Does the autecology of core species reflect the synecology of functional groups during the assembly of vegetation in abandoned extracted peatlands?

Abstract

The combined autecology of individual species is expected to reflect the synecology of their respective functional groups and vice versa, but this assumption has been rarely assessed. We estimated this similarity in limiting ecological filters using vegetation survey data from 64 abandoned extracted peatlands in Estonia, which form a 50-year chronosequence of secondary succession. Partial overlap was found between filters predicting the occurrence of individual core species and richness in their respective functional groups. These overlapping filters were microtopographical form (flats, margins, ditches), time since abandonment, and various properties of peat. At the functional group level, time since abandonment and habitat properties showed clear interactions with microform type. Bog species and acidophilous bilocals successfully established on flats and ditch margins when residual peat was acidic and poorly decayed, while species of fens and mineral soils preferentially established in ditches of large extraction fields, where residual peat had higher pH and higher mineral content. We also detected some effects of landscape-level (patch area and forest neighbourhood) and regional filters (continentality); however, their limiting role was inconsistent. Many ecological filters also were shared between functional groups at the species level, but the optimal levels of these filters differed between groups. We conclude that even in species-poor habitats, both the autecology of individual species and the synecology of functional groups should be considered during habitat restoration. In peatland restoration, the following management strategies are advised to direct a faster and more successful trajectory: controlling the depth of peat extraction, partial filling of ditches, introducing plant propagules and managing mineral dust pollution