Byron Flora and Fauna Study 1999 - Byron Shire Council

A GREENPRINT FOR A SUSTAINABLE FUTURE
4.4.2 Ground-truthing
Ground-truthing involved driving and walking throughout the project area validating and checking boundaries
of polygons mapped from the API (Section 4.4.1). Basic structural (crown cover) and floristic (dominant
species of the upper stratum) attributes of polygons were recorded.
In addition, the previous studies carried out in the Shire (Table 4.1) were used to validate the interpretation
of some polygons. The use of previous work was limited to cases where the methodologies could be adapted
to the requirements of this study, and when the studies were recent enough to be reliable for the vegetation type.
Plot-based vegetation surveys (Section 4.4.4) also provided validation for a number of polygons.
The location of native fig trees was recorded throughout the ground-truthing process.
4.4.3 Incorporation into GIS databases
Polygon boundaries from aerial photo overlays were digitised, and identifiable ground control points were
used to compensate for distortion in the aerial photography and allow incorporation as a layer into the GIS
mapping system. Codes (Fig. 4.3) linked to each polygon were entered into a database.
4.4.4 Plot-based vegetation survey
Site selection
Survey sites were located to illustrate the major vegetation associations identified by API, and were chosen
to sample sites that capture a broad representation of the environmental variability found across the Shire.
Many environmental attributes are useful predictors of the distribution of floral and faunal groups. A suite
of environmental domains (synthesized by numerical classification techniques from a broad spectrum of
environmental information) developed by CSIRO was the basis of initial site selection.
Other considerations were:
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• the inclusion of areas identified during API ground-truthing as having particular significance (e.g.
areas of old-growth)
• the inclusion of at least one, and usually two, sites in each vegetation association with low to
substantial representation in the Shire (some associations with very low occurrence remained
unsurveyed)
• a good geographical spread of sites across the Shire
• the limitations of available survey effort
Survey methods
Sites were located within relatively homogeneous vegetation patches and comprised an area of 0.283 ha
(circle of 30 m radius). Species composition and abundance (semi-quantitative) was recorded for each
vegetation stratum. Where time permitted, comprehensive species lists were recorded, otherwise the lists
were confined to the dominant species in each stratum. Environmental weeds were listed separately.
Physical details of the site (altitude, slope, aspect, morphology and geology), flora and fauna habitat attributes
(old-growth characteristics, epiphytes, the density of the leaf litter and the presence of rocks and surface
water), disturbance history (evidence of fire, logging, clearing and/or grazing) were recorded. The conservation
significance was assessed (direct or indirect evidence of Threatened flora and fauna species, relationship to
reserved land and other vegetated areas, and need/potential for rehabilitation).
In the field, data were recorded onto the Field Survey Data Form (Appendix 2), and later entered into the
computer Database Record Form (Appendix 3).
Data from other studies: In addition, data from additional reliable sources were incorporated into the
database. As methodologies differed slightly in other studies, the site numbers were coded to distinguish
between data sources.