Core conservation
Breeding programs are bolstering numbats and dibblers, while rangers are on the offensive with dieback.
FOLLOWING EUROPEAN COLONISATION, the flora and fauna of both ranges took a hit. Just half the mammal species identified by early collectors can be found in the Stirling Range today – a result of feral pests, altered fire regimes and land clearing. In a bid to boost populations, endangered numbats and dibblers were reintroduced through breeding programs with Perth Zoo and Western Shield.
Native flora has also fallen victim to the spread of root pathogen Phytophthora cinnamomi, which causes the plant disease known as dieback. “There are huge threats to many of these rare and endemic species,” explains Sarah Barrett, DPAW threatened flora conservation officer. “The effect of dieback on species that were already very rare has seen populations whittled down even more. On top of this there were two fires in close succession, in 1991 and 2000, in the eastern Stirlings and that had a major impact as seed banks of rare plants had not been replenished.”
While the threat from dieback is not as great in the Porongurups, introduced plants are a special challenge, with 113 weeds recorded in the park. The Porongurups’ vegetation communities are in a state of recovery, after a massive 2007 bushfire. The previous year, eight endangered noisy scrub birds had been reintroduced here, but only two survived the blaze.
Fox baiting programs have been carried out in the parks and phosphite spraying in the Stirlings is reducing the impact of dieback.