Defining the corridor

    Background

    The forested corridor between Boonah and Karawatha Forest Reserve in Brisbane City comprises the largest area of intact lowland eucalypt forest in South East Queensland (SEQ). In determining the extent of the corridor, numerous layers of information were considered including a biodiversity planning assessment (BPA) for SEQ. The Flinders Karawatha Corridor (the corridor) captures the key environmental, recreational, economic, social and cultural values of this regional landscape area.

    Biodiversity planning

    The 'Biodiversity Assessment and Mapping Methodology' (BAMM) (see availability) provides a consistent and transparent approach for assessing biodiversity values in Queensland bioregions. The department is using this mapping system to generate BPAs for each of Queensland’s bioregions. Supporting the BAMM is vegetation mapping (regional ecosystems) and a range of other biodiversity related data including flora and fauna records. BPAs are used by departmental staff, other government departments, local governments and members of the community to assist with land use planning and identifying conservation priorities.

    The biodiversity significance of an area is given according to its ecological value such as rarity, diversity, fragmentation, habitat condition, resilience, threats, and ecosystem processes. The BPA assigns 3 levels of overall biodiversity significance:

    • State significance—areas assessed as being significant for biodiversity at the bioregional or state scales. They also include areas assessed by other studies/processes as being significant at national or international scales.
    • Regional significance—areas assessed as being significant for biodiversity at the subregional scale. These areas have lower significance for biodiversity than areas assessed as being of state significance.
    • Local significance and/or other values—areas assessed as not being significant for biodiversity at state or regional scales. Local values are of significance at the local government scale.

    Expert panels have considered landscape corridors for the BPA using defined criteria and in the context of a proposal for a state wide terrestrial landscape corridor network. These corridors would be assigned state significance and are also complemented by riparian and regionally significant bioregional corridors.

    For more information on the BAMM mapping methodology see Biodiversity Planning Assessments.

    What do biodiversity corridors represent?

    Bioregional and subregional conservation corridors have been identified in the more developed bioregions of Queensland through the BPAs, using an intensive process involving expert panels. The Flinders Karawatha Corridor (the corridor) has been identified by an expert panel as being part of a state significant terrestrial bioregional corridor.

    Corridors are identified based on their role in:

    • facilitating seasonal movement (migration, altitudinal migration)
    • facilitating movement through highly modified landscapes and access to unexploited habitat
    • improving dispersal success
    • increasing the effective size of meta-populations by allowing for the exchange of genes between subpopulations
    • allowing colonisation of empty patches and prevent and reverse local extinction
    • providing habitat for resident populations; and
    • maintaining landscape scale ecological and evolutionary processes along geological, hydrological, altitudinal and climatic gradients and provide for ecological responses to climate change.

    A strategic corridor network should function effectively for a large range of species, particularly threatened species. Corridor selection should address issues of dimensionality (length/width), habitat type, quality and diversity, habitat patchiness within the corridor and consider potential edge effects when prescribing corridor widths.

    Terrestrial bioregional corridors, in conjunction with large tracts of remnant vegetation, maintain ecological and evolutionary processes at a landscape scale, by:

    • maintaining long-term evolutionary/genetic processes that allow the natural change in distributions of species and connectivity between populations of species over long periods of time
    • maintaining landscape/ecosystems processes associated with geological, altitudinal and climatic gradients, to allow for ecological responses to climate change
    • maintaining large-scale seasonal/migratory species processes and movement of fauna
    • maximising connectivity between large tracts/patches of remnant vegetation
    • identifying key areas for rehabilitation and offsets.

    The location of the corridors is determined by the following principles:

    • complement riparian landscape corridors (i.e. minimise overlap and maximise connectivity)
    • follow major watershed/catchment and/or coastal boundaries
    • incorporate major altitudinal/geological/climatic gradients
    • include and maximise connectivity between large tracts/patches of remnant vegetation
    • include and maximise connectivity between remnant vegetation in good condition.

    How the Flinders Karawatha Corridor administrative boundary was decided

    The administrative boundary of the corridor was determined by using BPA values, up-to-date landsat imagery, aerial photographs, regional ecosystem mapping and regrowth vegetation mapping (refer to source data versions below).

    To define the corridor, scientists first considered the BPA values. The boundary was refined using property boundaries and linear features such as railway lines, roads, ridgelines and creeks. Further refinements were made by considering suburb boundaries. The southern boundary was determined by identifying the southern extent of the Wyaralong Dam catchment.

    Areas excluded from the Flinders Karawatha Corridor

    Any approved or committed development, such as Springfield Lakes, was excluded from the corridor footprint. Greenfield communities in Greater Flagstone and Ripley Valley were excluded from the corridor boundary. These new urban areas were still being planned during the refinement of the boundary.

    Refinements to the Flinders Karawatha Corridor boundary

    Refining of the corridor boundary was undertaken following public consultation. Creating a corridor boundary or 'identity' focuses attention and action on an area. It is not intended to indicate that areas outside of the boundary are not valuable to the functioning landscape. The corridor can be viewed as a core area which enhances connectivity in the wider South East Queensland landscape.

    Available from the library catalogue

    The document referred to on this page is available from the department’s online library catalogue.