Functional diversity of macroinvertebrates as a tool to evaluate wetland restoration

Ecological restoration of aquatic ecosystems has become widespread in
recent decades. Whereas the recovery of biodiversity in restored wetlands
has been studied from a taxonomic perspective, our knowledge of how
functional biodiversity recovers remains poorly understood. We studied the
functional diversity of macroinvertebrate communities in 32 Mediterranean
temporary ponds six to seven years after their creation during a
restoration in South-West Spain, and compared them with 10 natural
reference sites during two consecutive hydroperiods. We compared alpha
functional diversity indices, and the individual contributions of new
ponds and reference sites to the regional functional beta diversity, as
well as to its turnover and nestedness components. We also investigated
the influence of environmental and spatial variables on the
dissimilarities of functional beta diversity and its components between
new ponds and reference sites. Alpha functional diversity in new ponds was
lower than in reference sites. Although the contribution of new ponds to
the regional functional beta diversity was similar to that of reference
sites, the latter contributed more to functional turnover, while new ponds
contributed more to functional nestedness. Dispersal limitation coupled
with environmental filtering structured the functional variation in
communities between new ponds and reference sites, but their relative
importance differed between beta components. New ponds can hold species
with unique functional compositions, but their contribution to the
regional functional beta diversity was mostly due to trait losses with
respect to reference sites. Synthesis and applications. Considering
different aspects of functional diversity of invertebrate communities can
help elucidate the processes and mechanisms through which ecosystems
recover following restoration. We encourage the use of trait-based
approaches to identify trends in processes and patterns that can guide
future wetland restoration projects.