The alien vegetation flourished and did its "job" very effetively, but at a cost. It has totally smothered much of the unique indigenous vegetation of the area, it has become a major fire hazard and has also reduced the level of the water table.
This sunset photo was taken shortly after a fire had swept through the area last year and the stark trees serve as a reminder of the constant threat of devastating fires. The alien invaders burn much hotter and faster than the indigenous vegetation and as a result also destroy a lot of wildlife that would otherwise have survived.
Major projects are now underway to remove the alien invaders. The moral of the story is don't mess with nature.