Fig. 4.

Number of non-native taxa per km² in the Arctic: NI North Iceland, JM Jan Mayen, FN North Fennoscandia, Kh Kharaulakh, SF Svalbard, KP Kanin–Pechora, CE East Chukotka, UN Polar Ural–Novaya Zemlya, GW Western Greenland, CS South Chukotka, Tm Taimyr-Severnaya Zemlya, AW Western Alaska, WI Wrangel Island, AN North Alaska–Yukon Territory, YG Yamal-Gydan, CW West Chukotka, YK Yana–Kolyma, GE Eastern Greenland, AO Anabar–Olenyok, HL Hudson Bay–Labrador, CC Central Canada, FJL Franz Joseph Land, EP Ellesmere Land–Northern Greenland. Regions with the number of non-natives per km² within the upper quartile were marked with red