Understanding the Brisbane Biodiversity Overlay

Biodiversity interactive mapping
20 February, 2015

In recent months, many clients have come to our Environmental Team with questions about the Brisbane Biodiversity Overlay. The Biodiversity Overlay made its debut in the new Brisbane City Plan in mid-2014 and has raised eyebrows among developers and land-owners.

The Biodiversity Overlay can be a major planning constraint for development projects, and so it’s important, to not only be aware of its presence, but to understand the intent behind its existence. Understanding a little more about the intent of the overlay from an ecological perspective can assist planners and developers in predicting possible outcomes, appropriately costing and planning for additional professional services and limiting headaches throughout the development assessment phase. 

We’ve put together a series of our most commonly asked questions from our clients regarding the Biodiversity Overlay and the associated Codes and Policies.

What is the Biodiversity Overlay for?

At its core, the Biodiversity Overlay and Code was developed by Council as a planning mechanism to achieve the aspirations set out in the Brisbane City Vision 2013 document. In particular to help achieve “Brisbane’s clean and green leading environmental performance”. More on this vision and strategy can be read in Council’s Strategic Framework inside the Brisbane CityPlan 2014.

In general, the purpose of the Biodiversity Overlay is for the conservation, consolidation, connection and restoration of lands with in-situ or strategic biodiversity values and functions within Brisbane. This also includes mapped Koala habitats and wetlands and is used to facilitate the provision of Environmental Offsets.

Words like ecological and biodiversity ‘values’ and ‘functions’ can be interpreted in widely differing ways, and this can sometimes be confusing for proponents. They are not limited to on-site trees and animals, they also include less intrinsic values that enhance the sum of parts across the city. Some examples include:

  1. Allowing the safe movement of fauna so that species continue to breed together, and are not isolated from reaching one another; and
  2. Less tangible functions, like air filtration and encouraging microclimate stability that some species rely upon for their habitat niche, and that we humans rely upon to feel comfortable in our cities’ climate.

My site has ‘High/Medium Ecological Significance’ mapped on it, but there are no trees in this mapped area – is the Overlay inaccurate?

Not necessarily.  The intent of the Biodiversity Overlay is not always to protect existing vegetation, but is also used to secure strategic corridors required to sustain the movement of fauna and flora materials through the wider landscape. So in that sense, it may not necessarily be inaccurate. Council may have identified this part of your site as required to reconcile a missing part of a local corridor that has values broader than those occurring just on the site. The mapping imposed on your property is likely to be in the interest of the broader landscape function.

A Detailed Ecological Assessment can assist in clarifying the site’s landscape values, and in some cases, challenge whether such mapping extent is warranted. While relaxations may occur, it is likely that offsets may still be required if native vegetation is removed from these areas.

But my site has no Biodiversity Overlay mapping at all, why am I being asked to retain vegetation?

Don’t get caught out! Under the Brisbane CityPlan 2014, the Subdivision Code also refers to ‘Significant Vegetation’. Significant Vegetation may be present on your site, but not be mapped in the Biodiversity Overlay at all. ‘Significant Vegetation’, as it is referred to in the Subdivision Code is a ‘catch all’ to identify and often protect vegetation with specific values that is not captured by the Biodiversity Overlay.
Such vegetation includes trees or any plant that is listed as threatened under Commonwealth or State legislation, is a critical food source for a threatened animal species or provides significant visual amenity, cultural or historical values.

What right does Council have to impose this overlay on a property?

While we don’t profess to provide legal advice, we can offer some words of clarification on the process. The Biodiversity Overlay is included in the Brisbane CityPlan 2014, which was the product of several years of research and planning. The CityPlan was approved by the Queensland State Government after a vigorous open public consultation and submission period. The Biodiversity Overlay Code is now a code that must be addressed as part of any assessable development for a site with this overlay.

These matters can be very challenging, but keep in mind they are always open for discussion. With the help of an environmental professional, you may be able to streamline discussions with authorities and find an effective solution that works for your project’s needs.