Wetland Revival Trust discovers new Eltham Copper Butterfly population in the Wimmera
Posted on 28 February, 2023 by Ivan
Connecting Country has partnered with local ecologist Elaine Bayes (Wetland Revival Trust) over many years to help monitor and conserve the critically endangered Eltham Copper Butterfly. We have delivered education programs and coordinated monitoring events in central Victoria, with Elaine tirelessly leading the campaign to improve land management practices and promote the survival of this iconic and fascinating species.
Elaine and her team at the Wetland Revival Trust recently reported some great news: they discovered the largest population of Eltham CopperButterfly and the largest area of habitat ever found! The new population is at Gerang Gerung, in the Wimmera region of northwest Victoria.
We congratulate Elaine and the team on their perseverance and recent exciting discovery!
The full media release is provided below, courtesy of the Wetland Revival Trust.
Wetland Revival Trust discovers National treasure in the Wimmera with the largest population of the Eltham Copper Butterfly found at Gerang Gerung
Wetland Revival Trust’s (WRT) long term butterfly project in northern Victoria discovered the largest population of the nationally endangered Eltham Copper Butterfly (ECB) (Paralucia pyrodiscus lucida) in the Wimmera, at two Gerang Gerung nature reserves.
Elaine Bayes, an ecologist from Wetland Revival Trust, a not-for-profit environmental charity, has been involved in the protection of this tiny butterfly since 2009.
Elaine started a search and find mission in 2019 in north central Victoria, where there are several ECB populations. The search spread to the Wimmera which may be the prime location for this species. Elaine said, ‘ECB numbers at the two very small known populations in the Wimmera were at much higher densities than in the north central where we had been searching.’
‘This year, our team searched 1,600 hectares of public land for the butterflies, 1,400 ha of which was in the Wimmera. And we were certainly rewarded for the effort, with around 500 ECB seen between the two Gerang Gerung reserves. To give perspective, in north central Victoria last year, we searched 1000 ha and found a total of 43 ECB peppered across a large area. To see 500 ECBs in one season is exceptional, and so far, this is the largest number of ECB and the largest area of ECB habitat ever found.’
This search was funded thanks to the Victorian Government Biodiversity On-ground Action Program (Icon Species Projects) which supports actions to protect nationally endangered species like ECB. ECB were first found in the Wimmera in 1988 at Salisbury Bushland Reserve and in a small area of Kiata Flora Reserve. In 2011, another tiny population (6 hectares) was found on a Wail roadside by local entomologist Fabian Douglas. In the intervening years, the Salisbury population became extinct, believed to be caused by sheep grazing out the butterfly’s food plants. The two remaining populations at Kiata and Wail are separated by a sea of agriculture, with nowhere for their young to disperse to.
There is no way for the populations to move around as environmental conditions change, and no corridors of native vegetation for the butterflies to move along so they can share DNA to make them more resilient. Also being small the sites are under threat from pests, weeds and roadworks.
Elaine believes that part of the reason ECB is rarely seen is that they require very specific conditions. As well as being dependent on one plant species to feed their larvae, the Sweet Bursaria (Bursaria spinosa), they require one specific ant species (Notoncus ectatommoides) to act as a bouncer for their larvae, scaring off predators that would otherwise feast on their juicy bodies. Their other very specific needs are that these delicate little butterflies are solar powered and only fly when it is 20-30 degrees with no wind or rain. The adults only emerge when there is abundant nectar around November and December usually peaking at Christmas and New Year (with a smaller emergence in March and April). Finding field staff to search for ECB at Christmas and New year is as rare a thing as finding the ECB themselves!
To find this elusive species you first find the one and only plant species it relies on, Sweet Bursaria (Bursaria spinosa) which is much easier to map as it is large, stays still and is present all year round! Previous searches have shown that ECB only occur where Sweet Bursaria plants are dense (more than 30 plants in a ¼ hectare). So, the first part of the plan is to search for and map dense Bursaria patches. The second part is to search those dense patches for ECB during their flying period.
Given the cool start to summer this year the number of days that ECB were flying before it became too hot for them was less than fourteen. WRT had ten field staff and several volunteers out searching the 1400 hectares. Ten very dedicated people who put this conservation work before summertime at the beach. The team searched areas including Gerang Gerung Mallee Dam, Gerang Gerung South Reserve. Glenlee NCR, Barrett NCR, Lierschs NCR, Coker Dam Wildlife Reserve and Lil Lil Dam and at a few locations in Castlemaine.
This work builds on WRT searches between 2019 and 2021 and a similar search in 2011, when large areas were mapped and collectively thirteen new populations around Central Victoria and at one at Wail were found. The new populations were very localised with the butterfly only occurring in 3-25 per cent of suitable habitat (where the ant and the host plant are present). This is reflected in this year’s survey where, out of 1400 ha, ECB was only found on 36 hectares.
The butterfly is listed as critically endangered under the Victorian Flora and Fauna Guarantee Act 1988 and as endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999. 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.
The threats to this species in the Wimmera are numerous. Given the amount of historical land clearing in the Wimmera you can be confident that any quality remnant vegetation has a high likelihood of containing rare species, including insects, orchids and other plants and animals. Management and protection of these sites will bring benefits to multiple species as well as places of recreation and learning for future generations, impacts on local climate etc. Next year funding applications are in for weed and pest management, signage, translocations and more.
According to Elaine, it is undoubtable there will be ECB populations on private land where remnant vegetation occurs.
‘It is easy to check if you have any. First search your property or nearby bushland for dense patches Sweet Bursaria plants (easiest to see when flowering in December). Then look for the copper sparkle of flying adults in December on still days that are between 20-30 degrees. Tap each plant with a stick, which will cause them to fly and be more easily seen. Use the fact sheet and butterfly look alike sheet from the Eltham Copper Butterfly website (www.butterflies.net.au). Sightings can be reported on this site, the inaturalist app (www.inaturalist.org) or on the Butterfly Australia app (butterflies.org.au).’
Landholders can help protect this and other rare species by retaining and restoring native understorey plants on their properties.
Wetland Revival Trust
Please enjoy the following photographs provided by the Wetland Revival Trust, showing the beauty and size of this national treasure.