Manag. Biolog. Invasions, 2011, 2 ISSN 1989‐8649 Abstract The study was conducted at the Awash National Park (ANP) Ethiopia, Survey and documentation of the potential and actual invasive alien plant species and other biological threats to biodiversity in Awash National Park, Ethiopia to Tamene YOHANNES , Tesfaye AWAS and Sebsebe DEMISSEW document Invasive Alien Species (IAS) and to assess the spread of Prosopis juliflora (Sw.) DC. A total of 64 sample plots were laid systematically along the diversity within it. Through the Introduction altitudinal gradient of 750 to 1916 m. Potential IAS were recorded. IAS which may threaten biodiversity of the park includes species such as Prosopis juliflora, Parthenium hysterophorus L., conservation of biodiversity not only Ethiopia spans a remarkable number the survival of many threatened of the world’s broad ecological species and habitats can be ensured, regions but also these valuable resources due to its dramatic geological history, broad latitudinal will spread and immense altitudinal generations and also the well being range. the of eco‐system functions protected. Xanthium strumarium L. Except P. depressions in the Afar (126 m In‐situ is considered the most juliflora and P. hysterophorus, all others below sea level) to the spectacular appropriate were not recorded in Ethiopia as IAS. P. mountaintops of Ras Dashen in the biodiversity. Conserving the areas juliflora was recorded in three plots north (4620 m) and the Bale where populations of species exist with cover of 1% to 10%. P. juliflora was Mountains in southeast Ethiopia naturally is an underlying condition also found spread in different parts of (4272 m). This variety of habitats for the conservation of biodiversity. the park particularly following the route also supports a rich variety of That is why protected areas form a of cattle movement. P. hysterophorus different species which contributes central element of any national was recorded in and around nine to the overall biodiversity of the strategy to conserve biodiversity. sample plots. Plot 46, 47 and 48 were country (IBC 2005). Cryptostegia grandiflora Roxb. ex R. Br. , Parkinsonia aculeata L., Senna occidentalis (L.) Link, Datura ferox L. and This range from highly infested by P. hysterophorus be secured way for of future conserving Awash National Park (ANP) is which covered more than 60, 70 and Biodiversity conservation is one of the protected areas in 80% of the ground layer respectively. C. the protection, restoration and Ethiopia. It shelters 81 mammal grandiflora was recorded in 11 plots sustainable management of wildlife species such as Beisa Oryx (Fig. 1), and natural resources such as Lesser Kudu, Waterbuck, Somme forests and water and the biological ring’s with cover ranging from 1% to 35%. In view of all the natural as well as anthropogenic threats to the Gazelle, Hamadryas and biodiversity of the Park, the ANP is at high risk. The rich biodiversity needs immediate management intervention. Keywords Cryptostegia grandiflora, Datura ferox. Parkinsonia aculeata, Parthenium hysterophorus, Prosopis juliflora, Senna occidentalis, Xanthium strumarium. 3 DOI: http://dx.doi.org/10.3391/mbi.2011.2.1.01 Fig 1. Beisa Oryx, one of the many species with high conservation value of the Awash National Park. T. Yohannes et al. Plant Invasions in Awash National Park , Ethiopia Anubis Baboon. There are also more proximity of ANP to Amibara (one of than 460 bird species and several the Districts bordering it, where plant species including the endemic there is a high infestation of P. tree juliflora. Together with uncontrolled species Acacia prasinata Schweinf. In Ethiopia as a whole, movement the major threats to protected areas domestic animals to the Park, the emanate from settlement within the invasion of the Park by P. juliflora National may Parks/Sanctuaries or be of both wild inevitable and unless adjacent to them, crop cultivation, precautionary measures are taken grazing and deforestation (Hillman at an early stage. 1993; Jacobs & Schloeder 1993; IBC 2005). Therefore, this study was initiated to assess and document Most of the National Parks the Invasive Alien plant Species and of Ethiopia are found in Acacia‐ the spread of P. juliflora in the Park Commiphora Woodland Ecosystems and to identify other threats to the including the ANP (IBC 2005). This Biodiversity of the Park in order to ecosystem is currently under strong provide information for appropriate environmental stress. Over forty decision making on the biodiversity taxa conservation of ANP. in this ecosystem are threatened (Ensermu Kelbessa et al. 1992). The failure to manage the Material and Methods expansion of Invasive Alien Species (IAS), such as Prosopis juliflora (Sw.) Description of the study area DC. to the ANP and the ecosystem in which it is included is threatening The study was conducted in ANP, the biodiversity (IBC 2005). In order located between 8°45′ to and 39°45′ obtain for the such as Middle Awash Basin at the southern prevention, control, eradication and tip of Afar Regional State and designing mitigation measures for northeastern the impacts. It is important to Regional State. The Park is located in incorporate proactive assessment of the geographical boundaries of IAS in vegetation studies in addition Awash‐Fantale and Kereyu‐Fantale to other ecological parameters. Districts management information to 9°15′ N of IAS of to 40°5′ E in the part Afar of and Oromia Oromia Regional States respectively. Currently compiled information on the current status of The ANP was established in plant diversity of ANP as well as the 1966. It is located 225 kilometers spread of invasive plant species is east of Addis Ababa with its not available. Due to the close southern boundary along the Awash Resumen El estudio se llevó a cabo en el Parque Nacional de Awash (ANP) en Etiopia, con el objetivo de documentar Especies Exóticas Invasoras (IAS) y evaluar la pro‐ pagación de Prosopis juliflora (Sw.) DC. Se establecieron sistemáticamente un total de 64 parcelas de muestreo a lo largo de un gradiente altitudinal de 750 a 1916 m, registrando posibles IAS. Las IAS que pueden amenazar la biodiversi‐ dad del parque incluye especies como Prosopis juliflora, Parthenium hyste‐ rophorus L., Cryptostegia grandiflora Roxb. ex R. Br. , Parkinsonia aculeata L., Senna occidentalis (L.) Link, Datura fe‐ rox L. y Xanthium strumarium L.. Excep‐ to P. juliflora y P. Hysterophorus, el resto no estaban registradas en Etiopia como IAS. P. juliflora se registró en tres parcelas con coberturas del 1% al 10%, encontrándose dispersa en diferentes partes del parque siguiendo la ruta de movimiento del ganado. P. hysteropho‐ rus se registró en el interior y alrededor de nueve parcelas de muestreo; las par‐ celas 46, 47 y 48 fueron intensamente infectadas por P. hysterophorus abar‐ cando más del 60, 70 y 80% de la su‐ perficie, respectivamente. C. grandiflora se registró en 11 parcelas con una co‐ bertura del 1% al 35%. En vista de todas las amenazas naturales y antropogeni‐ cas de la biodiversidad del parque, el ANP presenta un riesgo elevado, preci‐ sando de medidas de gestión inmedia‐ tas.. Palabras clave Cryptostegia grandiflora, Datura ferox. Parkinsonia aculeata, Parthenium hys‐ terophorus, Prosopis juliflora, Senna occidentalis, Xanthium strumarium. 4 Manag. Biolog. Invasions, 2011, 2 ISSN 1989‐8649 River, and covers 756 km2. The encountered in each sample plot abundance vegetation of the study area is were recorded and their cover was hysterophorus described grassland, recorded by visual estimation of the grandiflora Roxb. ex R. Br. and riverine percentage foliage cover of each Prosopis juliflora (Sw.) DC. vegetations (Jacobs & Schloeder species in the sampling plot and 1993), woodland and grassland with recorded as percentage. Sampling Even though, not all alien altitudinal range between 750 and sites in ANP. Park areas where species will become invasive or 1916 m.a.s.l. (Gamachu 1977). distributed among grasslands such threaten the environment, this is an as the Illala Sala area. Other area in which an early investigation The main rainy season is inaccessible areas and areas with should be made to reduce the from July to September, with a short security problems were excluded potentially rainy season from February to April. from sampling. when they do become invasive, and as open bushland/shrubland and The nature of rainfall in the study area is irregularly distributed and Data Collection Cryptostegia wide‐ranging impacts financial costs and in reversing the impacts. Invasive Alien Species are The Sampling Design and data collection L., Parthenium because of the difficulties, including the mean annual rainfall is 550.9 mm (Ebro et al. 2004). of following environmental species which are an introduced parameters were measured for each species sampling plot: habitats, non‐native (or alien) to the which invades natural ecosystem and whose introduction ‐Altitude, by using pocket During the reconnaissance survey, based on visual observation and by altimeter and Garmin GPS; other environmental gradients, the ANP was into grouped seven vegetation stands. Data collection or environmental harm or harm to ‐Slope, by using clinometer consideration of the vegetation and causes or is likely to cause economic human health. and ‐Geographical coordinates, by using Garmin GPS. The study showed that, in the ANP there are plant species was conducted during October to which are known to be invaders, November 2008 and March 2009. The average cover abundance of The assessment was conducted plant species from 64 sampling plots cultivation along altitudinal gradient ranging recorded by visual estimation of the naturalized. Plant species which from 750 to 1916 m by using percentage foliage cover of each were observed in different parts of systematic sampling design. Nine species in the sample plot and the Park and which are alien to the transect recorded as percentage. ecosystem in general and to the lines were established systematically at different places based on identified vegetation noxious weeds and escape from that became semi ANP in particular; with actual and Results and Discussion stands. In nine transects, 64 sample future invasive potential and which needs serious management plots each with a size of 20 x 20 m Average cover abundance of measures are Prosopis juliflora (Sw.) were established at every 200 m three most abundant alien plant DC., Parthenium hysterophorus L., interval along the transect or 50m species is shown in Fig. 2. Appendix Cryptostegia grandiflora Roxb. ex R. altitudinal drops when there is a 1 shows the relative coverage of the Br., Parkinsonia aculeata L., Senna steep slope. All woody vascular species recorded in the relevés. The occidentalis (L.) Link, Datura ferox L., plant results Xanthium strumarium L. Except 5 species as well as IAS showed the greater T. Yohannes et al. Plant Invasions in Awash National Park , Ethiopia Prosopis juliflora and Parthenium hysterophorus which were recorded in Ethiopia as IAS, the other five species were not so far recorded as IAS in Ethiopia. Even Parkinsonia aculeate is grown by many nursery sites and being distributed to growers in different parts of the country. the Among Cover (%) government and non‐government different altitudinal ranges covered, all the IAS were observed intermediate to low in the altitude between 770 to 1047 m a.s.l. which are plain areas, river sides, foot of mountains and road sides. The higher altitude (1094 to 1916 m Fig. 2. Cover (%)of three Invasive Alien Species from 64 sampling plots a.s.l.) from the middle of Mount Fentale to the top up to the edge of is located in between. Among the 64 Even though, there is no the volcanic crater, which is mainly sample plots of the study, P. juliflora written document when and at dominated by the endemic tree was recorded in plots 30, 31 and 32 which place of the Park was P. species Acacia prasinata Schweinf. with cover percentage of 10, 3 and juliflora first observed, the age of is so far free from such IAS. This may 1% respectively (Fig. 2). It is the trees shows that it is a recent be because of its inaccessibility. extensively places introduction which could be during where cattle overnight for long the last three to five years. As it is period of time. Also out of the shown in the map the direction of (Fabaceae) sample plots there are several parts the spread of P. juliflora coincide Prosopis juliflora is one of the IAS of the Park were P. juliflora is with the pastoralist’s movement which becomes a threat globally as growing (Fig. 3). given by Jacobs & Schloeder (1993), Prosopis juliflora (Sw.) Dc. emerging in well as locally in Ethiopian. In Ethiopia P. juliflora has become a except a single tree observed The direction of the around Kereyu lodge which is found problematic species expanding at an introduction of P. juliflora into the in area where there is no cattle alarming rate in Afar and Somali Park also coincided with the major movement. The two major possible regions. P. juliflora is extensively direction of pastoralist movement introduction and direction of spread spreading following the main road to the Park, which is from the of P. juliflora are expected to be of Djibouti ‐ Addis Ababa, passing northeast and south part of the Park from northeast and south part of several towns like Mille, Gewaine by Afar and Kereyu/Ituu pastoralists the Park by Afar and Kereyu/Ituu and others. It has reached to Awash respectively. pastoralists respectively. and Metehara towns where the ANP 6 Manag. Biolog. Invasions, 2011, 2 ISSN 1989‐8649 Kudu valley and in places where a) cattle overnight for long period of time. Figure 4 shows part of the Park which is invaded by P. hysterophorus, a place which was used by Pastoralists as a “Cattle Barn”. This shows that animals play a great role in transporting and disseminating certain weeds like P. hysterophorus. Parthenium hysterophorus was recorded in and around the following nine sample plots 22, 23, 24, 25, 35, 46, 47, 48 and 49 (Fig. 2). The first four plots are located along the road from ANP main gate on the way to Kereyu Ras Hotel and the last four plots are located along the b) riverbank of Awash around 7 km above the water fall on the way to Ajotere (Wario Asebo) kebele. Plots 46, 47 and 48 were highly infested by P. hysterophorus which covered more than 60, 70 and 80% of the ground layer respectively (Fig. 2). This may be due to the seasonal overflow of the Awash River which may bring seeds of P. hysterophorus from the infested areas above the Park such as Welenchiti and others. Cryptostegia grandiflora Roxb. ex R. Br. (Asclepiadaceae) Fig. 3. P. juliflora spreading along the road side of Awash town (a), P. juliflora on the foot of Mount Fentale, part of Awash National Park (b). Parthenium hysterophorus L. especially seasonally (Asteraceae) along road inundated sides, areas, has following the riverbank of Awash spread over many parts of the ANP, above the camping site, around Parthenium 7 hysterophorus Fig. 2 shows that in ANP Cryptostegia grandiflora was recorded in 11 plots with cover percentage ranging from 1% to 35%. The two highly invaded sample plots were plot 43 (10%) and plot 47 (35%) of the ground cover was T. Yohannes et al. Plant Invasions in Awash National Park , Ethiopia occupied by C. grandiflora. These plots are similarly infested with Parthenium hysterophorus which are found along the Awash riverbank. This may be an indication that the weed is being dispersed by water particularly by the Awash river. Cryptostegia grandiflora is a climber, growing extensively in ANP along rivers and seasonally inundated areas. It is quite common in a number of spots along the Awash River down to the lower Fig. 4. Partial view of parts of the Park invaded by P. hysterophorus. Awash basin. Afar and Kereyu pastoralists and tree can grow to 10 meters, ways Amibara District are complaining of however, 2‐8 meters is the average changing ecosystems. In 2001 the its invasiveness, toxicity to domestic range (Nathan & Robert 2007). In Lake Eyre basin Coordinating Group animals and mechanical barrier to Australia P. aculeata has been expended $295,000 for controlling animal movement to water sources recognized as a Weed of National P. aculeata in the Lake Eyre Basin (Fig. 5). The main impact of C. Significance. It continues to threaten (Nathan & Robert 2007). grandiflora observed during the the invasion of 70% of Australia’s present study was that it strangle mainland. impenetrable Though, P. aculeata was not and kill the native trees by climbing thickets are still forming along river recorded in all sample plots it was over them around and ANP Dense and wetlands completely completely eliminating access to light. It has been introduced to most tropical and subtropical regions by humans because of its attractive flowers and the fact that its latex contains commercial quality rubber gives its common name Rubber Vine. Parkinsonia aculeata L. (Fabaceae) Parkinsonia aculeata is a thorny tree of lime green appearance that has zigzagged branches, yellow petaled flowers, produces brown seed pods, 1‐3 seeds/pod, slender leaf branches and oblong leaves. The Fig. 5. C. grandiflora encroachment . 8 Manag. Biolog. Invasions, 2011, 2 ISSN 1989‐8649 domestic animals in the park should be regulated or restricted. As that of other national Parks and protected areas in Ethiopia, apart from the natural threats such as wildfire, drought, bush encroachment and others; the major threats to the biodiversity of the ANP originate from anthropogenic factors, although it must be noted that there are several root causes that lead the people around the Park to take such actions. Some of the human actions which are highly affecting the Park Fig. 6. P. aculeata, Planted as ornamental around Kereyu lodge of ANP has grown in some parts of the Park as semi naturalized plant. biodiversity are: Settlement within and areas planted as ornamental tree around domestic animals in the Park is not Kereyu lodge, and also it has grown restricted. adjacent to the Park Agricultural expansion within and around the Park as escape or semi naturalized plant along the road side of Addis Ababa ‐ Datura ferox L. (Solanaceae) Djibouti which crosses the Park (Fig. Datura ferox is widely found around 6). This shows that unless serious “Addis Ketema”, a small town in Deforestation, illegal charcoal control measures are taken, it may front of Metehara Sugar Factory. It production and fire wood collection control large area of the Park in the may be an escape from cultivation form the Park near future. where it is grown as an ornamental Grazing plant or it may be introduced with Senna occidentalis (L.) Link vehicles. In ANP, D. browsing by domestic animals In reality it is very difficult to is differentiate the real (exact) border (Fabaceae) observed growing of the Park, the buffer zone and In ANP, S. occidentalis is found along together with D. stramonium but core area of the Park; there are a lot the road side of Addis Ababa ‐ localized only around an old “Cattle of settlements in the Park (Figure 8). Djibouti, which passes through the Barn” by Strikingly, anywhere in the Park Park. At present S. occidentalis do pastoralists (Figure 7) to sustain starting from down in the Awash not occupied large area, but as the their cattle during the dry season. gorge to the top of Mount Fentale seeds are dispersed by grazing This shows that the movement of there are a variety of domestic animals (Sánchez & Uranga 1993); it domestic animals in the Park could animals: Sheep, may colonize large area in the create serious impact on the Park Cattle and Donkeys (Fig. 9). Also future, if the movement of grazing biodiversity. the forest destruction and charcoal movement of cattle and other production are affecting the Park 9 in aggressively ferox and the Park, used Therefore, Goats, Camels, T. Yohannes et al. Plant Invasions in Awash National Park , Ethiopia of the Park by Afar and Kereyu/Ituu pastoralists respectively. In view of all the above natural as well as anthropogenic threats to the biodiversity of the Park, it is not overstating the matter to say that the ANP is at high risk. The rich immediate biodiversity needs management intervention with the participation of the local community as well as local government for the immediate action. Recommendations Fig. 7. D. ferox grown as an escape in the ANP near an old “Cattle Barn”. biodiversity (Fig. 9). This is a strong of the introduction of P. juliflora 1) Due attention should be alarm which warns that the Park is into the Park also coincided with the given for the prevention of actual under grave risk. major pastoralist and potential Invasive Alien Species movement to the Park, which are from establishing themselves in the from the northeast and south part ANP. It may be difficult to eradicate Conclusions directions of them once established. The case of In addition to the natural threats to biodiversity such as: wildfire, drought, bush encroachment and others; anthropogenic factors such as settlement within the Park, agricultural expansion, grazing and browsing by deforestation, domestic animals, illegal charcoal production and fire wood collection are the major threats to the ANP. Potential invasive species which may threaten biodiversity of the Park includes species such as Prosopis juliflora, Parthenium hysterophorus, Cryptostegia Parkinsonia occidentalis, grandiflora, aculeata, Datura ferox Senna and Xanthium strumarium. The direction Fig. 8. Partial view of settlements in the ANP. 10 Manag. Biolog. Invasions, 2011, 2 ISSN 1989‐8649 a) b) c) d) Fig. 9. Pictures which shows the impacts of domestic animals on the Park biodiversity (A and B), Illegal charcoal produc‐ tion and deforestation (C and D). Prosopis juliflora in Afar Regional around Kereyu lodge (Kereyu Ras production and fire wood collection. State is a good lesson for us, which Hotel) found in the ANP. There is a These continues several need for periodical assessment of association with the sustenance of thousands of hectares of grazing the road sides of the Addis Ababa ‐ local lands despite of the efforts being Djibouti road which crosses the livestock. This issue should be the made to control it. Park. Eradication of the IAS detected core focus and major objective of in such places is the easy, fast and the Park management and should effective be invading 2) Great care should be taken way to reduce the human communities settled while planting or introducing new propagule pressure and likelihood of participation plant species into the Park. Even new invasion, since it may be the communities, though, so far there is no binding potential entrance for IAS. administrative legislation which regulates the use actions and have their with the active of the local political bodies to and have sustainable management of the of alien species; national parks 3) The major anthropogenic should have there own mechanisms threats to the biodiversity of ANP to regulate the introduction of new are settlement within the Park, plant species into the Park. Since the agricultural expansion, grazing and antagonistic interests in the ANP i.e. IAS Parkinsonia aculeata was also browsing found planted as ornamental plant deforestation, 11 by resources and for better utilization. 4) Since there are two domestic animals, to conserve the biodiversity of the illegal charcoal Park on one side and the strong T. Yohannes et al. Plant Invasions in Awash National Park , Ethiopia need to use land for human Management which is a process activities on the other side; this through conflicting the institutions are involved in the anthropogenic degradation of the decision making process with rights area to interest will lead to and subsequent which manage grass and roots control their increase of IAS establishment. Thus, environment. there is a need to compromise benefit accrued from the Park to the between local these two conflicting interest. Therefore: Also sharing the communities community important through services for its is very sustainability. a) areas should be prioritized Conservation to be successful and to those which are most in need of sustainable there needs the strong conservation, better to identify local involvement of local communities. biodiversity “hotspots”. b) The actual boundary of the Acknowledgements Park should be re‐delineated. c) Core area and buffer zones should be identified. d) creation The financial assistance of the GoE UNEP/GEF “Removing Barriers to Continuous campaigns awareness should be Invasive Plant Management in Africa (RBIPMA) Project through the conducted in order to enable the Ethiopian Institute of Agricultural local communities to know and Research implement resource Agency of the Project in Ethiopia) is reduce gratefully acknowledged. sustainable management, to (National dependency on Park resources and The to Conservation, soften and improve the Institute of Executing Biodiversity Addis relationship between the Park and University, local communities. Conservation Authority and Awash e) Alternative livelihood options for local communities which Ethiopian Ababa Wildlife National Park who facilitated the work, are highly acknowledged. do not compete with the Park resources and also which do not have much impact on the Park should be identified for better conservation and sustainable utilization of the resources by the government as well as by the local communities. f) On the buffer zone of the Park, it is better to practice a Community‐Based Natural Resource 12 ISSN 1989‐8649 Manag. Biolog. Invasions, 2011, 2 References Ebro A, Snyman HA, Smit GN (2004) Rangeland Evaluation in the Middle Awash Valley of Ethiopia: Woody Vegetation. Pp. 335‐344. In: Farm Animal Biodiversity in Ethiopia: Status and Prospects. (Asfaw Yimegnuhal and Tamrat Degefa, Eds.). Proceedings of the 11th Annual conference of the Ethiopian Society of Animal Production (ESAP) held in Addis Ababa, Ethiopia, August 28‐30, 2003. ESAP, Addis Ababa. Gamachu D (1977) Aspects of Climate and Water Budget in Ethiopia. Addis Ababa University, Addis Ababa. Kelbessa E, Demissew S, Woldu Z, Edwards S (1992). Some threatened endemic plants of Ethiopia. In: Sue Edwards and Zemede Asfaw (eds.), The Status of Some Plant Resources in Parts of Tropical Africa. Botany 2000: East and Central Africa. NAPRECA Monograph Series No. 2. Published by NAPRECA, Addis Ababa University, Addis Ababa. Hillman JC (1993) Ethiopia: Compendium of Wildlife Conservation Information. Vol.1: NYZS ‐ The Wildlife Conservation Society ‐ International, New York Zoological Park, Bronx, NY. IBC (Institute of Biodiversity Conservation) (2005) National Biodiversity Strategy and Action Plan. IBC, Addis Ababa, 103p. Jacobs M J, Schloeder CA (1993) Awash National Park management plan: 1993 –1997. EWCO, Addis Ababa, Etiopía, 301 pp. Nathan M, Robert C (2007) Review of Progress Towards The Implementation of The Parkinsonia Strategic Plan (2006 – 2007). National Prickle Bush Management Group, Australia. 20 pp. Authors Bio­sketch Tamene Yohannes is an Associate Research Officer working in Institute of Biodiversity Conservation, Ethiopia. He is a Botanist with MSc degree in Botanical Sciences from Addis Ababa University and B.Sc degree in Plant Sciences from Alemaya University, Ethiopia. He is now a PhD. Candidate in Environmental Science in Addis Ababa University, Ethiopia and working on Biodiversity Conservation, Invasive Alien Species, Ecology and Climate change related issues. YOHANNES, Tamene (1) (Corresponding author] (1) tameneyohannes@yahoo.com AWAS, Tesfaye (1) tesfayeawas@yahoo.com DEMISSEW, Sebsebe (2) Tesfaye Awas (Botanist, Curator of Gene Bank, Institute of Biodiversity Conservation, Addis Ababa, Ethiopia), was born in Bale/Ethiopia in 1967. He obtained his BSc. degree from the Asmara University in 1989 (Eritrea), MSc. degree from the University of Addis Ababa (Ethiopia) in 1997 and PhD degree from the University of Oslo (Norway) in 2007. He is one of the experts in the flora of the region and also the author of some scientific articles in the field. sebsebed@bio.aau.edu.et or s_demissew@yahoo.com (1) Institute of Biodiversity Conservation, PO Box 30726 Addis Ababa, Ethiopia. Sebsebe Demissew (2) (Leader of the Ethiopian Flora Project & Keeper of the National Herbarium, Plant Biology and Biodiveristy Management Unit, Faculty of Life Sciences, College of Natural Sciences, Addis Ababa University, Addis Ababa), was born in Shewa in 1953. He obtained his BSc. and MSc. degrees from the University of Addis Ababa in 1978 and 1980 respectively, and his PhD degree from the University of Uppsala, Sweden, in 1985. He is one of the leading experts in the flora of Ethiopia and Eritrea and he is also the author /co-author of many scientific articles in refereed journals and also a number of books in the field. Copyrights 2011 owned by The Authors 13 The National Herbarium, Addis Ababa University, P.O.Box 3434, Addis Ababa, Ethiopia T. Yohannes et al. Plant Invasions in Awash National Park , Ethiopia Appendix 1. Average percent coverage of species recorded from 64 sample plots. Species Name Cover percentage Acacia oerfota (Forssk.) Schweinf. 2.01 Acacia etbaica Schweinf. 4.89 Acacia mellifera (Vahl) Benth. 1.27 Acacia nilotica (L.) Willd. ex Del. 0.16 Acacia nilotica (L.) Willd. ex Del. subsp.kraussiana (Benth.) Brenan 0.23 Acacia nilotica (L.) Willd. ex Del. subsp. indica (Benth) Brenan 2.42 Acacia prasinata Schweinf. 2.01 Acacia robusta Burch. subsp. usambarensis (Taub.) Brenan 2.34 Acacia senegal (L.) Willd. 13.84 Acacia seyal Del. 1.11 Acacia tortilis ( Forssk.) Hayne 2.94 Balanites aegyptica (L.) Del. 0.31 Balanites rotundifolia (Van Tieghem) Blatter 1.41 Berchemia discolor (Klotzsch) Hemsl. 0.42 Boswellia papyrifera (Del.) Hochst. 1.98 Cadaba farinosa Forssk. subsp. farinosa 0.03 0.13 Cadaba rotundifolia Forssk. Capparis tomentosa Lam. 0.33 Celtis toka (Forssk.) Hepper & Wood 0.89 Cissus rotundifolia (Forssk.) Vahl 0.03 Clerodendrum myricoides (Hochst.) Vatke 0.08 Combretum molle R.Br. ex G. Don 0.52 Commiphora africana (A. Rich.) Engl. 0.27 Cordia monoica Roxb. 0.32 Cordia myxa L. 0.03 Cryptostegia grandiflora Roxb. ex R. Br. 1.05 Dalbergia lactea Vatke 0.45 Dicrostachy cinerea (L.) Wight and Arn. 0.72 Dobera glabra (Forssk.) Poir. 1.08 Dodonaea angustifolia L. f. 0.06 Ehretia braunii Vatke 0.02 Ehretia obtusifolia Hochst. ex DC 0.09 Euclea racemosa Murr. subsp. schimperi. DC) White 0.01 Euphorbia nigrispinioides M. Gilbert 0.19 Species Name Cover percentage Ficus sycomorus L. 3.17 Greiwia erythraea Schweinf. 0.56 Grewia schweinfurthii Burret 2.34 Grewia flavescens Juss. 0.05 Grewia tenax (Forssk.) Fiori 2.58 Grewia trichocarpa Hochst. ex A. Rich. 0.53 Grewia villosa willd. 4.05 Heracleum abyssinicum (Boiss.) Norman 0.02 Hyphaene thebaica (L.) Mart. 5.00 Jasminum grandiflorum L. subsp. floribundum 0.02 0.01 Lantana viburnoides (Forssk.) Vahl Maerua angolensis D.C. 0.50 Manikara butugi Chiov. 3.67 Olea europaea subsp. cuspidata (Wall. ex G. Don) 0.16 Osyris quadripartita Decn. 0.02 Ozorea insignis Del. 0.31 Parthenium hysterophorus L. 3.28 Pentarrhinum sp. 0.02 Pergularia daemia (Forssk.) Chiov. 0.02 Prosopis juliflora (Sw.) Dc. 0.22 Rhus retinorroea Oliv. 0.72 0.72 Salvador persica L. Sarcostemma viminale (L.) R. Br. 0.02 Solanum glabratum Dunal 0.03 Solanum incanum L. 0.16 Solanum somalense Franch. 0.20 Sterculia africana (Lour.) Fiori 0.08 Tamarindus indica L. 4.38 Tamarix nilotica (Ehrenb.) Bunge 0.02 Terminalia brownii Fresen. 0.63 Trilepisium madagascariense DC. 0.41 Vernonia bipontini Vatke 0.02 0.23 Vernonia cinerascens Sch. Bip. Ziziphus sp. 1.05 Ziziphus mucronata Willd. 0.03 14