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Plant re-colonisation
Seeds and spores naturally disperse into rehabilitated areas. However, Alcoa designs its rehabilitation practices to facilitate this happening as soon as possible.  For example, roads and tracks around the edge of rehabilitated areas can act as barriers to plant and animal dispersion so these are removed during the rehabilitation process.
 
Animals are important natural dispersers of many plant seeds and fungal spores. For example, fleshy-fruited jarrah forest plants are eaten by animals and then deposited into rehabilitated pits. Emus are the most prolific dispersers of seeds because they can eat large amounts of fleshy fruited seeds and travel long distances.  Encouraging animals into rehabilitated areas therefore speeds up the return of these types of plants.  During the rehabilitation process, after the topsoil has been returned, wood debris and rocks are returned to the areas as small heaps and as scattered individual pieces to provide nesting and shelter for animals. See the Fauna Return Management section for more information.
 
Some plant species are naturally introduced early into rehabilitated areas by animal dispersal methods. Others, in particular orchids, are only found in more mature rehabilitated areas (older than five years), despite having seed as small as dust which is easily spread by the wind.  This is because orchids have a symbiotic relationship with a particular fungus, and therefore this fungus needs to be present in the soil for orchids to survive and grow. This fungus is only present in rehabilitated areas when substantial leaf litter has accumulated on the ground, which in turn depends on the growth of the vegetation.
 

After eating seed in surrounding forest the emu tr

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After eating seed in surrounding forest the emu spreads the seed by depositing it later in rehabilitated areas. This is Leucopogon nutans seed germinating from an emu dropping.

Cakadenia Flava orchid

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Orchids such as Caladenia flava have a special relationship with certain fungi.