¾ =ƒäåá ¾Ów` U`U` = e+ƒ ƒ Ethiopian Institute of Agricultural Research

Transcription

1 ¾ =ƒäåá ¾Ów` U`U` = e+ƒ ƒ Ethiopian Institute of Agricultural Research UNEP/ GEF Removing Barriers to Invasive Plant Management in Africa (RBIPMA) Project DESCRIPTIONS OF PILOT SITES ETHIOPIA

2 1.1. Amibara District DESCRIPTIONS OF PILOT SITES ETHIOPIA The Amibara District, the location chosen as the pilot site for the management of Prosopis species, a thorny shrub of American origin, is located in the Middle Awash Basin (approximately 9 o 17 N, 40 o 22 E) in the Afar Regional State. The District has a semi-arid climate with a mean annual rainfall of c.600 mm falling between February and August. Temperatures vary between 10 C and 42 C. The natural vegetation around the project site is acacia savannah. The best remaining example of this habitat is found in the Awash National Park. The Park covers an area of 827 km 2. Over 460 bird species have been recorded from the park, which has been designated an Important Bird Area (ET028, BirdLife International 2003). 76 mammals species have been recorded from the park, including the Threatened (IUCN 2001) Swayne s Hartebeest Alcelaphus buselaphus swaynei It also houses significant populations of the Endangered Grevy's Zebra (Equus grevyi), which is now restricted to Ethiopia and Kenya. The park is 40 km away from the pilot site. Pastoralism accounts for the majority of the land use in the area with cattle, camels, goats and sheep being the dominant species. In addition there is seasonal cultivation of staple crops such as tef and sorghum and large state and privately owned farms growing cotton, citrus fruits, sesame and groundnuts under irrigation. Prosopis was introduced to the Amibara District in 1988 as a windbreak, to protect the citrus and for general amelioration of the harsh environment of the area. The most aggressive species of Prosopis is believed to be Prosopis juliflora. Prosopis soon became noticeably invasive and it now threatens fields, rangelands and protected areas. It is aggressively invading pastoral areas where it covers thousands of hectares in the Middle and Upper Awash Valley, and Eastern Harerge, destroying natural pasture, displacing native trees, forming impenetrable thickets, reducing grazing potential and increasing the incidence of crop pests. In spite of its uses surveys conducted under the PBF B phase of the project (Regassa et al. 2004) indicate that local communities are convinced that the harmful effects of Prosopis dramatically outweigh its benefits. Prosopis is currently not present in the Awash National Park but will establish itself there if present trends continue. This prospect constitutes a serious threat to biodiversity Awash River Catchment System Water hyacinth (Eichhornia crassipes), an aquatic plant native to the Amazon Basin, has been gradually spreading in Ethiopia over the last 30 years. It is at its most serious in the White Nile watershed of Southwest Ethiopia, towards Sudan, and in the Awash River system, which supports major agricultural activities. Major fresh water lakes e.g. those of the Great Rift Valley are infested. Hydroelectric schemes, fishing, transport, water loss through evapotranspiration, irrigation and disease vectors are all issues to be addressed. The project sites for the management of Water hyacinth have been selected in the Awash River catchments from Aba-Samuel Dam (8 52 N, E), near Akaki, down to Lake Melka Denbi, 7 km away from Alem Tena town to the west. Lake Melka Denbi is highly infested with Water Hyacinth and is thought to be the source of infestation for neighbouring water bodies. Inhabitants of the area relate the introduction of Water hyacinth as ornamental plant by the foreign people who established and worked in the nearby fruit and vegetable farm. Water hyacinth now covers the entire water body. In surveys carried out under the PBF B phase of the project (EARO 2004) farmers from the area reported that the weed prevents access for animals to drink and for 1

3 people to fetch water. It makes the water impure as it favours the growth of parasites that affect human and animals. The lake is connected to another lake, Melka Berbere, to the east, which is now also affected by the weed. During rainy season Melka Denbi joins the Awash River and becomes the source of infestation in Lake Koka, a major source of hydroelectric power and for irrigation canals and reservoirs at Wonji, a sugar producing area. In both cases the infestation is resulting in appreciable economic losses. The Water hyacinth infestations in both these areas are exacerbated by the effects of eutrophication, from a tannery in the case of Lake Koka and from heavy fertiliser use in the case of Wonji. The Akakai-Aba-Samuel wetlands are an Important Bird Area for Ethiopia (ET029, BirdLife International 2003). The threatened Wattled Crane (Grus carunculatus) and the near threatened Lesser Flamingo (Phoenicopterus minor) are found in the area. There is also an important population of Common Crane (Grus grus) and the rare and restricted Wattled Ibis (Bostrychia carunculatus). It is a regular site for more than 20,000 waterbirds of at least 12 species. Although data do not exist on the effects of Water hyacinth on these bird populations they are highly likely to be negative in many cases Welenchiti Area Welenchiti in the Oromia region of Ethiopia, is located about 40 Km to the west of the Awash National Park at approximately 8 o 43 N, 39 o 31 E. It is situated at an altitude of 1700 m and receives an annual rainfall 850 mm. The natural vegetation type is similar to found around the Amibara District though tree densities would have been higher given the greater rainfall and lower evapotranspiration in the Welenchiti area. The major crops growing around Welenchiti are tef, maize, sorghum and common bean. Cattle, camels, goats and sheep are dominant livestock. Parthenium hysterophorus, a low annual shrub native to sub-tropical areas of North and South American, is believed to have been introduced accidentally into Ethiopia through aid shipments in the 1980s. The route of the spread of Parthenium has been along main roads from Addis Ababa to Dire Dawa to the east (which passes through Welenchiti and to Mekele to the north. From these new foci along movement corridors Parthenium invades adjacent fields that are used for crops and, after harvest for livestock. Parthenium plants are found at high infestation levels both during the crop growing and fallow periods. It is one of the very few green plants found at all growth stages after harvest during dry season. The weed's germination is not tied to a specific time of the year as it can germinate, grow and reproduce throughout the year. In contrast, most native species germinate at the beginning of the rainy season (June September). Between Parthenium plants, one finds bare soil indicative of the high grazing pressure on fallow lands used as rangeland in this site. Parthenium is having a substantial impact in arable and grazing land in the Welenchiti area. It is reported to reduce forage production by up to 90%. Sorghum grain yield losses varied from 40-97%, depending on the year and site, if Parthenium is left uncontrolled throughout the cropping season (Tamado and Milberg 2004). This invasive species is not used as forage nor favoured by livestock. Medical and veterinary effects of this species are just starting to come to light in some parts of the country. Parthenium clearly poses a major threat to rangelands but may also threaten protected areas, where it is known to be present, if combined with overgrazing. The latter is a likely to occur should Prosopis become widespread in the Awash National Park. This will increase pressure on existing grazers. Increased incursion of domestic livestock into the park (under the pressure of Prosopis and Parthenium invasion) would also result in overgrazing, facilitating Parthenium invasion resulting in a positive feedback process of ecosystem degradation and invasion. 2

4 EIAR - ETHIOPIA 3

5 EIAR - ETHIOPIA Elevation ranges of the study districts 4

6 EIAR - ETHIOPIA Dominant soil types of the study districts 5

7 EIAR - ETHIOPIA Agroecological zones of the study districts 6

8 EIAR - ETHIOPIA National Parks in the vicinity of the Project Pilot Sites 7