Assessment on the Invasion Rate of Prosopis juliflora. The Case of Amibara District, Afar Regional State, Ethiopia

Master's Thesis from the year 2009 in the subject Biology - Ecology, Mekelle University, language: English, abstract: P. juliflora is a powerful invader equipped with a number of special features that promote its rapid invasion of new areas. This invasive species is currently becoming a problematic weed in Ethiopia, especially in Afar Regional State. The objective of the study was to analyse the invasion rate of P. juliflora through detection LULUC using multi-temporal Landsat imagery data obtained in 1973, 1987, 1999 and 2004. A field survey was conducted to analyse impacts of invasion, to identify management techniques which reduce the invasion and re-invasion of P. juliflora and to fill the information gap that arise from the imagery analysis.

This study then reveals, over the period of 31 years, LULCC in relation to P. juliflora invasion was changed significantly. The annual invasion rate of P. juliflora during 1973-1987,1987-1999 and 1999-2004 was 5.61 km2/annum, 0.80 km2/annum and 3.95 km2/annum respectively. The average annual invasion rate was 3.45km2/annum. This study also indicated that, 121.66 km2 (23.04%), 128.56 square kilometres (24.35%),145.81 square kilometres (27.62%) and 163.064 square kilometres (30.89%) of the study area would be under P. juliflora by the year 2008, 2010, 2015 and 2020 respectively, if proper controlling measures are not taken without delay. Invasion of P. juliflora causes loss of biodiversity and ecological service, affect livelihood of the pastoralist and agro-pastoralist, crop production and human health. If properly managed it shows positive implication on the soil amelioration, micro-climate and income generation for charcoal makers. But the pastoralist and agro-pastoralist call for its eradication because under the current management system the disadvantages outweigh the advantages.

Management techniques explored was clearing and digging out of the root system below 10-30 cm from the ground, seedling uprooting with continuous follow-up during wet season, utilization of P. juliflora as a resource by making charcoal, pod collection and crushing; since livestock is the main dispersal agent of the species. To ensure the successfulness and sustainability of management techniques, commitment, participation and continuous follow up of the community and different stakeholders should be given more focus to control the invasion and re-invasion of P. juliflora.