However , the population of Pherosphaera fitzgeraldii seems to have been stable over the last fifty years .
In the past hundred years , stream water quality has deteriorated , due to urban sprawl in the Blue Mountains .
The population of Pherosphaera fitzgeraldii seems to have been stable over the last fifty years .
In the past hundred years , stream water quality has deteriorated , due to urban sprawl in the Blue Mountains .