Assessing land use and land cover changes and Effects of Large-scale Agricultural Farm Expansion in Southwester Ethiopia by using remote sensing/GIS tools.


 Development initiatives like the recent increase in large-scale investment agriculture have made a significant impact on the forest. In the name of development, the land is often given to investors often in long-term leases and at bargain prices. Research on deforestation has been mostly restricted to poverty and population growth as the driving forces for tropical deforestation; however, explanations emphasizing market factors such as increases in large-scale investment agriculture as a cause of deforestation have only been carried out in a small number of areas. The aim of this study is to explore the effects of agricultural land expansion in changing land use and land use cover changes using remote sensing/GIS tools in Sheka zone southwester Ethiopia from 1995 to 2015. The results showed that expansion of investment agriculture has a clear impact on both the local people and the forest ecosystem. The conversion of forestland to investment agriculture has caused varied and extensive environmental degradation to the Sheka forest. The Land Use and Land Cover changes in the Sheka zone are discussed based on underlying socioeconomic factors.


Introduction
In the name of development, the land is often given to investors often in long-term leases and at bargain prices. This trend is often referred to as ''land-grabbing''. A variety of terminologies has been in use to describe the meaning of ''land-grabbing'', such as large-scale land acquisitions, enclosures, and global land rush. Even if a variety of de nitions of the term ''land-grabbing'' has been suggested, this study will make use of the "large-scale agricultural investment" throughout this research article for the purpose of explaining land transfer.
Development initiatives like the recent increases in large-scale investment agriculture have made a signi cant impact on the forest and change indigenous forest resource management practices (Nepstad et al., 2006). Suck kind of scenarios bene t primarily outside economic interests, but could possibly weaken traditional knowledge and degrade local culture. Research on deforestation has been mostly restricted to poverty and population growth as the driving forces for tropical deforestation; however, explanations emphasizing market factors such as increases in large-scale investment agriculture as a cause of deforestation have only been carried out in a small number of areas. There appear to be relatively few studies in the literature that explicitly examine the impact of global economic and political processes on forest ecology.
Most large-scale agricultural investment processes happened in the tropical region of the world, particularly in forested areas, for their high investment returns (GRAIN, 2008). To put it differently, tropical forests are the target of the process of the 'global land grab'. The global process of large-scale agricultural investments not only affects the forest ecosystem, but also engenders a growing impact on food and agro-fuel, climate change, migration, and economic relations (ABN, 2007;Campbell, 2009;Andrianirina-Ratsialonana et al., 2011;Cotula, Vermeulen, Mathieu, & Toulmin, 2011).
Large-scale agricultural investments have been identi ed as major contributing factors for the current high rate of deforestation in the tropics (FAO FRA 2010). According to FAO (2010) estimates that the global rate of gross loss of standing forest was 16 million hectares per year during the 1990s, and there was a loss of 13 million hectares per year between 2000 and 2010. Therefore, analysis of its impact in the study area is very urgent and vital because the trend of land grabbing undermines local people's culture and generates massive displacements of people.
Ethiopia is a country characterized by high rate of deforestation and rapid rate of forest cover change this is mainly because of various adverse human actions, like the expansion of cases of large-scale investment agriculture and the declining of traditional forest conservation culture. Subsequently, a precise investigation land-use/land-cover (LU/LC) change is so pivotal to precisely fathom the degree of the change and bring important measures to downsize the rate of changes and secure the land cover assets reasonably. This study assessed changes in forest cover in Sheka zone southwestern Ethiopia between 1985 and 2015 by looking at classi ed satellite images coupled by GIS investigations and analyzed the relationship of forests cover change with the social, political, economy and natural rami cations the past and current forests cover change in Sheka forest.
This LU/LC study has made use of sequential satellite images (1985, 1995, 2005 and 2015) and GIS technologies in combination with ground veri cation. The study detected both types of changes (conversion and modi cation) and four major land use types namely Dense forest, open forest, agricultural land and settlement in the Sheka zone Masha and Anderacha woreda.

Study area
The Sheka Zone is located at about 670km from Addis Ababa. It is found in the South Nations Nationalities and Peoples Regional State. The Sheka zone shares boundaries with the Oromia Regional State in the North, Bench Maji Zone in the South, Gambella Regional State in the West, and Kefa Zone in the east. The total area of Sheka was 2175327 ha. Geographically, the Sheka Zone lies between 7°24'--7°52' N latitude and 35°31'--35°35'E longitude. The Zone has three woredas namely: Masha, Andracha, and Yeki. In the Zone, there are 56 rural and seven urban peasant associations (Pas) in three woredas.

Methods for GIS
Various soft wares and equipment were used during the study. The soft wares like ENVI 5.0 and Arc GIS 10.4.1 were used to analyze the satellite image and to classify the images. The ArcGIS 10.4.1 was used to analyze the classi ed data and to delineate the study area. Other materials like topo sheet (1:50,000 scale). Multi-temporal Landsat imageries of TM (1985TM ( , 1995 and ETM+ (2005ETM+ ( , 2015 data were used to classify the land use and land cover map of the study area. Freely available time series Landsat satellite images were downloaded from USGS website and proper Imageries of bands combinations are important for image enhancement to identify changes in landuse/land-cover features (table 3). The four-time period Landsat satellite images were obtained from Multi-temporal Landsat imageries of Landsat 5 TM (1985,1995) and ETM+ for 2005 and 2015 Landsat 7 and 8 respectively.
The preprocessing and processing of these land use/ cover data were done by using ENVI 5.0 and Arc GIS 10.4.1 software. The images were georeferenced into the same map projection of World Geodetic System UTM 1984 Zone 37 N. All satellite images were sub-mapped (subset) for covering only the study area. Images freely downloaded from USGS were analyzed using the following procedure for land use land cover change analysis. It is trusted that the time hole of around thirteen years between the four-satellite imagery is su ciently wide to indicate changes and patterns in Land Use and Land Cover in the Sheka forest and encompassing region. These wellsprings of data were utilized to break down land cover and land use changes throughout the years for the investigation zone.
Topographic maps and map of the Sheka forest, both at 1: 50,000 scales and associated population information were obtained from Ethiopian Mapping Authority (EMA) and Central Statistics Authority (CSA), respectively.
Land use land cover classi cation Classi cation process and analysis of the different LULC classes were done using four Landsat satellite images covering the Multi-temporal Landsat imageries of TM (1985TM ( , 1995 and ETM+ (2005ETM+ ( , 2015 acquired in 2017. These images include; Landsat 5 for the year 1985 and 1995 (path 170, rows 55) and Landsat 7 for the year 2005 (path 170, rows 55) and Landsat 8 for the period 2015 see (table 3).
The Landsat images were downloaded from United States Geological (USGS) Earth Explorer (https://earthexplorer.usgs.gov/). The selection of the Landsat satellite images dates was in uenced by the quality of the image especially for those with limited or low cloud cover in the dry month of the year.
Each Landsat was georeferenced to the WGS_84 datum and Universal Transverse Mercator Zone 35 North coordinate system.

Status of Land Use Land Cover of Sheka zone during Study Years
Using Satellite Remote Sensing and Geographic Information System, this research work analyzes the land use and land cover change dynamics in the Sheka zone southwestern Ethiopia. The four images were taken from the Multi-temporal Landsat imageries of TM (1985TM ( , 1995 and ETM+ (2005ETM+ ( , 2015. All images were geo-referenced and images classi cation was prepared by using the maximum likelihood classi er algorithm. In Sheka zone, Masha and Anderacha woreda four major land cover classes were identi ed in each date of the satellite image. The land cover classes and coverage in each date of the image are given below (table 4).
Conversion of dense forests to other forms of land use has been the general trend in Sheka zone Masha and Anderacha woreda. Such changes have been broad in the previous quite a few years in the Sheka forest. (MELCA Mahiber, 2007). The fast extension of investment agriculture and the declining of traditional forest conservation culture in the study area have required this sort of change. The same trend has been observed in the Masha and Anderacha woreda in the Sheka zone.
The present examination was expected to dissect the nature and degree of land use/ land-cover changes in Masha and Anderacha woreda since most recent three decades and recognize the fundamental powers behind them. The land use/ land-cover changes statistics of 1985 and 2015 and the change and growth in areal degree in various land use/ land-cover changes between the three times periods in Sheka zone Masha and Anderacha woreda are given in (Table 5 and Figure 5).
The study area has been divided into the four major land use/ land-cover classes as shown in (Table 5).
The forest of Sheka in Masha and Anderacha woreda in Sheka zone is the main natural resource. Most of the forestlands are reserved by traditional forest conservation cultures like DEDO, GUDO, and KOBO.
Nevertheless, gradually, the dense forest is being lost to open forest, agricultural land, and settlements. The study area has four land use land cover categories, which were dense forest, open forest, agricultural land, and settlement. The description of these land cover categories was presented previously (Table 5).  (Table 6). Most segment of the land use land cover class was thick forest amid this period.
The land use land cover classi cation for 1995 from TM+ satellite image ( g 7) showed that dense forest and open forest accounting for 824 sq. km (51.82%) and 469 sq. km (29.49%) respectively, while agricultural land and settlement amounted to about 284 sq. km (17.86%), 13 sq. km (0.81%) respectively.   This appraisal is completed to assess the classi cation e ciency of the ERDAS IMAGINE 2015 software programming in order to speak to the present land use /cover map of the investigation territory. The procedure had decided how adequately pixels were assembled into the right component classes under scrutiny. It is expert the characterized image with the ground by the assistance of eld survey or reference map. To evaluate the productivity of classi cation precision, a confusion matrix was developed.
To conduct this assessment 100 random points were decided to be collected using thump rule; states that 30 points for each land use land cover class and the image were containing four classes. The overall accuracy for the four-time period of classi cation results 86% and accuracy of each Land Use Land Cover classes are present in the table below.  (1985,1995), ETM+ (2005ETM+ ( , 2015 data were an overlay, and the transformation of landuse and land-cover classes from one to another was observed. The spatial extent of various land /land cover statistics of the changes in land use/ land cover categories over the period from 1985 to 2015 was generated.    (Table 13 and Figure 12). The dense forest has reduced from 57.35% in 1985 to 51.82% in 1995 thus registering a decrement in growth by 5.53%. Deforestation, expansion of agricultural land and increasing settlement are putting massive weight on the woodland assets of the investigation zone.
Since the area is very rich in cash crops like coffee and timber, it has attracted many migrants from distance and neighboring this coupled with the rapid rate of urbanization in the study area has brought about the speeding up in the deforestation procedure. Open forest cover is one of the major land-cover categories in the Masha and Anderacha woreda in the Sheka zone and has registered a further growth of   The change has an adverse impact on the physical environment as degradation of natural resources, deforestation, soil erosion, soil fertility reduction, biodiversity losses are the main results of the land cover change in the study area. The following map (Figure 12) showed the coverage of LU/LC in the years between 1995 and 2005. As can be seen from Figure

Discussion
Africa has been a speci c focus of land-and eager for water nancial specialists, involving in excess of 70 percent of the speculators' request (Deininger and Byerlee, 2011). The recent expansion of large-scale investment agriculture in developing countries, particularly in Africa has been attributed largely to the global food and energy crises. There have been a number of studies that has tended to focus on the drivers for the expansion of large-scale investment agriculture in Africa particularly focusing on food and energy crises as a driving force (GRAIN 2008, Cotula et al. 2009, McMichael and Scoones 2010; Arezki et al., 2011;Brüntrup, 2011;Zoomers 2010, De Schutter 2011Anseeuw et al., 2012a). Similarly, growing interest in agricultural land investment in Ethiopia has been linked in addressing the food crisis (Collier 2008); creating employment (Deininger & Byerlee 2010) and earning foreign exchange.
The expansion of large-scale agricultural investment has been widely recognized by national inventories and media reports. Data on the scale and patterns of expansive scale arrive exchange, for the most part, has originated from National inventories like Cotula et al (2009), Görgen et al. (2009, World Bank (2010) and media reports included on the blog of the International Land Coalition. In any case, solid gures on scale and patterns are yet hard to get, therefore, gures obtained from national inventories and media reports must be treated with extreme caution.
Quantitative data for the total land areas acquired for investment not yet clear, however, the lion share of global land transfer is from Africa. As indicated by the World Bank, more than 56.6 million hectares of land had been all around exchanged, over 70% of the land is in Sub-Saharan Africa (The World Bank, 2011).In July 2013 alone there were 1,044 deals, and representing 51.6 million hectares out of this around 54% of these deals are located in Africa (Kerstin Nolte 2016). One study by EIA (2011) examined the trend in large-scale agricultural investments(LSAIs) in Ethiopia found that there is a signi cant rise in the number of large-scale land acquisitions (LSLAs) and this has earmarked an area of over three million hectares. A subset of these LSLAs will lead to "large-scale agricultural investments" (LSAIs) (PhilippBaumgartne et al., 2015). A recent study by CSA (2009) indicates that the contribution of commercial farms in Ethiopia is less than 5% of the country's total agricultural production. However, there has seen a critical ascent in expansive scale agrarian interests as of late.
When looking into the regional distribution of agricultural investments in Ethiopia, the majority of these large-scale land acquisitions are occurring in the southern and western parts of Ethiopia, namely the states of Benishangul-Gumuz; Gambella; Southern Nations, Nationalities, and Peoples' Region (SNNPR) and Oromia. According to the Oakland Institute (2011a), the regional distribution of land transfers for investment in four regions of the country has amounted to 1,319,214 hectares in Oromia, 635,831in Benishangul Gumuz, 470,287 in SNNP and 256,000 in Gambella respectively. These are the most affected regions in the processes of land transfer to investors.
Previously, the Ethiopian federal government's rural development strategy has focused on smallholders' agricultural production by encouraging labor-intensive agriculture to increase productivity. On the off chance that the pattern proceeds along these lines, before the nish of 2015 an aggregate land exchanged to nancial specialists will gauge almost 7 million hectares, which is equivalent to around 38 percent of the land as of now used by smallholders (Rahmato, 2011).
Most of the large-scale land acquisition projects are focused either on food crops or on non-food agricultural commodities, such as owers, silk, or honey for export. Other projects also included biofuels, timber, and conservation. MELCA Mahiber's (2008) report looks at the extent of land allocated for biofuel investments in Ethiopia. The report shows that critical levels of farmland are being procured for fuel has a plan to acquire additional 500,000 ha of land in Gambella and other states to grow a projected one million tons of rice, as well as maize, teff, sugarcane and oilseed (Land Deal Brief, 2011).
Other studies by World Bank (2012) has reported that the Indian oricultural and agro-business conglomerate Karuturi global ltd has leased 10,000 hectares of land in Bako, Oromia provinces and 100,000 ha in Gambella, and this agro-business company has an option for 200,000ha of land in Gambella. Taken together, these results suggest that there is a large-scale land acquisition in Ethiopia.

Conclusion
In the Sheka zone southwestern Ethiopia, demographic growth and large-scale land investment has caused social and environmental impacts, as forests are cleared and communities are displaced, or lose access to farmland and forest resources. Particularly, large-scale land investment without proper environmental impact assessments were the cause of enormous LULCC in the Sheka zone southwestern Ethiopia.
The results of this research revealed the existence of signi cant LULCC over the last 30 years. The observed changes varied from one LULCC category to another. This study showed that the expansion of large-scale commercial farmland increased in 2015 compared to 1985. The expansion of small-scale farmland between 1985 and 2015, on the other hand did not show any signi cant change, and it is less than 2% area change unless one would expect a higher increase to a massive population growth. This shows the dominant in uence of commercialization on agriculture in the region. In addition, barren land has increased considerably during the last two decades. On the other hand, tropical grassland and forest areas are declining at a rapid pace.
The Sheka forest, which is the nation's largest forest reserves, has been affected by LULCC. The conversion of tropical grasslands and forestland to large-scale farmland has caused varied and extensive environmental degradation in the Sheka forest, and major negative outcomes for local people's livelihood. For instance, the establishment of the new large-scale farmland resulted in a loss of large parts of the wetland vegetated area and water bodies. Identifying the complex interaction between changes and its drivers over time is signi cant in determining future change, setting up decision-making mechanisms and constructing alternative scenarios. Therefore, in future, sustainable development LU/LC has to be monitored at regular intervals and an integrated LU policy is required.
In general, this study advocates the use of Multi-temporal Landsat images of TM (1985TM ( , 1995 and ETM+ (2005,2015) data were used to classify the land use and land cover map of the study area comprehensively. Only local eldwork and the compilation of additional sources can enable the observed changes to be put into a larger perspective, and to be able, nally, to understand the LU/ LC dynamics in the Sheka forest. This is a prerequisite to formulating successful LU strategies required for the appropriate and sustainable development of the study area.
To sum up, this paper has documented LULCC in the Sheka forest of Ethiopia. It quanti es the changes and illuminates reasons and effects. The Sheka zone is among the least developed and the most fertile regions of Ethiopia. It has large natural reserves in terms of pristine forests, wetlands, tropical grasslands and biodiversity.

Declarations
Competing interest: The authors declare that they have no competing interests.