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: 3/2:77-111.

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<0.2 unpolluted 0.2<BC<1.2 unpolluted 1.2<BC<3.3 slightly polluted 3.3<BC<4.3 meanly polluted 4.3<BC<5.0 meanly polluted 5.0<BC<5.5 heavily polluted 5.5<BC<6.0 heavily polluted Azoic extremely polluted 6 7 (azoic)

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

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

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

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

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).

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.

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)

January 1999 May 2000 April 2002 December 2000

* 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

 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

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

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 (1993-2002).

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

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)

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.