Impact of afforestation on earthworm populations in Iceland

• Main Authors: Bjarni Diðrik Sigurðsson 1966-, Bjarni E. Guðleifsson 1942-
• Other Authors: Landbúnaðarháskóli Íslands
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2013
• Subjects: Ánamaðkar; Skógrækt; Iceland
• Online Access: http://hdl.handle.net/1946/19632

Earthworms were collected from different vegetation types in East and West Iceland. The vegetation types in East Iceland were Siberian larch (Larix sibirica) forests, native mountain birch (Betula pubescens) woodlands and open heathlands. The study areas in West Iceland were Sitka spruce (Picea sitchensis), lodgepole pine (Pinus contorta) forests, mountain birch woodlands and open heathlands. Four earthworm species (Dendrobaena octaedra, Dendrodrilus rubidus, Aporrectodea caliginosa, Lumbricus rubellus) were identified at both study areas and two additional ones in the West Iceland (Aporrectodea rosea and Octolasion cyaneum). No significant differences were detected in average earthworm species number and biomass between treeless heathlands and forests in East or West Iceland. There were, however, significant differences between the native deciduous forests and the coniferous plantations in West, but not East Iceland. Time since afforestation was found to have a significant effect on both earthworm diversity and density and should always be included in future studies. All earthworm parameters were positively related to soil N and amount of monocots, but negatively related to soil C/N ratio, tree LAI and tree height. Soil pH had no significant influence on any of the earthworm parameters. The most noteworthy finding was that earthworms were generally found in similar biomass and species richness in the exotic coniferous plantations in Iceland compared to the treeless heathlands, even if earthworm species composition showed strong changes. The findings apply to the first 50 years after establishment of coniferous trees, but an unexpected, large increase in earthworm biomass and species richness in the oldest thinned Siberian larch forests in East Iceland make any generalisation about future trends uncertain. Further earthworm studies in the oldest coniferous forests in Iceland are therefore still needed. Áhrif skógræktar á tegundafjölda, þéttleika og lífmassa ánamaðka á Íslandi Ánamöðkum var safnað í mismunandi ...