Data from: Functional responses of multi-taxa communities to disturbance and stress gradients in a restored floodplain

1. Trait-based approaches can reveal the mechanisms through which
disturbances or stress impact communities, allowing comparisons of the
role of different mechanisms in shaping communities among taxonomic
groups. Such information can lead to higher comparability, transferability
and predictability of the outcome of restoration projects. However,
multitaxa trait-based approaches were rarely used in the context of
ecosystem restoration. 2. We investigated the responses to environmental
gradients of seven taxa (vascular plants, staphylinid and carabid beetles,
spiders, isopods, diplopods and earthworms) in a restored floodplain using
a species traits approach. We assessed the impact of flood disturbances
and soil hydric stress on the functional diversity (FD) and
community-weighted mean (CWM) response of traits for each taxon. 3.
Ordination of hydrological variables revealed two main gradients. The
first was related to the spatiotemporal dynamics of flood disturbances and
the second to the average changes in soil hydric conditions. 4. The
analysis of CWM revealed that larger, poorly mobile species with narrow
ecological tolerances were filtered by regular floods and/or changes in
soil hydric conditions. 5. Functional diversity patterns differed between
the two gradients: decreasing with increasing flood disturbance, but
increasing along the soil hydric stress gradient. This suggests that the
mechanisms shaping community composition differ between the two gradients
with environmental filtering being dominant with increasing flood
disturbances and competition decreasing with more soil hydric stress. 6.
Synthesis and applications. Our study shows that the impact of restored
flood disturbances and soil hydric stress on plant and invertebrate
functional diversity and community-weighted mean can be positive, negative
or more complex depending on the taxonomic group and environmental
gradient considered. The patterns can to some extent be explained by the
specific characteristics of each group. Larger, poorly mobile species with
narrow ecological tolerances were particularly vulnerable to changes in
disturbance and stress regime following floodplain restoration. These
species may therefore be lost in the initial phases of restoration
projects, but other more characteristic species of dynamic floodplains
will be favoured. Understanding the consequences of these contrasted
responses for biodiversity conservation and ecosystem functioning
constitutes the next challenge for ecosystem restoration.