Ecological Archives E096-150-A1

Thomas L. Anderson and Howard H. Whiteman. 2015. Asymmetric effects of intra- and interspecific competition on a pond-breeding salamander. Ecology 96:16811690. http://dx.doi.org/10.1890/14-0479.1

Appendix A. Additional figures and tables of experimental design, model selection results, and parameter estimates.

FigA1

Fig. A1. Density combinations of the response surface design. All treatments had five replicates, except for the 12:0 and 6:0 (A. talpoideum: A. maculatum) treatments which had four replicates due to erroneous mixing of animals resulting in their exclusion from analyses.


 

Multinomial Regression Results

Table A1. Multinomial regression models that compared the production (# of individuals) of each phenotype in the mole salamander (Ambystoma talpoideum). "Spotted" refers to the spotted salamander
(A. maculatum). The metamorph phenotype was set as the reference level. ω is the AICc weight.

Model

Covariates

ΔAICc

ω

Additive

Mole Density+Spotted Density

0.0

0.76

Interactive

Mole+Spotted+Mole:Spotted

2.3

0.24

Overall

Overall Density

12.7

<0.001

Conspecific

Mole Density

38.4

<0.001

Spotted Date

Mean Date of Spotted Metamorphosis

132.3

<0.001

Spotted Survival

Spotted Survival

136.2

<0.001

Null

Null (intercept only)

136.7

<0.001

Heterospecific

Spotted Density

139.9

<0.001

 

Table A2. Parameter estimates, standard error and 95% confidence intervals (lower and upper) from the top model of the multinomial regression (Model 1 in Table A1), which included terms of the initial abundance of mole (Ambystoma talpoideum; "Mole") and spotted salamanders (A. maculatum; "Spotted"). The metamorph phenotype was set as a reference level.

Covariate

Estimate

SE

lower

upper

larva(intercept)

-3.68

0.54

-4.74

-2.62

paedomorph (intercept)

1.10

0.46

0.2

2.01

larva:Mole

0.19

0.03

0.14

0.24

paedomorph:Mole

-0.19

0.04

-0.27

-0.11

larva:Spotted

0.15

0.03

0.09

0.21

paedomorph:Spotted

-0.05

0.03

-0.11

0.01

 

Table A3. Model selection results comparing the Linear, Ricker, and Exponential competition models for body size of the three phenotypes of mole salamanders (Ambystoma talpoideum). *Ricker would not converge. ω is the AICc weight.

Phenotype

Model

ΔAICc

df

ω

Metamorph

Linear

0

10

1

 

Exponential

28.7

10

<0.001

 

Ricker

188.2

10

<0.001

OW Larvae

Linear

0

10

1

 

Exponential

129.7

10

<0.001

 

Ricker

320.2

10

<0.001

Paedomorph*

Linear

0

10

0.9005

 

Exponential

4.4

10

0.0995

 

Inividual Growth Rate Results

Table A4. Model selection results for growth rates of individually marked larvae of mole salamanders (Ambystoma talpoideum).

Model

ΔAICc

ω

Michaelis-Menten

0.0

1.0

Power Law

237.1

<0.001

Gompertz

475.2

<0.001

 

Table A5. Parameter estimates for individual growth rates of each phenotype (metamorph, paedomorph, and overwintered (OW) larvae) of mole salamanders (Ambystoma talpoideum). Abundance is the initial number of A. talpoideum. a is the asymptote, b is the half-maximum scale parameter, and b*a-1 is the initial slope. The lower and upper CI are 95% confidence intervals. "n" is the total sample size (number of individuals from all tanks with that density).

 

a

b

b*a-1

Phenotype

Initial tank
abundance

n

lower CI

estimate

upper CI

lower CI

estimate

upper CI

estimate

Metamorph

3

5

52.61

57.46

62.30

35.94

45.51

55.07

0.79

 

6

19

41.19

51.44

61.69

12.88

33.07

53.27

0.64

 

9

10

33.45

43.79

54.14

4.29

24.76

45.22

0.57

 

12

15

41.11

51.42

61.73

18.25

38.71

59.18

0.75

 

18

6

36.52

47.55

58.58

15.44

37.98

60.51

0.80

 

24

6

34.12

45.36

56.61

12.41

35.30

58.19

0.78

OW Larva

6

5

48.64

53.11

57.58

31.24

39.11

46.98

0.74

 

12

6

32.26

42.75

53.24

7.12

25.52

43.91

0.60

 

18

3

31.71

42.85

54.00

9.78

29.48

49.17

0.69

 

24

7

26.97

37.26

47.55

1.55

19.68

37.81

0.53

Paedomorph

3

5

62.09

69.13

76.17

45.81

56.79

67.76

0.82

 

6

5

37.72

54.61

71.50

10.04

36.05

62.06

0.66

 

12

4

39.09

56.58

74.06

15.85

43.20

70.54

0.76


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