APPENDIX 7.1           Rapid Ecological Assessment (REA) Evaluation Framework

 

Tier I - Categorisation of Benthic Cover

Upon the completion of the survey at each transect, five ecological and seven substratum attributes were assigned to one of seven standard ranked (ordinal) categories (Tables 1 and 2 refer).

 

Table 1        Categories to be used in the Surveys - Benthic Attributes

Ecological

Substratum

Hard coral

Hard substrate

Dead standing coral

Continuous pavement

Soft coral

Bedrock

Black coral

Rubble

Macroalgae

Sand

Turf algae

Silt

 

Large boulders (>50 cm)

Small boulders (<50 cm)

 

Table 2        Categories to be used in the Surveys - Ordinal Ranks of Percentage Cover

Rank

Percentage Cover (%)

0

None recorded

1

1-5

2

6-10

3

11-30

4

31-50

5

51-75

6

76-100

 


Tier II - Taxonomic Inventories to Define Types of Benthic Communities

An inventory of benthic taxa (including counts of coral colonies) was also compiled for each transect.  Taxa were identified in situ to the following levels:

·          Scleractinian (hard) corals to species wherever possible.

·          Soft corals, anemones and conspicuous macroalgae shall be recorded according to morphological features and to genus level where possible.

·          Other benthos (including sponges, zoanthids, ascidians and bryozoans) shall be recorded to genus level wherever possible or phylum plus growth form.

 

Following the completion of the survey at each transect, each taxon in the inventory was ranked in terms of abundance in the community (Table 3).  These broad categories rank taxa in terms of relative abundance of individuals, rather than the contribution to benthic cover along each transect.  The ranks are subjective assessments of abundance, rather than quantitative counts of each taxon.

Table 3        Ordinal Ranks of Taxon Abundance

Rank

Abundance

0

Absent

1

Rare*

2

Uncommon

3

Common

4

Abundant

5

Dominant

Note:    * The classification of “rare” abundance refers to low abundance (small quantity) on the transect, rather than in terms of distribution in Hong Kong waters.