Figure 1

Figure 2

Figure 3

Figure 4

Taxa richness and mean abundance of benthic macroinvertebrates collected above and below the Beni Haroun dam in the Kebir–Rhumel wadi_
| Taxon | Code | Above the dam | Below the dam | ||
|---|---|---|---|---|---|
| Rhumel wadi (Rh) | S-TR | Kebir wadi (Kr) | T-TR | ||
| TRICLADIDA | |||||
| Dugesia gonocephala | D.gon | 1 | 4 | 7 | 1 |
| Polycelis felina | - | 1 | 2 | 2 | |
| OLIGOCHAETA | |||||
| Lumbriculidae | 1.67 | 1 | - | - | |
| Tubifex sp. | Tub | 270 | - | - | - |
| Naididae | Nai | 16.67 | 92 | 3 | - |
| HIRUDINEA | |||||
| Dina lineata | D.lin | 29.33 | 22 | - | - |
| Erpobdella octoculata | 0.67 | - | - | - | |
| Helobdella stagnalis | H.sta | 2.67 | 3 | - | - |
| Placobdella costata | 0.67 | - | - | - | |
| GASTROPODA | |||||
| Physa acuta | P.acu | 29.33 | 42 | 12 | 2 |
| Ancylus fluviatilis | A.flu | - | 4 | - | 13 |
| Lithoglyphus naticoides | 1 | - | - | - | |
| ARACHNIDA | |||||
| Unionicola sp. | Uni | - | - | 28.33 | 60 |
| DECAPODA | |||||
| Atyaephyra desmarestii | A.des | 1.33 | 28 | 5.33 | - |
| AMPHIPODA | |||||
| Gammarus sp. | - | - | 0.67 | 4 | |
| DIPTERA | |||||
| Chironomidae | Chi | 475 | 253 | 241.33 | 440 |
| Limnophora riparia | L.rip | - | 3 | - | 16 |
| Simulium hispaniola | S.his | - | - | 0.67 | 52 |
| S. (S.) ornatum | S.orn | - | 10 | 76.33 | - |
| S. (W.) pseudequinum | S.pse | 196.67 | 25 | 116.67 | 116 |
| S. (E.) aureum | S.aur | - | - | 32.33 | 120 |
| Ceratopogonidae | Cer | - | 11 | 6.67 | 57 |
| Tabanus sp. | 4 | 2.33 | - | ||
| Culex sp. | - | 2 | - | - | |
| Tipulidae | Tip | 0.33 | 4 | 2.33 | 5 |
| Empididae | 0.67 | 2 | 1.33 | - | |
| Syrphidae | 2.33 | - | - | - | |
| Hexatoma sp. | Hex | 3.67 | 4 | 7 | 7 |
| Dicranota sp. | - | - | - | 3 | |
| Stratiomyidae | - | - | 1.67 | 2 | |
| Atherix sp. | Ath | - | - | 1.67 | 5 |
| PLECOPTERA | |||||
| Capnia nigra | - | - | 1.67 | 1 | |
| Isoperla sp. | Iso | - | - | - | 11 |
| Leuctra sp. | - | - | - | 9 | |
| EPHEMEROPTERA | |||||
| Acentrella sinaica | A.sin | - | - | 19.33 | 26 |
| Baetis pavidus | B.pav | 401.67 | 41 | 177 | 448 |
| Baetis rhodani | B.rho | - | - | 2 | 85 |
| Cloeon dipterum | C.dip | 1.67 | 7 | - | 23 |
| Cloeon saharense | - | - | - | 5 | |
| Procloeon stagnicola | P.sta | - | - | 3.33 | 6 |
| Caenis luctuosa | C.lus | 1 | 310 | 89 | 77 |
| Caenis pusilla | C.pus | - | - | 3.33 | 67 |
| Ecdyonurus rothschildi | E.rot | - | - | 1.33 | 41 |
| Choroterpes atlas | C.atl | - | - | - | 62 |
| Choroterpes lindrothi | C.lin | - | - | - | 13 |
| COLEOPTERA | |||||
| Laccophilus hyalinus | 1 | 3 | 0.67 | - | |
| Aulonogyrus striatus | A.str | - | - | 6.67 | - |
| Gyrinus dejeani | - | 2 | 1 | - | |
| Limnius intermedius | L.int | 0.33 | 11 | 0.67 | 37 |
| Esolus filum | E.fil | 7 | - | 1.67 | 20 |
| Stenelmis consobrina | S.con | - | - | - | 41 |
| Dryops sp. | Dry | 0.33 | 6 | 6.33 | - |
| Hydraena sp. | 3 | - | 1 | - | |
| Ochthebius | - | 1 | - | - | |
| Hydrobius sp. | 0.67 | 7 | - | - | |
| Laccobius gracilis | L.gra | 3.33 | - | 2 | - |
| Crenitis sp. | - | 8 | - | - | |
| Coelostoma sp. | - | 1 | - | - | |
| Helochares obscurus | 2.67 | - | - | - | |
| Hydrochus sp. | 2 | - | - | - | |
| Hydrocyphon sp. | - | - | - | 7 | |
| TRICHOPTERA | |||||
| Hydropsyche lobata | H.lob | 51.33 | 48 | 91.33 | 193 |
| Hydropsyche maroccana | H.mar | 2.33 | 27 | 23 | 49 |
| Cheumatopsyche lepida | C.lep | - | - | 6 | 24 |
| Rhyacophila munda | - | - | - | 2 | |
| Pararhyacophila sp. | Par | - | - | 1 | 15 |
| Chimarra marginata | C.mar | - | - | - | 64 |
| Psychomyia pusilla | - | - | 2 | 1 | |
| ODONATA | |||||
| Gomphus lucasii | G.luc | - | - | 6.67 | - |
| Praragomphus genei | - | - | - | 2 | |
| Onychogomphus costae | - | - | 1.33 | - | |
| O. unguiculatus | - | - | 1.67 | 2 | |
| Boyeria irene | - | - | - | 3 | |
| Orthetrum chrysostigma | - | 2 | 0.67 | - | |
| Sympetrum fonscolombii | 0.67 | - | 1 | - | |
| Sympetrum striolatum | 0.33 | - | 0.67 | - | |
| Brachythemis impartita | 1.67 | 4 | 2.33 | - | |
| Coenagrion sp. | Coe | 2.33 | 3 | 1 | - |
| Erythromma lindenii | - | 5 | - | - | |
| Ischnura graellsii | 0.67 | 3 | - | - | |
| Platycnemis subdilatata | - | - | 0.33 | - | |
| HETEROPTERA | |||||
| Nepa sp. | 0.67 | - | 0.67 | 1 | |
| Micronecta sp. | Mic | 110.33 | 420 | 20.67 | - |
| Corixa punctata | 2 | - | - | - | |
| Paracorixa concinna | 2.67 | - | - | - | |
| Microvelia pygmaea | - | 6 | - | - | |
| Gerris lacustris | G.lac | 1.67 | 4 | 3.33 | - |
| Naucoris maculatus | - | 4 | 2.67 | - | |
| Naucoris cimicoides | - | - | 0.67 | - | |
| Notonecta obliqua | N.obl | 3.33 | - | - | - |
| Anisops sardea | 1 | - | - | - | |
| Abundance | 1634.35 | 1438 | 1032.68 | 2240 | |
| Number of taxa | 43 | 41 | 54 | 46 | |
SIMPER and one-way ANOSIM on pairwise comparisons of sites using Bray–Curtis dissimilarities_ Upper triangular matrix shows the overall average dissimilarity (%) and lower triangular matrix shows the R-statistic_ Ns: not significant difference (p > 0_05)_
| Above the dam | Below the dam | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| R-UC | R-C | R-DC | S-TR | K-UC | K-C | K-DC | T-TR | ||
| R-UC | 45.56 | 40.77 | 61.68 | K-UC | 45.57 | 42.99 | 62.75 | ||
| R-C | 0.35 | 39.48 | 56.5 | K-C | 0.24 | 48.99 | 61.10 | ||
| R-DC | 0.05Ns | 0.20Ns | 61.33 | K-DC | 0.19Ns | 0.20Ns | 60.41 | ||
| S-TR | 0.97 | 0.97 | 1.00 | T-TR | 0.99 | 1.00 | 0.79 | ||
Output from SIMPER analysis of macroinvertebrates, showing the most influential taxa to total dissimilarity among segments (Rh, S-TR, Kr, and T-TR)_ List of taxa, which cumulatively account for 50% of the dissimilarity between sample groups_ Av_%_ dissim: average% dissimilarity,%_ Cont_ dissim: % Contribution to the dissimilarity_
| Pairwise comparison | R-statistic | Av.%. dissim | Most discriminating taxa | %. Cont. dissim | Most discriminating taxa | %. Cont. dissim |
|---|---|---|---|---|---|---|
| Rh vs. S-TR | 0.95 | 59.84 | Caenis luctuosa | 7.72 | Tubifex sp. | 4.28 |
| Micronecta sp. | 6.17 | Hydropsyche maroccana | 3.35 | |||
| Naididae | 5.97 | Limnius intermedius | 2.83 | |||
| Simulium. (W.) pseudequinum | 5.59 | Dina lineata | 2.52 | |||
| Baetis pavidus | 5.49 | Esolus filum | 2.26 | |||
| Atyaephyra desmarestii | 4.3 | |||||
| Rh vs. Kr | 0.87 | 59.09 | Simulium. (S.) ornatum | 5.77 | Physa acuta | 3.71 |
| Caenis luctuosa | 5.47 | Hydropsyche maroccana | 3.56 | |||
| Tubifex sp. | 4.84 | Simulium. (W.) pseudequinum | 3.42 | |||
| Micronecta sp. | 4.5 | Acentrella sinaica | 2.94 | |||
| Dina lineata | 4.29 | Baetis pavidus | 2.61 | |||
| Chironomidae | 4.1 | Gomphus lucasii | 2.40 | |||
| Simulium. (E.) aureum | 3.98 | |||||
| Kr vs. T-TR | 0.9 | 61.42 | Baetis rhodani | 4.44 | Caenis pusilla | 3.06 |
| Chimarra marginata | 4.18 | Chironomidae | 2.79 | |||
| Choroterpes atlas | 3.99 | Caenis luctuosa | 2.71 | |||
| Simulium. (S.) ornatum | 3.83 | Simulium. (E.) aureum | 2.7 | |||
| Limnius intermedius | 3.53 | Cloeon dipterum | 2.69 | |||
| Simulium hispaniola | 3.52 | Stenelmis consobrina | 2.56 | |||
| Ecdyonurus rothschildi | 3.49 | Unionicola sp. | 2.39 | |||
| Simulium. (W.) pseudequinum | 3.18 | |||||
| S-TR vs. T-TR | 1 | 70.58 | Micronecta sp. | 5.78 | Simulium hispaniola | 2.99 |
| Naididae | 3.97 | Caenis luctuosa | 2.97 | |||
| Baetis rhodani | 3.85 | Atyaephyra desmarestii | 2.80 | |||
| Baetis pavidus | 3.67 | Physa acuta | 2.58 | |||
| Chimarra marginata | 3.36 | Caenis pusilla | 2.57 | |||
| Choroterpes atlas | 3.21 | Simulium. (W.) pseudequinum | 2.49 | |||
| Simulium. (E.) aureum | 3.05 | Acentrella sinaica | 2.17 | |||
| Ecdyonurus rothschildi | 3 | Stenelmis consobrina | 2.06 |
Mean ± SD values of physicochemical variables at the sampling stations above and below the Beni Haroun dam in the Kebir–Rhumel wadi_ Values in bold indicate significant differences based on ANOVA_
| Variable | Above the dam | Below the dam | p-value | ||||||
|---|---|---|---|---|---|---|---|---|---|
| R-UC | R-C | R-DC | S-TR | K-UC | K-C | K-DC | T-TR | ||
| T (°C) | 18.00 ± 6.08 | 18.00 ± 6.24 | 18.00 ± 7.00 | 14.67 ± 5.51 | 16.33 ± 6.66 | 15.67 ± 6.35 | 15.33 ± 6.66 | 12.33 ± 4.93 | 0.526 |
| pH | 8.23 ± 0.47 | 8.17 ± 0.35 | 8.10 ± 0.53 | 8.90 ± 0.35 | 8.80 ± 0.46 | 8.53 ± 0.38 | 8.67 ± 0.25 | 9.33 ± 0.35 | 0.062 |
| DO (mg l−1) | 5.17 ± 0.85 | 5.23 ± 1.08 | 4.83 ± 0.99 | 6.40 ± 0.61 | 6.53 ± 0.70 | 6.73 ± 0.83 | 6.67 ± 0.65 | 7.93 ± 0.40 | 0.003 |
| EC (μS cm−1) | 1701 ± 290.11 | 1693.33 ± 344.29 | 1728.33 ± 358.34 | 1370 ± 329.7 | 986.67 ± 100.66 | 1048.33 ± 101.15 | 1050.67 ± 115.52 | 718.33 ± 163.58 | 0.0001 |
| Salinity | 0.87 ± 0.25 | 0.89 ± 0.30 | 0.92 ± 0.34 | 0.62 ± 0.13 | 0.51 ± 0.14 | 0.51 ± 0.13 | 0.52 ± 0.13 | 0.29 ± 0.08 | 0.034 |
| NH4+ (mg l−1) | 1.90 ± 0.79 | 3.68 ± 1.83 | 3.98 ± 1.69 | 1.85 ± 2.82 | 0.14 ± 0.04 | 0.13 ± 0.03 | 0.12 ± 0.03 | 0.08 ± 0.03 | 0.009 |
| NO2− (mg l−1) | 2.58 ± 2.46 | 1.94 ± 1.69 | 2.26 ± 2.06 | 0.36 ± 0.33 | 0.07 ± 0.05 | 0.06 ± 0.04 | 0.06 ± 0.05 | 0.02 ± 0.02 | 0.028 |
| NO3− (mg l−1) | 2.75 ± 2.37 | 2.40 ± 1.71 | 3.23 ± 3.02 | 3.56 ± 1.09 | 0.67 ± 0.29 | 0.89 ± 0.27 | 0.98 ± 0.30 | 0.32 ± 0.16 | 0.023 |
| PO43− (mg l−1) | 2.37 ± 0.59 | 2.52 ± 1.00 | 2.51 ± 0.87 | 1.56 ± 0.46 | 0.46 ± 0.12 | 0.44 ± 0.17 | 0.45 ± 0.16 | 0.31 ± 0.17 | 0.0001 |
Value of BMWP’ (Alba-Tercedor & Pujante, 2000) and ASPT biotic indices (Hynes, 1998) and color codes according to corresponding water quality classes_
| Bioclassification of water quality | |||||
|---|---|---|---|---|---|
| BMWP’ score | ≤15 | 16–35 | 36–60 | 61–100 | 101–150 |
| Color codes | Very critical | Critical | Dubious | Passable | Good |
| ASPT values | <3.9 | 4–4.9 | 5–5.9 | 6–6.9 | >7 |
| Color codes | Very poor | Poor | Moderate | Good | Very good |
Value of EPT richness according to corresponding water quality bioclassification categories (Bode et al_, 1996)_
| EPT richness index | <2 | 2–5 | 6–10 | >10 |
|---|---|---|---|---|
| Water quality | Poor | Clean | Good | Excellent |
Water quality classification system based on the BI values (Hilsenhoff, 1987)_
| Biotic index | Water quality | Degree of organic pollution |
|---|---|---|
| 0.00–3.50 | Excellent | Organic pollution unlikely |
| 3.51–4.50 | Very good | Possible slight organic pollution |
| 4.51–5.50 | Good | Some organic pollution probable |
| 5.51–6.50 | Fair | Fairly substantial pollution likely |
| 6.51–7.50 | Fairly poor | Substantial pollution likely |
| 7.51–8.50 | Poor | Very substantial pollution likely |
| 8.51–10.00 | Very poor | Severe organic pollution likely |
Pearson’s correlation between diversity and biotic indices with water physicochemical parameters_
| S | H′ | EPT | EPT/(EPT + Chironomidae) | BI | BMWP′ | ASPT | |
|---|---|---|---|---|---|---|---|
| T°C | –0.83* | –0.93** | –0.83* | –0.74* | 0.86** | –0.85** | –0.82* |
| pH | 0.87** | 0.92** | 0.81* | 0.60 | –0.81* | 0.87** | 0.81* |
| DO | 0.76* | 0.97** | 0.81* | 0.74* | –0.89* | 0.79** | 0.91* |
| EC | –0.65 | –0.92** | –0.76* | –0.66 | 0.78* | –0.69 | –0.91** |
| Salinity | –0.71* | –0.95** | –0.77* | –0.69 | 0.84** | –0.74* | –0.90** |
| NH4+ | –0.47 | –0.79* | –0.52 | –0.43 | 0.77* | –0.50 | –0.73* |
| NO2− | –0.66 | –0.92** | –0.53 | –0.74* | 0.79* | –0.64 | –0.76* |
| NO3− | –0.36 | –0.69 | –0.66 | –0.50 | 0.57 | –0.44 | –0.87** |
| PO3− | –0.55 | –0.87** | –0.61 | –0.62 | 0.75* | –0.57 | –0.83* |
Mean ± SD values of biological indices and classification of water quality at the sampling stations above and below the Beni Haroun dam in the Kebir–Rhumel wadi_ Values in bold indicate significant differences based on ANOVA_
| Biological index | Above the dam | Below the dam | p-value | ||||||
|---|---|---|---|---|---|---|---|---|---|
| R-UC | R-C | R-DC | S-TR | K-UC | K-C | K-DC | T-TR | ||
| Taxonomic richness (S) | 14.00 ± 1.00 | 18.00 ± 1.73 | 13.33 ± 2.31 | 24.33 ± 5.13 | 20.33 ± 2.08 | 14.00 ± 1.73 | 23.33 ± 4.16 | 27.67 ± 1.53 | 0.006 |
| Shannon-Wiener index (H’) | 1.57 ± 0.25 | 1.82 ± 0.02 | 1.46 ± 0.43 | 2.19 ± 0.43 | 2.13 ± 0.39 | 2.16 ± 0.12 | 2.25 ± 0.21 | 2.57 ± 0.10 | 0.003 |
| EPT index | 2 | 2.66 ± 0.58 | 2.33 ± 0.58 | 2.66 ± 0.58 | 3.66 ± 0.58 | 2.66 ± 0.58 | 4 | 8.33 ± 1.53 | 0.009 |
| Water-quality-evaluation rating | Clean | Clean | Clean | Clean | Clean | Clean | Clean | Good | |
| EPT/(EPT + Chironomidae) | 0.37 ± 0.04 | 0.64 ± 0.22 | 0.51 ± 0.16 | 0.65 ± 0.15 | 0.53 ± 0.25 | 0.71 ± 0.21 | 0.71 ± 0.31 | 0.76 ± 0.27 | 0.30 |
| Hilsenhoff biotic index (BI) | 6.41 ± 1.94 | 6.38 ± 1.11 | 7.07 ± 0.64 | 5.85 ± 0.09 | 6.29 ± 0.49 | 5.79 ± 0.50 | 5.90 ± 0.56 | 5.54 ± 0.57 | 0.34 |
| Water-quality-evaluation rating | Fair | Fair | Poor | Fair | Fair | Fair | Fair | Fair | |
| BMWP’ index | 47.00 ± 20 | 64.66 ± 7.57 | 42.00 ± 7.21 | 83.33 ± 14.29 | 70.00 ± 16.64 | 47.66 ± 2.08 | 86.00 ± 15.62 | 108.66 ± 12.42 | 0.001 |
| Water-quality-evaluation rating | Dubious | Passable | Dubious | Passable | Passable | Dubious | Passable | Good | |
| ASPT index | 3.52 ± 0.21 | 4.22 ± 0.20 | 3.42 ± 0.23 | 3.96 ± 0.24 | 4.74 ± 0.40 | 4.62 ± 0.41 | 4.99 ± 0.25 | 6.05 ± 0.28 | 0.0001 |
| Water-quality-evaluation rating | Very poor | Poor | Very poor | Very poor | Poor | Poor | Poor | Good | |