Islands, such as the British Isles, can be adversely affected by the introduction of non-native species. Often an island will have several distinct species not present on the nearest mainland, and vice versa. The native flora and fauna of islands which have been isolated for a longer period of time such as New Zealand or Hawaii (which have been isolated for millions of years) are more vulnerable than islands such as Great Britain and Ireland, which became isolated more recently (8,000 years ago at the end of the Last Glacial Period).