Parthenium Weed Invasion and Biodiversity Loss in Ethiopia: a Literature Review

Parthenium weed invasion and biodiversity loss in Ethiopia: A literature review

LISANEWORK NIGATU1 & J.J. SHARMA1 1College of Agriculture and Environmental Sciences, Haramaya University, P.O Box 138, Dire- Dawa, Ethiopia Corresponding author: [email protected]

Abstract Parthenium weed (Parthenium hysterophorus L.) is an invasive alien species whose mode of introduction is uncertain, although it was first recorded in Ethiopia in 1968. Since then it has been colonizing disturbed sites very aggressively, impacting pastures, croplands and forests by outcompeting native species and has become a major threat to the natural environment. It has been found to be widespread in north, east and southwestern regions of Ethiopia. It is rapidly expanding in urban and rural areas. Initially, the weed was confined to railway tracks, roadsides, non- crop areas but now found to colonize pasturelands aand cropped areas rapidly in Ethiopia. The invasion by P. hysterophorus is causing biodiversity degradation, yield losses in field and horticultural crops, health problems to human beings and animals. Germination and growth of indigenous plants are inhibited by its allelopathic effect. It is being increasingly seen as a threat not to only to biodiversity and ecosystem but also economic development and human wellbeing. Most of the studies conducted focused on changes in floristic communities in Western Hararghe, Afar, Jigiga and northeast pasturelands. Based on ecoclimatic index Ethiopia is highly favourable for the parthenium. Based on CLIMAX it is likely that with time it has potential to increase its range. The studies conducted have depicted substantial decline in species richness and abundance. Invasion has reduced species diversity of native plants and fodder supply to animals. In north–east grazinglands of Ethiopia, a regression analysis showed a highly significant but negative relationship between the aboveground species diversity and evenness with parthenium abundance. The invasion by parthenium was found to critically endanger biodiversity of the grazinglands. Parthenium was negatively correlated with species composition, aboveground biomass and evenness and to the diversity indices in Jijiga. Also parthenium was found to be one of the most dominant species in Afar region. Experimental evidences have also shown buildup of soil seed bank in favour of parthenium in medium to highly infested areas. Thus this invasive alien plant species pose significant challenges to managing and maintaining indigenous biodiversity in natural ecosystems. Despite the growing evidence of placing constraints on sustainable development, economic growth, poverty alleviation and food security, the level of awareness amongst decision-makers is still relatively low. Mass awareness among urban and rural population, students needs to be done as in case of HIV-AIDS to manage and further contain the spread of the weed.

Key words: Abundance, ecoclimatic index, ecosystem, invasive, Parthenium hysterophorus, species richness

Introduction Mexico, Mozambique, Nepal, New Caledonia, Pakistan, Papua New Guinea, Puerto Rico, Seychelles, South Africa, The invasion of weeds into natural areas has been Sri Lanka, Swaziland, Tanzania, Trinidad, Uganda, United associated with human movements throughout the States of America, Venezuela, Vietnam, West Indies and evolutionary development. The exploitation of natural Zimbabwe. In Africa, it is likely to be present in other areas resulted in colonisation and establishment of tropical and sub-tropical regions in future. introduced plants. The invasions by alien species are In many introduced ranges parthenium has posed thought to be one of the most serious threats to both serious threats to crop production, natural biodiversity, natural and managed ecosystems worldwide (Mack et al., animal and human health because of prolific growth, rapid 2000). Weeds are repeatedly excellent at surviving and spreading and production of toxic allelochemicals reproducing in disturbed environments and are the first (Chippendale & Penetta, 1994; Kohli et al., 2006; Asresie species to colonise and dominate the ecosystem and et al., 2008). Although, P. hysterophorus was first recorded impose severe losses to farm and forest productivity. in Ethiopia in 1968 (Haramaya University, Herbarium) its Weeds invade crops, smother pastures and grazinglands, mode of introduction is still uncertain. Probably it remained and in some cases even harm livestock and human. They unnoticed and the major spread of the weed took place aggressively compete for water, nutrients and sunlight, after 1980 when infestation was observed at Dire Dawa. It resulting in reduced crop yield and poor crop quality. is also believed that parthenium was introduced to Eastern Parthenium weed (Parthenium hysterophorus) also Hararghe, Jijiga and Dire Dawa during the Ethio-Somalia known as carrot weed is an annual multi-branched herb of war in 1976-77 by army vehicles (Tomado & Milberg, 2000). the family Asteraceae. It is native to tropical and The second major center of infestation was subsequently subtropical Americas and is one of the world’s worst found near Dessie, Wello and North-eastern Ethiopia which invasive weeds in the tropical and sub-tropical regions. are major food distribution centers and there is strong Parthenium is currently distributed in Argentina, Australia, proposition that the weed was imported from sub-tropical Bangladesh, China, Cuba, Dominican Republic, Ethiopia, America during 1988 famine (Murphy & Cheesman, 2006). Haiti, Honduras, India, Jamaica, Madagascar, Mauritius, Thus, it is likely that the entry occurred as a seed 378 LISANEWORK NIGATU & J.J. SHARMA contaminant of food grains imported from overseas where reserve of approximately 7000-8000 seeds m2 (Nguyen et parthenium occurred on farmlands. The area coverage is al., 2010). Parthenium roots of decayed plant release enormously increasing across the agro climatic zones of soluble sesquiterpene lactones, mainly partenin (Jarvis et Ethiopian and has become an environmental weed. Higher al., 1985; Pandey et al., 1993). These chemicals inhibit the infestations reported in Eastern Ethiopia, notably in the germination and growth of other plants including pasture range and cropping lands of the East and West Hararghe grasses, cereals, vegetables, and other plant species regions. By 1999, parthenium weed was reported to be (Navie et al., 1996; Evans, 1997). spreading to western Ethiopia. Even though there is no actual data on the total area of land infested by parthenium Impact on biodiversity. Infestation by parthenium weed, widespread occurrence of the weed has been degrades natural ecosystems. With the passage of time; reported in the north, east and south-western regions parthenium invasion enriches the compositional diversity surveyed (Mc Connachie et al., 2010). Currently, but may result in extinction of native species (Noss, 1990). parthenium is spreading at an alarming rate in Eastern It is known to exert significant impact on the natural Ethiopia; the central rift valley; and neighboring localities communities causing their displacement and hence exert of Afar Region, East Shewa, Arsi; Bale and in Southern imbalance in the natural and agricultural ecosystem (Sakai Ethiopia. A recently developed CLIMAX model has shown et al., 2001). This imbalance causes the formation of large that much more land within Ethiopia is suitable for the monoculture of invasive alien plants in the environment. growth of parthenium (Mc Connachie et al., 2010) and it is Several studies revealed the adverse effects of parthenium anticipated that the problems caused by this weed are weed on plant biodiversity (Cock, 2001; Kohli et al., 2004). likely to grow in future as the weed continues to spread. Lisanework et al. (2010) found that within the soil seed Impact of Parthenium bank, the viable seed density for parthenium was 68.5% The weed has economic, environmental and social as against 25.7% and 5.8% for grass and other species impacts. This weed is destroying native habitats; respectively. Similarly, in grasslands dominated by threatening native plants and thus reducing plant parthenium, native plant species composition and biodiversity. Consequently, the weed has led to the abundance was found to be low (Taye et al., 2010). For degradation of natural vegetation and has become as one example in Australia, parthenium weed has caused a of the major threats to the natural environment. It competes significant reduction in native plant diversity (Nguyen et with beneficial pasture grass in pasturelands, hazard to al., 2010). Therefore, it is increasingly seen as a threat not health of livestock especially cattle, reduces crop yield, only to biodiversity and ecosystem services, but also to and increases management cost. To humans, it is economic development and human well-being. In sorghum responsible for many diseases; reduces recreation and fields 79.5 % of the weed diversity and 61.4% of the species aesthetic values resulting loss in ecotourism. evenness was attributed due to parthenium invasion in The reasons for parthenium heavy invasion in new Kobo, northeastern lowlands of Amhara region (Asresie areas included the absence of natural enemy viz., insects et al., 2008) and the plant species heterogeneity decreased and diseases that control it in natural habitats and fast with the increase in parthenium infestation and the disturbances in the existing environment due to population evenness index was higher in low infested areas. There pressure and development that provides conditions was considerable reduction in species richness as the suitable for invasion. It grows faster than native plants density of parthenium increased. They further observed and aggressively competes for available nutrients, water, that the area covered by parthenium was 34% of the total space and sunlight. It releases growth inhibitors like area covered by the weeds with importance value of 45.6 lactones and phenols into the soil through exudation from % that demonstrated the invasiveness of parthenium with roots and decay of residues. These growth inhibitors the potential to replace other native species. suppress the growth and yield of native plants. Therefore The infestation of native pastoral lands with it reduces natural diversity by smothering native plants parthenium has led to significant decrease in native flora and may exhibit natural heterogeneity to homogeneity. seed banks, sharp decline in diversity index, evenness Parthenium weed is extremely prolific, has a wide range of and species richness in Ethiopia (Lisanework et al., 2010). ecological adaptation, ability to spread quickly and grow Although in Ethiopia, the exact estimates of pastoral lands in diverse habitats (Annapurna & Singh, 2003). Parthenium invaded by parthenium are not known, this weed has been can invade new areas rapidly by means of relatively high causing their degradation not only by its presence but numbers of seeds, dispersal by vehicles and rails, water, also by grazing pressure. This grazing pressure further animals, farm machinery and rapid growth. Construction has been creating conditions for parthenium to spread sites are more vulnerable to the infestation of this weed and dominate the ecosystem. The prolonged drought in not only through vehicles/ heavy machinery as means of some parts of the country has favoured the invasion of dispersal but also the construction materials such as this weed which may be due to the selective consumption gravel, sand and soil. Parthenium on average produces of palatable species thereby conceding to the enhanced 810 flower heads and 15,000 seeds per plant are produced. smothering effect of parthenium and making it more Under favorable conditions for example, in a highly infested dominant and problematic. However, our experience field in India, a single plant produced 200, 000 seeds/m2 revealed that even with those areas with sufficient soil (Joshi, 1991). Seeds are very light in weight and easily moisture, many flushes of weeds can be witnessed in a scattered to other areas. It has a huge soil seed bank year. Parthenium weed invasion and biodiversity loss 379 The parthenium is an aggressive weed which possess reduced and the structure of many native plant a serious threat to the environment and biodiversity communities is being altered (Pandey et al., 1993; Kumar rapidly replacing native vegetation (Pandey & Saini, 2002). & Rohatgi, 1999). It is an aggressive pioneer that generally The invasion of non- crop areas near roadsides has caused colonises disturbed areas before encroaching on native a considerable decrease in the native plant diversity and vegetation. Its invasion has changed the natural diversity the extinction of native flora that may have indirect effects and balance of ecological communities. These changes on soil erosion especially on sloppy terrain. It is shocking threaten the survival of many plants and indirectly animals that the Serengeti–Masai, the largest wildlife migration is because the competition with native plants for space, under attack from parthenium and threaten the migration nutrients and sunlight. In Ethiopia, native plant of millions of animals in Kenya (Chadwick, 2010). The communities have been invaded, or are vulnerable to infestation of parks and other reserve areas has been invasion by this exotic weed that could result in changes reported in India (Goyal & Brahma, 2001) and also found to the structure, species composition, abundance of native creating great challenge on herbaceous plant diversity of communities in grazing lands. In Australia, it has become Awash National Park in Ethiopia (Fish et al., 2010; Ayana dominant species and inhibits all beneficial forage plants. et al., 2011) which may also call for immediate attention of This based result in monoculture of non-nutritious all of us. vegetative matter causing hard strips to sustain cattle due The most frequent and sturdy flushes are observed to drop in productivity of pastures consequently reducing during rainy season coupled with comparatively higher the carrying capacity of farms up to 40% (Chippendale & temperature producing a large number of seeds. Therefore, Penetta 1994) and 90% reduction in forage production in with the change in climate, the increasing temperature may India (Nath, 1988). Invasive parthenium in pastures reduce not only facilitate the spread of parthenium to new areas forage quality and yield, and increase management costs but also the intensity and robustness of plants in a and reduce animal performance. It aggressively colonizes community. The atmospheric CO2 level has been increasing disturbed sites where it limits pasture growth and steadily over a number of years (Houghton et al., 1991). It depresses forage production. Plant biodiversity is an is believed that enhancement of atmospheric CO2 will important parameter in any rangeland study since high greatly increase the growth C3 plants (Kimball, 2002; diversity is an indicator of good rangeland condition that Nowak, 2004) and the growth of exotic invasive plants will is capable of sustaining high forage production. It is also increase more than the native C3 because of specific growth capable of improving the nutritional conditions of land traits that help them to use more CO2 (Grotkopp & due to mixed diets and giving greater niche differentiation. Rejmanek, 2007; Leishman et al., 2010). Parthenium is Species diversity refers to the variety of living organism considered both as C3 and C4 plant (Rao & Rajendrudu, on the earth and is measured by the total number of species 1989; Devi & Raghvendra, 1994). Like in other countries, in a given study area, habit or ecosystem (Herlocker, 1999). the grazing and pasturelands in Ethiopia are also High values in the index of diversity suggested variability dominated by grasses mostly which are C4 plants. Thus in the type of species and heterogeneity in the community parthenium is likely to become more problematic in Ethiopia. whereas lesser values suggested homogeneity. In a study

Another possible effect of elevated CO2 upon promoting conducted in rangelands of Mieso District, Ethiopia, suppressive ability of parthenium weed may be through parthenium had 21.3% cover abundance value and 0.32 promotion of its allelopathic potential against close diversity index among broadleaved herbaceous weeds growing plants. (Temesgen, 2010). The major problem facing the pastoral production in Ethiopia is the wide scale degradation of Impact on agriculture. Parthenium reduces yields of native pasture undesirable shrubs like Acacia spp., agricultural crops and forests, decrease water availability, Prosopis juliflora and herbaceous weeds like Xanthium cause costly land degradation, block transport routes and and Parthenium (Temesgen, 2010). In Mieso and Talalak contribute to the spread of disease. It generates districts (Afar) rangelands, the highest relative density, allelopathic effects in the soils, and outcompetes crops relative frequency importance valve and cover abundance for available nutrients and moisture. It has allelopathic were found for parthenium among the herbaceous species effects on plants due to parthenin. This exhibits inhibitory (Temesgen, 2010; Natnael, 2011). effects on number of plants including pasture grasses Parthenium weed is producing a large amount of cereals, vegetables, weeds and trees. Its pollen is known undesirable biomass thus grazing and pasturelands are to inhibit fruit set in many crops. Parthenium infestation continuing to be degraded due to the pressure put forth has been reported to cause detrimental effect on sorghum by the weed. Lisanework et al. (2010) observed that as the yield other crops. In eastern Ethiopia with heavy above ground dry biomass of parthenium increased that infestation of the weed, sorghum grain yield reductions of grass and other species decreased in grazing lands of ranged from 40% to 97% (Tamado et al., 2002b) and in northeastern Ethiopia. According to that study, the density 18.5-86.4% in common bean (Mitiku, 2011). In India, yield and biomass reduced by 67.6% and 59.6% in areas that decline of up to 40% in crop production has been reported were infested with parthenium (Kohli et al., 2004). Weeds (Khosla & Sobti, 1981). are increasingly affecting the utilization of both natural Parthenium weed is an environmental weed which can and sown pastures. In Ethiopia, natural pastures constitute cause a total habitat change in native grasslands and the highest portion of the available grazing resources. forestlands. In India, the forest biodiversity is being Kimball (1983) estimated that doubling ambient CO2 levels 380 LISANEWORK NIGATU & J.J. SHARMA stimulated biomass yield of C3 plants by 40% while it was Ayana E.K. Ensermu & Teshome, S. 2011. Impact of

11% for C4 plant species. The seed production of the Parthenium hysterophorus L. (Asteraceae) on standing vegetation influences the composition and size Herbaceous Plant Biodiversity of Awash National Park of the seed bank (Coffin & Lavenroth, 1989). Hence, seed (ANP), Ethiopia. Management of Biological Invasions banks are fundamental to the ecology of communities and 2, 69-80. to the recruitment of species, especially those that mostly Chadwick, N. 2010. Noxious weed threatens the biggest or totally have non-vegetative means of reproduction. In wildlife migration on the planet.http:/www.iucn.org/ rangelands, high grazing pressure usually leads to a decline iyb/media/?6511/news story. in the density of perennial grasses and increases the Chippendale, J.F. & Panneta, F.D. 1994. The cost of density of weeds and annual species in the vegetation parthenium weed to the Queensland cattle industry. (O’Connor & Pickett, 1992). The richness and diversity of Plant Protection Quarterly 9, 73-76. the seed bank of grassland community was low when the Cock, M. 2001. CABI Bioscience Switzerland Center, 1 Rue dense infestation of parthenium was present (Navie et al., des Grillons, CH-2800 Delemount, Switzerland. 2004). Hence, the prolonged presence of parthenium may www.cabi.org/bioscience/switz.htm. have substantially reduced the diversity of the species in Coffin, D.P. & Lauenroth, W.K. 1989. Spatial and temporal seed bank thereby reducing the ability of some of the variation in the seed bank of a semiarid grassland. native species to regenerate in the future. In seed bank of American Journal of Botany 76, 53-58. rangelands in Jijiga and eastern Amhara parthenium was Devi, M.T. & Raghavendra, A.S. 1994. Formation of found abundantly indicating that among all the species, it photorespiratory glycollate or glyoxylate in leaf discs had the highest number of seeds in soil (Shashie, 2007; of C3-C4 intermediates: reduced sensitivity to external Lisanework et al., 2010)). The domination of parthenium bicarbonate. Photosynthetica 30, 455-463. in the seed bank suggests that the weed is having a Evans, H.C. 1997. Parthenium hystrophorus: A review of substantial negative impact on the ecology of the plant its weed status and the possibilities for biological community (Navie et al., 2004). control. Biocontrol News and Informations 18, 389- 398. Management strategies. Control of parthenium by any Fish, J., Chiche, Y., Day, R., Efa, N., Witt, A., Fessehaie, R., means, is difficult because the area occupied may be so de G. Johnson, K., Gumisizira, G. & Nkandu, B. 2010. large that such efforts are time-consuming and costly. To Mainstreaming gender into prevention and combat the menace of parthenium to biodiversity, management of invasive species. Global Invasive agricultural production, human and animal health, Species Programme (GISP), Washington DC, US, environmental and economic losses, a sound management Nairobi, Kenya. p.64. strategy has to be formulated. This should include, Goyal, C.P. & Brahma, B.C. 2001. A ray of hope against prevention, implementation of biological methods like parthenium weed in Rajaji National Park. Indian Forester introduction of insect bioagents and competitive plants 127, 409-414. in large areas with severe parthenium infestation on Grotkopp, E. & Rejmánek, M. 2007. High seedling relative roadsides and non-crop areas. Herbicides and cultural growth rate and specific leaf area traits of invasive methods may have scope limited only in crop fields and species: phylogenetically independent contrasts of orchards. To contain the further spread of the weed and woody angiosperms. American Journal of Botany 94, soil seed bank build up for future infestation, parthenium 526-532. plants should be utilized for composting and production Herlocker, D. 1999. Rangeland and Resource Development of biogas and paper. For grazing and pasturelands in East Africa. Portland, Oregon, USA. 203p. herbicide as well as rehabilitation with useful fodder Houghton, J.T., Ding, Y., Griggs, D.J., Noguer, M., van species has to be developed. Above all mass awareness der Linden, P.J. & Xiaosu, D. 2001. Climate change and eradication programmes with the participation of 2001: The Scientific Basis. Contribution of Working students, urban and rural people, and officials’ of Group I to the 160 Third Assessment report of the government as well as NGO’s should be widely conducted Intergovernmental Panel on Climate Change. using various media. The success can be achieved only if Cambridge University Press, Cambridge, United it is accomplished sincerely. Kingdom and New York. Jarvis, B.B., Pena, N.B., Rao, M.M., Comezoglu, N.S., References Comezouglu, T.F. & Mandava, N.B. 1985. Allelopathic agents from Parthenium hysterophorus and Baccharis Annapurna , C. & Singh, J. 2003. Variation of Parthenium megapotamica. In: Thompson,A.C. (Ed.). The hysterophorus in response to soil quality: implications chemistry of allelopathy, Biochemical interactions for invasiveness. Weed Research 43, 190-198. among plants, American Chemical Society, Washington Asresie Hassan, Lisanework Nigatu & Sharma, J.J. 2008. D.C. pp. 149-159. Impact of Parthenium on herbaceous vegetation and Joshi, S. 1991. Biocontrol of Parthenium hysterophorus soil seed Bank Flora in Sorghum Fields in North- L. Crop Protection 10, 429-431. Eastern Ethiopia. Ethiopian Journal of Weed Khosla, S. N.& Sobti, S.N. 1981. Effective control of Management 2, 1-11. Parthenium hysterophorus L. Pesticides 15, 18-19. Parthenium weed invasion and biodiversity loss 381 Kimball, B.A. 1983. Carbon dioxide and agricultural yield: Parthenium hysterophorus L. Weed Biology and an assemblage and analysis of 430 prior observations. Management 4, 154-167. Agronomy Journal 75, 779-788. Nguyen, T., Navie, S., O’Donnell, C. a& Adkins, S.W. Kimball, B.A., Kobayashi, K. & Bindi, M. 2002. Responses 2010. Biology of parthenium weed (Parthenium

of agricultural crops to free air CO2 enrichment. hysterophorus L.). Unpublished data, The University Advances in Agronomy 77, 293-368. of Queensland, Brisbane, Australia. Kohli, R.K., Batish, D.R., Singh, H. and Dogra, K.S. 2006. Noss, R.F. 1990. Indicators for monitoring biodiversity: a Status, invasiveness and environmental threats of hierarchial approach. Conservation Biology 4, 355-364. three tropical American invasive weeds (Parthenium Nowak, R.S., Ellsworth, D.S. & Smith, S.D. 2004. hysterophorus L., Ageratum conyzoides L., Lantana Functional responses of plants to elevated atmospheric

camara L.) in India. Biological Invasions 8, 1501-1510. CO2 - do photosynthetic and productivity data from Kohli, R.K., Dogra, K.S., Rani, D. & Singh, R.B. 2004. FACE experiments support early predictions? New Impact of invasive plants on the structure and Phytologist 162, 253-280. composition of natural vegetation of Northwestern O’Connor, T.G. & Pickett, G.A. 1992. The influence of India, Himalayas. Weed Technology 18, 1296-1300. grazing on seed production and seed bank of some Kumar, S.& Rohatgi, N. 1999. The role of invasive weeds African savanna grasslands. Journal of Applied in changing floristic diversity. Annals of Forestry 7, Ecology 29, 247-260. 147-150. Pandey, D.K., Kauraw, L.P. & Bhan, V.M. 1993. Inhibitory Leishman, M.R., Thomson, V.P. & Cooke, J. 2010. Native effect of parthenium (Parthenium hysterophorus L.) and exotic invasive plants have fundamentally similar residue on growth of water hyacinth (Eichhornia carbon capture strategies. Journal of Ecology and crassipes Mart Solms.): I Effect of leaf residue. Journal Environmental Sciences 98, 28-42. of Chemical Ecology 19, 2651-2662. Lisanework, N., Hassen, A., Sharma, J.J. & Adkins, S.W. Pandey, R.K. & Saini, S.K. 2002.Parthenium threat to 2010. Impact of Parthenium hysterophorus on grazing biological diversity of natural forest ecosystem in land communities in north-eastern Ethiopia. Weed Madhya Pradesh: A case study in people’s protected Biology and Management 10, 143-152. area of Baiga Chak, Dindori forest division. Vaniki Mack, R.N., Simberloff, D., Lonsdale, W.M., Evans, H., Sandesh 26, 21-29. Clout, M. & Bazzaz, F. 2000. Biotic invasions: Causes Rao, P.A.& Rajendrudu, D. 1989. Net photosynthetic rate epidemiology, global consequences, and control. in relation to leaf anatomical characteristics of C3, C3- Ecological Applications 10, 689-710. C4 and C4 dicotyledons. Plant Science 99, 529-537. Mc Connachie, A.J., Strathie, L.W., Mersie, W., Sakai, A.K, Allendorf, F.W., Holt, J.S., Lodge, D.M., Gebrehiwot, L., Zewdie, K., Abdurehim, A., Abrha, B., Molofsky, J., Baughman, K.A., Cabin, S., Cohen, R.J., Araya, T., Asaregew, F. Assefa, F.,, Gebre-Tsadik., Allstrand, J.E., McCauley, N.C.,O’Neil, D.E., Parker, Nigatu, L., Tadesse, B. & Tana, T. 2011. Current and I.M., Thompson, J.N. & Waller, S.G. 2001. The potential geographical distribution of the invasive population biology of invasive species. Annual Review plant Parthenium hysterophorus (Asteraceae) in of Ecology and Systems 32, 305-332. eastern and southern Africa. Weed Research 51, 71- Shashie, A. 2007.The impact of parthenium (Parthenium 84. hysterophorus L.) on the range ecosystem dynamics McFadyen, R. E. 1995. Parthenium weed and human health of the Jijiga rangeland, Ethiopia. A MSc. thesis, School in Queensland. Australian Family Physician 24, 1455- of Graduate Studies, Haramaya University, Ethiopia. 1459. Tamado T., L. Ohlander and P. Milberg, 2002b. Interference Mitiku, Woldesenbet, 2011. Competitive study between by the weed Parthenium hysterophorus L. with grain parthenium (Parthenium hysterophorus L.) and sorghum: influence of weed density and duration of common bean (Phaseolus vulgaris L.).M. Sc. Thesis, competition. International Journal of Pest Management Haramaya University, Ethiopia. 48(3), 183 - 88. Murphy, S. & Cheesman, O. 2006. The Aid Trade- Tamado, T. & Milberg, P. 2000. Weed flora in arable fields International assistance programs as pathways for the of Eastern Ethiopia with emphasis on the occurrence introduction of invasive alien species, World Bank’s of Parthenium hysterophorus L. Weed Research 40, Environmental Department, Washington D.C. 507-521. Natnael Demelash, 2011.Composition and diversity of Temesgen Terefe, 2010. Characterization, abundance and invasive plant species and socio economic impacts on diversity of invasive rangeland weeds in Mieso livelihoods of pastoralists in the rangeland of Telalak District, West Hararghe Zone, Ethiopia. A MSc thesis, District, Afar Regional State, Ethiopia. A MSc thesis, School of Graduate Studies, Haramaya University, School of Graduate Studies, Haramaya University, Ethiopia. Ethiopia. Taye Tessema, Rupschus, C., Wiesner, M., Rezene, F., Nath, R. 1988. Parthenium hysterophorus L. A general Firehun, Y., Ulrichs, C. & Büttner, C. 2010. Parthenium account. Agricultural Review 9, 171-179. Weed (Parthenium hysterophorus L.) Research in Navie, S. C., Panetta, F.D., McFadyen, R.E. & Adkins, Ethiopia: Impacts on food production, plant S.W. 2004. Germinable soil seed banks of Central biodiversity and human health. Ethiopian Journal of Queensland rangelands invaded by exotic weed Agricultural Sciences 20(1/2), 128-150.