Border control is the implementation of border controls on travel between Svalbard, which maintains a policy of free migration as a result of the Svalbard Treaty (Norwegian: Svalbard-traktaten; ) and the Schengen Area, which includes the rest of Norway. The Kingdom of Denmark also maintains a complex system of subnational countries with autonomous customs policies, since they aren’t within the European Union like the Danish mainland. These are Greenland () and the Faroe Islands (). These areas do not maintain strict immigration controls with the Schengen Area, but border controls are sporadically enforced for customs purposes. Other examples of effective internal border
Greenland from Europe. There are no native or free-living reptiles or amphibians on the island. Phytogeographically, Greenland belongs to the Arctic province of the Circumboreal Region within the Boreal Kingdom. The island is sparsely populated in vegetation; plant life consists mainly of grassland and small bushes, which is regularly grazed by livestock. The most common tree native to Greenland is the European white birch ("Betula pubescens") along with gray-leaf willow ("Salix glauca"), rowans ("Sorbus aucuparia"), common junipers ("Juniperus communis") and other smaller trees, mainly willows. Greenland's flora comprises about 500 species of higher plants, i.e. flowering plants, ferns, horsetails and lycopodiophyta.