The following is a list of ecoregions in Yemen, as identified by the Worldwide Fund for Nature (WWF).
Yemen lies on the boundary between two of the world's biogeographic realms. The Afrotropical realm covers the southeastern portion of the Arabian Peninsula, as well as Sub-Saharan Africa and Madagascar. The Palearctic realm covers the rest of the Arabian Peninsula as well as temperate Eurasia and Northern Africa.
Yemen's seas are divided into three marine ecoregions, all part of the Western Indo-Pacific marine realm.
The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa.
The Global 200 is the list of ecoregions identified by WWF, the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their species dynamics, and environmental conditions". So, for example, based on their levels of endemism, Madagascar gets multiple listings, ancient Lake Baikal gets one, and the North American Great Lakes get none.
The Afrotropical realm is one of Earth's eight biogeographic realms. It includes Africa south of the Sahara Desert, the majority of the Arabian Peninsula, the island of Madagascar, southern Iran and extreme southwestern Pakistan, and the islands of the western Indian Ocean. It was formerly known as the Ethiopian Zone or Ethiopian Region.
A bioregion is an ecologically and geographically defined area that is smaller than a biogeographical realm, but larger than an ecoregion or an ecosystem, in the World Wide Fund for Nature classification scheme. There is also an attempt to use the term in a rank-less generalist sense, similar to the terms "biogeographic area" or "biogeographic unit".
The Arabian Peninsula coastal fog desert, also known as the Southwestern Arabian coastal xeric scrub, is desert ecoregion on the southern coasts of the Arabian Peninsula, which experiences thick fogs where visibility may be reduced to 10 metres (33 ft). It is classed as an Afrotropical fog desert
The Southwestern Arabian foothills savanna, also known as the Southwestern Arabian Escarpment shrublands and woodlands, is a desert and xeric shrubland ecoregion of the southern Arabian Peninsula, covering portions of Saudi Arabia, Yemen, and Oman.
The South Arabian fog woodlands, shrublands, and dune is an ecoregion in Oman and Yemen. The fog woodlands lie on mountainsides which slope southeastwards towards the Arabian Sea. The mountains intercept moisture-bearing winds from the Arabian Sea, creating orographic precipitation and frequent fogs that sustain unique woodlands and shrublands in a desert region.