Soil fauna development during heathland restoration from arable land: role of soil modification and material transplant

Heathlands are threatened habitats throughout the whole Europe, which have initiated numerous restoration programmes aimed mostly at plant community reconstruction; however, little is known about soil fauna restoration. Here we have studied newly established wet and dry heathlands in the Netherlands after topsoil removal of previously agricultural land, where we manipulated the soil pH (acidification by Sulphur or liming by Ca ions as Dolokal) and introduced plant or soil material to speed up the restoration process. We sampled experimental plots and nearby mature heathlands (used as local reference habitat) over five years (2013–2017) for nematodes, mesofauna (mainly springtails and mites) and macrofauna. Although soil inoculation proved to be a substantive step in target plant community development and also helped to shift soil faunal assemblages towards the target, the latter were still far from reference heathland after five years. Only macrofaunal densities showed similar densities in 2017 as in local reference spots. The succession dynamics of all studied groups and trophic composition of macrofauna and nematodes differed in wet and dry heathlands. Soil amendments improved the initial colonisation as well as liming at the wet sites, which probably created suitable microhabitats for soil fauna development.