Chapter 5: Natural Vegetation of Ethiopia PDF

Chapter 5 6.3. Natural Vegetation of Ethiopia 6.3.1. Introduction Natural vegetation refers to a plant cover that develops with little or no human interference. It can also be seen as any original plant cover grown in an area. Its distribution on the surface of the earth is uneven majorly control...

Chapter 5 6.3. Natural Vegetation of Ethiopia 6.3.1. Introduction Natural vegetation refers to a plant cover that develops with little or no human interference. It can also be seen as any original plant cover grown in an area. Its distribution on the surface of the earth is uneven majorly controlled by factors such as climate, soil types, drainage, etc. However, to a large extent, temperature and precipitation affect the spatial distribution and the original plant cover of a region. That is why, more than any other single element, the natural vegetation of an area becomes a very good indicator of the climatic conditions. Natural vegetations are vital for human beings in many ways. Plants can provide shelter, food, source of fuel, pasture and grazing, raw material for industries, source of timber and non-timber products. The other uses include moderating effect on local climate, as home of wild life, medicinal values, minimizing soil erosion etc. The characteristics of Ethiopia's natural vegetation are to a large extent determined by elevation (and temperature) and rainfall. In Ethiopia, since temperature is mostly controlled by elevation, the spatial distribution of natural vegetation in the country is strongly correlated to it. Lowlands due to their low rainfall and high temperature have harsh environment and are characterized by xeromorphic plants (plants which are adapted to drought and high temperatures). Highlands (up to about 3000 m) are cooler than the lowlands and where there is adequate moisture a variety of forests can be seen. Plants whose growth is limited by the low temperature characterize high altitude areas (mostly above 3000 m). Ethiopia possesses an estimated number of 6000 species of higher plants of which 10% are endemic. 6.3.2. Major Natural Vegetation Types of Ethiopia Taking altitude into consideration it is possible to broadly classify the vegetation belts of Ethiopia into the following five groups. 1. Afro-alpine and sub-afro alpine Region 2. Forest Region 3. Woodland Savannah Region 4. Steppe Region 5. Semi-desert Region 78 1. Afro-alpine and Sub-afro alpine Region Ethiopia has the largest extent of Afro-alpine and sub afro-alpine habitats in Africa. This vegetation type, also known as high mountain vegetation is similar to the Alpine vegetation in temperate regions. These ecosystems are found on mountains having an elevation ranging between 3,200 and 4,620 meters above sea level. The Afro-alpine habitat covers nearly 1.3% of the total landmass of Ethiopia. The Afro-alpine region is found at very high altitudes (4,000 – 4,620 m). Like any other landform in Ethiopian, the climate of Afro-alpine ecosystems is controlled by latitude and altitude. The annul precipitation which ranges between 800 and 1,500 mm, is mostly in the form of sleet or snow. Temperature records of 0oC and below are widely experienced in these ecosystems. Soils in this ecosystem are mostly shallow and eroded. The Bale and Semein mountains are typical examples of afro-alpine vegetations. Compared to the Afro-alpine, the Sub-afro-alpine region is found at a lower elevation, roughly between 3,300 and 4,000 meters. As a result, the plants in this region are adapted to somewhat less extreme environment than the Afro-alpine. Vegetation in the Afro-alpine region consists of tussock grasslands, scrub, scattered mosses and lichens while the Sub-afro alpine region is dominated by woodland, often degraded to scrub stages and also wet grasslands. Lobelia rhynchopetalum (giberra) and Erica arborea (Asta) are some of the dominant species in the Afro-alpine and Sub- afro alpine regions respectively. 2. Forest Region Forest is a complex ecosystem consisting predominantly of trees that shield earth and support numerous life forms. Not all forests are similar in terms of species composition, structure and physiognomy. In any geographical region, environmental factors such as climate, soil types, topography and elevation determine the types of forests. In Ethiopia, forests are found at different elevations, 450 to 3,500m in humid parts and 2,300 to 3,300 m in most arid parts. Moreover, forests are characterized by variation in mean annual rainfall that range between 200 and 2,200mm. These wide variations in rainfall and altitude result in two broad classification of forests: Highlands and Lowland forests. Highland forests include Hagenia Abyssinia (Kosso), Juniper procera (tid), Arundinaria Alpina(kerkha), Podocarpus falcatus (zigba), Aningeria adolfi-friedericii (keraro) and Olea africana (Weyra) 79 forests; while Baphia are classified as lowland forests. Moreover, there are also Gallery (Riverine) Forests. These are forests that stretch along the banks of the lower courses of rivers. Riverine forests are classified as lowland forests and are found in some places such as the banks of Awash, Wabishebelle, Ghenale etc. Dominant species include Ficus sur (sholla) and different kinds of acacia trees. 3. Woodland Savannah Region Like the forests, the woodland savannahs are also found in areas of wide altitudinal ranges (250 to 2,300 m). Although the mean annual rainfall ranges between 200 and 1,400 mm, the large part of this region is found at a lower elevation and in a drier environment. The plants in the woodland savannah are known for their xeromorphic characteristics like shading of leaves during the dry season. Vegetation types with intermediate characteristics between savannahs and woodlands are shrublands and bushlands. Woodland savannah region can be broadly classified into three divisions:  Juniper procera (tid) is dominant species for both the Junipers Forests and Junipers Woodlands. The difference is in height: 3 - 45 meters tall in the forests and 10 -15 meters in the woodlands.  Acacia woodlands are dominated by both trees and shrubs, which belong to the same genus 'Acacia'. E.g. Acacia etbaica(grar),Acacia mellifera (Konter).  Mixed deciduous woodlands: As the name implies, most of the trees in mixed deciduous woodlands shed their leaves during the dry season. Table 6.1: Woodland Savanna Region Woodland savanna type Altitude(m) MeanAnnual RF (mm) Growing Dominant species season(No. of months) Junipers woodland 1,350-2,200 500-900 4-8 Acacia woodland 250- 2,300 200-1,000 1-9 Junipers procera Mixed Acaci aetabica(Grar) deciduous woodland 300- 1,300 800-1.400 5-12 Mixed trees 80 4. Steppe and Semi Desert Regions These are regions in the arid and semiarid parts of the country where the temperature is very high and the rainfall very low. Both are found at low elevations, the steppe at elevations of 100 to 1,400 m above sea level and the semi-deserts at 130 meters below sea level to 600 meters above sea level. The steppe gets a mean annual rainfall of 100 to 550 mm as compared to 50 to 300 mm for the semi desert areas. Growing period lasts up to 2 months for the steppe and a maximum of one month for the semi-deserts. Even though there is a variation in the degree of alkalinity and salinity; soils in both regions are generally alkaline and saline. In these regions xerophytic (i.e. drought-resisting plants) are the dominant vegetations. Xerophytic plants such as short shrubs, scattered tufts of grass species and a variety of acacias are some of the examples. Where there are moist soils, rich vegetation of acacia and palm trees may be observed. Trees are normally restricted to fringes along watercourses. 6.3.3. Natural vegetation Degradation Over the past century, a rapid growth of the already dense Ethiopian population has led to overexploitation of the land. In areas with settled agriculture, new land has been cleared at the expense of forests. Ethiopia's forest resources have been disappearing at an alarming rate. A century ago, forests covered about 40 percent of the total land area. For the last few decades, forests have been cleared for different reasons. Major causes for the gradual disappearance of the natural vegetation in Ethiopia are:  Clearing of forests for cultivation  Timber exploitation practices  Charcoal burning and cutting for fuel  Extensions of coffee and tea production areas  Overgrazing  Expansion of settlements both rural and urban, and clearing for construction. 6.3.2. Natural Vegetation Conservation Conservation of biodiversity is protection and management of biodiversity so as to maintain at least its current status and derive sustainable benefits for the present and future generation. There 81 is an urgent need of conservation of the ever-degrading biodiversity. There are three main approaches of biodiversity conservation:  Protection: through designation and management of some form of protected area. Protected areas include sanctuaries, national parks, and community conservation areas.  Sustainable forest management: involving sustainable harvesting of forest products to provide a source of financial income  Restoration or rehabilitation: is the process of assisting the recovery of a forest ecosystem that has been degraded, damaged, or destroyed. This may involve the re establishment of the characteristics of a forest ecosystem, such as composition, structure, and function, which were prevalent before its degradation. 6.4. Wild Life/wild animals in Ethiopia 6.4.1. Introduction Ethiopia is one of the few countries in the world, which possess unique and characteristic fauna with a high level of endemicity. Existence of wide range of ecosystems endowed Ethiopia with great varieties of habitats contributing for the occurrence of high faunal diversity. However, data on faunal resource of the country is as a whole is limited to mammals, birds, reptiles, amphibians and a few groups of arthropods. Ethiopia has about 860 avian species (16 endemic species and two endemic genera), 279 species of mammals (31 endemic species and six endemic genera), 201 species of reptiles (14 endemic species), 23 species of amphibians (23 endemic species), and 150 freshwater fish (6 endemic species). A total of 279 mammalian species of which 31 are endemic are known to occur in Ethiopia including those that require urgent conservation action i.e. Walia Ibex (Capra walie), Gelada Baboon (Theropithecus gelada), Mountain Nyala (Tragelaphus buxtoni), Ethiopian Wolf (Canis simensis), Starck‟s Hare (Lepus starcki). Generally speaking, the main wild life concentrations in the country occur in the southern and western parts. The wild animals in Ethiopia can be classified into five major groups: 1. Common wild animals (those animals that are found in many parts of the country (e.g. hyenas, jackals) 82 2. Game (lowland) animal, (which include many herbivores like giraffes, wild asses, zebras etc. and carnivores like lions, leopards, and cheetahs) 3. Tree animals or arboreals (which include monkeys, baboons) 4. A variety of birds in the Rift Valley lakes 5. Rare animals (gelada baboon and Semien fox) scattered in highlands; walia- ibex in the Semien Massifs, Nyala in the Arsi Bale massifs). 6.4.2. Wildlife Conservation What are the challenges of wildlife conservation in Ethiopia? Wildlife plays an important role in several ways. The importance of wildlife can be categorized as ecological importance, economic importance, investigatory importance, conservation of biological diversities etc. Wild animals can be used for:  scientific and educational researches (valuable information for medical purposes and environmental studies)  physical and mental recreation (aesthetic value)  promotion of tourism (economic value)  its potential for domestication  maintaining ecological balance To prevent the destruction of wildlife a total area of nearly 100,000 square kilometers of national parks, sanctuaries, community conservation areas, botanical gardens, wildlife reserves etc. have been established in different part of the country. Hence in Ethiopia there are:  21 major national parks (see Table 6.2),  2 major wildlife sanctuaries,  3 wildlife reserves,  6 community conservation areas,  2 wildlife rescue centres,  22 controlled hunting areas,  2 botanical gardens, and 3 biosphere reserves 83 Figure 6.2. Spatial distribution of National Parks Source: CSA Shapefile, 2012 (four national parks are not mentioned) Even though the number and the predominant animals may vary, many of the national parks in Ethiopia have different turnovers of animals. These include buffaloes, zebras, lions, elephants, ostriches, giraffes, oryx, African wild asses, etc. 84 85 Table 6.2: National Parks of Ethiopia Source: Young, 2012 Some of the national parks are unique in their wild animals they have. E.g. 1. Abiyatta-Shalla lakes National Park is predominantly bird sanctuary. Important bird species include the flamingos and pelicans. 2. Omo, Mago, and Gambela National Parks have hippopotamus and crocodiles in rivers and lakes. 3. Semien and Bale Mountains National Parks have rare animals like Walia ibex, Semien fox, gelada baboon and Nyala. S.no Name Region Year est. Area in sq.km 1 Kafeta Shiraro Tigray 1999 5000 2 Semien Mountains Amhara 1959 412 3 Alatish Amhara 4 Bahir Dar Blue Nile River Millennium Amhara 2008 4729 5 Borena Saynt Amhara 2008 4325 6 Yangudi-Rassa Afar 1969 4731 7 Awash Oromiya and Afar 1958 756 8 Dati Wolel Oromiya 2010 1031 9 Bale Mountains Oromiya 1962 2200 10 Yabello Oromiya 1978 1500 11 Abijata Shala Oromiya 1963 887 12 Arsi Mountains Oromiya 2012 13 Geralle Somali 1998 3558 14 Gambella Gambella 1966 4650 15 Nechsar SNNPR 1966 514 16 Omo SNNPR 1959 3566 17 Mago SNNPR 1974 1947 18 Maze SNNPR 1997 202 19 Gibe Sheleko SNNPR 2001 248 20 Loka Abaya SNNPR 2001 500 21 Chabra Churchura SNNPR 1997 1190 6.4.3. Challenges of wildlife conservation in Ethiopia Do you know that if you leave nature to its own system, it has notable system of taking care of itself! Conservation of Ethiopia‟s biodiversity and ecosystems is vital to ensure sustainable development, to mitigate and adapt to the effects of climate change and to prevent the collapse of life-supporting ecosystem services. Protected areas were created to protect the major biodiversity. However, it is a sad fact that these ecologically fundamental resources are usually undervalued and are under threat from various dimensions. Here are some of the major challenges that Ethiopian protected areas are facing;  Limited awareness on the importance of wild life  Expansion of human settlement in protected areas.  Conflict over resource  Overgrazing (fodder and wood) Check! 1. Discuss the major soil types of Ethiopia. 2. What are the three types of soil degradation?  Illegal wildlife trade  Excessive hunting  Tourism and recreational pressure  Mining and construction material extraction  Forest fire