Offsets, what are they good for?

Why “Offsets” are not compensation for mature, old-growth vegetation


Main Roads Western Australia (MRWA) is one of many organisations, private and public, who claim offsets constitute equal compensation when applying for Native Vegetation Clearance permits.

MRWA in their September update on improvements to Toodyay Road includes the statement that: “In accordance with State and Federal environmental regulations, an environmental offset for these upgrades includes a property of 196 hectares of prime Wandoo woodland adjacent to the Clackline Nature Reserve…“.  They also claimed as an offset, the transplanting of approximately 50 Native Grass Trees and the revegetation of land at the Toodyay Rd/Racecourse Rd intersection up to the railway crossing and alongside the new road developments.

revegetation offset at the junction on Racecourse Rd and Toodyay Rd - showing a bare landscape

“Revegetation offset” at the junction on Racecourse Rd and Toodyay Rd – showing a bare landscape, with very little revegetation.

The community, in good faith, will therefore draw the conclusion that the large trees with their complex understory that are going to be destroyed along Toodyay Road will be made up for by these offsets. Unfortunately, that is not the case, and this article explains why it is necessary to have some understanding of what is meant by “offset”.

A vegetation offset is a chosen location where native vegetation condition and species habitat are protected in perpetuity and can be improved by effective management actions, such as protective fencing, weed and pest control and planting of locally appropriate native plant species.

The concept of biodiversity offsets was first developed in the USA in the 1970s to mitigate damage to wetlands, and this concept has now been adopted in over 100 countries worldwide.

Essentially, it means setting aside an area to be conserved as compensation for losses of native flora and fauna habitat due to development with the aim that there be “no net loss” for biodiversity.  But has this been achieved?

In Western Australia, the concept of offsets was incorporated as part of the Environment Protection Act of 1986 and later in the WA Environmental Offsets Policy of 2011 for which guidelines were completed in 2014.

There has been no intent to provide additional gains beyond equivalent loss from development.

Biodiversity is an exquisitely complex entity involving a network of interconnected ecosystems, species, and organisms both micro and macro, in tune with seasons and population mass to provide a healthy sustainable, genetically diverse natural system. Much of this remains unknown or not understood by humankind.

This complexity is why the intended Biodiverse Offset equivalents cannot be achieved by any governments across the globe and are destined to fail in reaching their alleged goals. The very idea of preserving an existing area of native vegetation as an equivalent replacement for areas destroyed by development is flawed thinking from the start.

Instead, the steps taken in any development, including road improvements, should be in the order of:

Step 1

Avoidance of damage & destruction completely

Step 2

Minimisation if avoidance is impossible

Step 3


Unfortunately, it is all too common that Steps 1 and 2 are bypassed and the first option presented by developers for clearance approvals is Step 3.

transplanted grass trees

Transplanted grass trees (Xanthorrhoea) near the Jingaling Brook roadworks section. Approximately 50% look to have perished or are struggling.

The outcome of a 10 year study published in 2017 by the Australian National University revealed by careful calculation, that in NSW where approximately 22,000 ha of native vegetation were approved for clearing and 83,500 ha were established as offsets, it would take 146 years to achieve a biodiverse equivalent of  “no net loss” status for that 10 year period alone.

The reason for this was that 82% of the total area of offsets was obtained by covering losses with already existing areas of native vegetation instead of newly planted biodiverse areas that would replace destroyed vegetation. There cannot possibly be a “net gain” with this type of offset, and such practices are not offsets in the sense of the original concept. The remaining 18% were plant transplantation and revegetation of areas with seedling plants.

Furthermore, revegetation areas with seedlings were calculated as an equivalent to a “gain” when replacing difficult to replace mature vegetation and complex habitat, such as mature trees and diverse vegetative growth areas.  Here in our Toodyay region, multiple mature trees, some of them hundreds of years old, are in line to be cleared for the new Toodyay Road development and no amount of seedlings can replace them.

Our local Wheatbelt Natural Resource Management (NRM) report states that the majority of the Wheatbelt falls well below the 30% native vegetation area required to maintain a viable biodiverse ecology.  More specifically, the Avon region alone has been reduced to only 11% of remaining native bushland, much of it being road verges and road reserves forming important wildlife corridors and habitat.

Between 2019-2022, 514 ha were approved for clearing in the Wheatbelt region, and of this, approximately 50% (257 ha) were cleared for road development or upgrades. This makes MRWA and local shires the largest clearers of land in an area that has very little remaining natural vegetation.

It is therefore perhaps unsurprising that MRWA continues to claim the unsubstantiated and increasingly disputed use of “offsets” as equivalent and acceptable replacement for diverse vegetation lost by their roadworks.

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