Analysis of the invasion rate, impacts and control measures of Prosopis juliflora: a case study of Amibara District, Eastern Ethiopia

Abstract

The tree Prosopis juliflora, introduced to Ethiopia in the 1970s to curb desertification, is imposing significant ecosystem and socioeconomic challenges. The objectives of this study are therefore to analyze the dynamics and associated impacts of the P. juliflora invasion over the period 1973-2004 and to evaluate the effectiveness of the management measures implemented to date. This required the analysis of Landsat images, field surveys, the use of structured questionnaires, and interviews. P. juliflora was found to invade new areas at an average rate of 3.48 km(2)/annum over the period 1973-2004. The high germination nature of the seed, mechanisms of seed dispersal, and its wide-range ecological adaptability are the main drivers for the high invasion rate. By the year 2020, approximately 30.89 % of the study area is projected to be covered by P. juliflora. The expansion has affected human health, suppressed indigenous plants, and decreased livestock productivity. The management measures that have been implemented are not able to yield the desirable results because of the limited spatial scale, cost, and/or improper planning and implementation. Therefore, the formulation of a strategy for management approaches that include the engagement of the community and the limiting of the number of vector animals within the framework of the current villagization program remain important. Moreover, risk assessment should be completed in the future before an exotic species is introduced into a certain area.

Effect of substrates on the yield, yield attribute and dietary values of oyster mushroom (Pleurotus ostreatus) in the pastoral regions of northern Ethiopia

“…Recurrent droughts are challenges to food security in the region and during acute drought, all socio-economic activities are seriously affected. These factors have led to the degradation of natural resources and growing vulnerability of different agro-pastoral groups to ecological and economic stress, often resulting in poverty [2]. High malnutrition rates are common in the pastoral regions in different parts of the world.…”

Reimagining invasions: The social and cultural impacts of Prosopis on pastoralists in southern Afar, Ethiopia

“…Whilst 'conflict' (Haregewyn et al 2013) is central to conceptualisations of many invasive species with differentiated impacts and conflict is, to a degree, normalised in pastoral areas (Meier et al 2007, p. 718), the introduction of an invasive species disrupts pre-existing patterns of behaviour. This introduction introduces conflict across different social scales, posing a direct challenge to initiatives which look to different forms of utilisation, and different actors, as a means of P. juliflora management (Birhane et al 2017).…”

“…The relationship is complex and at times contradictory; analysis of the impacts of P. Juliflora in eastern Ethiopia by Zeray et al (2017) found the invasion increased income from crop production and off-farm activities whilst reducing income from dairy production, and in South Africa, Shackleton et al (2015) conclude that land users accessing common property resources recognise the perceived costs but are less focused on management than private landowners. In pastoral areas of Kenya, both direct and indirect economic costs and benefits of P. juliflora have been studied and documented (Mwangi and Swallow 2008) and illustrate the idea of P. juliflora as a 'conflict' species (Haregewyn et al 2013). Resilience is also impacted by dependencies upon specific ecosystem services (Ayanu et al 2015), dependencies which are culturally and socially moderated.…”

“…Southern Afar provides an informative context within which to study the livelihood impacts of IAS. P. juliflora coverage is extensive within the Afar region, and Haregewyn et al (2013) estimate that by 2020, a third of Amibara woreda in southern Afar will be covered by P. juliflora, with an annual spread of at least 20,000 ha per annum, an alarmingly high growth rate (Tilahun and Asfaw 2012). Additionally, the Afar constitute one of the most significant pastoral groups in the Horn of Africa and are subjected to the marginalisation and misrepresentation which commonly confront pastoralists (Devereux and Tibbo 2013).…”

“…It was actively introduced in the 1970s and 1980s by governments and development professionals in East Africa to provide fuelwood and regenerate arid regions (Odour and Githioni 2013;Muturi 2012;Muanda et al 2009;Mwangi and Swallow 2005), although in Ethiopia there is a lack of clear documentation relating to its exact introduction pathway (Mehari 2015). The extensive invasion in the study area in eastern Ethiopia now affects a considerable, and growing, portion of Afar (Wakie et al 2014;Haregewyn et al 2013;Tilahun and Asfaw 2012). Whilst studies exist on a local level stressing the environmental and economic impacts (Muanda et al 2009;Mwangi and Swallow 2005), articulation and exploration of the social impacts are generally absent.…”