Yemen’s wild plants [Archives:2006/955/Last Page]

June 15 2006

By: Ismail Al-Ghabiri
Yemeni vegetation is known for its diversity due to the country's variations in terrain, climate and water resources, with each terrain and region having its own types of plants and vegetation.

Yemen's natural terrain is divided into coastal regions, plateaus, mountain highlands and deserts.

Coastal plains region

This refers to areas extending more than 2,000 km. overlooking the Red Sea, the Gulf of Aden and the Arabian Sea. The plains form a coastal strip, beginning with the Tihama in the west and other flat or winding plains to the country's south and southeast, with altitudes ranging from 0 to 300 meters. Regional temperatures range between 20 and 40 C and annual rainfall is estimated between 50 and 100 millimeters.

Various basins and wadis (valleys) interlace the region, the most significant of which are: Moure, Rama, Zabeed, Seham, Rasyan and Sardod in the west and Bana, Toban, Hassan and Mayfaa in the south and southeast.

Coastal plants are those that can grow in high temperatures and humidity. Vegetation density doesn't exceed 30 percent and resembles that of Africa's coastal strip, with plants growing scattered on lower plains, clefts and valleys interconnecting these plains.

The most important coastal plant varieties are: Avicennia marina, Aeluropes lagopoides, Halopyrum mucronatum, Acacia tortilis, Tamarix aphylla and Odyssea mucronata.

Mountain highlands region (medium and high altitudes)

This area represents the western Tihama hills and highlands overlooking the Red Sea and Hadramout plateaus' southern and southeastern highlands overlooking the Gulf of Aden and the Arabian Sea. The region is known for medium and high altitudes ranging between 300 and 1,800 meters, with a summer temperature of 40 C and 30 C in winter.

Average annual rainfall in the southern and western highlands ranges between 200 and 700 millimeters, whereas rainfall in the eastern highlands receives lower levels between 35 and 175 millimeters, sometimes reaching 200 millimeters.

The region shows many apparent plant variations and high vegetation density, especially in important areas like the mountains of Bura'a, Erf and Houf.

This area's plants are categorized under the Sudanese region. The most important plant and tree varieties are: Acacia mellifera, Acacia asak, Acacia etbacia, Acacia tortilis, Euphorbia inarticulata, Adenium obesum, Commiphora spp., Grewia spp., Belapharis and Justicia flava, among others.

Mountain highlands (high altitudes) and plains regions

This includes areas with altitudes exceeding 1,800 meters. Average annual rainfall in the eastern highlands is between 250 and 500 millimeters, while average temperatures are 26 C in summer and 10 C in winter.

In the northern highlands, recorded rainfall is between 200 and 800 millimeters and temperatures reach 30 C in summer and 10 C in winter.

In highland plains areas, average annual rainfall is moderate, estimated between 250 and 450 millimeters, and temperatures reach 31 C in summer and 5 C in winter.

The most dominant mountain highlands plants are: Acanthus arboreus, Acacia origena, Rosa abyssinica, Columbaria scabiosa, Micromeria biflora kniphofia, Euphorbia ammak, Rumex nervusus, Euryops arabica and Thymus serphyllum.

Regional vegetation is dominated by trees, herbs and grasses, whereas small trees and grasses are found in mountainous plains, of which the following are important: Peganum harmala, Acacia origena and other grasses, in addition to other plant varieties like Kleinia semperviva, Lycium shawii and Pluicaria undulata, among others.

Eastern mountain region

This refers to mountains of medium height sloping gradually toward the desert, with altitudes between 1,200 and 1,800 meters and annual rainfall between 50 and 135 millimeters and less than 50 millimeters in areas approaching the desert. The region's climate is that of a desert and characterized by high temperatures.

Vegetation is scarcer in this area, including small trees and grasses, among which are the following: Lavandula pubescens, Acacia oerfota, Acacia etaica, Euphorbia fruticosa, Seddera arabica, Fagonia indica and Helichrysum pumilum, among others.

Eastern desert region

This area extends along the northern highlands and slopes down from 1,000 meters northward and to the east and northeast to less than 500 meters. Covered by shifting sands and dunes, the area is characterized by a dry climate and extremely high temperatures ranging between 40 C in summer and 30 C in winter, with annual rainfall estimated between 0 and 70 millimeters.

Regional vegetation rarely is observed, but includes grasses and small thickets in lowlands and wadis. The most important plant varieties are: Acacia tortilis, Aerva javanica, Dipterygium, Panicum turgidum, Suaeda aegyptiaca, Sasola imbricate and Calotopis procera. Other plant varieties observed include: Inigofera spinosa, Jatropha spinosa, Acacia oerfota, Aerva javanica, Salvia merjamie, Tamarix arabica and Pennisetum setaceum, among others.

Yemeni islands

One of Yemen's most important islands is Socotra, with an altitudes ranging from 0 meters at the sea coast to 1,506 meters at the island's highest peak. Island temperatures reach 37 C in summer and 29 C in winter and rainfall annually averages between 33 and 290 millimeters.

Socotra Archipelago is characterized by its unique vegetation, comprising more than 800 different types of plants and trees, of which 237 varieties only grow on this island. Other plants recently have been discovered on the island but not characterized yet.

The island's most important tree and plant varieties are: Croton socotranus, Jatropha unicostata, Dendrobia arbuscula, Rhus thyrsiflora, Aloe perryi and Cissus hamaderohensis, among others.

The picture and the names of plants are taken from 'Wild Plants from Yemen' guide, issued by General Authority for Environment Protection.