Restoration of Raised Bogs in the Khanty-Mansiysk Ob Region after Reclamation of Oil- and Salt-Polluted Peat Soils in 2003–2005

Abstract

The process of natural remediation of oil- and soil-contaminated raised bogs reclaimed 14–16 years ago in Khanty-Mansiysk Autonomous Okrug–Yugra (KHMAO–Yugra) is analyzed. Revegetation is generally successful, although mesophytic grasses sown during reclamation almost completely disappeared in the grass stand. There is a gradual desalination of peat soil in salt-contaminated areas; it is accompanied by a succession change of halophytic (hemihalophytic) vegetation by communities that dominated by Calamagrostis epigeios, Eriophorum angustifolium, and Phragmites australis; a certain contribution is also made by sphagnum, green mosses, and liverworts. A characteristic feature of these habitats is the colonizing by a number of rare protected species (Heterogemma laxa, Thelypteris palustris, and Triglochin maritimum). In oil-contaminated bogs, hydrocarbons often enter from the underlying peat soil horizons during revegetation, resulting in the formation of a surface crust. Under these conditions, grass–sedge–cotton-grass and other communities are replaced by grass stands of Eriophorum angustifolium and some other species with strong root systems. A certain role in the overgrowth of crusted surfaces is also played by mosses (Sphagnum riparium, Warnstorfia fluitans, etc.). Unsuccessful restoration is observed in hollows with restricted runoff for salt-contaminated bogs and in most significantly drained segments for oil-contaminated ones.