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Table 4 Marginal effects of each of the measured environmental variables on total fish and species abundances. RDA analyses were performed on average numerical data of three seasons (August, December, and March) in the year 2013/2014. All variables except pH were log-transformed before analysis. *significant at P < 0.05, **significant at P < 0.01

From: Habitat selectivity of fresh water fishes of two second-order tropical streams in Tigray, Northern Ethiopia

Explanatory variable R squared F-ratio P value
Pool (habitat) 0.159 6.435 0.003**
Depth 0.126 4.906 0.004**
Gereb Tsedo (GTS) stream 0.126 4.915 0.006**
Elala (ELA) stream 0.126 4.915 0.003**
Corixidae 0.125 4.865 0.012*
Tabanidae 0.120 4.631 0.016*
Riffle (habitat) 0.118 4.557 0.012*
Lymnaeidae 0.079 2.917 0.051
Damselfly larvae 0.074 2.705 0.049*
Dissolved oxygen 0.070 2.551 0.050
Velocity 0.040 1.427 0.058
Transparency (Snell) 0.037 1.304 0.051
Naucoridae 0.065 2.347 0.107
Planorbidae 0.052 1.869 0.133
Turbidity 0.051 1.819 0.136
Chl a 0.049 1.733 0.162
Psychodidae 0.033 1.172 0.284
Dragonfly larvae 0.032 1.127 0.312
Riparian cover 0.029 1.031 0.053
Gerridae 0.028 0.987 0.318
Herudinia 0.023 0.807 0.400
Temperature 0.022 0.780 0.402
Chironomid 0.018 0.611 0.545
Ephydridae 0.017 0.599 0.534
Mayfly larvae 0.016 0.543 0.567
Run (habitat) 0.015 0.512 0.653
Cuilcidae 0.015 0.501 0.629
Macrophytes 0.013 0.462 0.650
pH 0.013 0.453 0.602
Syrphidae 0.012 0.403 0.696
Nepidae 0.011 0.373 0.705
Altitude 0.070 0.242 0.807
Dystiscidae 0.070 0.238 0.820