Besides both species missing the usual body parts, Striped Legless Lizards (Delma impar) and Grassland Earless Dragons (Tympanocryptis pinguicolla) have a few things in common. For example, both species live out their lives in the ACT’s dwindling areas of native temperate grassland. Similarly, both are severely under threat (Legless Lizards are listed as vulnerable in the ACT while Dragons are listed as endangered). Lastly, both species are currently the subject of intense interest to the ACT’s environmental offsets team. I was lucky to be working with this team during the term break, helping conduct a survey of all ACT offsets that contain, or supposedly contain, populations of Lizards and Dragons. Besides gaining an opportunity to contribute to the conservation of some of the ACT’s most elusive grassland species I was also interested to see how the theory behind offsetting translates into practice.
During my stay with the offsets team, I conducted surveying at two offset sites: Mulanggari Grasslands in Canberra’s North-West, and Jerrabomberra East in the ACT’s South. Both sites were a mixture of Native Temperate Grassland (‘NTG’), and exotic grassland species such as Phalaris (Phalaris aquatic). The sites had been put aside as offsets because of both the presence of NTG and the vulnerable fauna living in the grassland itself. The surveys were conducted on large 100 m2 plots each with 30 roofing tiles placed at even intervals across the plot. The tiles were then left for a two-week ‘settling-in’ period so that they could become a normal part of the landscape (at least from the lizard’s perspective). The idea is that these tiles act as refuges for lizards and other small creatures in much the same way as small scattered rocks and logs. Once this two-week period is over the sites are surveyed for any fauna using the tiles. I was involved in the initial stages of the project. My job therefore consisted mostly of carrying heavy roofing tiles around wet grasslands. Luckily, this also gave me the opportunity to talk to a group of highly knowledgeable and interesting people.
What I learnt
Aside from learning about Legless Lizards and Dragons, the key lesson that came out of the experience for me was an appreciation of the difficulties of managing offset sites. Having gained a basic theoretical understanding of offsetting, I appreciated the opportunity to gain an insight into the particular issues involved in managing these sites once they are selected. For example, while Legless Lizards and Dragons both live in NTG they prefer different grassland structures. Legless Lizards, for example, prefer grasslands with a thick tussock level and with high levels of surface soil cracks. Conserving both Legless Lizards and Dragons in the same area therefore becomes a struggle between managing the same NTG site for conditions suitable to both Lizards and Dragons, often an impossibility. This management issue is compounded by the legal nature of offsets which result in guarantees from the Government to protect, and increase, populations of both species on these sites. Another example of this can be found at the offsets managed for the Golden Sun Moth (Synemon plana). Many of these sites are managed both for the presence of Golden Sun Moth and for the conservation of NTG. However, these two management commitments can come into conflict with each other. Alongside the NTG at a number of sites is Chilean Needle Grass (Nassella neesiana), an exotic which is also excellent habitat for Golden Sun Moths. There is tension between removing Chilean Needle Grass and therefore removing Golden Sun Moths habitat and leaving the needle grass to potentially encroach upon the NTG. Clearly, meeting both management targets will be a difficult task.
Another issue with the management of offset sites involves their separation from other types of conservation within the ACT’s environmental management framework. This came up in two ways during my short stay with the offset team. The first was the occasional lack of data sharing between different groups of managers. This can lead to a situation in which two management teams surveying for similar data at adjacent sites do not have all of the available information. Another issue was the inability to manage for issues within offset sites by carrying out activities outside those sites. One example of this is the management of weeds to maintain healthy structure amongst the NTG at some offset sites in the ACT. Often weed management is only effective when it can be conducted both within and outside the borders of the offset sites, something which is not possible.
Despite the hurdles presented by the offset system I was impressed by the dedication and effectiveness of the offset team. Although I have focused on some of the management issues with offset sites, I witnessed far more positives while working with the team. For example, Jerrabomberra East is an old farm that would have had little potential conservation value without its inclusion within the offset scheme. Instead, a number of professional environmental managers and one decidedly unprofessional student were crawling over the farm doing their best to preserve two vulnerable lizard species. With continuing management by the team (and hopefully more funding) Dragons, Legless Lizards, and the native temperate grassland in which they live have a much better chance at survival than they would otherwise.
Department of the Environment 2016, ‘Delma impar – Species Profile and Threats Database’, Department of the Environment, Canberra, <http://www.environment.gov.au/sprat>, viewed: 11 Sep 2016.
Department of the Environment 2016, ‘Tympanocryptis pinguicolla – Species Profile and Threats Database’, Department of the Environment, Canberra, <http://www.environment.gov.au/sprat>, Accessed: 11 Sep 2016.
Environment and Planning Directorate ACT 2016, ‘Environmental Offsets’, Environment and Planning Directorate, Canberra, <http://www.environment.act.gov.au/cpr/environmental-offsets-policy>, viewed: 12 Sep 2016.
Gibbons P, Lindenmayer, D 2007, ‘Offsets for land clearing: No net loss or the tail wagging the dog?’ Ecological management and restoration, vol. 8, no. 1, pp. 26-31.
Hunter D 2012, Grassland Earless Lizard, photograph, <http://www.environment.nsw.gov.au/threatenedSpeciesApp/ImageHandler.ashx?graphicsId=45685>, viewed: 14 Sep 2016.
Miller K et al. 2014, ‘The development of the Australian environmental offsets policy: From theory to practice’, Environmental Conservation, vol. 42, no. 4, pp. 306-314.
Robertson P Date Unknown, Striped Legless Lizard, photograph, <https://museumvictoria.com.au/pages/12318/ImageGallery/vic-StripedLeglessLizard-large.jpg>, viewed: 14 Sep 2016.