Forty years of vegetation change in former coppice-with-standards woodlands as a result of management change and N deposition

Question: Did vegetation of former coppice-with-standards woodlands, which were in conversion towards high forest for about 100 yrs, change over the last 41 yrs (1970-2011)? What were the main drivers of vegetation change? Location: Dransfeld Plateau, central Germany. Methods: Repetition of 85 historical semi-permanent vegetation plots located in 13 forest patches on limestone soil. Differences in species composition and plant functional types between historical and recent plots were analysed using a blockmulti-response permutation procedure (bMRPP), NMDS, indicator species analysis (ISA) and ANOVA. Results: We found significant changes in all vegetation layers. In the tree layer, Fagus sylvatica and Hedera helix had increased, while Quercus robur and Carpinus betulus had decreased. In the understorey, tree regeneration had strongly increased. In the herbaceous layer, species richness had decreased from 30 to 24 species per 100 m y, and the abundance of plant functional types had changed: the proportion of geophytes and therophytes had increased, while the proportion of hemicryptophytes had decreased. Spring-green species (i.e. species active mainly before tree foliation) had increased, while summer-green species had decreased. In addition, the estimated mean SLA of herbaceous species had increased. The proportion of closed-forest species had slightly increased, while the proportion of species of forest edges and clearings had decreased. NMDS ordination separated the herbaceous layers from 1970 and 2011 along the second axis, which correlated with the indicator values for continentality (decrease over time) and N (increase over time). Conclusions: Although the stands still shared many characteristics of coppicewith-standards woodlands, the vegetation had clearly shifted towards that of darker andmore nutrient-rich forest. This indicates both a marked legacy of historic coppice management and a strong influence of recent high forest management, aswell as N deposition.