Subarctic afforestation: effects of forest plantations on ground-nesting birds in lowland Iceland

Planting forests is a commonly suggested measure to mitigate climate change. The resulting changes in habitat structure can greatly influence the diversity and abundance of pre-existing wildlife. Understanding these consequences is key for avoiding unintended impacts of afforestation on habitats and populations of conservation concern. Afforestation in lowland Iceland has been gaining momentum in recent years and further increases are planned. Iceland supports internationally important breeding populations of several ground-nesting, migratory bird species that mostly breed in open habitats. If afforestation impacts the distribution and abundance of these species, the consequences may be apparent throughout their non-breeding ranges across Europe and Africa. To quantify the effects of plantation forests on the abundance and distribution of ground-nesting birds (in particular waders, Charadriiformes), surveys were conducted on 161 transects (surrounding 118 plantations) perpendicular to forest edges throughout Iceland. The resulting variation in density with distance from plantation was used to estimate the likely changes in bird numbers resulting from future afforestation plans, and to explore the potential effects of different planting configuration (size and number of forest patches) scenarios. Of seven wader species, densities of five (golden plover (Pluvialis apricaria), whimbrel (Numenius phaeopus), oystercatcher (Haematopus ostralegus), dunlin (Calidris alpina) and black-tailed godwit (Limosa limosa)) in the 200 m surrounding plantations were just over half of those further away (up to 700 m). Redshank (Tringa totanus) densities were lowest