DOI: 10.5061/dryad.2p0g7
title: Data from: Food web heterogeneity and succession in created saltmarshes

description: Ecological restoration must achieve functional as well as structural
 recovery. Functional metrics for re-establishment of trophic interactions
 can be used to complement traditional monitoring of structural attributes.
 In addition, topographic effects on food web structure provide added
 information within a restoration context; often, created sites may require
 spatial heterogeneity to effectively match structure and function of
 natural habitats. We addressed both of these issues in our study of
 successional development of benthic food web structure, with focus on
 bottom-up-driven changes in macroinvertebrate consumer assemblages in the
 saltmarshes of the Venice Lagoon, Italy. We combined quantified estimates
 of the changing community composition with stable isotope data (13C:12C
 and 15N:14N) to compare the general trophic structure between created
 (2–14 years) marshes and reference sites and along topographic elevation
 gradients within saltmarshes. Macrofaunal invertebrate consumers exhibited
 local, habitat-specific trophic patterns. Stable isotope-based trophic
 structure changed with increasing marsh age, in particular with regard to
 mid-elevation (Salicornia) habitats. In young marshes, the mid-elevation
 consumer signatures resembled those of unvegetated ponds. The
 mid-elevation of older and natural marshes had a more distinct Salicornia
 zone food web, occasionally resembling that of the highest
 (Sarcocornia-dominated) elevation. In summary, this indicates that primary
 producers and availability of vascular plant detritus structure consumer
 trophic interactions and the flow of carbon. Functionally different
 consumers, subsurface-feeding detritivores (Oligochaeta) and surface
 grazers (Hydrobia sp.), showed distinct but converging trajectories of
 isotopic change over time, indicating that successional development may be
 asymmetric between ‘brown’ (detrital) guilds and ‘green’ (grazing) guilds
 in the food web. Synthesis and applications. Created marsh food webs
 converged into a natural state over about a decade, with successional
 shifts seen in both consumer community composition and stable isotope
 space. Strong spatial effects were noted, highlighting the utility of
 stable isotopes to evaluate functional equivalence in spatially
 heterogeneous systems. Understanding the recovery of functional properties
 such as food web support, and their inherent spatial variability, is key
 to planning and managing successful habitat restoration.
description: Stable isotope data for
 macroinvertebrates in natural and created salt marshes in the Venice
 LagoonVenice_isotopes_csv
 contains stable isotope data (delta13C and delta15N) for primary producers
 and primary consumers in Venice Lagoon salt marshes. Values given as mean
 per taxon per elevation per marsh.Venice_isotopes.csvInfauna counts for natural and created salt marshes in the Venice LagoonVenice_infauna.csv contains faunal counts (average number of individuals per core). Site descriptors are as follows: FE: Fossei Est; TF: Tezze Fonde; CE: Cenesa; CA: Capo; N: Natural marsh; C: Created marsh; LOW: Low elevation; MID: Mid elevation; HIGH: High elevationVenice_infauna.csvEnvironmental variables for natural and created salt marshes in the Venice LagoonVenice_environmental_variables.csv contains data for the following variables: Age_young: young, created marshes Age_mature: natural (reference) marshes Elevation_low: low elevation habitat Elevation_high: high elevation habitat Vegetation_S: species richness of vascular plants Plant_cover: per cent (%) cover of vascular plants Bg_biomass: belowground biomass (g per core)Venice_environmental_variables.csv