DOI: 10.5061/dryad.6hc8q
title: Data from: Maintained functional diversity in benthic communities in spite of diverging functional identities

description: Ecological studies based on time-series often investigate community
 changes centered on species abundance or biomass but rarely expose the
 consequential functional aspects underlying such changes. Functional
 diversity measures have proven to be more accurate predictors for
 ecosystem functioning than traditional taxonomic approaches and hence
 gained much attention. There are only limited studies available that
 analyse the functional implications behind decadal changes of entire
 communities. We studied zoobenthic communities of two habitats, sheltered
 and exposed, of a coastal system subject to contrasting changes in
 community composition over the past four decades. Besides eutrophication
 and climate-related impacts, the system has been invaded by a non-native
 polycheate Marenzelleria spp., adding altered functional properties to the
 communities. The functional dispersion (FDis) metric was used as a measure
 for comparing the functional diversity of the contrasting habitats, with
 special focus on the role of Marenzelleria for the entire communities. We
 highlight changes in the functional identity of the communities, expressed
 as community-weighted means of trait expression (CWM), using multivariate
 techniques, and investigate the relationship between taxonomic and
 functional changes. Despite contrasting community developments in the two
 habitats, with characteristics traditionally suggesting different
 environmental quality, we found that the FDis in both habitats remained
 similar and increased with the introduction of Marenzelleria. Although
 showing maintained functional diversity across time and space, the
 functional identity (CWM) of communities changed irrespective of
 taxonomical differences. Examples include inter alia alterations in
 palatability proxies, feeding position and sediment transportation types,
 indicating changed functionality of zoobenthos in coastal systems. We
 show, when focussing on qualitative functional changes of communities, it
 is important to evaluate the underlying functional identity, and not only
 rely on measures of the diversity of functions per se, as the quality
 indication of expressed functional traits can be concealed when using
 multi-functionality approaches.
description: Species_x_TraitsThis file contains the species by trait matrix for all observed species included in the study. The trait scoring follows the fuzzy coding procedure as described in the manuscript. Species names are abbreviated by the first three letters of their genus. The functional traits are sorted by number (1-9) and followed by their trait-categories. See the "Abbreviations species and traits. csv" file below and the manuscript for details.Station_x_SpeciesThis file contains the station by species abundance matrix. Stations are labeled by their exposure classification (E = exposed, S = sheltered), their station ID, and their collection year. Species abundances are the mean abundance of five Ekman-Birge grab samples per site. Species names are abbreviated by the first three letters of their genus. See manuscript for details.CWM_PERMANOVAThis file contains the matrix of community weighted means of trait category expression (CWM) for all included sampling stations and years. CWM values were calculated from the species by trait matrix and station by species matrix and used for the CWM PERMANOVA. See manuscript for details.Abbreviations species and traitsThis file contains details to the abbreviations of included species and traits