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TableĀ 3 The frequency and percentages of the categorical predictor variables used to assess the occurrence and abundance freshwater snail species in the Ethiopian Rift Valley

From: Environmental and biotic factors affecting freshwater snail intermediate hosts in the Ethiopian Rift Valley region

Predictor variable Category Tropical rainy climate zone Warm temperate rainy climate zone
Frequency Percentage Frequency Percentage
Emergent macrophyte cover Very low 32 34 11 13
Low 13 14 7 8
Moderate 15 16 25 29
High 19 20 13 15
Very high 10 11 29 34
Submerged macrophyte cover Very low 44 47 40 47
Low 45 48 44 52
Moderate 0 0 0 0
High 0 0 0 0
Very high 0 0 1 1
Floating macrophyte cover Very low 30 32 30 35
Low 38 41 40 47
Moderate 9 10 7 8
High 6 7 3 4
Very high 6 75 5 6
Substrate type Grass 50 56 72 85
Silt 25 28 7 8
Detritus 14 16 6 7
Predators occurrence Absent 6 6 6 7
Present 83 86 79 85
Competitors occurrence Absent 87 90 81 87
Present 2 2 4 4
Farming Absent 71 80 62 73
Present 18 20 23 27
Solid waste dumping Absent 82 92 69 81
Present 7 8 16 19
Grazing Absent 52 58 34 40
Present 37 42 51 60
Silviculture Absent 73 82 64 75
Present 16 18 21 25
Drainage of land Absent 80 90 73 86
Present 9 10 12 14
Open defecation Absent 86 97 77 91
Present 3 3 8 9
Effluent discharge Absent 88 99 83 98
Present 1 1 2 2
Fishing Absent 75 84 70 82
Present 14 16 15 18
Bathing and swimming Absent 80 90 72 85
Present 9 10 13 15
Clothes washing Absent 81 91 71 84
Present 8 9 14 17
Car washing Absent 85 96 84 99
Present 4 5 1 1
Boating Absent 82 92 84 99
Present 7 8 1 1
Settlement Absent 63 71 79 93
Present 26 29 6 7