2016-12-12 General Committee - Attachment 1 to Item 6 - Biodiversity Assessment Report

                                                Noosa Biodiversity Plan – Biodiversity Assessment Report



type for vegetation added to the contiguous category was assigned through the API process and through the RE pre-clearing information associated with that
location.

The second objective of the Lidar and API analysis was to improve the community assignment of remnant and contiguous vegetation to facilitate better
association to values such as conservation significance and Threatened Ecological Communities. Specifically, many vegetation polygons within the RE
datasets (both remnant and pre-clearing) consist of mosaic, or mixed, polygons. These polygons have several (up to 5) communities assigned to the same
location. Mixed polygons greater than 5 ha were identified and subjected to API to ascertain internal boundaries between comprising vegetation types.

A suite of ‘Lidar indices’ were developed to support the identification of vegetation communities and the separation of communities within mixed polygons.
These indices involved GIS neighbourhood analyses of the previously developed Lidar tree height model and of a Lidar-derived Digital Elevation Model (DEM)
of the ground surface. The indices developed included:

    •   Mean tree height within a 90m x 90m neighbourhood (reflects characteristics of dominant tree species and canopy cover);
    •   Standard deviation of tree height within a 60m x 60m neighbourhood (potentially reflects canopy cover and diversity of tree species);
    •   Topographic ruggedness – standard deviation of ground elevation within a 90m x 90m neighbourhood (reflects steepness and proximity to steep
        terrain);
    •   Topographic position – difference between elevation at a point and the mean elevation within a 90 x 90m neighbourhood (reflects whether a location
        is on a ridge, valley, mid-slope, or flat ground)

Vegetation communities were assumed to exhibit a signature for these measures. For example a community with uniform tall trees would look different to a
community with a mixture of dominant tree types of varying heights. Example signatures for each index were compiled for the individual REs which commonly
comprised mixed polygons. Signatures were selected from protected areas based on the assumption that vegetation would more likely be validated within
these areas. Signatures were compiled as reference posters used by API investigators as a visual aid in conjunction with GIS layers representing indices and
aerial imagery. Recompiled mixed polygons were then integrated back into the composite vegetation mapping.

A subset of all API validated polygons were ground-truthed as a quality check and adjusted as necessary. Ground-truthing consisted of a rapid assessment
technique where information on RE type and condition was recorded for each polygon. Where access was limited, information was gathered via the use of
binoculars or through extrapolation using nearby contiguous vegetation. A certainty / reliability score was applied to each assessment as follows:

1 = Ground-truthed (certain); 2 = Not directly ground-truthed but reasonably confident; 3 = Not confident but determination should be in proximity; 4 = uncertain

Any assessments deemed uncertain were not incorporated into the final mapping.




  © ECO LOGICAL AUSTRALIA PTY LTD                                                                      134