Appendix 1. Pressures that might impact environmental quality and the deterioration of ecosystems were calculated at each sampling site in order to establish the stressor gradient.

Pressure code / Description /

Calculation

/ Data used
DQO_AC / Cumulative effects of biodegradable discharges from wastewater treatment plants (urban and industrial), and untreated biodegradable discharges. An extinction coefficient is considered downstream. /


/ DQOEDAR = Increase of organic matter, chemical oxygen demand (COD) dumped from waste water treatment plants, in the river (mg/L).
Qd = Water discharge from waste water treatment plants (L/s).
DQO media = Average of chemical oxygen demand (COD) dumped from the waste water plants (mg/L)
RN = Flow regime in the river. Median discharge from a period since 1985 to 2000 (m3/s).
DQOHAB = Increase of organic matter, COD dumped from untreated biodegradable discharges, in the river (mg/L).
DQO hab = Absolute value of chemical oxygen demand (COD) from the untreated urban areas (mg/L).
DQOtot = Increase of organic matter, COD dumped from waste water treatment plants and untreated biodegradable discharges, in the river (mg/L).
Long_río = River length from the discharge site until the sampling site analysed (m)
DSU / Effects of sewage discharges from storm water systems. /
/ V_esc = Annual runoff from storm water systems (L)
Prec_anual = Annual rainfall upon storm water system (L/m2)
S_urb = Storm water drainage area (m2)
coef_imp. = Coefficient of impermeability = 0,75
conc_DQO = Average COD from storm water discharges = 702,6 mg/L
UA / Diffuse pollution pressure due to agricultural land uses /
/ Superf_UAi = Drainage area for every 3 types of agricultural land uses (a, b, c) (km2)
i = agricultural land uses types: (a) Non intensive agriculture (e.g. pastures), and non irrigated areas (e.g. cereals), (b) Intensive agriculture (e.g. vineyards, orchards) and irrigated fields, (c) rice fields.
Imp. Coef. i= Impact coefficient for every 3 type of agricultural land uses (a = 0.25; b = 0.5: c = 1)
Coef_ap = Runoff coefficient = runoff in each sampling site (L/m3) / watershed average runoff (L/m2)
Superf_CA = Drainage area (km2)
UU / Diffuse pollution pressure due to urban land uses / / Superf_UU= Urban area (km2)
EN / Diffuse pollution pressure due to excess nitrogen from agricultural and cattle activities in the basin / / Carga_N = Nitrogen discharge calculated from fertilisation treatments, Irrigation return flows, and cattle activities in the basin (Kg N/year)
SC / Diffuse pollution pressure due to contaminated and potentially contaminated soils / / Superf_SC = Contaminated soil area in the basin (km2).
RS / Diffuse pollution pressure due to mining zones, saline wastes and landfills. / / Superf_RS = Mining zones, saline activities and landfills areas in the basin (km2).

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Appendix 2. Metrics used to calculate the multimetric water quality indices analysed in the Spanish Mediterranean rivers using the macroinvertebrate communities. The metrics based on both qualitative and quantitative data are separately shown.

Metric name / Assessment / Origin/source / Type of metric
Based on qualitative data
IASPT / IBMWP value / number of families / Alba-Tercedor Sánchez-Ortega, 1988) / Sensitive taxa
ASPT / BMWP value / number of families / Armitage et al., 1983 / Sensitive taxa
Num. Fam. / Number of families / AQEM Consortium, 2002 / Taxonomic composition / abundance
EPT / Number of families of Ephemeroptera, Plecoptera and Trichoptera / AQEM Consortium, 2002 / Taxonomic composition
% Sel ETD / Percentage of families of Heptageniidae, Ephemeridae, Brachycentridae, Goeridae, Odontoceridae, Limnephilidae, Polycentropodidae, Athericidae, Dixidae, Dolichopodidae, Empididae and Stratiomyidae / AQEM Consortium, 2002 / Taxonomic composition, sensitive taxa, major taxonomic groups
% Sel EPTCD / Percentage of families of Leptophlebiidae, Ephemerellidae, Chloroperlidae, Nemouridae, Leuctridae, Philopotamidae, Limnephilidae, Psychomyiidae, Sericostomatidae, Elmidae, Dryopidae and Athericidae) / Proposed by the authors of the present work in the Med-GIG intercalibtarion exercise / Taxonomic composition, sensitive taxa, major taxonomic groups
Based on quantitative data
Shannon Diversity / Shannon diversity index
/ Shannon & Weaver, 1949
Böhmer et al., 2004 / Diversity
Evenness / Shannon diversity / Ln (number of families) / Böhmer et al., 2004 / Diversity
1-GOLD / 1 – relative abundance of Gasteropoda, Oligochaeta and Diptera / Pinto et al., 2004 / Taxonomic composition, sensitive taxa, major taxonomic groups
Log(Sel EPTD+1) / Log 10 (sum of Heptageniidae, Ephemeridae. Leptophlebiidae, Nemouridae, Brachycentridae, Goeridae, Polycentropodidae, Limnephilidae, Odosntoceridae, Dolichopodidae, Stratyomyidae, Dixidae, Empididae, and Athericidae (ind./m2) + 1) / Buffagni & Erba, 2004; Buffagni et al., 2005 / Taxonomic composition, sensitive taxa, major taxonomic groups
Log (Sel ETD+1) / Log 10 (sum of Heptageniidae, Ephemeridae, Brachycentridae, Goeridae, Odontoceridae, Limnephilidae, Polycentropodidae, Athericidae, Dixidae, Dolichopodidae, Empididae and Stratiomyidae (ind./m2) + 1) / Buffagni & Erba, 2004; Buffagni et al., 2005 / Taxonomic composition, sensitive taxa, major taxonomic groups
Log (Sel EPTCD+1) / Log 10 (sum of (Leptophlebiidae, Ephemerellidae, Chloroperlidae, Nemouridae, Leuctridae, Philopotamidae, Limnephilidae, Psychomyiidae, Sericostomatidae, Elmidae, Dryopidae, and Athericidae (ind./m2) + 1) / Proposed by the authors of the present work in the Med-GIG intercalibtarion exercise / Taxonomic composition, sensitive taxa, major taxonomic groups

Appendix 3. Most appropriate regression formula for the IBMWP, ICM-10 and ICM-11a indices converted to the ICM-Star index. The coefficient regression is also shown. The corrected Akaike’s Information Criterion (AICc) values (see Figure 6) were used to select the best fit model.

Biological indices

River type

/ IBMWP / ICM-10 / ICM-11a
R-M1 / Regression formula / ICM-Star = 1.99 – 1.94 (1/IBMWP+1) / ICM-Star = 0.05 + 0.94 ICM-10 / ICM-Star = 0.10 + 0.90 ICM-11a
Coefficient (r2) / 0.88 / 0.95 / 0.91
R-M4 / Regression formula / ICM-Star = 1.75 – 1.58 (1/IBMWP+1) / ICM-Star = 0.20 + 0.78 ICM-10 / ICM-Star = 0.37 + 0.58 ICM-11a
Coefficient (r2) / 0.63 / 0.81 / 0.62
R-M5 / Regression formula / ICM-Star = 1.96 – 1.92 (1/IBMWP+1) / ICM-Star = 0.06 + 0.93 ICM-10 / ICM-Star = 0.07 + 0.94 ICM-11a
Coefficient (r2) / 0.83 / 0.89 / 0.89

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