Table 1.

Performance of the GLMM models for ecological stoichiometry (C:N, C:P, and N:P ratios), stable isotope signatures (δ¹³C and δ¹⁵N) and trophic position, with estimated fixed effects (distance, trophic groups, and their interaction) and random effects (taxonomic composition).

Factor	Estimate	SE	t	P	σ
C:N ratio (n = 180; marginal R 2 = 0.87; conditional R 2 = 0.95)
Fixed effects
Intercept	1.45	0.05	28.2	2 × 10−16*
Distance	−0.26	0.07	−3.9	9 × 10−4*
Primary consumers	−0.64	0.06	−10.0	6 × 10−9*
Secondary consumers	−0.66	0.07	−10.0	5 × 10−9*
Distance × Primary consumers	0.25	0.08	3.0	0.007*
Distance × Secondary consumers	0.27	0.09	3.1	0.006*
Random effects
Taxa nested in trophic group × Intercept					0.11
Taxa nested in trophic group × Distance					0.14
Residual					0.05
C:P ratio (n = 143; marginal R 2 = 0.82; conditional R 2 = 0.93)
Fixed effects
Intercept	2.99	0.06	46.3	2 × 10−16*
Distance	−0.42	0.12	−3.6	0.002*
Primary consumers	−0.88	0.08	−10.9	2 × 10−9*
Secondary consumers	−0.80	0.08	−9.5	2 × 10−8*
Distance × Primary consumers	0.53	0.15	3.7	0.002*
Distance × Secondary consumers	0.46	0.15	3.1	0.007*
Random effects
Taxa nested in trophic group × Intercept					0.13
Taxa nested in trophic group × Distance					0.23
Residual					0.08
N:P ratio (n = 142; marginal R 2 = 0.12; conditional R 2 = 0.60)
Fixed effects
Intercept	1.57	0.06	26.2	6 × 10−16*
Distance	−0.17	0.08	−2.2	0.04
Primary consumers	−0.18	0.08	−2.4	0.03
Secondary consumers	−0.07	0.08	−0.9	0.4
Distance × Primary consumers	0.27	0.10	2.8	0.01
Distance × Secondary consumers	0.19	0.10	1.9	0.07
Random effects
Taxa nested in trophic group × Intercept					0.12
Taxa nested in trophic group × Distance					0.13
Residual					0.09
δ13C (n = 181; marginal R 2 = 0.22; conditional R 2 = 0.77)
Fixed effects
Intercept	−29.75	1.09	−27.3	2 × 10−16*
Distance	0.59	0.87	0.7	0.5
Primary consumers	−2.42	1.37	−1.8	0.09
Secondary consumers	−4.07	1.40	−2.9	0.009
Distance × Primary consumers	−0.94	1.09	−0.9	0.4
Distance × Secondary consumers	−0.58	1.12	−0.5	0.6
Random effects
Taxa nested in trophic group × Intercept					2.21
Taxa nested in trophic group × Distance					0.65
Residual					1.66
δ15N (n = 181; marginal R 2 = 0.75; conditional R 2 = 0.83)
Fixed effects
Intercept	−1.20	0.50	−2.4	0.03
Distance	7.19	0.70	10.2	6 × 10−9*
Primary consumers	1.99	0.63	3.2	0.006*
Secondary consumers	4.60	0.65	7.1	3 × 10−6*
Distance × Primary consumers	−0.02	0.88	0.0	1.0
Distance × Secondary consumers	−2.20	0.90	−2.4	0.03
Random effects
Taxa nested in trophic group × Intercept					0.85
Taxa nested in trophic group × Distance					0.89
Residual					1.17
Trophic position (n = 138; marginal R 2 = 0.30; conditional R 2 = 0.64)
Fixed effects
Intercept	1.78	0.16	11.1	2 × 10−8*
Distance	0.04	0.14	0.2	0.8
Secondary consumers	1.00	0.24	4.1	0.001*
Distance × Secondary consumers	−0.80	0.21	−3.7	5 × 10−4*
Random effects
Taxa nested in trophic group × Intercept					0.42
Distance × Secondary consumers					0.15
Residual					0.37

Reported are the number of observations (n), the overall model performance for the fixed effects only (marginal R ²) and for the fixed and random effects combined (conditional R ²). For the fixed effects, the regression coefficients (Estimate) with their standard errors (SE), t values, and P values estimated using the Satterthwaite approximations are presented. For the trophic groups, the primary producers are used as a reference. The fixed effects for the primary consumers and secondary consumers are expressed with respect to this reference level. For the random effects, the standard deviation (σ) is presented. Significant fixed effects are indicated with an asterisk (Bonferroni corrected, P < 0.0083). Note that C:N, C:P, and N:P ratios were log₁₀(x + 1)‐transformed. For details of the individual taxa, see Appendix S3: Table S1, S2.