Initiation of microtopography in revegetated cutover peatlands

Abstract

Question: How many years are required for a gradient of microtopography to be initiated in revegetated cutover peatlands and become similar to natural bogs? Location: Newly formed Sphagnum carpets on cutover peatlands that revegetated spontaneously after site abandonment (in Estonia), or following active restoration (in Canada) and on undisturbed natural bogs nearby. Methods: Moss surface height was measured along linear transects above a local reference level (the lowest point for a given transect). Heights of at least 20 cm were associated with hummocks. Frequency distributions of surface height and principal component analyses (separately for Canada and Estonia) were conducted to follow the evolution of microtopography in revegetated sites and their similarity with those of natural peatlands. In Canada, regressions were also performed to estimate the time required for the microtopography in revegetated cutover peatlands to become similar to that found in natural bogs. Results: Only 10–30 yr were needed for microstructures comparable to those in natural bogs to develop on restored peatlands where Sphagnum diaspores have been reintroduced. However, this process may take more than a century in cutover peatlands left to revegetate spontaneously. Conclusions: In cutover peatlands with spontaneous revegetation, hummock–hollow formation starts on bare peat which lacks both plant propagules and viable seed banks, and the initiation of microstructures is probably more akin to the process that occurs naturally. Nonetheless, hummock–hollow microtopography resembling that found in natural bogs without pools appeared, in all of the examined cutover peatlands, over periods that are short in terms of peatland development time‐scales. Active peatland restoration could effectively reduce the time required for initiation of microtopography by about 70 yr.

Trajectories of Plant Recovery in Block-Cut Peatlands 35 Years After Peat Extraction

“…Overall, among the three peatland regions studied, the Atlantic seemed to be most clearly on a trajectory toward recovery, with a higher abundance of moss species relative to ericaceous shrubs and trees. The greater abundance of hummock species in the second survey could indicate the initiation of a hummock-hollow gradient, as it takes only 10-30 yr for a microtopography typical of bogs to develop in restored cutover bogs (Pouliot et al, 2011). However, some caution is warranted since the increased dominance of hummock species could also simply reflect a decrease in hollow species, associated with drier conditions.…”

Assessment of an integrated peat-harvesting and reclamation method: peatland-atmosphere carbon fluxes and vegetation recovery

“…Some collars in the experimental plot became more like hummocks and others more like hollows, providing a possible pathway towards re-establishing a characteristic hummock-hollow microtopography and biodiversity (Rydin and Jeglum 2006). The re-establishment of hummock-hollow microtopography pattern can take more than a century in abandoned cutover peatlands, but there is evidence that this recovery time might be reduced to between 10 and 30 years if restored using the moss-transplant (diaspore dispersal) method (Pouliot et al 2011). Our results suggest that the PBR method could further enhance the recovery of microtopography.…”

“…Price and Whitehead (2001) discovered Sphagnum recovery was greatest in shallow ditches and absent in raised baulks. Even after several decades, recovery of Sphagnum mosses are limited to shallow ditch areas, with adjacent raised baulks devoid of Sphagnum, leaving plant communities dissimilar to those that existed preharvest (Elling and Knighton 1984;Yli-Petäys et al 2007;Pouliot et al 2011Pouliot et al , 2012González et al 2013). In vacuum harvested peatlands, active restoration and reclamation techniques such as ditch blocking (Price et al 1998) and the moss-transplant method, where Sphagnum diaspores are re-introduced onto bare peat surfaces (Ferland and Rochefort 1997;Graf et al 2012;González and Rochefort 2014), can sometimes promote the re-establishment of plant communities and may help to restore pre-harvest peat-accumulation and carbon-sequestration functions (Waddington and Warner 2001;Tuittila et al 2004;Waddington et al 2010).…”

High-throughput sequencing reveals diverse oomycete communities in oligotrophic peat bog micro-habitat

“…These three microhabitats often lie close to each-other ( Fig. 1F) (Pouliot et al, 2011;Marcisz et al, 2014). In addition, we studied two other habitats in the periphery and margin of the peatlands: i) tall pine forests ( Fig.…”