BIRD DIVERSITY OF AFFORESTATION HABITATS IN IRELAND: CURRENT TRENDS AND LIKELY IMPACTS

A programme of afforestation has increased forest cover in Ireland from around 1% to more than 10% in less than a century. This study describes planting trends up to 2005 according to habitat and characterises the bird assemblages of the most commonly afforested habitat types. Most afforestation has taken place on peats, gleys [typical of wet grassland (WG) habitats] and well-drained mineral soils [typical of improved grassland (IG) habitats]. Since 1986, afforestation of gley sites increased dramatically, and afforestation rates on both peats and gleys were more than two times greater than on well-drained mineral soils. Bird diversity was assessed at 27 peatland, WG and IG sites. Bird density and species richness were positively related to shrub and tree cover, which was highest in WG and lowest in peatland sites. Indicator analysis identified several characteristic bird species of WG and peatland, but no characteristic species were identified for IG sites. The ways in which choice of afforestation habitat and subsequent management of plantations could affect bird diversity in Ireland are discussed. Afforestation is likely to benefit the birds most in areas of high-productivity grassland managed at high intensity for grazing and/or cutting, with relatively low levels of shrub cover.