Ecological Archives E087-167-A6

Selene Báez, Scott L. Collins, David Lightfoot, and Terri L. Koontz. 2006. Bottom-up regulation of plant community structure in an aridland ecosystem. Ecology 87:2746–2754.

Appendix F. Multiple regressions of rodent densities in grass- and shrub-dominated vegetation against annual and seasonal precipitation from current and previous years between 1989 and 2004. Statistically significant predictors are presented in bold.

 

df

SS

MS

F

P

Variable

Estimate

Std. Error

t

P

Shrub

 

 

 

 

 

 

 

 

 

 

R2 = 0.44

 

 

 

 

 

 

 

 

 

 

Model

2

0.222

0.111

5.154

0.023

Intercept

0.580

0.146

3.980

0.002

Error

13

0.280

0.022

 

 

Annual precipitation

0.001

0.000

2.560

0.024

C. Total

15

0.502

 

 

 

Annual precipitation previous year

0.001

0.000

2.370

0.034

R2 = 0.55

 

 

 

 

 

 

 

 

 

 

Model

4

0.274

0.068

3.300

0.052

Intercept

0.548

0.145

3.770

0.003

Error

11

0.228

0.021

 

 

Summer

0.001

0.001

1.010

0.333

C. Total

15

0.502

 

 

 

Winter-spring

0.001

0.001

1.870

0.088

 

 

 

 

 

 

Summer previous year

0.002

0.001

2.570

0.026

 

 

 

 

 

 

Winter-spring previous year

0.000

0.001

0.090

0.932

Grass

 

 

 

 

 

 

 

 

 

 

R2 = 0.06

 

 

 

 

 

 

 

 

 

 

Model

2

0.054

0.027

0.403

 

Intercept

0.449

0.416

1.080

0.302

Error

12

0.811

0.068

 

0.677

Annual precipitation

0.001

0.001

0.730

0.478

C. Total

14

0.866

 

 

 

Annual precipitation previous year

0.001

0.001

0.670

0.517

R2 = 0.49

 

 

 

 

 

 

 

 

 

 

Model

4

0.425

0.106

2.415

0.118

Intercept

0.653

0.369

1.770

0.107

Error

10

0.440

0.044

 

 

Summer

0.000

0.001

-0.450

0.662

C. Total

14

0.866

 

 

 

Winter-spring

0.001

0.001

0.870

0.406

 

 

 

 

 

 

Summer previous year

0.002

0.001

2.020

0.071

 

 

 

 

 

 

Winter-spring previous year

-0.002

0.001

-1.280

0.228



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