Vegetation Types, Composition and Conservation Status of Forest Ecosystems in Ethiopia

Abstract

Diversity is unevenly distributed over the surface of the earth. The most conspicuous spatial pattern of species diversity is a latitudinal gradient of decreasing richness of species from equator to poles (Willig et al. 2003). This pattern is consistent for several organismal groups such as terrestrial plants (Mutke and Barthlott 2005). However, notable exceptions to this classical pattern are quite common for different taxonomic groups (Heywood 1995). Some taxonomic groups such as vascular plants richness in Africa increases towards temperate latitudes (Heywood 1995), hotspots of gymnosperm diversity are located in Southeast Asia especially in China while tropical Africa is considered as a cold spot of Gymnosperm species diversity (Mutke & Barthlott 2005).

Ethiopia’s boundaries encompass the major part of the eastern African highland massif. On the northern and western boundaries lie the foothills of the main massif. The Great Rift Valley cuts diagonally across the country from north east to south, creating a vast depression. The dry areas have isolated the highlands. Thus, there is a great variation of altitude from 116metres below sea level to 4620 meters above sea level. Rainfall also varies widely in amount and distribution. These factors strongly influence Ethiopia’s extraordinary range of terrestrial and aquatic ecosystems and have contributed to a high diversity and of endemism (Tesfaye Awas et al. 2003).

According to Leul Kidane et al. (2010), Ethiopia is one of the centers of plant genetic diversity and that its indigenous vegetations have been depositors of biodiversity including micro-organisms , fungi, soil fauna and flora, medicinal plants , wild animals, birds insects as well as human beings (Tewolde Berhan Gebre Egziabher 1991; Legesse Negash 2002).It was believed that, in early 20^th century about 42 million hectares or equivalent of 35% of Ethiopia’s land area which is 110 million hectares was covered with high forest. With the inclusion of savannah woodlands, about 66% of the country was covered with forest or/and woodland at that time (EFAP 1994).However, with high population pressure, expansion of urbanization and the increasing demand for agricultural land, the present forest resource is on the verge of complete depletion (Zenebe Gebre Egziabher et al. 1998).Forest conservation is currently the top agenda for a number of world conservation organizations, authorities and interest groups. Concern over forest conservation generally hinges on anthropogenic activities that lead to depletion forest resources. Conservation biologists have sought to protect forests using several different strategies from strict protection in National Parks, to sustainable forest management and other integrated conservation and development programs (Bruner et al. 2001).