Vegetation and land use change in north-eastern Ireland

A survey of the vegetation of south County Antrim, UK, originally carried out in 1982, was repeated in 1992, in order to assess the impact of recent changes in the intensity of agricultural land use. Botanical composition was recorded in 200 randomly placed quadrats (200 m2), of which 157 were on non-arable agricultural land in both sampled years. Land management information relating to these quadrats was collected in 1992. Changes in composition were observed across the range of plant communities sampled, but were greatest in the more species-rich grasslands. Agriculturally preferred competitive species replaced species characteristic of less intensively managed grassland by seed dispersal and plant establishment, rather than by artificial reseeding. Higher elevation (over 200 m) enclosed fields and unenclosed grassland patches in the uplands experienced the greatest net change in composition. Increased grazing intensities, fertiliser usage, the absence of major physical constraints to land use, and recent changes in land ownership were factors associated with agriculturally beneficial changes in botanical composition.