Assessment of an abandoned grassland community and the soil seed bank of a hilly relief

The importance of grasslands is closely linked to biodiversity and soil health. Changes in plant diversity reflect the environmental conditions and practices of grasslands management. The aim of this study was to investigate the impact of abandonment on the grassland community and soil seed bank under the conditions of a hilly relief. The experiment was carried out at the Vezaiciai Branch of the Lithuanian Research Centre for Agriculture and Forestry on the hilly topography of zemaiciai Highland. The study analyses long-term monitoring data of a soil erosion experiment set up on the slopes of 9-11 degrees steepness. The soil of the southern exposition slope was a slightly eroded Eutric Retisol. In 1993, to protect the hill from erosion, a mixture of five grasses consisting of 20% timothy grass (Phleum pratense L.), 20% red fescue (Festuca rubra L.), 20% meadow grass (Poa pratensis L.), 20% white clover (Trifolium repens L.), and 20% common bird's-foot trefoil (Lotus corniculatus L.) was sown in different parts of the hill: the summit, the midslope, and the footslope. The grassland had not been fertilised and used. After 27 years, 56 vascular plant species were identified. In the summit, midslope, and footslope parts of the hill, the relative abundance (P%) of the sown species was 17.2%, 23.9%, and 27.2%, respectively. A good growth of Festuca rubra did not depend on abandonment. In all parts of the hill, P% of other sown species significantly decreased. The low value plants (Elytrigia repens L., Cirsium arvense L., and Equisetum arvense L.) spread in grasslands. The soil seed bank of abandoned grasslands was composed of the arable weeds: Chenopodium album L. was the dominant species in the soil seed bank of the summit of the hill (0-15 cm depth), while Stellaria media (L.) Vill in the soil seed bank of the midslope, 31.3% and 18.4%, respectively, of the total seed number.