Ecological Archives A016-055-A1

Alejandro C. Costamagna and Douglas A. Landis. 2006. Predators exert top-down control of soybean aphid across a gradient of agricultural management systems. Ecological Applications 16:1619–1628.

Appendix A. Tables showing Poisson regression results of the effect of agricultural management system and predator manipulation treatments on the establishment of Aphis glycines at the Kellogg Biological Station Long Term Ecological Research site, Michigan, USA, 2003.

a) Fixed effects


   

Adults

 

Nymphs

 

df

F

P

 

F

P


Agricultural treatment

2, 10

0.48

0.6314

 

0.35

0.7103

Predator treatment

2, 30

8.77

0.001

 

4.41

0.021

Agricultural treat. × pred. treat.

4, 30

0.39

0.8156

 

1.02

0.4125


 

b) Random effects


 

Adults

 

Nymphs

 

Estimate

Z

P

 

Estimate

Z

P


Block

0.06 ± 0.05

1.15

0.1241

 

0.06 ± 0.09

0.73

0.233

Block × Agricultural treat.

0.02 ± 0.03

0.45

0.3265

 

0.12 ± 0.11

1.13

0.1284

Residual

0.35 ± 0.10

     

1.75 ± 0.49

   



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