Abstract
To date, changes in C and nutrient cycling during succession are somewhat studied, however, results are often contrasting for different nutrients and successional sequences. Generally, due to increment of litter rich in lignocellulosic components during late succession, mineralization of nutrients is expected to decelerate, and large amounts of nutrients become captivated within tree biomass. We investigated the changes in community composition following secondary succession of oak-hornbeam forest after grassland abandonment, along with the differences in soil chemistry between early- and late- successional stages. We aimed to discover whether late succession increases soil organic C and total N and S pool, but decreases the pools of plant available P and K, and that of micronutrients due to their captivation within the tree biomass.The successional sequence studied had a following pathway: Helictotrichon pubescens haypastures à Brachypodium pinnatum successional grasslands à Cornus sanguinea scrubs à late-successional Populus tremula forests à late-successional oak-hornbeam (Quercus-Carpinus) forests. Total species number was highest in haypastures and lowest in late-successional P. tremula forest. Species richness of haypastures was higher from that of mid-successional scrub and late-successional forest stages. Species richness did not differ between mid-successional scrub and late-successional forest stages. Occurrences of plant species throughout secondary succession was mostly stage-specific; only Fragaria vesca, Ajuga reptans, Cornus sanguinea, Prunus spinosa, and Viola hirta showed survival ability throughout almost all stages. Late-successional forest stages had a higher soil organic carbon (SOC), soil organic matter (SOM), and KA concentration, along with the higher soil C:N and C:S ratio in A horizon compared to early-successional grassland stages, whereas concentrations of plant available P and total N, S, Mn, Zn, Ni, Cu, and Fe remained unaltered.Even though late-successional forest stages tighten the nutrient cycles through nutrient captivation within the tree biomass, we found that late succession efficiently retained PA and micronutrient pools and even increased KA concentration in the A horizon, despite the fact that great amounts of these nutrients were already excluded from the nutrient cycle. Despite the contradicting C inputs, soil total N and S concentration did not differ between late-successional forest and early-successional grassland stages.