Biodiversity Offset for a Highway Upgrade
A highway upgrade will clear 12 hectares of native vegetation, including 3 hectares of a listed ecological community that provides habitat for a threatened bird. The proponent proposes an offset: protecting 40 hectares of similar vegetation 30 km away, which is currently grazed but not cleared, plus a payment to a conservation trust. The 40 ha site is on good soil and is part of a larger vegetated corridor. However, the listed community at the impact site has a distinct soil and hydrology, and the offset site has not been surveyed for the threatened bird. Approval conditions require the offset to achieve 'no net loss' of the listed community and of habitat for the threatened bird. The regulator must decide whether to accept the offset as proposed.
1. Assess whether the proposed offset can meet the 'no net loss' condition, applying the principles of offsetting.
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Several offsetting principles are relevant. Offsets should be like-for-like, additional, and should not substitute for avoiding or minimising impact. They should also be measurable and secure in the long term.
Like-for-like: the offset site has not been shown to support the listed community, and its soil and hydrology differ from the impact site. Protecting 40 ha of similar vegetation is not the same as protecting the listed community, so equivalence is unproven. The 3 ha loss of the listed community is therefore not clearly compensated.
Threatened bird habitat: the offset site has not been surveyed for the bird. Without survey data, the claim that it provides equivalent habitat is unsupported. The impact site's habitat value may depend on features the offset site lacks.
Additionality: the offset site is currently grazed but not cleared. Protecting it may be genuinely additional if grazing would otherwise continue and degrade it, but this needs to be demonstrated, not assumed. A payment to a trust is not itself an ecological outcome.
Avoidance and minimisation: the proposal does not show that the 12 ha clearing, and especially the 3 ha of listed community, was reduced as far as practicable. Offsets come after avoidance, not instead of it.
Measurability and security: no survey, no condition baseline, and a 30 km separation mean the outcome cannot be verified or guaranteed. On the evidence given, the offset cannot be accepted as meeting no net loss.
2. State the decision you would make as regulator and the conditions or further work required.
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Decision: do not accept the offset as proposed. It fails the like-for-like test for the listed community and is unsupported for the threatened bird, and the avoidance step is not demonstrated.
Conditions and further work:
Require the proponent to demonstrate avoidance and minimisation first - show why the 3 ha of listed community cannot be avoided by realignment or reduced in extent, and document the alternatives considered.
Require a flora and fauna survey of the offset site, using methods consistent with those used at the impact site, to establish whether the listed community and the threatened bird are present and in what condition. If the listed community is absent, the 40 ha site cannot offset that component.
If the listed community is absent from the offset site, require identification of a site that does support it, or a rigorously justified alternative with a clear, conservative ratio reflecting the difficulty of recreating that community.
Set measurable condition targets and a monitoring program with a baseline, reporting intervals, and a remedy if targets are missed, plus a secure long-term protection mechanism (e.g. a binding covenant) so the offset persists beyond the proponent's involvement.
Make clear that the payment to the trust is supplementary, not a substitute for measurable ecological outcomes.
If these cannot be met, the appropriate outcome is refusal or approval with reduced clearing, not acceptance of an unverified offset.