Table 1 Average (∆CSav) and net changes in fish compositional similarity (∆CS %), maximum taxonomic homogenization or differentiation (Max TH/TD), and percentage of watersheds with no variation in compositional similarity (∆CS = 0 %) between watersheds found in different biotic units (i.e., between units). Significant probabilities (p < 0.05) supporting evidence for ∆CS (ANOSIM) and TH versus TD are in italics

U1-U2

1.8

54.3

45.7

34.0/−31.2

0

0.31

0.001

TH: 0.012

U1-U3

2.1

61.3

38.7

27.0/−19.0

0

0.34

0.013

TH: 0.030

U1-U4

1.4

57.2

42.8

23.0/−26.3

0

0.43

0.001

TH: 0.018

U1-U5

1.9

53.8

46.2

21.7/−34.3

0

0.39

0.034

TH: 0.021

U2-U3

2.4

87.9

12.1

57.0/−18.0

0

0.32

0.001

TH: 0.020

U2-U4

1.7

74.2

25.8

25.0/−21.0

0

0.41

0.001

TH: 0.010

U2-U5

4.3

68.0

31.4

22.0/−26.0

1

0.53

<0.001

TH: 0.010

U3-U4

2.9

63.4

35.1

28.0/−23.8

19

0.40

0.001

TH: 0.026

U3-U5

−2.5

45.0

54.9

3.0/−35.2

1

0.50

<0.001

TD: 0.320

U4-U5

−4.2

22.5

77.5

37.0/−19.9

44

0.45

0.001

TD: 0.001

U5-U6

1.3

53.2

46.8

36.0/−33.3

49

0.35

<0.001

TH: 0.519