Fig 4.

(A) δ¹⁵N signatures of all soil mesofauna species in the upper salt marsh (USM), lower salt marsh (LSM) and pioneer zone (PZ). Boxplots represent mean (red line) and median (black line) of δ¹⁵N signatures; different letters represent significant differences between zones (Tukey’s HSD; p < 0.05). (B) δ¹³C and δ¹⁵N stable isotope values (means with standard deviation) of dominant mesofauna species: Collembola (orange squares), Mesostigmata (blue squares) and Oribatida (green squares). Black dashed horizontal lines represent estimated trophic level boundaries with each trophic level spanning 3.4‰ δ¹⁵N: I = primary decomposers, II = secondary decomposers, III = first order predators, and IV = second order predators. Number of replicates are included in parentheses; see Table C in S1 File for full species names.