Is 15 % restoration sufficient to safeguard the habitats of boreal red-listed mire plant species?

Abstract

We used habitat suitability modeling to investigate whether the 15% ecosystem restoration target set in the previous Convention of Biological Diversity (CBD) and EU Biodiversity strategy targets, is sufficient to safeguard red-listed mire plant species. We assessed six theoretical restoration scenarios for drained peatland landscapes by altering the proportion of drained and undrained peatland area in 25-ha grid cells. The proportions represented steps when 15%, 30%, 45%, 60%, 75% and 100% of the drained peatland is restored. We modelled the habitat suitability for 48 red-listed plant species in the aapa mire region in boreal Finland. Model outcomes were assessed at the level of five species groups: calcareous species, rich fen species, decaying wood species, mesotrophic fen species, and spruce swamp species. The predicted distribution increased for 34 (71%) of the 48 red-listed plant species when 15% of drained peatland area was predicted to be restored. At the same time the potentially occupied area of species increased by 9%. In the scenario where all peatlands were restored, the predicted distribution of 43 (90%) of species increased, and on average the distribution of species quadrupled. According to our predictions, meeting the 15% ecosystem restoration target, set in the previous CBD and EU Biodiversity strategy targets would be beneficial for most of the boreal red-listed mire plant species, but a larger restoration area would expand their distribution considerably more. Our study shows that a landscape level approach is important to assess thresholds for the potential biodiversity benefits arising from peatland restoration. The models can also be used to select suitable areas for restoration.