Establishment and colonisation of new plantations with woodland ground flora

Afforestation schemes require an evidence-based study to assess the distribution and colonisation rate of their associated ground flora. Thirty Northern Irish broadleaf plantations were investigated during April and June 2017 to ascertain the colonisation rates of 14 herbaceous species. This included 9 vascular plants classified as ancient woodland indicator species (AWIS), 4 classified as species growing in woodland (Woodland Indicator Species (WIS)), and one classified as a frequent coloniser of plantations (Lesser Celandine (LC)). Using measurements of maximum dispersal distances (m) of the study species demographic changes were investigated. The main aim of the study was to establish if the 3 groups had significantly different colonization rates and to propose a set of management strategies for the improvement of their dispersal rates. The study found that the AWIS colonise new habitats significantly more slowly (p<0.001) than the other woodland study species. The effect of twelve selected habitat variables on the colonisation rate were investigated. Improvement in species dispersal range was associated with increasing source length, having adjacent mature woodland and an integrated riparian zone together with a mosaic of inter-connected hedges which are also species rich. These results show succession from grassland into woodland only begins with the planting of trees; the colonization of AWIS into new plantations should be a key objective of farmland afforestation schemes and requires active management practices.