Soil–vegetation interactions in abandoned farmland within the temperate region of Europe

Abstract

Forests are becoming increasingly dominant in the landscape of north-eastern Europe as a result of a decline in agriculture, land abandonment and the related trend of afforestation. This is also the case in Latvia, where former agricultural land is either artificially afforested or taken over by the natural process of secondary succession. A large spatial and temporal variety of succession and compositional diversity of tree species colonizing fields is observed in the central part of Latvia. Understanding of the possible scenarios in the development of plant communities after land abandonment is important for deciding on viable management solutions, e.g. restoration of semi-natural grasslands or forest regeneration. The aim of the research was to determine the factors affecting the course of secondary succession at its initial stage and the composition of tree species that are colonizing abandoned fields. Ten abandoned fields were surveyed, recording species composition and vegetation structure, determining soil properties and analysing correlations between these factors. The research results help to explain the mechanisms of how soil properties affect the course of succession. On fertile soils a dense herbaceous layer developed, which in abandoned fields resulted in accumulation of a thick cover of litter. Such conditions hinder establishment of typical pioneer species, e.g. grey alder Alnus incana, aspen Populus tremula and birch Betula pendula, whereas Norway spruce Picea abies is able to compete with grass species and thus can more easily establish in abandoned fields, creating favourable conditions for invasion by other tree species.