Land Use and Land Cover Dynamics in the North-Eastern Somali Rangelands of Eastern Ethiopia

International Journal of Geosciences, 2019, 10, 811-832 https://www.scirp.org/journal/ijg ISSN Online: 2156-8367 ISSN Print: 2156-8359 Land Use and Land Cover Dynamics in the North-Eastern Somali Rangelands of Eastern Ethiopia Fikre Zerfu1*, Abdurehman Mektel2, Biniyam Bogale3 1Department of Biology, College of Natural and Computational Science, Jigjiga University, Jijiga, Ethiopia 2Department of Rural Development and Extention, College of Dryland Agriculture, Jigjiga University, Jijiga, Ethiopia 3Department of Sociology, College of Social and Humanity Science, Jigjiga University, Jigjiga, Ethiopia How to cite this paper: Zerfu, F., Mektel, Abstract A. and Bogale, B. (2019) Land Use and Land Cover Dynamics in the North-Eastern So- Drastic changes have occurred in Siti zone rangeland over nearly the last mali Rangelands of Eastern Ethiopia. Inter- three decades, due to rapid land conversion dynamics in the area. In the zone, national Journal of Geosciences, 10, 811-832. https://doi.org/10.4236/ijg.2019.109046 the land-use change over time and space and temporal trends rangeland con- dition have never been studied. This study analyzed land use and land cover Received: May 30, 2019 (LULC) change dynamics since the 1980s. Three dates, 1985, 2001 and 2017, Accepted: September 24, 2019 Landsat images were used for classification and analysis of the various LULC. Published: September 27, 2019 The three images were geo-referenced, re-sampled and processed for classifi- Copyright © 2019 by author(s) and cation, using the maximum likelihood classifier algorithm. Moreover, field Scientific Research Publishing Inc. observations and information from local people were used for triangulation This work is licensed under the Creative Commons Attribution International to patterns LULC dynamics. From 1985 to 2017, the general trend observed License (CC BY 4.0). in the land use/cover change in the rangeland resources in the study districts http://creativecommons.org/licenses/by/4.0/ implies a loss of grassland cover was compensated by an increase in cultivated Open Access areas, settlement and shrub/bush land cover. Moreover, the encroachments of invasive plant, Prosopis, settlement and the promotion of cultivation to pastoral way of livelihood have exacerbated the decline of rangeland cover. The study findings have shown important changes in the LULC patterns in the north-eastern Somali rangelands of eastern Ethiopia. These trends are cer- tainly the characteristics of a pastoral way of life turn to settlement. This sug- gests that major changes in the socio-ecological driving forces affecting landscape dynamics have occurred in the last three decades or so. Keywords Pastoralist, Remote Sensing, Prosopis, Agriculture, Rangeland, Land Use/Cover DOI: 10.4236/ijg.2019.109046 Sep. 27, 2019 811 International Journal of Geosciences F. Zerfu et al. 1. Introduction Somali Regional State (SRS), a major pastoral ecosystem in East Africa, has a total land area of about 327,000 km2, of which about 90% is classified as rangeland [1]. The rangelands are suitable for pastoralism, more than 80% of the popula- tions in the SRS depend fully or partially on livestock production for their livelihood [1], so it is the dominant types of land-use systems in the region [2]. Moreover, more than half of Ethiopian pastoralists live in SRS [3]. Pastoralists raise livestock under extensive conditions using natural rangelands as the main forage for their herds. Livestock production serves pastoralists as a source of food, cash, social security and status, transport and pack animals [3]. Besides, pastoralists make a significant contribution to Ethiopian economy [1]. Recent studies on total economic valuation of pastoralism in Ethiopia have shown that 45% of agricultural GDP is sourced from livestock sector in 2008/09 and almost all of Ethiopia’s live animal and meat exports come from pastoral areas of the country [4]. Pastoralism is rarely viewed as a major future form of land use, because well-documented cases of rangeland degradation and the subsequent losses of ecosystem services [5] that threaten the livelihoods of pastoralists, due to its conversion to other land use [6]. For instance, increasing sedentarisation of pastoralists in Ethiopia [7] [8] [9] has heightened pressure on rangeland resources. Demand for firewood, charcoal and construction materials was behind a dra- matic 97% decline in woodland cover between 1972 and 2007 in Afar rangeland of North-eastern Ethiopia [9]. Similarly, declines in the density of multipurpose woody species in Siti and Liben zones of SRS were due to the tree falling for construction material and firewood and charcoal demand of growing nearby towns [3] [8]. Moreover, the conversion of rangelands into cultivated land has been reported in Ethiopia [10] [11]. All these changes have an adverse effect on bio- diversity of the ecosystems and sustainability of rangeland productivity [12] [13]. It is, therefore, important to understand the drivers and trends influencing these conversions as a prerequisite for analysis of land use and land cover change processes [14] [15]. Land-use/cover change is a multifaceted process caused by the interaction between anthropogenic and natural factors at different temporal and spatial scales [6] [16]. However, understanding of land-use/cover dynamics and consequences is negligible due to lack of empirical information at local le- vels, particularly in the Ethiopian rangelands [16] [17]. The Somali rangeland in North-eastern Ethiopia is one notable example where not only no information exists regarding land-use/cover changes, but also the driving factors behind the on-going processes have not been thoroughly investigated. A better understanding of the socio-environment interactions associated with land-use/cover changes requires an in-depth analysis of how the changes affect the physical environment (i.e., land degradation) and the feedback on livelihood strategies and vulnerability of the people [13] [16]. To track landscape structural changes and complexities over time requires the mapping of changes from past to present. In DOI: 10.4236/ijg.2019.109046 812 International Journal of Geosciences F. Zerfu et al. this regard, the recently increased availability of satellite data and advancements of remote sensing and geographic information systems (GIS) tools help to quan- tify and detect land-use/cover changes [16] [18] [19]. In this study, remotely sensed satellite data and people perception data were integrated to investigate land conversion dynamics. Besides, LULC maps can be a powerful tool to com- pare their changes in an area over time and with them possible to analyze a large area of land in a short period of time [20]. The objective of this study is to analyze the land use and land cover dynamics for the past 32 years (1985-2017) in north-eastern Somali rangelands of eastern Ethiopia. The study provides insight that demonstrates the importance of integrating multiple data sources in ana- lyzing land conversion dynamics. Moreover, the findings are expected to draw recommendations on sustainable rangeland management that might guide deci- sions and provides insight to policymakers on sustainable pastoral livelihood development programs. 2. Materials and Methods 2.1. The Study Areas The Siti administrative zone is located in the north-west of the SRS, lies within 40.554˚-42.966˚ east and 9.265˚-11.096˚ north [3] [21]. The zone is made up of seven districts. Among these, Shinile, Aysha’a and Afdem were selected for this study (Figure 1). Most of the landscapes of the study areas are characterized by low-lying flat terrain (undulating hills), stony outcrops interspersed with plains of loose soil covered by bush and woody grasses, while only insignificant lands are steeply dissected mountains ranging from 950 to 1350 m above sea level. The zone receives an average of 500 to 700 mm of rain annually [22] and mean an- nual temperature ranges between 22.5˚C and 32.5˚C, depending on the location within the zone [23]. There are two rainy seasons, namely the “Diraa” or “Gu” (short rains) from mid-March to mid-May and the “Karan” (long rains) from mid-July to mid-October. The dry seasons are “Hagaa”, from mid-May to mid-July, and “Jilaal”, from mid-October to mid-March [2] [22]. The dominant tree species include, Acacia tortilis, few and scattered Acacia senegal, Acacia bussei, Acacia aeforta, Zizyphus mauritania, Acacia mellifera, Balanites rotundi- folia and Tamarix aphylla. In most parts of the study Districts, Prosopis juliflora has spread over most parts of the bush land along the main roads and along the seasonal and perennial water courses [2] [3]. The Siti zone has an estimated population of 456,434, of which 245,928 are males and 210,506 females [24]. It is estimated that 80% of the 96,988 rural inhabitants in Shinile district, all the 50,043 rural inhabitants in Aysha, and all of the 31,991 rural inhabitants in Af- dem are pastoralists. The other 20% in Shinile are engaged in agro-pastoralism. Less than 5% of the population is involved in commercial activities in urban or trading centers (Population estimates for 2007 based on 1994 census: in [22]). The main ethnic group in Site is Somali, representing 95% of the population [24]. DOI: 10.4236/ijg.2019.109046 813 International Journal of Geosciences F. Zerfu et al. Figure 1. Map of the study areas, Siti zone. 2.2. Data Collection The data used for land use and land cover (LULC) classification in the study were remotely sensed images. Three dates (1985, 2001 and 2017) of Landsat imageries, with path 166 and row 52 and 53 for Ayisha, and path 167 and row 52 and 53 for Afdem and Shinile, were acquired (source: https://earthexplorer.usgs.gov/) and their brief descriptions are summarized in Table 1. These Landsat satellite images were choice in terms of their image quality, with no cloud cover; and the need to ascertain the LULC trends over the 32 year period was considered long enough to generate adequate changes.

Load more