Biodiversity offsets in practice: the case of the Striped Legless Lizard

Last week I joined a field trip run as part of the Biodiversity Conservation (ENVS3039) course at the ANU.  The students have been introduced to the concept of biodiversity offsetting during lectures, but now they can put that knowledge into practice.

As part of their assessment, the students were asked to develop a biodiversity offset proposal to compensate for the loss of habitat for the Striped Legless Lizard (Delma impar), which is a species listed as Vulnerable under the federal Environment Protection and Biodiversity Conservation 1999 (EPBC) Act.

First, we arrived to inspect the impact site – where a new development is proposed to occur. Despite the presence of a number of invasive grasses, several horses and the proximity to a busy road (let’s face it – it’s essentially a paddock), the site holds a lot of value for the striped legless lizard.


We heard from Michael Mulvaney from the ACT Government, and James Tresize from the Australian Government’s Department of Sustainability, Environment, Water, Population and Communities, who explained how they dealt with biodiversity offsetting policy at their respective levels of government. The students then undertook a site assessment to estimate the impact the proposed development on the striped legless lizard.

Next, we traveled to the offset site, where it’s proposed that a grassland reserve is to be expanded to include an area with very high density of D. impar. The question the students now have to answer is if the proposed offset will be adequate to ensure a no net loss of  striped legless lizard. Now, that’s a tricky question to answer, and there are a lot of variables to think about (and I won’t say much here, given it’s part of their course assessment!).


Perhaps the key thing to remember when considering whether an offset will be effective is to estimate the expected benefit of the offset correctly. That is, what would happen to the proposed offset site with protection? Are there plans to improve management of the site, and increase the population of striped legless lizards? Or is the plan simply to protect the site from future loss via a covenant or other form of protection? And what would happen without protection? Would the site be likely lost in the future, or is it in an area unsuitable or unviable for residential/agricultural/industrial development?

I thought this was a really valuable practical class for the students, which gave them a great opportunity to speak with relevant experts and put ideas into practice in the field (plus I got an afternoon out of the office :-)) – well done Phil for organizing a great class!

One response to “Biodiversity offsets in practice: the case of the Striped Legless Lizard”

  1. Thanks Megan for contributing to this exercise as well. Students variously calculated that 200% of the impact was offset by the proposal! Phil

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