Data for: Species richness and composition differ in response to landscape and biogeography. Aggemyr, Auffret, Jädergård and Cousins. 2018. File descriptions: "2009-2010Baltic_explanatoryVariables.csv" IslandID - a unique ID for each island matching IslandID in the other files. Island Group - refers to which island group each island belongs to based on their geographical distribution, see "2009-2010Baltic_map.jpg" for clarification. Decimal Degrees (WGS84) - the coordinates for the centroid of each island in WGS84. Island Area, square metres - the size of each island in square metres. Island Height, metres - the highest point on each island in metres. Distance to mainland - refers to the Euclidean distance between island edge and a border to the inner archipelago, see "2009-2010Baltic_map.jpg" for clarification. Shannon diversity index, habitat heterogeneity - index used as a measure of the habitat heterogeneity on each island. Connectivity Buffer 100 metres - the structural connectivity within a buffer radius of 100 metres from island edge. The unit of the connectivity measure is square metre. Connectivity Buffer 1000 metres - the structural connectivity within a buffer radius of 1000 metres from island edge. The unit of the connectivity measure is square metre. Connectivity Buffer 4000 metres - the structural connectivity within a buffer radius of 4000 metres from island edge. The unit of the connectivity measure is square metre. "2009-2010Baltic_speciesComposition.csv" A matrix with IslandID and presence(1)/absence(0) of all found species on all islands. "2009-2010Baltic_speciesRichness.csv" Number of species found on each island, IslandID identifies the islands. "2009-2010Baltic_lifeFormClassification.csv" All species classified in accordance to life form: forb, graminoid, shrub, or tree. "2009-2010Baltic_map.jpg" - map illustrating Stockholm archipelago in the Baltic Sea and the surveyed islands.