(Table 1) Cover of shrub and tree species, and number of stems (>=3.5 cm DBH) during 1976-1977 and 2009-2010, respectively

• Main Authors: Rundqvist, Sara, Hedenås, Henrik, Sandström, Anneli, Emanuelsson, Urban, Eriksson, Håkan, Jonasson, Christer, Callaghan, Terry V
• Format: Dataset
• Language: English
• Published: PANGAEA 2011
• Subjects: Abisko_ANS; Abisko; Lappland; northern Sweden; Abisko Scientific Research Station; Area/locality; Betula nana; cover; Betula pubescens czerepanovii; DATE/TIME; Date/time end; International Polar Year (2007-2008); IPY; Juniperus communis; Number of stems; Populus tremula; Salix spp.; Sorbus aucuparia; Trees and shrubs; Arctic; Climate change; Dwarf birch; Global warming; International Polar Year; Northern Sweden
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.819497; https://doi.org/10.1594/PANGAEA.819497

Shrubs and trees are expected to expand in the sub-Arctic due to global warming. Our study was conducted in Abisko, sub-arctic Sweden. We recorded the change in coverage of shrub and tree species over a 32- to 34-year period, in three 50 x 50 m plots; in the alpine-tree-line ecotone. The cover of shrubs and trees (<3.5 cm diameter at breast height) were estimated during 2009-2010 and compared with historical documentation from 1976 to 1977. Similarly, all tree stems (>=3.5 cm) were noted and positions determined. There has been a substantial increase of cover of shrubs and trees, particularly dwarf birch (Betula nana), and mountain birch (Betula pubescens ssp. czerepanovii), and an establishment of aspen (Populus tremula). The other species willows (Salix spp.), juniper (Juniperus communis), and rowan (Sorbus aucuparia) revealed inconsistent changes among the plots. Although this study was unable to identify the causes for the change in shrubs and small trees, they are consistent with anticipated changes due to climate change and reduced herbivory.