Importance of Australian butterflies

There are 400 species of butterfly in Australia, 50% of which are endemic (found nowhere else in the world). In Victoria there are 130 species

There are five families of Butterflies in Australia, one of which is the Blue Butterfly family (Lycaenidae). Eltham Copper Butterflies (ECB) are a member of the Blue family, of which there are 41 species in Victoria.

‘Many of Australia’s butterflies are unique and provide crucial understanding of the origin and evolution of the worlds Butterflies’ (Braby, 2004).

ECB are a flagship species which represents the complexity of our environment and the importance of protecting remnants. They represent an increasingly long list of precious species which are hanging on by a thread in a fragmented landscape. 66% of Victoria’s forests and woodlands have been cleared and the scattered remnants that remain frequently contain rare species. By protecting the small percentage of remnants that are left, you are preserving the rare and threatened plants and animals that live within them. As ECB have complex ecological interconnections they are ‘indicators for maintaining ecosystem health’ (Braby 2004).

Conservation status

The Eltham Copper Butterfly (Paralucia pyrodiscus lucida) was listed as nationally endangered under The Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) in 2016. ECB is also listed as threatened under the Victorian Flora and Fauna Guarantee Act 1988.

Although there are several known populations around the state, the future of this special butterfly remains uncertain. This places considerable importance on managing the small number of known population sites and locating any potential new sites so they can be protected from threats.

There is no Action Plan to guide the management of ECB however there is ‘DOE (2016) Conservation Advice Paralucia pyrodiscus lucida Eltham copper, which provides some management and research priorities.

Eltham Copper Butterflies are one of twenty Victorian butterflies are listed under the Victorian Advisory list for threatened invertebrates (DSE 2009): 3 are extinct, 3 are critically endangered, 6 are Endangered (including ECB) and 8 are vulnerable.

Across the three regions in which ECB occur, they are at various levels of conservation risk. Each region has different threats, different population sizes and different levels of connectedness to their neighbouring colonies in order to be able to exchange genetic material and disperse/adapt. ‘Land clearing, planned burning, grazing and weed invasion are the main threats to this species.

At a regional level ECB are most secure in North Central Victoria where thirteen small colonies occur within National Parks managed by Parks Victoria or other government managed land. In these areas it is believed they exist as a metapopulation, that is in a number of small colonies peppered through an area which are able to move between small patches and exchange genetic material. Most of these North Central ECB colonies despite being protected in National Parks, occur in Asset Protection Zones (APZ) which are burnt to 80% fuel reduction every 5-7 years. The impact this may have has on ECB is unknown as it has not been studied. See planned burns section.

The habitat around butterfly populations is vital and must be protected from planned burns for the butterfly and their complex ecological relationships to survive. Recent surveys at Kalimna Park and other Central Victorian populations, by local ecologists and the community have resulted in important changes being proposed to fuel reduction burns, allowing land managers to reduce fuel load but ensure vital habitat is maintained for butterfly survival (Bayes and Just 2020).

In the Wimmera ECB are currently only known from two separate locations: Kiata Flora Reserve on 6 hectares of a 113-ha reserve and on a roadside in Wail (total area of 3ha). The Wail population is highly vulnerable to roadworks.

In Eltham/Greensborough ECB movement and genetic exchange is limited by the small size of the remnants that constrain them. However, these sites are managed by their relevant councils and the ECB numbers appear to be stable (see Eltham/Greensborough section).

There are undoubtably other ECB populations that exist but which we do not know about. Locating these populations is critical so they can be protected from threats.

ECB History

It is a story of lost and found and lost and found again. The Eltham Copper Butterfly was formally described in 1951 having been collected from several sites around Eltham in 1923-56 (Crosby 1951). Subsequent lack of records over the next 37 years combined with land clearing and housing development clearing them from areas where they once thrived (Tallarook, Murtoa, Dimboola, Keilor, Broadmeadows and Yarrambat) resulted in the belief that they had become extinct. Sixty-six percent of forests and woodlands in Victoria have been cleared for urbanisation and agriculture.

They were rediscovered at Eltham in 1987 on a property about to be subdivided. Community campaigning for this tiny insect resulted in a total of 8 hectares around Eltham/Greensborough being purchased and protected. The 1987 discovery also triggered and funded a state-wide search, and 9 colonies were discovered in 1988, including in two new regions: Castlemaine and the Wimmera (Kiata/Salisbury). Since this time many small ECB small colonies have been found each of which gives this species hope of survival.

Populations lost (>1988)

Finding where a rare species occurs is the first step in conserving it, protecting them from threats is the next. Sadly since 1988 three known populations have been lost; two in the Melbourne area through housing development (Montmorency, Lower Eltham Hills) and the recently discovered one in Salisbury (last seen in 1994). The Salisbury population is now considered extinct most likely from sheep grazing and the resultant loss of the butterfly host plant and other flowering food plants. An unknown number have been lost from areas where they had yet to be discovered.

Populations Found (>2011)

Many remnants in the two northern Victorian regions have not been searched for ECB. So more populations may exist. Bursts of effort over the decades has led to new populations being discovered. In 2011 a 3000ha search resulted in ten new small populations being found mostly in North Central Victoria but also from a roadside in Wail (Bayes, et al., 2012). All new populations are very localised within a larger habitat patch, with the butterfly only occupying 3-25% of habitat. Numbers of butterflies within these areas is also very small, with populations being around 50-100 but being peppered through a larger area.

Currently what makes good habitat for a truly interconnected species is unknown and very complex. More ECB surveys are underway in Northern Victoria in 2021-2022.