Comparing monitoring methodologies for assessing restoration success in peatlands

Restoration specialists are often criticized for not establishing a proper monitoring program that would help judging the achievement of the restoration. Here, we present a study case where monitoring has taken place during 7 years after restoring a cut-over bog. The aim of this presentation is 1) to assess peatland restoration success when using the dry surface restoration approach and 2) to compare different monitoring methods for assessing restoration success. The site is a cut-over bog of 11.4 ha, of which 8.5 ha were restored in 1999. The restoration approach consisted mainly in reintroducing bog-plant diaspores, spreading a straw mulching, blocking the former drainage ditches, and applying a low dose of phosphorus fertilizer. The vegetation was surveyed by point interception method using a systematic grid of approximately 6900 points (every 3 m × 5 m) before (1999) and after restoration (2001, 2003 and 2005). In addition, permanent plots were established and surveyed every year since 1999. The recovery of vegetation was assessed with a reference ecosystem. Sphagnum had a frequency of occurrence of 55% in 2005 from the point interception survey, which is close to what was found in the reference ecosystem. The cover of the nursing moss Polytrichum strictum were two times more abundant in the restored site than in the reference ecosystem in 2003 but slowly decreased since 2005. The cover of the herb strata was also higher than in natural peatlands but we expect a decrease of the main herb species, Eriophorum vaginatum (cotton-grass) with time. Overall, the dry surface restoration approach appears to be efficient for successfully re-establishing plant diversity on cut-over bogs. Discrepancies between the two survey techniques will be discussed for vegetation strata and particular species.