Vegetation trajectories over 150 years of temporary ponds created in the Camargue delta (Southern France)

Abstract Introduction Temporary ponds in the Mediterranean climate have a high conservation value, but many have been severely destroyed or degraded. Pond restoration and new pond creation have been engaged widely. Evaluations of the success of such operations are generally carried out over 10–15 years and show divergent results over this timeframe. In the Camargue (Rhône delta, South of France), several temporary ponds were created with various objectives since the second half of the 19th century. Objectives Study the long‐term trajectory of plant communities in created temporary ponds and compare them with those of reference temporary ponds. Methods We carried out vegetation surveys and measured environmental parameters in 25 ponds created in the 19th, 20th, and 21st centuries, as well as in 27 natural reference ponds (space‐for‐time substitution approach). Results Submerged macrophyte communities (composition, abundance, and species‐richness) converged toward the reference communities after one or several decades. Emergent plant communities (terrestrial plants and helophytes) converged more slowly toward the reference communities (composition and abundance). Even after 150 years, the emergent plant communities with the highest conservation interest (in particular Natura 2000 habitat) were not found in created ponds. Conclusions The creation of temporary ponds in the Camargue is of conservation interest but cannot compensate for the loss of natural temporary ponds.