BioCondition is a vegetation condition assessment framework that provides a measure of the capacity of a terrestrial ecosystem to maintain biodiversity values at a local or property scale. It is a site-based, quantitative and repeatable assessment procedure that provides a numeric score to reflect functional, through to dysfunctional, vegetation condition states for biodiversity.
In BioCondition, vegetation condition is defined as the relative capacity of a site to support the suite of species expected to occur in a site of the same regional ecosystem in its reference state (or ‘best-on-offer’) condition. The higher the BioCondition metric score, the more flora and fauna species will be supported in a specific ecosystem type.
The BioCondition framework was first developed in 2006 to assist with decision making for vegetation management and biodiversity conservation and has evolved through a substantial science-based research program. The BioCondition framework currently supports the Queensland Environmental Offsets Policy, bushland restoration prioritisation (e.g. Natural Resource Investment Program) and market-based programs such as Accounting for Nature and the Land Restoration Fund.
The framework is underpinned by three key components:
- a suite of assessable vegetation attributes that are based on a pressure-state-response conceptual framework
- a clear definition of the reference state from which benchmarks for the assessable attributes are set
- a scoring system that provides a condition metric that is comparable between and within ecosystems over space and time.
The BioCondition assessment framework is applicable at the site-scale, where condition attributes are measured in the field at a fixed site that represents a homogenous patch at a localised scale. Assessment of landscape-level condition attributes relative to that site are calculated remotely and can also be included in the BioCondition score.
Benchmarks provide an objective comparison of vegetation condition states within and between regional ecosystems and are quantitative values for each assessable attribute in BioCondition. They are derived as the average or median values from field data collected from reference or best-on-offer sites in the landscape during optimal seasonal conditions, as far as practicable. For rare and highly disturbed regional ecosystems, expert elicitation may be used to determine benchmarks.
Benchmarks have been developed by the Queensland Herbarium and are available online for specific regional ecosystems. Where benchmarks are currently not available, the BioCondition reference site manual provides a method for deriving benchmarks. A BioCondition reference site manual datasheet is provided for use.
The recommended approach is to use the reference site assessment protocol to locate the site and conduct an assessment at the same time as the BioCondition assessment. The information obtained can be used to augment and refine the range of benchmark values for each attribute, particularly:
- tree canopy cover
- shrub canopy cover
- grass cover
- species richness for the shrub, grass and forb, and other life form groups.
The benchmark values are determined through the site assessment, taking into account variability caused by seasonal fluctuations or factors such as drought effects.
The BioCondition Site Assessment manual provides an assessment protocol to measure how well an area of vegetation is functioning for the maintenance of biodiversity values. The assessment protocol works in conjunction with the benchmarks. The BioCondition datasheet is available for use.
Vegetation condition is applicable at multiple scales across space and time, and there is an increasing need for mapping that represents not only vegetation type and its remnant status, or changes in its extent, but its biodiversity condition state as well.
Vegetation condition mapping is required to provide landscape scale information to support natural resource and environmental management decisions, particularly around habitat for threatened species and biodiversity, such as those required by natural capital accounting schemes and biodiversity markets. To address this requirement, a new Spatial BioCondition framework has been developed.
The Spatial BioCondition framework aligns with Queensland’s regional ecosystem and BioCondition vegetation assessment frameworks. The methods used in the framework model the distance, or departure, of the current landscape (represented by 30 x 30 m pixels) from its expected reference state in multi-dimensional space, using three types of input data:
- Site-based training data of sites in reference state (Best-on-Offer) condition and across the spectrum of condition states, scored using the BioCondition (response variables).
- A suite of contemporary, state-wide remote sensing data products which provide land cover information as proxies for landscape state and change information (predictor variables).
- Environmental domain mapping, represented by state-wide pre-clear regional ecosystem mapping.
Initial outputs included mapping of vegetation condition classified into four classes. A continuous index is now being developed to align better with the site based BioCondition score and to allow for greater flexibility when using the outputs.
Next steps in the development of Spatial BioCondition will focus on the collection of further training and BioCondition benchmark data to fill gaps and improve model output. A field program will seek to field-validate draft model outputs, with particular focus on the Southeast Queensland and Brigalow Belt bioregions. This will help identify how much training data is required to ensure reasonable accuracy in the model outputs and provide estimates on the level of uncertainty in the mapped condition estimates.
The Spatial BioCondition framework and methods were subject to an independent scientific peer-review, led by CSIRO, to ensure the new methods are reliable and scientifically valid. Refer to the SLATS methodology for more details.
Details about the initial methods and outputs of the Spatial BioCondition framework are available in the peer-reviewed report Spatial BioCondition – Vegetation condition map for Queensland .