Unexplored freshwater communities in post‐mining ponds: effect of different restoration approaches

Abstract

Many studies examining plant and terrestrial invertebrate communities have revealed the high conservation potential of spoil heaps. On the other hand, the freshwater communities inhabiting post‐mining ponds within these human‐made habitats are almost unexplored. We focused on aquatic macroinvertebrate, zooplankton, and phytoplankton communities in the littoral zones of 24 ponds situated on spoil heaps created after lignite mining in the Czech Republic. We compared environmental factors, taxa richness, and conservation value (number of threatened aquatic macroinvertebrate species) in the ponds, based on the type of restoration approach applied, that is, technical reclamation, spontaneous succession, and their combination (semi‐spontaneous succession). While macroinvertebrate and zooplankton taxa richness did not differ significantly between the three types of pond, the phytoplankton community did, with the highest taxa richness recorded in technically established ponds. From a nature conservation point of view, the spontaneously developed ponds hosted almost twice as many threatened macroinvertebrates as the other ponds; nevertheless, even the technically constructed ponds hosted considerable populations of rare species, e.g. the regionally extinct beetle Limnebius nitidus (Marsham, 1802), and contributed to the overall conservation value of the spoil heaps. The most significant driver structuring post‐mining pond freshwater communities was the percentage of vegetation in the littoral zone.