Factors affecting the re-vegetation of abandoned extracted peatlands in Estonia: a synthesis from field and greenhouse studies

Abstract

Re-vegetation of extracted peatlands is a slow and sporadic process. The aim of our study was to clarify whether this process is affected by the distance from vegetated areas and propagules arrival or by the conditions for propagules germination and plant growth. Our analysis is based on three extracted peatlands in Estonia, abandoned 26-31 years ago. In all study areas vegetation was analysed on the gradient from a neighbouring vegetated area towards the central part of the peatland. In addition, peat blocks were collected from the marginal and central parts of the peatlands, held in favourable moisture conditions for seed germination in a greenhouse, and half of them were fertilized with a complex fertilizer.Our study showed the species pool to be present everywhere on abandoned extracted peatlands, but the germination was influenced by different factors such as water table, peat chemistry, etc. The species richness on extracted peatlands was higher close to the neighbouring vegetated areas and decreased towards the central part of the peatland, but for the peat blocks held in the greenhouse, the number of species was higher for the blocks collected from the central parts of the peatlands. The proximity of the vegetated area did not increase the number of species developed in the greenhouse whereas higher moisture and temperature conditions initiated the growth of many additional species not found on the extracted peatlands. Our study demonstrated that fertilization with a complex fertilizer did not have an overall influence on the number of species, indicating that the re-vegetation of extracted peatlands is more controlled by moisture conditions than by the availability of nutrients or propagules arrival.

Factors affecting re-vegetation dynamics of experimentally restored extracted peatland in Estonia

“…Stripping is not particularly laborious , and since it is also required to level surfaces, stripping should be applied for faster recovery of carpets of Sphagnum mosses. The results confirmed earlier findings from a greenhouse experiment (Triisberg et al 2013) that the germination of propagules and spontaneous revegetation of extracted peatlands is affected mainly by moisture conditions. The water-table depth had a significant effect (p=0.03, Table 2) on the cover of bryophytes, although this effect may be species-specific.…”

“…It has been shown that the time since the end of peat extraction has a positive effect on spontaneous re-vegetation of extracted peatlands (Triisberg et al 2013). There has been a remarkable establishment of Sphagnum cover for the third year of restoration compared to the scanty plant cover in abandoned extracted peatland (control site).…”

Relationships between bryophyte production and substrate properties in restored milled peatlands

“…Grosvernier et al () found that peat organic content or total C content is positively correlated with Sphagnum growth. Triisberg et al () also established that the distribution pattern of Sphagnum communities on abandoned peatfields is connected with a low peat ash content.…”

“…Substrate properties (pH, moisture, peat organic content, and nutrient content) are essential for the formation and development of moss species composition and thus for the outcome of restoration activities. According to Triisberg et al (), the peat organic content is one of the main factors determining the vegetation structure on abandoned milled peatlands, well related to other relevant factors like pH, decomposition level, the content of K, Mg, and P (Paal et al ), and the thickness of residual peat (Triisberg et al ).…”

Lowbush blueberry plantation age influences natural biodiversity on an abandoned extracted peatland

“…Therefore, well-lighted conditions hindered development of this species in blueberry plantations and bare peat area in our experiments. D. polysetum has been recorded in a natural revegetation study in harvested peatlands, abandoned 26-31 years ago (Triisberg et al, 2013). However, the species appeared to a small degree.…”