Table 1.
ANOVA table for analysis of arthropod densities as a function of island category (reference island (RF), abandoned cormorant island (AB), active cormorant island (AC) and cormorant island (CO) including both abandoned and active islands).
Figure 1.
Soil (A) nitrogen (NH4+ and NO3−) (mg/100 g dry soil) and (B) phosphorus (mg/kg dry soil) content and (C–E) elemental ratios (mean ± SE) of herbs and grasses on reference islands (RF) (non-cormorant islands), abandoned cormorant islands (AB) and active cormorant islands with low (COL) and high (COH) nest density.
Different letters indicate significant differences in linear mixed effect model (A and B) and post-hoc test (C–E).
Figure 2.
Relationship between soil and plant nitrogen (%N) (A) and phosphorus (%P) (B) on active, abandoned and reference islands.
The horizontal range corresponds to the range of the soil N and P. The grey diagonal line represents the 1∶1 relation. See Table S3 for ANOVA tables.
Figure 3.
Elemental ratios (mean ± SE) of algae nearby reference (RF), abandoned (AB) cormorant and active cormorant islands with low (COL) and high (COH) nest density.
Different letters indicate significant differences in linear mixed effect model.
Figure 4.
Relationship between consumer and resource N:C (A and B), P:C (C and D), and N:P (E and F) for terrestrial arthropods (A, C, E) and brackish invertebrates (C, D, F).
Solid lines indicate herbivores, dashed lines detritivores, and dotted lines predators. The horizontal range corresponds to the data range of the resource. The grey diagonal line represents the 1∶1 relation. Resource: Plants: Col: Collembola, Iso: Isopoda, Lep: Lepidoptera larvae, Cer: Cercopidea, Cur: Curculionidae, Chr: Chrysomelidae, Aph: Aphids; Resource: adult Chironomidae: Ara: Araneidae, Lin: Linyphiidae, Tet: Tetragnathidae, Lyc: Lycosidae; Resource: Collembola: Car: Carabidae; Resource: Epiphytes: The: Theodoxus fluviatilis, Chi: Chironomidae larvae, Id: Idotea spp, Gam: Gammarus spp, Ia: Jaera albifrons; Resource: Fucus: Id_f: Idotea spp.
Figure 5.
Mean (±SE) body N:C (A), P:C (B), and N:P (C) mass ratios for terrestrial herbivores (H), terrestrial detritivores (D), adult chironomids (C) and terrestrial predators (P).
Table 2.
Results of linear mixed effects model (lme) testing for differences in elemental ratios of terrestrial arthropods and insects between reference islands and cormorant islands (abandoned and active).
Table 3. Results of linear mixed effects model (lme) testing for differences in elemental ratios (mean ± SE) of brackish invertebrates between reference islands and cormorant islands (abandoned and active cormorant islands with low and high nest density).
Table 4.
Results of linear regressions (lm) and generalized linear models (glm) testing for a linear relationship between plant quality (leaf N:C and P:C-content) and plant quantity (aboveground plant biomass (g/62.5 cm2) and arthropod densities.
Table 5.
Results of linear mixed effect models (lme) testing the relationship between algal N:C (P:C)-content, epiphytic alage:Fucus-ratio (Epi:Fu-ratio) (sqrt-transformed), and wave exposure to brackish invertebrate biomass (mg dry-weight invertebrate/g dry-weight algae) (sqrt-transformed).
Figure 6.
Relationship between the elemental mass ratios (N:C and P:C) of invertebrate taxa(A and C), the elemental mismatch between consumers and their resources (B and D) and the effect size of terrestrial arthropods (density) between reference and active cormorant islands (E1terr) and reference and cormorant islands (E2terr) and of brackish water invertebrates (biomass) between reference and active cormorant islands with high nest density (E1brack).