Boreal Peatland LIFE -project – The effect of peatland drainage and restoration on Odonata species richness and abundance

Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, over the half of the original peatland area has been drained and during recent years restoration of some of the drained peatlands have been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known how other species groups in addition to vascular plants and bryophytes respond to restoration efforts. We studied how abundance and species richness of Odonata (dragonflies and damselflies) respond to restoration by sampling larvae in three sites (restored, drained, pristine) in 12 different study areas. We sampled Odonata larvae before restoration (n = 12), during the first (n = 10) and the third (n = 7) year after restoration and used generalized linear mixed models to analyze the effect of restoration. Before restoration drained sites had lower abundance and species richness than drained sites. During the third year after restoration both abundance and species richness had risen in restored sites. Adults of pre-selected indicator species were detected more often in restored sites than in drained sites. Our results show that Odonatas suffer from drainage but seem to benefit from peatland restoration and are able to colonize newly formed water pools relatively rapidly.