Colonisation of farmland deciduous plantations by woodland ground flora

Abstract

ABSTRACT Newly planted broadleaved woodlands under agri-environment schemes lack floral diversity. The dispersal range and colonisation rates of herbaceous ground flora in thirty newly planted broadleaved woodlands in Northern Ireland were investigated during spring and early summer (2017). The colonisation rates of 14 species conventionally recognised as Ancient Woodland Indicator Species (AWIS) and Woodland Indicator Species (WIS) together with Lesser Celandine were assessed and the maximum dispersal distances from potential source populations was measured. The study found that the nine selected AWIS colonise new habitats significantly more slowly (p < 0.001) than the four woodland study species and colonisation rates corresponded approximately to the classifications AWIS and WIS. The effect of twelve selected habitat variables on species colonisation rates revealed that greater species dispersal range was associated with the management of the sources both within and bordering to the newly planted broadleaved woodlands. Ensuring connectivity to mature deciduous woodlands with an integrated, riparian zone together with a mosaic of inter-connected, species-rich hedges increased species dispersal. These results suggest succession from grassland into woodland only begins with the planting of trees. Colonisation of woodland plant species should be a key objective of establishing newly planted broadleaved woodlands within farmland afforestation schemes and should be facilitated by active management practices.