Random and Systematic Land Use/Land Cover Transitions in Semi-Arid Landscapes of Ethiopian Central Rift Valley Lakes Region (East Africa)

Abstract

The analysis of land use/land cover (LULC) change has always been a topic of interest in land dynamics research. The majority of previous studies used the conventional method of "net change" analysis to show spatiotemporal LULC transitions. However, such analysis failed to indicate whether the transition is clearly systematic or due to an apparently random process. Hence, this study aimed to identify the most prominent signals of landscape transitions over the last three decades, using the landscapes of East African Rift Valley Region. We used Remote Sensing and GIS to quantify and map the changes in LULC for 1986 and 2016, and then the two maps compared to produce transition matrices. Results show that net change and swap change accounted for 43% and 57% of total change on the landscape respectively. Accordingly, 6% of scattered acacia woodland and 5% of bush land have been converted to agricultural land, whereas 7% and 3% of scattered acacia woodland have been degraded towards grazing land and bush land respectively. These changes were found to be clearly systematic and hence indicate the dominant and prominent signals of landscape transformation. Hence, future land use policies need to consider such prominent signals of LULC change in order to plan an integrated approach to safeguard the fragile ecosystems of the region, while searching for alternative livelihood options.

Review on Contribution of GIS and RS for Soil Degradation Assessment in Ethiopia

“…One method, GIS and RS techniques integrates with USLE or RUSLE soil erosion model's parameters. The second method, simultaneously assessing by using both GIS and RS integrate with USLE or RUSLE as well as field survey and community survey (Bekele et al, 2018a, Worku et al, 2014Temesgen et al, 2017).…”

“…There is a few researchers have assessed LULCC by using GIS and RS in different parts of the country. For example, Worku et al (2014) LULCC already categorized as a catalyst for land degradation in form soil erosion in central rift valley lakes of Ethiopia (Bekele et al, 2018a). Land-use changes can alter or affect the hydrological flow direction, which highly enforced to increase surface runoff (especially during the study period from 1986 to 2009) due to the sever expansion of agricultural land to forest, grassland and shrubland (Demeke and Andualem, 2018).…”

“…Figure 5: Influence of vegetation on soil erosion Soil erosion highly affects both chemical and physical quantity of soil, in which soil nutrient deficiency reflected (Rabia, 2012). Socio-economic and environment, soil productivity decline, land degradation, shortage of wood, shortage of grazing land, climate change, soil erosion, loss of biodiversity and lake water withdrawal are some of the basic challenges happened due to land degradation through LULCC in central rift valley lakes of Ethiopia (Bekele et al, 2018a). As previously discussed under soil loss estimations, the amount of soil loss was almost all above the maximum soil loss tolerant (18 t ha year) standard given for Ethiopia (Hurni, 1985a).…”

“…which already known as desertification (Hailu, 2017). These and other causes of soil erosion easily assessed by using GIS and RS (Bekele et al, 2018a;Gebrekidan et al, 2018;Temesgen et al, 2016).…”

“…For example, it used to examine watershed characteristics and delineate (Gebre et al, 2015;Chernet, 2018), identify eroded area, estimate amount of soil loss and prioritize soil severity area (Lencha and Moges, 2015;Demeke and Andualem, 2018;Gizaw and Degefie, 2018). Also, it helps for assessing land use land cover change (LULCC) and its impacts (Worku et al, 2014;Bekele et al, 2018a;Bekele et al,2018b;Gashaw et al;2014). Besides, it helps to develop a strategic plan and recommending the appropriate mitigation measure (e.g.…”