OVERVIEW

This hotspot includes all the islands of Micronesia and Polynesia, plus Fiji, scattered across 40 million km² of the Pacific Ocean. Included in this enormous expanse are at least 4,500 islands, representing 11 countries, eight territories, and one U.S. state (Hawai’i). The hotspot, which is one of the smallest hotspots in terms of land area, covering only 46,488 km² (the size of Switzerland), stretches from the Mariana and Palau archipelagos in the northwest to Easter Island (Rapa Nui) in the east, and from the Hawaiian Islands in the north to the Cook Islands, Tonga, and Niue in the south.

Geologically, the islands of Polynesia-Micronesia vary from rocky islets, low-lying coral atolls, and uplifted limestone islands to larger, higher volcanic islands such as those found in Hawaii, Fiji, and Micronesia that support most of the human population in the region. Ongoing or potential volcanic activity is found in Hawaii, Tonga, Samoa, and the Northern Mariana Islands.

A wide range of ecosystems are found throughout this hotspot. There are 12 principal vegetation biomes, the most widespread of which is strand vegetation, consisting of salt-tolerant plants found along the shores of most Pacific Islands. Other principle vegetation associations include mangroves, coastal wetlands, tropical rainforests, cloud forests, savannas, open woodlands, and shrublands.