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Table 3 Effects of Lycaon pack size and population size on demographic traits

From: Do social groups prevent Allee effect related extinctions?: The case of wild dogs

Abundance (x) ⇒

  

Pack size

Population size

Fitness trait (y) ⇓

R

E

N1

N2

χ2

P

fit (y =)

SE

N1

N2

χ2

P

Litter size

Y

N

34

16

4.49

0.034

4.328 + 0.411x

0.857, 0.110

34

16

3.49

0.062

Per Capita productivity

Y

N

46

16

7.60

0.006

– 0.317 + 0.163x

0.090, 0.027

46

16

2.42

0.120

     

6.42

0.011

- 0.008x2

0.002

    

Survival of adults

Y

B

47

17

1.55

0.214

  

47

17

0.00

0.981

Survival of yearlings

Y

B

25

12

0.55

0.457

  

25

12

0.94

0.332

Survival of pups

Y

B

38

17

8.83

0.003

- 4.515 + 0.931x

1.005, 0.198

38

17

1.17

0.280

     

7.28

0.007

- 0.040 x2

0.009

    

Survival of dispersers

Y

B

17

9

4.38

0.036

- 0.873 + 0.346x

0.978, 0.117

21

11

0.18

0.673

Pack growth rate

Y

N

34

16

4.73

0.030

0.115 + 0.266x

0.147, 0.044

34

16

0.95

0.329

     

4.55

0.033

- 0.013x2

0.002

    

Pack life span

N

N

 

18

11.96

<0.001

11.467 + 3.874x

6.099, 0.940

 

18

  

Pack formation*

N

N

 

13

8.99

0.003

- 0.630 + 0.409x

0.598, 0.114

 

13

1.03

0.311

Population growth rate**

N

N

       

12

2.39

0.122

  1. R indicates whether the model has a repeated measure term or not (Y: yes, N: no). E indicates the type of distribution of errors of the models (N = normal, B: binomial). N is the sample size: the number of packs per year (N1) and the number of different packs (N2). Chi-square (χ2) and P are statistics for the GLM performed – in bold when significant. Fits are shown only for statistically significant models, with the standard errors (SE) of the estimates. * Pack formation is tested against the number of packs in the population instead of the pack size. **Sample size corresponds to the number of years of monitoring (from 1990 to 2002).