Land Use Cover changes in the western escarpment of Rift Valley in the Gamo Zone, Southern Ethiopia

LULC changes are caused by natural and human alterations of the landscape that could largely affect forest biodiversity and the environment. The aim of the study was to analyzed LULC change dynamics in the western escarpment of the rift valley of the Gamo Zone, Southern Ethiopia. Digital satellite images downloaded from USGS were analyzed using ERDAS Imagine (14) and Arc GIS 10.2 software and supervised image classification was used to generate LULC classification, accuracy assessment and Normalized Difference Vegetation Index (NDVI). Drivers of LULC change were identified and analyzed. Four land classes were identified such as forest, farmland, settlement and water-wetland. Settlement and farmlands have increased by 7.83% and 5.88%, respectively. On the other hand, both forest and water bodies and wetland decreased by aerial coverage of 11.03% and 2.68%, respectively. The overall accuracy of the study area was 92.86%, 94.22% and 94.3% with a kappa value of 0.902, 0.92 and 0.922, respectively. NDVI values ranged between -0.42 to 0.73. Agricultural expansion (31.4%), expansion of settlement (25.7%) and Fuelwood collection and Charcoal production (22.9%) were the main driving forces that jeopardize forest biodiversity of the study area. Integrated land use and policy to protect biodiversity loss, forest degradation and climate changes are deemed necessary.


INTRODUCTION
Land use land cover change (LULCC) is a major issue of concern with regards to change in a 38 global environment [1]; changes are so pervasive such that, when aggregated globally, they 39 significantly affect key aspects of Earth System functioning [2,3]. This directly impacts 40 biodiversity throughout the world [4]; contribute to local and regional climate change [5] as 41 well as to global climate warming [6]; are the primary sources of soil degradation [7]; and, by 42 altering ecosystem services, affect the ability of biological systems supporting human needs 43 [8]. Such changes also determine, in part, the vulnerability of places and people to climatic, 44 economic, or socio-political perturbations [9]. 45 The land is the major natural resource in which economic, social, infrastructure and other 46 human activities are undertaken [10]. Thus, changes in land use that has occurred at all times 47 in the past, currently on-going, and is likely to continue in the future [11,12]. These changes 48 have beneficial or detrimental impacts, the latter being the principal causes of global concern 49 as they impact human well-being and safety [13; 3]. LULC changes are widespread, 50 accelerating, and the trade-offs offset human livelihood [14]. The rapid growth and expansion 51 of urban centers, population pressure, scarcity of land, changing technologies are among the 52 many drivers of LULC in the world today [15]. 53 [16] Stated that land cover change occurs through conversion and intensification by human 54 intervention, altering the balance of an ecosystem, generating a response expressed as system 55 changes. For centuries, humans have been altering the earth's surface to produce food through 56 agricultural activities [17]. In the past few decades, the conversion of grasslands, woodlands, 57 and forests into croplands and pastures has risen dramatically, especially in developing 58 countries where a large proportion of the human population depends on natural resources for 59 their livelihoods [17, 18, and 19]. The increasing demand for land and related resources often 60 results in changes in land use/cover [16] and it has local, national, regional and global causes 61 and implications [20].     The study area has a bimodal rainfall type. Maximum and minimum mean annual rainfall  (Table 2).

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Results revealed that the extent of land cover changes from forest to farmland in the last three 217 decades was rapid. The decline of water bodies and wetlands was not as dramatic as the loss 218 of forests (Table 4). The conversion of farmlands to settlements was equally high. Similar   (Table 5). This was due to the conversion of forest and water_wetland, to settlement 238 and farmlands increased and also Lake Abaya might be fluctuated increased and or decreased 239 its volume, but mostly at the expense of forest lands (Table 5). [44] shown that urban 240 settlements and farmland expansion gained the most in the area compared to other LULC 241 types, while forest areas exhibited a decreasing trend ( Figure 5). Demand for food and 242 grazing land for the growing population seems the probable driving force, among others. 243

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The statistics and visual observation of the NDVI images over three successive periods  (Table 9). NDVI analysis has proven that there had been changes in vegetation cover 283 between 1999 and 2019 images and higher values were recorded in the period 1999 in the 284 study area.
285 The results of FGD and KII reveal the five major direct driving forces (Table 10). Among Charcoal production take large shares.
292 The demographic data of the study area over the past three decades has revealed that 294 population pressure ranked as the top cause of LULC changes (Table 11) [46]. The work of 295 Lambin et al (2003) show that impact human population pressure is causing the accelerated

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There were four land classes in the study area including forest, farmland, settlement and