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Habitat condition is measured using several mostly quantifiable criteria with only very few qualitative ones. Each criterion is on a three-point scale or measurement levels that are mostly ordinal or ranked, with a few being nominal or type-based. In order to determine habitat condition, the SGBA employs primary data instead of solely habitat maps, augmenting its accuracy at doing so 1. As a result, the SGBA utilises 27 habitat condition criteria between terrestrial and freshwater ecosystems, with those of a marine ecosystem in-progress (see figure below).
Figure: Habitat condition criteria for terrestrial and freshwater ecosystems (marine ecosystem in-progress).
The SGBA metric employs a two-tier system of habitat condition criteria estimation: (1) criterion-based evaluation followed by (2) aggregate scoring based on scores from (1). The SGBA has measurable quantitative condition criteria, each with three levels (ordinal ranks) based on different bands of a specific unit. The resulting criterion-based scores are subsequently binned or aggregated into ordinal or ranked bands of varying score ranges. Hence, these two tiers of somewhat broad categorizations reduce the granularity of measurement.
To access the above, click on the relevant SGBA sheet(s) of the "Freshwater Condition Criteria" file as shown below (see Resources to access the SGBA metric):
As far as criterion-based evaluation of all habitats are concerned, the SGBA offers three condition measurement levels most of which are associated with quantifiable parameters. For instance, the following lists out both quantitative and quantitative criteria employed for terrestrial habitat conditions in the SGBA, each of which are on a three-level grading (as shown above) rubric of specifications (see figure below):
Figure: Mapping of condition criteria to terrestrial habitats. *: qualitative relative approximations. Est.: estimated. Diff.: difference. Two items (‘developed land’ and ‘bare ground’) of no HBU value excluded from terrestrial habitat.
Figure: Mapping of condition criteria to freshwater habitats. *: qualitative relative approximations. Est.: estimated. Diff.: difference.
It is noteworthy that to date, there are at least 15 terrestrial habitat types considered in the SGBA above, many of which are contextualised within an urbanised environment, thus, making the SGBA a valuable assessment tool for cities, towns and other comparable urbanised settings.
The following is a sample record showing how habitat condition may be recorded in the SGBA once habitat type, area and distinctiveness have been determined. Habitat area, distinctiveness and condition are multiplied in order to generate HBU scores (see table below):
Table: SGBA sample record of habitat type, baseline area, distinctiveness and condition.
To access the above, click on the relevant SGBA sheet(s) as shown below (see Resources to access the SGBA metric):
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