Table 1.

Wald F-tests for linear mixed effect models to describe response parameters. Top-predator body mass, M_C′, as continuous and nitrogen fertilizer, Nut, as binary fixed effects (inserted sequentially). Treatment block is taken into account as a random effect. The community response variables are: average community body mass, M; species richness, S; overall density of individuals, N; and overall biomass density, B. Population response variables are: the biomass density of Perciformes, the individual density of meiofaunal micrograzers, and the chlorophyll concentration on glass slides. p-values are the likelihood for a parameter to equal zero. Nut:M_C′ is the test for an interactive effect of both explanatory parameters. Numerator degrees of freedom, d.f. = 1; denominator d.f. = 25; F- and p-values for Wald tests. *p < 0.05; **p < 0.01; ***p < 0.001.

	F-value	p-value	F-value	p-value	F-value	p-value	F-value	p-value
	log10 M (g ind.−1)		log10 S		log10 N (ind. m−2)		log10 B (g m−2)
(intercept)	7217.654	<0.001***	17013.970	<0.001***	11541.500	<0.001***	3201.263	<0.001***
Nut	5.112	0.033*	5.880	0.023*	6.256	0.019*	0.479	0.495
MC′	5.593	0.026*	0.089	0.768	0.162	0.690	5.903	0.023*
Nut:MC′	0.251	0.621	0.438	0.514	0.043	0.837	0.122	0.730
	log10 B Perciformes +1 (g m−2)		log10 N grazer (ind. m−2)		log10 chlorophyll (mg m−2)
(intercept)	543.221	<0.001***	17061.320	<0.001***	2194.009	<0.001***
Nut	2.661	0.115	6.939	0.014*	1.246	0.275
MC′	9.433	0.005**	5.493	0.027*	4.286	0.049*
Nut:MC′	0.030	0.864	0.001	0.975	0.987	0.330