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.

The natural recovery of vegetation on abandoned peat extraction areas lasts for decades and the result of restoration succession can be unpredictable. The aim of the study was to specify environmental factors that affect the formation of the pioneer stages of mire communities and, therefore, be helpful in the prediction of the resulting ecosystem properties. We used the national inventory data from 64 milled peatlands in Estonia, distributed over the region of 300 × 200 km. This is the first national-scale statistical evaluation of abandoned extracted peatlands. During surveys, vascular plants, bryophytes, and residual peat properties were recorded on three microtopographic forms: flats, ditch margins, and ditches. The microtopography was the main factor distinguishing the composition of plant communities on flats and ditches, while ditch margins resembled flats. The extracted indicator species suggested two successional pathways, toward fen or raised bog community. A single indicator trait-the depth of residual peat, which combines the information about peat properties (e.g. pH, ash content, and trophicity status), predicted the plant community succession in microtopographic habitats. We suggest that peatland management plans about the costefficient restoration of abandoned peat mining areas should consider properties of residual peat layer as the baseline indicator: milled peatfields with thin (<2.3 m) and welldecomposed residual peat should be restored toward fen vegetation types, whereas sites with thick (>2.3 m) and less decomposed residual peat layer should be restored toward transitional mires or raised bogs. Specific methodological suggestions are provided.

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