Table 2 Outputs of models used to test whether the relative abundance of each plant family was significantly correlated with NDVI

From: Linking diet switching to reproductive performance across populations of two critically endangered mammalian herbivores

Species

Variable

Standard deviation of random effect

AIC

Variable

Df (explanatory variable, total)

β

se

t

p

Black rhino

Proportion of Poaceae (grasses) in the diet

0.043

−380.33

NDVI

1, 174.3

0.0028

0.00043

6.45

<0.001***

Proportion of Fabaceae (legumes) in the diet

0.12

9.96

NDVI

1, 183.72

−0.0037

0.0011

−3.43

<0.001***

Proportion of Ebenaceae in the diet

0.17

−51.36

NDVI

1, 155.2

−0.0011

0.00085

−1.25

0.21

Grevy’s zebra

Proportion of Poaceae (grasses) in the diet

 

−76.54

NDVI

1, 153

2.88

0.19

15.52

<0.001***

   

NDVI2

1, 153

−1.13

0.19

−6.08

<0.001***

Proportion of Fabaceae (legumes) in the diet

 

−85.23

NDVI

1, 153

−2.58

0.18

−14.30

<0.001**

   

NDVI2

1, 153

0.92

0.18

5.08

<0.001***

  1. There are two linear regression models for Grevy’s zebra, with Poaceae and Fabaceae relative abundances as dependent variables, and three linear mixed effect models for black rhino, using black rhino ID as a random effect, with Poaceae, Fabaceae and Ebenaceae relative abundances as dependent variables. All predictors were included as second-order polynomial predictors, which were dropped if they were not significant. Variable = predictors in the model with a superscript 2 indicating predictors included as second-order polynomials, Df = degrees of freedom, β = regression coefficient, se = standard error, t = t-value, p = p-value with significance codes *** = p < 0.001, ** = 0.001 < p  < 0.01, * = 0.01 < p < 0.05.
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