Ecological Archives E088-013-A1

Pamela Graff, Martín R. Aguiar, and Enrique J. Chaneton. 2007. Shifts in positive and negative plant interactions along a grazing intensity gradient. Ecology 88:188–199.

Appendix A (Table A1). Results of complete randomized split-plot ANOVA for the effect of grazing intensity (G), barrier to belowground competition (B), and distance to neighbor (D) on different biomass compartments of Poa ligularis and Bromus pictus.

   

Total plant biomass

Shoot biomass

Root biomass

Panicle biomass

Source of Variation

df

F

P

F

P

F

P

F

P

Poa ligularis

                 

Main plot

                 

Grazing (G)

2

4.08

0.07

6.02

0.0368

0.98

0.42

6.48

0.0317

Main plot error

6

MS = 0.3934

MS = 0.0543

MS = 0.0257

MS = 0.0066

Subplot

                 

Barrier (B)

1

12.59

0.0023

7.42

0.0139

53.22

<0.0001

2.94

0.10

Distance(D)

1

3.21

0.09

4.40

0.05

0.28

0.60

0.00

0.99

B × D

1

7.41

0.0140

3.56

0.07

4.30

0.05

0.12

0.73

G × B

2

11.41

0.0006

8.90

0.0021

13.44

0.0003

4.32

0.0294

G × D

2

5.49

0.0138

6.58

0.0071

0.58

0.57

1.02

0.38

G × D × B

2

2.25

0.13

0.99

0.39

2.52

0.10

0.06

0.94

Subplot error

18

MS = 0.0883

MS = 0.0202

MS = 0.0036

MS = 0.0059

 

Bromus pictus

                 

Main plot

                 

Grazing (G)

2

4.58

0.06

8.38

0.0183

1.61

0.27

61.23

0.0001

Main plot error

6

MS = 0.1422

MS = 0.0213

MS = 0.0153

MS = 0.0015

Subplot

                 

Barrier (B)

1

6.17

0.0231

0.09

0.77

45.35

<0.0001

1.18

0.29

Distance(D)

1

10.50

0.0045

12.82

0.0021

0.88

0.36

0.01

0.90

B × D

1

1.15

0.29

0.32

0.57

7.05

0.0161

0.42

0.52

G × B

2

1.39

0.27

0.68

0.51

0.86

0.44

2.55

0.10

G × D

2

2.04

0.15

2.76

0.08

0.42

0.66

0.05

0.94

G × D × B

2

0.66

0.53

0.77

0.47

0.03

0.96

0.65

0.53

Subplot error

18

MS = 0.0356

MS = 0.0132

MS = 0.004

MS = 0.0040



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