Fighting carbon loss of degraded peatlands by jump-starting ecosystem functioning with ecological restoration

Abstract

Esitetään Jyväskylän yliopiston matemaattis-luonnontieteellisen tiedekunnan suostumuksella julkisesti tarkastettavaksi yliopiston vanhassa juhlasalissa S212 maaliskuun 28. päivänä 2014 kello 12.Academic dissertation to be publicly discussed, by permission of the Faculty of Mathematics and Science of the University of Jyväskylä, in building Seminarium, auditorium S212, on March 28, 2014 at 12 o'clock noon. The wide and rapidly increasing human land use has caused extensive degradation of natural landscapes, extinctions of species and loss of ecosystem functions and services. Subsequently, ecological restoration has been raised to a major global strategy for safeguarding ecosystem values. However, concerns have been raised on the real potential of restoration to re-establish ecosystem structures and functions. Here, I studied the effects of ecological restoration on the structure and functions of forestry drained boreal peatland ecosystems in southern Finland. To better understand structural and functional changes, the effects of drainage and restoration on water table level, pore water chemistry and peat chemistry were explored as well. Drainage lowered the water table and induced changes in pore water chemistry and plant community composition. Drainage retarded the accumulation of surface peat and resulted in significant reduction in the sequestration of carbon therein. Re-establishment of water table level and significant recovery of pore water and surface peat chemistry were observed after restoration. Restoration induced the recovery of ecosystem structure i.e. plant community composition towards the target. The recovery was dependent on the within-site degree of ecosystem degradation. The original ecosystem structure was not needed for the re-establishment of important peatland ecosystem functionality in terms of surface peat accumulation. However, a more profound recovery of structure and conditions may be needed for some other functions like surface peat carbon sequestration to recover. Overall, my results are promising from the perspective of restoration. However, they highlight the need for patience in drawing conclusions on the effectiveness of restoration. Practitioners should also be prepared for temporarily increased leaching of nutrients into downstream water courses. UNIVERSITY

Recovery of plant communities after ecological restoration of forestry‐drained peatlands

“…They could proliferate clonally from relict populations and colonize new areas rapidly after the recovery of suitable environmental conditions (see Table ). The fast recovery of the abundances in remnant populations plays an important role in the early recovery of the ecosystem functioning (Kareksela et al., ; Maanavilja, Kangas, Mehtätalo, & Tuittila, ). On the other hand, the rapid recovery of certain competitive species is suspected to hinder the re‐establishment of other species later on (e.g., Hedberg et al., ).…”

Water‐table‐dependent hydrological changes following peatland forestry drainage and restoration: Analysis of restoration success

“…However, one study in Finland found that restoration operations on a previously drained minerotrophic fen achieved 50% cover of peat‐forming species (e.g., Eriophorum vaginatum , which evolves to Carex and Sphagnum ) already in 3 years [ Jauhiainen et al ., ]. Other studies report recovery of peat‐forming Sphagnum mosses within a few years of restoration [ Laine et al ., ; Maanavilja et al ., ], while reestablishment of whole wetland communities may take much longer [ Haapalehto et al ., ; Kareksela et al ., ]. Furthermore, restoration operations performed on peatlands drained for forestry have been shown to result in more rapid recovery than operations on cut‐away peatlands [ Huopalainen et al ., ].…”

The effects of long-term drainage and subsequent restoration on water table level and pore water chemistry in boreal peatlands

“…The greatest hydrological change caused by drainage is the decadal drawdown of water table observed in our study. This drawdown affects not only peatland structures, such as above and below ground communities (Laine et al 1995;Jaatinen et al 2007), but also ecosystem functions such as soil respiration, nutrient circulation and accumulation of peat and C (Braekke 1987;Martikainen et al 1995;Mäkiranta et al 2009;Kareksela et al 2014). As the average water table level could be re-established and maintained for 10 years, restoration of studied peatlands was successful in regaining the single most important condition needed for further recovery of ecosystem.…”