Protecting a threatened species unique to our region
Tablelands Telegraph - April 2021
In December 2019, the large Gosper's Mountain bushfire threatened the township of Lithgow and burnt nine of the twenty-one known Purple Copper Butterfly sites in the Lithgow area.
While previous studies have indicated that appropriately timed low intensity fire can benefit the Purple Copper Butterfly by rejuvenating the caterpillars food plant, blackthorn (Bursaria spinosa ssp lasiophylla), we were very concerned that the Gosper's Mountain fire could have had a detrimental impact on the butterfly, if caterpillars had not yet retreated underground as pupae, which usually occurs in December/January. We were also uncertain if the high intensity bushfire could have impacted on the pupae by heating the soil they are sheltered in.
So it was with some trepidation that we started the site inspections during the flying season (September-October). Thanks to the plentiful rain over autumn and winter, the blackthorn was regenerating, presenting an abundance of fresh green foliage, and at most of the sites, small numbers of the Purple Copper were observed fluttering about! Sometimes it was just one or two, however, one large site had been burnt in a mosaic, and large numbers of butterflies were observed in both burnt and unburnt sections of the site. As the butterflies start to take advantage of the rejuvenated habitat, an increase population over the next few years is expected at this site.
Fire and the following wet autumn and spring have also created great conditions for many weeds, including those that can impact on the quality of butterfly habitat. We observed significant growth of blackberry which is encroaching and deteriorating the butterfly's habitat.
To ensure that weeds do not continue to impact on the post-fire recovery of the butterfly's habitat, a number of organisations have banded together to tackle the weeds and rehabilitate the habitat. Lithgow Oberon Landcare Association, Department of Planning, Industry and Environment's Biodiversity and Conservation Division, and Lithgow Council are working with us on 11 sites to ensure the Purple Copper Butterfly can make the best possible recovery.
Working with threatened species can be disheartening work sometimes, but when enthusiastic partners get together, the outcomes can only be positive.
