Friends of Grasslands
supporting native grassy ecosystems
PO Box 440
Macquarie ACT 2614
Bushfire Affected Species Assessments Section
Biodiversity Conservation Division
Australian Government Department of Agriculture, Water and the Environment
PO Box 858
Canberra ACT 2601
Golden Sun Moth (GSM) listing assessment
Friends of Grasslands (FOG) is a community group dedicated to the conservation of natural temperate grassy ecosystems in south-eastern Australia. FOG advocates, educates and advises on matters to do with the conservation of grassy ecosystems, and carries out surveys and other on-ground work. FOG is based in Canberra and its members include professional scientists, landowners, land managers and interested members of the public.
FOG has had a long-standing interest in the Golden Sun Moth (Synemon plana) and, in fact, was involved in a submission regarding the initial listing of this species. I was personally involved with Anett Richter (University of Canberra), Dr Will Osborne, Dr Sarah Hnatiuk, and Dr Michael Mulvaney to arrange, through FOG, a citizen science based Golden Sun Moth (GSM) survey and monitoring program for populations in and around Canberra in 2008/2009. This led to an Improved understanding of the species habitat requirements and the identification of additional moth sites.
FOG’s general arguments for retaining the current listing of the GSM follow, with specific comments relating to the consultation questions in the attachment.
We agree that, at face value, the application of IUCN criteria indicates that the GSM would not meet the criteria for keeping its current status. However, the current numbers of moths and their area of habitat, as discussed in the attachment, do not greatly exceed the criteria. We understand that IUCN criterion on the numbers of a species has been developed for larger animals – and that it is not suited to the listing of small, short-lived animals that can have major fluctuations in annual population size. We therefore consider that for insects like the GSM more latitude is required.
Before the listing is downgraded, an account should be prepared for all 162 extant GSM sites, that includes a measure of the actual area of moth habitat at each site, an estimate of population size (or relative abundance) in years of lower emergence abundance of moths at each site, and also a clear indication of the security (ownership, protection and management etc.) of each site.
The attachment points out a number of concerns that we have regarding the viability of the moth. Remaining populations throughout the range of the species are fragmented and mostly small. They vary considerably from year to year and, because of this, application of the precautionary principle suggests that the population estimates should include measurements made in years of low emergence. In addition, it should be noted that attempts at translocation have not yet proved successful (SMEC 2014, SMEC 2016). Moreover, many populations have been lost or reduced in spatial extent in recent years. For example, in the ACT very important and large populations have been destroyed to make way for development (e.g. at York Park). Threats to individual populations are ongoing with approved developments in areas of GSM habitat occurring at many sites throughout the range of the species (examples in the ACT include construction of Gungahlin suburbs, upgrade of Dudley St Yarralumla, urban development at Campbell 5) and other developments in the pipeline for approval likely to also impact on the moth.
In recent years when sites that have been deliberately destroyed with government approval, offsets have been given. However, there is no evidence that sites chosen as offsets lead to no net loss. In fact, our observations suggest that, at a majority of the sites chosen, there is no increase in the area of GSM habitat and no increase in the overall numbers of moths. This perhaps is not surprising given a lack of ecological information for this species. As an example, at the Franklin Grassland offset site in the ACT, moth numbers and the area they occupy are low and no work has started to increase moth habitat. Instead I have observed that kangaroo grass (Themeda triandra) and Phalaris, both unsuitable habitat for the moth, have further encroached on their habitat.
The argument made in referrals concerning a number of the aforementioned developments is that the areas of Golden Sun Moth (GSM) population and habitat to be impacted are relatively small and therefore should not prevent the development occurring (and would only require a small offset). These referrals appear over a number of years so that their cumulative impact is not considered (the exception being the last part of the development of Gungahlin in the ACT, where a strategic approach was taken (Umwelt 2013)). FOG has for many years been opposed to such a piecemeal approach since it generally results in environmental losses. For this reason, we have urged that the cumulative impact of the deletion of moth sites be investigated (e.g. in recent submissions on EPBC referrals 2019/0726, 2019/1216, 2019/8449). However, as far as we are aware, nothing has occurred in this regard to date.
There are some other factors that FOG would like to raise in the context of downgrading the status of the moth. The first are the findings of recent reviews of the current EPBC Act, which have been quite critical – both its existing procedures (ANOP review) and its failure to protect biodiversity (Samuel review). FOG’s experience matches that of these reviews – a continuing process of developments reducing the GSM population and habitat without observable gains resulting from offsets. As well, the impact of climate change on the moth is unknown but unlikely to be positive. More importantly, moth populations are small and highly fragmented and there is no known way to manage their recovery. FOG’s view is that more work should be done to address these issues before the moth’s status is downgraded.
22 February 2020
Attachment: FOG response to “Consultation Questions For Golden Sun Moth”
SECTION A - GENERAL
Q 3. Have you been involved in previous state, territory or national assessments of this species/subspecies? If so, in what capacity?
Several of the members of FOG have been involved in previous ACT, NSW and National assessments of the GSM. Dr Michael Mulvaney, a chief author of the following comments, wrote the 2012 ACT Strategic Conservation Plan of the species (Mulvaney 2012) and contributed to the 2017 ACT Action Plan (ACT Government 2017): both quoted in several locations in the current review of the nationally threatened status of the species. Dr Mulvaney recently retired from the ACT Government.
PART 1 – INFORMATION TO ASSIST LISTING ASSESSMENT
SECTION B: DO YOU HAVE ADDITIONAL INFORMATION ON THE ECOLOGY OR BIOLOGY OF THE SPECIES?
Q 5. Do you have any additional information in the ecology or biology of the species not in the current advice?
In the last 5 years GSM caterpillars have been translocated from development areas within the ACT to adjacent or nearby habitat. The results to date suggest that GSM can be relocated in the short term but creation of a new reproducing population has yet to be achieved (SMEC 2014, SMEC 2016, M Mulvaney pers comm).
The translocation targeted areas where high concentrations of adult moths were previously recorded, such as a small creek flat within wider occurrences of the moth across the now developed suburb of Taylor. These areas that had a higher density of moths were ripped to a depth of about 10cm exposing soil and the base of grass tussocks. What is instructive is that caterpillars were not evenly distributed across the grasslands, even though the grassland had been mapped as being the same quality of habitat throughout the area that was surveyed. For example, in a study conducted at Taylor-Kinleyside, along rip lines extending for hundreds of metres caterpillars were only found along tens of metres (M Mulvaney pers comm). The current method of determining extent of habitat from the distribution of adult records and then extrapolating this out across assumed habitat to include all continuous areas supporting suitable grass food plants is likely to significantly over-estimate the actual habitat area used by the moth.
SECTION C: ARE YOU AWARE OF THE STATUS OF THE TOTAL NATIONAL POPULATION OF THE SPECIES?
Q 7. Do you consider the way the population size has been derived to be appropriate? Are there any assumptions and unquantified biases in the estimates? Did the estimates measure relative or absolute abundance? Do you accept the estimate of the total population size of the species? If not, please provide justification for your response.
The approach taken in the assessment is probably close to the best which could be done with the limited information available, but it should be cautioned that
- We don’t know what proportion of emerging moths are actually fertile;
- We don’t know the success rate of males in finding females which may be low in areas of tall or rank grass growth which can be expected to occur in wet years and in small areas isolated from major herbivores (i.e. much of the remaining GSM habitat in the ACT and in the Melbourne region);
- The assessment notes that the lifespan of a moth is thought to be 2-3 years, but numbers of emerging moths per season do not vary in 2-3 year cycles. Rather, annual population counts at sites in the ACT where the counts have occurred annually for three or more consecutive years have revealed that there can be very large fluctuations in adult populations (Mulvaney 2012). The fluctuations in population size are thought to relate to variations in seasonal weather conditions and to site management activities (e.g. lack of grazing, mowing etc.). Because the emergent moths (the adults) are very short-lived (surviving for one or two days), it is clear that fluctuations in the early life stages (eggs, larvae and pupae) are responsible for these changes. Given that the larvae have been estimated to live for only three years (Richter et al. 2013), it is important that conservation assessments be based on the years when populations were the lowest. This is because basing a population assessment, like the IUCN criteria, on highest population counts inflates the long term population estimate (because the lower adult population resulting from a run of lower years is ignored);
- The population estimates used in the assessment are based on either the highest annual counts (at least in the ACT) or from surveys undertaken during favourable years when there is a large and prolonged emergence. A conservative approach would be to examine the smallest number of total emergences across a three year period, but such long term data is rare and to our knowledge in the ACT region is confined to a few sites including particularly the Canberra Airport and the former York Park so our ability to gain an understanding of long term fluctuations has been severely hampered;
- The species is categorised by a few sites (sub-populations) where relatively large numbers of moths have been recorded, plus the majority of sites where only a handful of moths have been observed. For example, in a 2012 review of ACT numbers, eighty-four percent of the total ACT maximum moth count was recorded from less than 10% of the total number of sites, with a median maximum count of 13 moths across the then 73 ACT sites;
- A precautionary approach is highly appropriate when considering the population size of this species.
SECTION E: ARE YOU AWARE OF INFORMATION ON THE TOTAL RANGE OF THE SPECIES?
Current Distribution/range/extent of occurrence, area of occupancy
Q 14. Has the survey effort for this species/subspecies been adequate to determine its national distribution? If not, please provide justification for your response.
The document states that the moth still occurs at 78 sites in the ACT, based on advice from the ACT Government in 2017. Since that time, at least one of the ACT sites has been cleared for development (York Park, EPBC referral 2017/8028). As well, there are development proposals in train that will impact on other sites (e.g. south Canberra light rail, City Hill redevelopment, William Hovell Drive duplication, Morisset Rd extension (EPBC referrals 2019/0726, 2019/1216, 2020/8703, 2020/8822)). Similarly, commercial development proposed for the Poplars in nearby Queanbeyan (EPBC referral 2020/8801) may impact on the moth population in this area. These ongoing development threats means that the moth’s distribution will be over-stated at any point in time in both and around the ACT and near Melbourne, where similar threats occur.
Q 15. Do you agree that the way the current extent of occurrence and/or area of occupancy have been estimated is appropriate? Please provide justification for your response.
An area of Occupancy of 2000 km means that the species has been recorded in 500 2km x 2km (400 ha) grid cells. The assessment utilised 164 site locations. Nearly all of the locations in the ACT and NSW are smaller than 100 ha, with the medium size in the ACT being 2.8 ha. Thus it would be expected that only a small number of the locations would occur across multiple grids of 400 ha and that probably just as many sites would occur within the one grid. If each location occupied one separate grid this would be an area of occupancy of 656 km. Consequently, an area of 2000 km seems very high and seems to be based on a mapping of potential habitat in Victoria. The minimum analysis should be based on recorded locations only, and the number of grids in which actual records occur. Record data should be cleaned to exclude museum records and other records where location is not accurate enough for the purpose.
Q 18. Can you provide estimates (or if you disagree with the estimates provided, alternative estimates) of the extent of occurrence and/or area of occupancy
If the number of sites has been accurately described in the assessment report then the Area of Occupancy is probably less than 1000 km
PART 2 – INFORMATION FOR CONSERVATION ADVICE ON THREATS AND CONSERVATION ACTIONS
SECTION G: DO YOU HAVE INFORMATION ON THREATS TO THE SURVIVAL OF THE SPECIES?
Q 21. Do you consider that all major threats have been identified and described adequately?
The threat posed by weed invasion has been understated. The grassland open woodland habitat in which GSM occurs is particularly under threat from invasion by weedy grasses. Loss of habitat from invasion by such species as African Lovegrass, Phalaris, Cocksfoot and Oats is already an issue across the moths range, while other “new invaders” such as Coolatai Grass are predicted as being highly likely or likely to invade remaining habitat, Even where GSM may be able to feed on those C3 grasses must closely related to Australian Stipa species such as Chilean Needle Grass and possibly Serrated Tussock – we do not know what the long term effects of their invasion may be on the fertility or behaviour of the moth. Maintaining GSM habitat within the ACT, in the face of weed invasion is likely to require ongoing annual funding of around $100,000. Such effort and funding is missing from much of the species range
Q 22. To what degree are the identified threats likely to impact on the species/subspecies in the future?
It is likely that much of the habitat of this species that is not under direct conservation management will be lost due the threats it faces, including invasion by weeds, mechanical disturbance to soil and inappropriate management of biomass.
ACT Government 2017. ACT native grassland conservation strategy and action plans (Environment, Planning and Sustainable Development, Canberra).
Mulvaney M 2012. Golden Sun Moth (GSM) ACT Strategic Management Plan. Report for the ACT Flora and Fauna Committee (ACT Conservation Planning and Research, Canberra)
Richter, A., Osborne, W., Hnatiuk, S., & Rowell, A. (2013). Moths in fragments: Insights into the biology and ecology of the Australian endangered golden sun moth Synemon plana (Lepidoptera: Castniidae) in natural temperate and exotic grassland remnants. Journal of Insect Conservation, 17(6), 1093-1104.
SMEC 2014. Arboretum Golden Sun Moth larvae retrieval. Report to ACT Parks and Conservation Service (SMEC Australia, Canberra).
SMEC 2016. Majura Parkway Golden Sun Moth Translocation Project. Report for Roads ACT (SMEC Australia, Canberra).
Umwelt 2013. Gungahlin Strategic Assessment Biodiversity Plan: Final. Report for ACT Environment and Sustainable Development Directorate (Umwelt Australia, Canberra)