Environmental influences on plant diversity in restored and natural peatland pools

Peatland pools are crucial habitats for biodiversity, but peat extraction removes vegetation and drains sites, often eliminating pools. This study compared environmental conditions and vegetation in 59 pools from 14 restored Sphagnum peatlands (≥7 years post-restoration) with 26 pools from nine reference peatlands in Eastern Canada. We examined three restored pool types: (1) created pools, (2) spontaneous pools, and (3) open water in ditches. Pool type explained 19% of the variation in species composition, while regionality, morphology, and water chemistry accounted for 32%. Larger restored pools resembled reference pools morphologically and had higher dissolved organic carbon and nitrogen. Spontaneous pools exhibited elevated nitrogen (2.1 mg/L vs. 0.57 mg/L) and phosphorus (0.08 mg/L vs. 0.02 mg/L), and a higher pH that may favor non-target species, e.g., Typha latifolia. Reference pools had a uniform composition, comprising 20 associated species, whereas restored pools exhibited greater variability, reduced richness, and higher beta diversity. Post-restoration surveys emphasized the importance of deeper pools for water retention and chemical stability. Complementary measures, such as reintroducing typical pool species, are essential to ensure their establishment and enhance plant biodiversity in restored peatlands.