Predictor variables

Model 1: Period 1 > 200

Model 2: Period 1 < 200

Model 3: Period 2 < 200+

b

s.e

Beta

b

s.e

Beta

b

s.e

Beta

Ave. length

−1.13 × 10−4

7.33 × 10−6***

−0.61

−9.13 × 10−6

3.32 × 10−6**

−0.22

−3.06 × 10−4

7.70 × 10−5***

−0.45

Water depth

9.04 × 10−5

3.12 × 10−5**

0.12

1.71 × 10−5

1.10 × 10−5

0.13

Density

−1.59 × 10−4

3.64 × 10−5***

−0.18

−1.75 × 10−5

1.36 × 10−5

−0.10

New culms

3.35 × 10−3

1.36 × 10−3*

0.28

NH4

−3.25 × 10−3

1.50 × 10−3*

−0.09

−1.32 × 10−3

6.17 × 10−4*

−0.20

SRP

1.46 × 10−2

1.43 × 10−2

0.10

TP

6.43 × 10−2

2.68 × 10−2*

0.27

Dummy (site)

1.49 × 10−3

7.00 × 10−4*

0.09

a

0.0374

0.0463

0.02382

R2

0.37

0.08

0.27

F

49.95

3.71

8.33

P

<0.001

<0.05

<0.001

Durbin-Watson statistics

1.7876

2.17

1.7710