Newly created ponds complement natural waterbodies for restoration of macroinvertebrate assemblages

Ecological restoration is becoming increasingly widespread to compensate for wetland loss worldwide. However, most post-restoration studies fail to establish whether the restored wetlands replace or complement natural wetlands for communities of aquatic organisms such as macroinvertebrates. During two consecutive hydroperiods (ca 6 months each), we studied the macroinvertebrate communities in 32 new temporary ponds created during a restoration 6–7 years previously in Doñana, SW Spain, and compared them with ten natural temporary sites nearby. We compared results for two dominant groups of active dispersers (Coleoptera and Hemiptera) and for the whole aquatic macroinvertebrate community (a mix of active and passive dispersers) to shed light on the role of dispersal constraints during ecosystem recovery. We also compared the ranks of new ponds and reference sites in nested matrices to assess whether communities in new ponds are impoverished subsets of communities in reference sites. Because of their young age, newly created ponds were predicted to have less stable communities over the two study years than reference sites, and to have lower species diversity for the whole community but not for active dispersers. On the other hand, communities in new ponds were predicted to approach the taxonomic composition of reference sites as time went on. New ponds differed in environmental conditions (particularly less emergent vegetation cover and lower chlorophyll concentration) from reference sites, but their invertebrate richness and diversity matched those in reference sites and invertebrate abundance was even higher. Richness and diversity increased in the second hydroperiod in new ponds, but not in reference sites. Significant differences in community composition occurred between new ponds and reference sites, but were largely explained by their environmental differences. As succession progressed within a hydroperiod, communities in new ponds were first dominated by large branchiopods, then by active dispersers such as Chironomidae and Coleoptera, then finally by halotolerant taxa such as the beetle Ochthebius viridis fallaciosus. Communities in new ponds were not impoverished subsets of those in reference sites, and communities in new and reference ponds diverged towards the end of the hydroperiods. We conclude that new temporary ponds can provide diverse and complementary habitats important for maintaining macroinvertebrate diversity at the regional scale.