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Table 7 Environmental variables and distribution of Anopheles larvae at Ghibe River basin (November 2014–October 2016)

From: Anopheles larval species composition and characterization of breeding habitats in two localities in the Ghibe River Basin, southwestern Ethiopia

Environmental factors

An. gambiae (s. l.)

An. christyi

An. pharoensis

Mean rank

U

p

Mean rank

U

p

Mean rank

U

p

Habitat permanence

 Temporary

81.69

3137

0.455

79.9

2960.5

0.019*

81.46

3115

0.047*

 Permanent

87.37

  

89.96

  

87.69

  

Presence of algae

 Present

90.08

2808

0.235

91.56

2722.5

0.09

84.85

3111.5

0.686

 Absent

80.77

  

79.98

  

83.55

  

Surface debris

 Absent

90.21

2117

0.009*

79.05

2267

0.00*

83.23

2746

0.429

 Present

68.6

  

96.27

  

85.92

  

Intensity of light

 Shade

41.5

228

0.028*

74

423

0.36

93.42

426.5

0.237

 Lit

85.58

  

84.37

  

83.65

  
 

An. gambiae (s.l.)

An. christyi

An. pharoensis

Mean rank

χ2

df

p

Mean rank

χ2

df

p

Mean rank

χ2

df

p

Water perimeter (m)

 < 10 m

85.96

5.17

2

0.075

83.45

2.13

2

0.343

81.3

68.74

2

0.00*

 10–100 m

83.3

   

90.88

   

83.23

   

 > 100 m

40.25

   

74

   

150

   

Turbidity

 Low

87.31

0.58

2

0.748

90.33

5.34

2

0.06

85.71

1.95

2

0.376

 Medium

80.54

   

79.9

   

85

   

 High

83.78

   

80.67

   

80.69

   

Distance to nearest house (m)

 ≤ 100

94.62

10.57

3

0.014*

76.04

24.91

3

0.00*

81.14

4.57

3

0.206

 101–200

82.36

   

83.41

   

88.31

   

 201–300

63.26

   

99.83

   

84.69

   

 301–400

60.9

   

116.33

   

79

   

Canopy cover

 Open

89.75

7.955

2

0.019*

84.42

0.454

2

0.797

81.54

9.469

2

0.009*

 Tree

64.32

   

83.36

   

92.86

   

 Shrub

83.33

   

74

   

79

   

Emergent plant

 Absent

93.22

8.65

3

0.034*

82.33

7.54

3

0.057

81.29

11.84

3

0.008*

 Grass

71.81

   

91.57

   

80.28

   

 Weeds

89

   

82.3

   

86.75

   

 Grass + weeds

68.9

   

73.5

   

95.6

   

Substrate type

 Gravel

71.69

2.066

2

0.356

94.44

21.06

2

0.00*

84.03

0.838

2

0.658

 Mud

87.37

   

77.66

   

84.81

   

 Stone

78.42

   

100.24

   

81.3

   
  1. *Statistically significant at p < 0.05
  2. Df degree of freedom