,then further studies should be conducted on the ecology of thenative species, i. e. seed biology of all species. Propagationtechniques and the order of re-establishing species should bestudied.
When rehabilitation work was conducted on the bauxitemines in the southwest of W. A. , special research was conductedon 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 removingtopsoil in summer to ensure maximum seed store this was achievedwhen the forest was cleared after seed set took place. Handseeding was done soon after ripping in order to ensured that theseeds other propagules were well established before germination. When conducting mining operations it is generally desirable thatrehabilitation 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 miningprocess. The topsoil is very important because is contains most ofthe seed, propagules and micro-organisms which are needed forsuccessful revegetation. Topsoil is often treated with fertiliser afterbeing reapplied as it is already nutrient poor and would not be ableto support new plant growth.
A major purpose for rehabilitation isto reduce of soil erosion. This also a problem that occurs duringthe early stage of revegetation. Young seedlings cannot provideenough 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 withother seedlings.
Before replacing soil it is important to ensure thatthe land is reshaped so to resemble the original landscape. Adequate drainage is necessary and can be achieved by deepripping the soil. This also ensures that the soil is not compacted,well aerated and root penetration is better achieved. Beforereturning soil to a site, it should be thoroughly tested for toxicity. It is extremely important to treat affected soil overburden before itis returned.
When the aim of a rehabilitation project is to return theland to a self-sustaining ecosystem, then a sound understandingof the nutrient cycle is required. The least abundant and most limiting nutrients in Australian soilsare phosphorus and nitrogen. Nitrogen is mostly present inorganic matter and is accumulated in the roots of nitrogen fixingplants i. e. legumes.
Most phosphorus can be added as fertiliser. This will aid the initial growth of vegetation but will not sustain theecosystems needs. The addition of mycorrhizal fungi in this casewould be most appropriate. Mine site rehabilitation is probably the most involved of all thetypes.
Before any rehabilitation or research is conducted, it isnecessary that the post-mined land use be agreed upon. It wouldbe at the best interest of the mining company to reduce costs. Asignificant cost reduction strategy is rehabilitating an area in a waythat it would require minimum post-mining management. Thismeans that the area will