1. Mediterranean Marine Science: 3/2:77-111.
Benthic indicators to use in Ecological Quality classification of Mediterranean soft bottom marine ecosystems, including a new Biotic Coefficient.
N. SIMBOURA and A. ZENETOS
National Centre for Marine Research, Institute of Oceanography, Anavissos 19013, Attiki, Greece.
Mediterranean Marine Science: 3/2:

2. Biotic Coefficient (Βorja et al. , 2000) {(0 x % GI) + (1
Biotic Coefficient (Βorja et al., 2000) {(0 x % GI) + (1.5 X % GII) + (3 x % GIII) + (4.5 X % GIV) + (6 X % GV)}/100
Biotic Index
Biotic Coefficient
0 (reference)
0.0<BC< unpolluted
0.2<BC< unpolluted
1.2<BC< slightly polluted
3.3<BC< meanly polluted
4.3<BC< meanly polluted
5.0<BC< heavily polluted
5.5<BC< heavily polluted
Azoic extremely polluted 6
7 (azoic)

3. a) reduction of the groups involved
GI: GI sensitive- GII indifferent
GII: GIII tolerant- GIV second order opportunistic
GIII: GV first order opportunistic

4. b) Selection of the numerical coefficients
c) Development of the formula

5. Examples of sensitive species in Ecol. Group (GI)
Benthic group
Sensitive indicator
species
Ecological Group
Pol
Aricidea capensis I
Aponuphis bilineata
Abarenicola claparedii
Mol
Timoclea ovata
Turitella communis
Ech
Labidoplax digitata
Ophelia bicornis
Laetmonice hystrix
Armandia cirrosa

6. Tolerant Indicator Species
Examples of tolerant species belonging to Ecological Groups GII and GIII
Benthic group
Tolerant Indicator Species
Ecological group
Pol
Levinsenia gracilis II
Eunice vittata
Lumbrineris latreilli
Mol
Loripes lacteus
Myrtea spinifera
Ech
Amphiura filiformis
Capitella capitata
III
Malacoceros fuliginosus
Corbula gibba

7. Bentix= { 6 X %GI) + 2 X (% GII + % GIII)}/100
Classification system based on the Bentix Index for soft bottom coastal communities proposed for the Mediterranean Sea
Bentix= { 6 X %GI) + 2 X (% GII + % GIII)}/100
Some refinement of the limits is suggested for physically stressed habitats as are muddy habitats: moderate (2,5-3), good (3-4) and high (>4).

8. moderate good high bad poor
Bentix index= { 6 X %GI) + 2 X (% GII + % GIII)}/100
GI: sensitive species-indifferent
GII: tolerant-second order opportunistic
GIII: first order opportunists
moderate
good
high
bad
poor
 Degradation model of benthic communities health illustrating percentages of ecological groups and Bentix index values.

9. Athens central Sewage outfalls (Psittalia Primary Treatment Plant)
Application and validation of the method in Saronikos gulf
EcoQS
Athens central Sewage outfalls (Psittalia Primary Treatment Plant)
high
good
moderate
poor
Representation of the EcoQ status in terms of the Bentix index in Saronikos gulf (December 2000 data)

10. January 1999
May 2000
April 2002
December 2000

11. * Dissolved oxygen concentration in the bottom layer
Particulate Organic carbon concentration in seawater
Relationship of the Bentix index to water quality factors in Saronikos gulf
* Statistically significant correlation
Total organic carbon content in sediment

12.  S/0.12 Bentix
Sandy mud
mud
Muddy sand
Comparison of the Bentix index results to the community Diveristy (H’) and the Species richness indices in Saronikos gulf stations

13. Larymna ferro-nickel plant
Application of the method in an area of dumping metalliferous waste (Larymna, N. Evvoikos Gulf)
EcoQS
good
moderate
Larymna ferro-nickel plant
Dumping ground

14. Bentix index Analysis of variance in control (BE1) and dumping stations (LA10, LA12, LA14).
Reduction trend of the Bentix index in station LA10 with continuing use as a dumping site ( ).

15. Advantages of using the Bentix Index
Independent of sample size
Independent of community type
Independent of seasonal variations of total abundance
Could be applied in the whole Mediterranean
Reflects faunal sensitivity or tolerance to disturbance which is in some cases a more reliable trait of the community than diversity measurements are
Easy and quick calculation, species can virtually be grouped into only two ecological groups: sensitive and tolerant
Use of only two ecological groups reduces overlapp in the grouping and uncertainty in species grouping
Proved robust and effective in classifying benthic communities into ECoQ classes
liable only to type 1 error-(stricter classification)
integrated descriptor facilitating classboundary setting of the macrozoobenthos quality element

16. Indifferent and negative traits of using the Bentix index
Requires satisfying level of taxonomic expertise to assign all specimens to an ecological group
does not reflect total abundance and diversity (quality element components required in WFD for benthic invertebrate fauna) but this is not proved essential for classification purposes
Not efficient for classification of lagoonar ecosystems
Does not reflect species richness which should also been taken into account for classification purposes in cases of very low abundance values (almost defaunated bottoms)

17. Future tasks
Validation and checking with more Mediterranean data sets
Testing with other Ecoregions data sets (North Atlantic, Baltic Sea)
development of a method to intergrate variation of the Bentix index among samples collected from the same site at different periods, due to varying ecological status, to a single representative for the site Ecological quality class.