Three decades of vegetation changes in a submontane grassland after the cessation of intensive fertilization

Abstract

Mesic semi-natural grasslands have usually been and mostly still are, too intensively managed in central Europe, which includes over application of fertilizer. Consequently, restoration of the structure of this vegetation and its species richness is desirable. We investigated three decades of spontaneous recovery of a submontane grassland (western part of the Czech Republic) after the cessation of two decades of applying 320 kg/ha of nitrogen fertilizer per year. The number of plant species in plots that were previously heavily treated with fertilizer approached the numbers in the controls within five years and in total species composition in approximately two decades. The number of species in both types of plots continued to increase until the end of the second decade and then more or less stabilized. Typical grassland species were mostly responsible for the increase. In the third decade, the parallel trajectories in both types of plots were substantially altered, probably due to a change in climate, which is recorded in the local meteorological data, but the type of vegetation in the grassland remained the same. Effective and low-cost spontaneous recovery of species richness in mesic grasslands in central Europe previously subject to yearly applications of fertilizer may work provided the landscape has not been too much altered by human activity and target species are still present in the surroundings. Under these conditions, no active restoration measures are needed to reduce soil nutrients and sowing seeds of target species is unnecessary.