Lulc Detection Ethiopia Mengistu 2008

7/28/2019 Lulc Detection Ethiopia Mengistu 2008

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Rapport/Report

NTNU

Norgesteknisk-naturvitenskapelige

universitet

Fakultetorsamunnsvitenskapog

teknologiledelse

Geografskinstitutt

Daniel Ayalew Mengistu

Remote sensing and gis-basedLand use and land cover change

detection in the upper Dijo river

catchment, Silte zone, southern

Ethiopia

Working papers on population and landuse change in central Ethiopia, nr. 17

Acta Geographica-Trondheim

Serie A, Nr. 23Series A, No. 23

Avhandlinger og rapporter/Theses and reports2008

I n n o v a t i o n a n d C r e a t i v i t y

Addis Ababa

University


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REMOTE SENSING AND GIS-BASEDLAND USE AND LAND COVER CHANGE DETECTION

IN THE UPPER DIJ O RIVER CATCHMENT,SILTE ZONE, SOUTHERN ETHIOPIA

DANIEL AYALEW MENGISTU


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ABSTRACT

Land use and land cover (LULC) change is one of the challenges which strongly influence the process

of agricultural development and the food security situation in Ethiopia in general and in the Upper Dijo

River catchment in particular. Remote sensing and geographic information systems (GIS) are important

for the monitoring, modelling and mapping of land use and land cover changes across a range of spatial

and temporal scales, in order to assess the extent, direction, causes, and effects of the changes. The

changes in land use and land cover which occurred between 1972 and 2004 in the Upper Dijo Rivercatchment, located in the middle Rift Valley system of Ethiopia, were monitored using such advanced

spatial technologies, supplemented by field verification. The study area covered 55.7 km2, and had

previously undergone substantial land use and land cover changes, mainly due to high population

pressure.

The main objective of the study was to assess and evaluate the extent and direction of changes in LULC

in the Upper Dijo River catchment, to explain the changes and identify some of their effects on both the

livelihoods of the local people and the local environment, and also to explore some of the conservation

measures designed to overcome problems associated with land use and land cover changes. Aerial

photographs taken in 1972, an EROS-1 satellite image from late 2004 and also geographic information

system (GIS) techniques were used to monitor the changes and to generate maps of the LULC of the

area in these periods. Information on the socio-economic conditions of 120 selected households and the

results of tests on soil samples taken from a depth of 30 cm at four different land use sites were used to

identify the underlying factors and explain the effects of LULC changes.

Observations showed that in the 32-year period between 1972 and 2004 shrub-grassland and riverine

trees covers had decreased at a rate of 21.5 and 16.3 ha per year respectively. Riverine trees suffered the

greatest devastation and by 2004 had been reduced to only 16% of their cover in 1972. In contrast,

eucalyptus tree plantations, annual crops and bare land/open grassland cover increased at a rate of 2.8,

12.5 and 24.8 ha per year, respectively. Correspondingly, bare land/open grassland increased by

344.5% at the expense of shrinking shrub grasslands, and have expanded in uninhabited areas.

Growing population pressure and its associated problems, such as the increasing demand for land and

trees, poor institutional and socio-economic settings, and also unfavourable government policies, such

as lack of land tenure security and poor infrastructure development, have been the major driving forces

behind the LULC changes. Hence, special attention should be given to the introduction of wise land

resource uses and management practices, secure land possession systems, regulated population growth,

and integrated environmental rehabilitation programmes. The existing tree plantation practices shouldbe encouraged by promoting the planting of indigenous tree species, rather than eucalyptus trees, in

order to enhance ecological harmony.

Keywords: Ethiopia, GIS, land use changes, land cover changes, population pressure, remote sensing

Acknowledgements: The study was supported by the NUFU-funded research and collaborationprogramme Population growth and land use changes in Central Ethiopia.


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INTRODUCTION

Land is the platform on which most human activities are performed and is the source of many

of materials needed for such activities. It is the most important natural resource for countries

such as Ethiopia, where the economy depends greatly upon the agricultural sector.

Developments in testing methods and differing abilities to use land resources often give rise to

changes in land use and land cover(LULC). At times such changes have beneficial while at

other times they have had detrimental and adverse impacts on the environment and peoples

livelihoods (Briassoulis 2000).

Research conducted in Ethiopia has shown that there were considerable LULC changes in the

country during the second half of the 20th century (Solomon 1994; Woien 1995; Gete 1997;

Crummey 1998; Kebrom & Hedlund 2000; Rembold et al. 2000; Belay 2002; Woldeamlak

2002; Muluneh 2003; see also Muluneh, unpublished data 19941). Most of these studies

indicated that deforestation and encroachment of cultivation into marginal areas were the majorcauses of land degradation, particularly in the highland part of the country. For instance, Gete

(1997) and Belay (2002) reported a serious trend in land degradation resulting from the

expansion of cultivated land at the expense of forestlands in Dembecha in north-western

Ethiopia and in the Derekoli watershed in South Wollo. Kebrom & Hedlund (2000) also

reported an increase in open grazing areas developing at the expense of shrublands and forests

in the Kalu area, north-central Ethiopia. Rotational LULC involving cultivation and vegetation

(forest and bush) was practised in the Metu area of south-western Ethiopia (Solomon 1994). In

contrast, Muluneh (2003; and unpublished data 1994) and Woldeamlak (2002) have reported

an increase in wood lots (eucalyptus tree plantations) and cultivated land at the expense of

grazing land in both Sebat-bet Gurage land in south-central Ethiopia, and in the Chemoga

River watershed in north-western Ethiopia. These reports have shown heterogeneity in the

changes in type, pattern, direction, and magnitude of LULC in the country and have revealed

the difficulty of extrapolating the known trends to areas that have not been surveyed.

1W.Muluneh (1994) Population pressure, land use change and patterns of agricultural productivity in Ezan-

Wollen and Cheha Weredas Sabat-bet Guragheland. Unpublished MA thesis, Department of Geography, AddisAbaba University, Addis Ababa.


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Hence, region-specific information of such changes in LULC is essential for land use planning

aiming at wise resource management and to maximize the productivity of both agricultural and

non-agricultural land at both regional and national levels. However, in Ethiopia information on

these changes is either lacking or unavailable for many small areas of land, for which it is

extremely difficult to make generalizations or doing so might lead to erroneous conclusions.

Many of the aforementioned studies were conducted in the northern-central highlands of the

country. The exceptions are those by Muluneh (2003; and unpublished data, 1994), Solomon

(1994) and Rembold et al. (2000). Rembold et al.s (2000) study, in particular, is probably the

only one to have been carried out in the Rift Valley area. This implies there is a gap in terms of

spatial representation in land use and land cover change studies in the country. In order to fill

this gap, the present study was carried out in the upper part of Dijo River catchment in Silte

Zone, SNNPR,2 Ethiopia. The aim of the study was to address the issues of LULC changes in

general, and in order to evaluate the magnitude and direction of the changes the aim was to

determine whether or not the changes are favourable, and to identify the forces working behindthe changes and the ensuing effects on the livelihood of the people and their environment.

The study was carried out using aerial photographs taken in 1972 and enlarged to a scale of

1:12000, a 1.8 m resolution panchromatic EROS satellite image taken in 2004, and also

geographic information systems (GIS) in conjunction with conventional techniques. Unlike

most of the aforementioned studies, this paper is the result of a detailed, large-scale analysis of

LULC changes in a small river catchment.

The study area, the Upper Dijo River catchment, was selected for research mainly because it

had previously undergone substantial land use and land cover changes, its magnitude was open

for in-depth study, it was subject to high population pressure, the interaction between land use

and population was complex, and it comprised a variety of physiographic features.

STUDY OBJECTIVES

2

Southern Nations and Nationalities Peoples Region (SNNPR) is one of the major national regions found in thesouthern part of Ethiopia (Fig. 1).


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The main objective of the study was to assess and evaluate the extent and direction of changes

in the LULC of the Upper Dijo River catchment and to explain the changes and identify some

of the effects of the changes on both the livelihoods of the people and the local environment,

and also to explore some of the conservation measures practised by local people to overcome

problems associated with land use and land cover changes in the area. Specifically, the aim of

the study was to: (i) identify and map the extent of LULC changes over a period of three

decades; (ii) investigate the proximate and underlying causes of LULC changes and their

subsequent impacts on the environment and livelihoods of the people; and (iii) examine

farmers responses to the impacts of LULC changes in the area.

STUDY AREA BACKGROUND

Location and size: The study area, in the newly structured Silte Zone, SNNPR, is located 164

km south of Addis Ababa, between 751N 759N and 3812E 3815E, and has a total

area of 55.7 km

2

(Fig. 1). It forms the western portion of the Shalla Lake drainage system,which in turn is part of the main Ethiopian Rift Valley system.


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Figure: 1

Location map of the study area: the Upper Dijo River catchment.

Physiology, geology and soils: The Upper Dijo River catchment, located on the western edge

of the main Ethiopian Rift Valley escarpment, is characterized by partly swelling and generally

undulating surface features in its central part but has almost flat topography in southern reaches

toward the Ethiopian Rift Valley floor, and is bordered by steep slopes toward the escarpment

on its northern side. The elevation falls from about 2900 to.2000 masl. The area is dissected

by several small streams that rise from the eastern edge of the Shewan Plateau and western

escarpment side. In addition, the topography of the area is highly influenced by structural

faults.


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The landscape has undergone a series of geomorphic processes. However, the evolution of

present-day landscape features is generally attributed to recent geological events of Tertiary

and Quaternary volcanic episodes and tectonic activity that occurred during the Upper

Pleistocene and beginning of the Holocene epochs and also between the late Quaternary and

the present. In addition, faulting occurred during and after these epochs and the subsequent

degradation processes have been responsible for reshaping the landforms of the study area.

Also, minor faults aligned NNESSW have led to the formation of very steep sloping land on

the back slope of the study area. These faults are down-thrown and have resulted in the

submergence of the lands on the sloping sides of the fault lines. The major faults passing

though the middle of the study area are partly responsible for the overall appearance of the

landscape in general and the study area in particular (Fig. 1).

With regard to the geology, the area is generally volcanic terrain which has been affected by

volcanism since the Pliocene and Quaternary periods, resulting in fissures and conical

eruptions (Sagri & Getahun 1998). The whole area is covered by a huge volume of silicic

pyroclastic materials and scoria cones. They are mainly per-alkaline rhyolitic ignimbrites

interlayered with basalt and tuffs (Di Paola 1972 quoted in Sagri & Getahun 1998). These

volcanic materials are either in situ or have been reworked by different geomorphic agents. In

general, the geology of the area consists of Tertiary intermediate to basic volcanites resting on

Mesozoic sediments and Precambrian basements.

On the basis of the information obtained from field survey and the results of laboratory

analyses, six major soil units were identified: Haplic Phaeozems, Luvic Phaeozems, Chromic

Cambisols, Rhodic Nitosols, Haplic Nitosols, and Eutric Vertisols (Abyiot 20053).

Vegetation and climate: The original vegetation type of the study area was woodland savanna

(Zemede 1998). It comprised a type of woodland and savanna vegetation where scattered trees

3 Abyiot Legesse was one of the four members of a research team who surveyed the problem of soil degradation

under the auspices of a NUFU research project run by the Department of Geography & Environmental Studiesat Addis Ababa University (AAU) in collaboration with the Department of Geography at NTNU, Trondheim.


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and shrubs occurred in herbaceous elements. Today, due to deforestation, the remnants of these

original vegetation types, particularly trees and shrub woods, are found in small patches only

around mosques and on the steeper slopes of the escarpment, and also along stream courses as

riverine trees. Exotic trees, specifically varieties of eucalyptus trees, are planted extensively

around settlements and along river courses.

According to the traditional agro-climatic zonation, which is based on rainfall, temperature and

altitude, the area that lies above 2400 m and accounts for about 40% of the total area falls

within dry dega agro-climatic zone, while the remaining 60% that has elevation between 2000

and 2400 m lies within the woina dega agro-climatic zone. The former is similar to a warm

temperate climate while the latter is more like a subtropical climate. The area has a mean

annual temperature of 18C and a mean annual rainfall of 1319 mm.

Population and settlement pattern: In 1972 the number of inhabitants of the area wasestimated by counting peasant tukuls4from an existing 1:50,000 topographic map of the area

compiled from aerial photographs taken in the same year. 5 The total number oftukulswas then

multiplied by 4.5 and the average rural household size of Shewa Province between 1968 and

1972 (CSA 1974 cited in Kahsay, unpublished data 20046). Accordingly, the population of the

Upper Dijo River catchment in 1972 was estimated to be 5792. The counting oftukulsfrom the

EROS satellite image taken in 2004 showed that there were 2535 houses. The household

survey conducted in 2004 showed that the average household in the study area consisted of

7.75 persons. Hence, the population of the Upper Dijo River catchment was estimated to be

19,646 in 2004. This shows that population of the area had increased more than threefold over

the previous three decades, with an average annual growth rate of 3.89%. This in turn created

new demands for additional space, food and other resources. As a result of such unprecedented

increases in population size, the pressure on existing natural resources is expected to intensify

in the area. Settlements in the area are predominantly rural and villages are generally linear in

4 farmhouse5After counting the number of dots representing peasant tukuls, the number oftukulswas multiplied by the average

household size at that time.6 B. Kahsay (2004) Land use/cover changes in Central Ethiopia: The case of Yerer Mountain & its

surroundings. Unpublished MA thesis, Department of Environmental Science, Addis Ababa University, AddisAbaba, Ethiopia.


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form. The local residents have access to road transport and there are also schools (two primary

schools and one secondary school), one health centre and two health posts. There are two

towns: Werabe, the seat of Zone level administration, and Alkeso, which is a small market

place located within the river basin.

Land use pattern: The land use pattern in the study area is similar to that of other areas where

enset (false banana) is cultivated, whereby farmers divide their lands into several plots for

different purposes such as for settlement and avenues, growing enset, chat and other cereals,

grazing, and tree plantations. Homestead plots are used for growing the most important crops

such as enset, chat and vegetables. Distant farms are used for growing annual crops such as

wheat, barley, teff, maize, sorghum, and beans. Land plots located outside the inner ring, the

land which is used forenset plantation and annual crops, and at some distance, and which are

marginally important, are used for livestock grazing and eucalyptus tree plantations. There are

also random areas of degraded grounds.

DATA SOURCES AND METHODS OF DATA COLL ECTION

Aerial photographs taken in December 1972 and a satellite image taken in December 2004

were the major source of data used to detect changes in the LULC in the area. The aerial

photographs and satellite image were obtained from the Ethiopian Mapping Authority (EMA)

and ImageSat International, Israel, respectively. The aerial photographs were at a scale of

1:12,500 and were enlarged from a scale of 1:50,000 after mosaicing, georeferencing and

rectification using photogrammetric techniques. The EROS-17

image had a radiometrically

corrected spatial resolution of 1.8 m. Aerial photos were the only source of spatial data in

image form for the period prior to when satellites were launched, while the satellite image was

used because there were no recent aerial photographs available for comparison with older

photographs. Thus, in order to detect and monitor the extent and direction of the changes in the

LULC, it was necessary to compare the aerial photographs of 1972 with the satellite image of

2004.

7EROS A High-Resolution Satellite Imagery. 2004.SAF 1-E 1222411. ImageSat International, Israel.


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LULC change reflects both the biophysical conditions and the history of the socio-economic

setting of a given area. Hence, a household survey was conducted to acquire data relating to the

socio-economic and demographic conditions of rural households which would help to explain

the changes observed in the LULC. First, a sub-catchment area was selected within the Dijo

River catchment, covering an area of c.600 km2 and comprising parts of three weredas

(districts): Silte, Dalocha and Aricho Weriro. In addition, there wee 31 kebele peasant

administrations (KPAs). The Upper Dijo River catchment, the sub-catchment area selected for

this study, was systematically delineated from a 1:50,000 topographic map of the area. The

selection of the study area took into consideration the relative location, drainage density and

topographic situations, soil degradation, agro-climatic conditions, settlement patterns and

access to road transport systems, and other basic infrastructure.

The Upper Dijo River catchment consists of parts of two KPAs: Anshebeso and Arat Ber. To

select 120 sample households, which accounted for approximately 5% of 2535 households ofthe two sample KPAs, four parallel transects were drawn (arrayed) at 200 m altitude intervals.

Sample quadrants (average size 300 m2) were set over each transect. Each transect had a

number of quadrants relative to its population density. Each quadrant contained a number of

households. Depending upon the number of households within the quadrants, sample

households were randomly selected using a lottery method.

Structured questionnaires were administered to the sample household heads. The

questionnaires included several issues relating to demographic situation, landholding size,

livestock and crops, soil fertility management, and off-farm and non-farm employment. The

questionnaires were pre-tested and modified in the field. Moreover, the soil sample results of

one of the members of a research team was chosen to evaluate the effect of LULC changes on

the soils, and the results of a soil survey and analysis made by Aby iot (2005). In addition, 10

soil samples were taken for analysis from pocket areas (areas with relatively little human

influence such as religious places and farm boundaries) where LULC changes were minimal

and which had not been subject to much disturbance in their history, such as sacred areas (e.g.

mosque compounds), remnants of natural vegetation and farm boundaries. The samples were

taken from 30 cm deep auger holes along the transects. This approach substitutes space for


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time and is referred to as a spatial analogue method (Woldeamlak & Stroosnijder 2003, 37). In

this regard, variations in soil properties are attributed to the observed differences in the LULC.

Some of the research findings made by Shiferaw Teka 8 were used to compare the implications

of LULC changes on the biodiversity of the area.

To evaluate changes in the LULC, data from both aerial photographs and the satellite image

were systematically processed, involving georeferencing, mosaicing, interpretation,

digitization, and mapping. The aerial photographs were first scanned, georeferenced in UTM

projection using control points collected in the field, and mosaiced after rectification using

photogrammetric techniques. Georeferencing of the EROS-1 image was made in the same

projection as the aerial photographs, using the selected ground control points (GCPs). Then,

the interpretation and LULC classification process was performed by establishing a

preliminary legend based on visual interpretations using a mirror stereoscope for air

photographs, followed by screen digitization. An automatic classification method was appliedto identify and delineate the different LULC units for the satellite image.

As the aerial photographs had been taken 32 years previously, the interpretation and

classification based on them could not be checked against ground truth. In contrast, the 2004

satellite image was taken during the research period and could be directly checked against

ground truth. To establish the classification in the latter case, six homogenous areas were

selected for each LULC unit as a testing site. Then the maximum likelihood classification

method was applied for identifying land use and land cover types for the study area as a whole.

The post-interpretation and classification phase involved preparation of LULC maps from both

the 1972 aerial photographs and the 2004 satellite image of the area, followed by detection and

recognition of their changes. Based on the first two, a third map was prepared showing LULC

transformations using the overlay function of ArcView Spatial Analyst software. Then, the

type, magnitude and trend of the LULC changes and their impact on the environment were

evaluated. The collected household socio-economic and demographic data were processed

using SPSS to generate descriptive statistics. The qualitative data obtained through group

discussions and interviews conducted with local authorities and experts in local agricultural

8 A member of the research team who surveyed the biodiversity status in the study area.


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offices, together with the descriptive statistics of the qualitative household data, were used to

identify the causes of LULC and to assess the impact of the changes on the livelihoods of the

rural population.

The 10 soil samples collected from different LULC types were analysed in the Holeta Soil

Laboratory (it is located in Oromia region, 45 km away from the capital Addis in the south).

The sample soils were first air dried, lightly ground and passed through a 2 mm sieve, and then

conventional analytical methods were used following procedures described by the Ministry of

Natural Resources Development and Environmental Protection (MoNRDEP 1990). Soil texture

was determined by the hydrometer method, total nitrogen determined by the Kjeldahl method,

and pH using a pH meter in a 1:1 soil to water ratio. The organic matter in the soil samples was

calculated first by determining the soils organic carbon content using the Walkley-Black

method, and then it converting to organic matter by multiplying by a factor of 1.724. Available

phosphorus (P) was identified using the Olsen and Bray II methods and potassium (K

+

) by theammonium acetate method. Then the laboratory test results were summarized using

percentages, one-way analysis of variance (ANOVA) and a least significant difference (LSD)

test, which in turn were used to characterize the soils of different LULCs, and thereby the

consequential effects of LULC changes on the soils were able to be reviewed.

LAND USE AND LAND COVER CHANGES IN THE UPPER DIJ O RIVER

CATCHMENT

Patterns of land use and land cover distribution: Six LULC types were identified in the

area: riverine trees, tree plantations, perennial cropland and settlement,9 shrub-grassland, land

used for growing annual crops, and bare land/open grassland. The description of each land use

and cover type is listed in Table 1.

9

Perennial croplands and settlements are treated as one category because perennial crops such as enset and chat weregrown in areas immediatelysurrounding peasant tukuls and it was not easy to distinguish the boundaries between them.


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Table 1: The LULC types identified in the Upper Dijo River catchment.

LULC Types Description

Riverine trees Trees grown along stream courses, including indigenous tree species

and exotic trees such as eucalyptus and juniperus trees.

Tree plantations Areas planted with exotic trees, mainly eucalyptus and juniperus

trees, and not found near river courses.Perennial crops and

settlements

Areas with ensetand chat treecrops, together with rural settlements(tukulsand avenues).

Shrub-grassland Areas with a cover of shrubs and short trees mixed with grasses.

Land for annual

crops

Areas used for growing annual crops such as wheat and barley.

Bare land/open

grassland

Areas with a cover of stunted and scant grass, and wastelands with

exposed rocks and badlands.

The proportion and distribution of LULC types by hectare and per cent, grouped by slope

class, is shown for 1972 and 2004 respectively in Tables 2 and 3 and Figs. 2a and 2b. In the

two periods considered, land used for growing annual crops was more important in the Upper

Dijo River catchment. It covered more than one-third (33.4%) of the total area in 1972,

followed by perennial crops and settlements (25.3%) and shrub-grassland (20.3%). Lands that

were under all types of trees, including riverine trees and exotic wood lots, together accounted

for 17% of the catchment area, while wastelands (i.e. areas with rock outcrops and badlands)

and areas with stunted and scant grass covered 4.1% of the basin area. In 1972 the riverine tree

cover was two times more than that of exotic tree plantations.

In 2004 the coverage of annual crops increased to 41% of the total area. Perennial crops and

settlements accounted for 24%, while waste lands and stunted and scant grass covered 18.4%.

The remaining area was occupied by riverine trees (1.8%), exotic tree plantations (7.3%) and

shrub and/or grassland (7.9%) (Fig. 2b).

The pattern and distribution of LULC types in different slope zones remained more or less similar

during the two periods. Approximately 80% of the LULC of the area occurred in an area where the

degree of slope was less than 15%; 15.3% of the total catchment area is located in a zone with a

slope of 1530%. Only 6% of all areas covered by different LULC types, particularly croplands

and shrub-grasslands, were located in zones with slopes exceeding 30%.


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Table 2: Distribution of the LULC of the Upper Dijo River catchment in 1972.

Land use and land cover types

Riverine tree Tree

plantations

Perennial crop

& settlements

Shrub-

grassland

Land for annua

crops

Bare land/open

grasslandTotal Area

Slope

class(ha) (%) (ha) (%) (ha) (%) (ha) (%) (ha) (%) (ha) (%) (ha) (%)

55 0.41.4

0.064.1

14.0

1.36.9

23.7

0.57.7

26.6

0.79.9

34.1

0.530.0

0.0

0.029.0 0.52

Total

623.6

11.2

100 319

5.7

100 1408.2

25.3

100 1129.

20.3

100 1858.7

33.4

100 230.8

4.1

100 5570.0 100* The upper figures refer to percentages calculated row-wise while the lower ones are computed column-wise.

Table 3: Distribution of the LULC of the Upper Dijo River catchment in 2004.

Land use and land cover types

Riverine trees Tree

plantation

Perennial

crops &

settlements

Shrub-

grassland

Land for

annual crops

& settlements

Bare

land/open

grassland

Total Area

Slope

class

(ha) (%) (ha) (%) (ha) (%) (ha) (%) (ha) (%) (ha) (%) (ha) (%)

550.6

2.2

0.62.8

9.6

0.79.4

32.5

0.70.5

1.6

0.110.3

35.6

0.55.4

18.5

0.5329.0 0.52

Total101.4

1.8

100407.2

7.3

1001334.4

24.0

100442.

7.9

1002258.9

40.6

1001025.6

18.4

1005570. 100

* The upper figures refer to percentages calculated row-wise while the lower ones are computed column-wise.


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PATTERN OF CHANGES IN LAND USE AND LAND COVER

Table 4 shows the pattern of changes in LULC between 1972 and 2004. Land used for growing

annual crops increased by 22% compared with the previous amount of cover and accounted for

8% of the total area. Bare land/open grassland and tree plantations showed similar patterns of

change, with increases of 345% and 28% respectively in the 30-year period. However, the

expansion of land/open grassland was approximately fivefold while that of tree plantations was

relatively less significant. In contrast, riverine tree cover showed a reverse trend, reducing by

84% during the same period of time. Shrub-grasslands showed a similar pattern of change and

decreased by 61% in this period. Lands used for perennial crops and settlements also showed a

decline, by approximately 5%, which may have been due to encroachment by annual crop

cultivation. In general, the pattern showed a tendency towards more land being brought under

annual crops, while at the same time tree plantations became more important at the expense of

shrub-grassland and riverine trees. In contrast, more and more land became degraded and was

abandoned.

Table 4: Pattern of LULC changes between 1972 and 2004 in the Upper Dijo River catchment.

Area (1972) Area (2004)Change between

1972 and 2004

Average rate of

changeLand use/cover

units (ha) % (ha) % (ha) (%) ha/yr (%)

Riverine trees 623.6 11.2 101.4 1.8 -522.2 -84 -16.3 -2.63

Tree plantations 319 5.2 407.2 7.3 +88.2 +27.7 +2.8 +0.87

Perennial crops

and settlements

1408.2 25.3 1334.4 24 -73.8 -5.24 -2.3 -0.16

Shrub-grassland 1129.7 20.3 442.5 7.9 -687.2 -60.8 -21.5 -1.9

Land for annual

crops1858.7 33.4 2258.9 40.6 +400.2 +21.5 +12.5 +0.67

Bare land/open

grassland230.8 4.1 1025.6 18.4 +795 +344.5 +24.8 +10.77

Total 5570.0 100 5570.0 100 ----- ----- ------ ------


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2a

2b


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Figure 2, a and b: Land use and land cover map of the Upper Dijo River catchment in 1972 and

2004.

Figure 3: Land use and land cover change map of the Upper Dijo River catchment between

1972 and 2004.


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Table 5: Matrix of land use and land cover change in the Upper Dijo River catchment.

Note: Figures in parentheses represent LULC that showed no change.

Table 5 and Fig. 3 show that only 7.5% of the area that was covered with riverine trees in 1972

remained the same in 2004. The remainder (92.5%) was cleared and had changed to other land

use/cover types by 2004: 10.5% to tree plantations, 22.7% to perennial crops and settlements,

11% to shrub-grassland, 29.2% to land used for growing annual crops, and 19% to bare

land/open grassland. In contrast, conversion of other land use/cover types to riverine treesamounted only 8.7% compared with 92.5% that was lost to other land use/cover types (Table

5). Further, only approximately 10% of the area that was covered with shrub-grassland in 1972

was still under the same cover in 2004. The rest (90%) was transformed to other LULC types

in 2004: 2.6% to riverine trees, 5% to tree plantations, 18% to perennial crops and settlements,

32% to land used for growing annual crops, and 31.8% to bare land/open grassland. The area

that was changed from other land use/cover types to shrub-grassland was small and accounted

for only 29% compared to the amount of shrub-grassland lost to other types (Table 5).

Land use and land cover units in 2004 (ha)

Riverine

trees

Tree

plantations

Perennial crops

& settlements

Shrub-

grassland

Land for

annual

crops

Bare

land/open

grassland

Total

area

Riverine trees 46.9 (7.5%) 65.6 141.9 69.0 181.8 118.4 623.6

Tree plantations 19.6 26.1 (8.1%) 59.3 43.7 96.8 73.6 319

Perennial crops &

settlements0.7 132.4 445.1 (31.6%) 98.4 579.5 152.2 1408.2

Shrub-grassland29.2 55.6 206.0

115.2

(10.2%)364.4 359.3 1129.7

Land for annual

crops1.0 119.3 465.1 88.0 968 (52%) 217.2 1858.7

Landuse/coverunits

1972

(ha)

Bare land/opengrassland

4.0 8.2 17.0 28.2 68.3 105 (45.5%) 230.8

Total area 101.4 407.2 1333.4 442.5 2258.9 1025.6 5570


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Of the total cultivated area and wastelands in 1972, 52% and 46% respectively remained

unchanged; 32%, 10% and 18% respectively of the original covers of perennial crops and

settlements, shrub-grassland and exotic tree plantations showed no change, while the

remaining largest portions of these LULCs were changed to other types of cover. Thus, it is

apparent that the three LULCs were most at risk of undergoing change.

Table 6: Distribution of changed and unchanged land use and land cover types by slope class in

the Upper Dijo River catchment area between 1972 and 2004.

Land use/cover types remained unchanged (ha)

Slope

class

Areas

changed

(ha)Riverine

trees

Tree

plantations

Perennial

crops &

settlement

Shrub-

grassland

Land for

annual

crops

Bare

land/open

grassland

Total

area

55 22.2 0.03 0.3 2.5 0.1 3.8 0.0 28.9

Total 3863.7 46.9 26.1 445.1 115.2 968.1 104.9 5570

Table 6 shows the pattern of changed and unchanged LULC types between 1972 and 2004 in

various slope zones, expressed in per cent. Approximately 3860 ha, accounting for 69% of the

total area of the catchment area, underwent change from one land use or land cover type to

another land use or land cover types, while the remaining 31% of the area remained under the

same use and cover type. Further, 94% of the changed land use and land cover types were

located on slopes of less than 30%.

With regard to agriculturally suitable terrain in terms of slope, i.e. areas in the 30% slope class

or less, 3100.3 ha (55.7%) were already under cultivation for annual crops in 1972 (Table 3)

and 3373.4 ha (64.3%) were under cultivation for perennial crops in 2004 (Table 4). This

Formatted: Left

Formatted: Centered

Formatted: Left

Formatted: Left

Formatted: Centered

Formatted: Left

Formatted: Left

Formatted: Centered

Formatted: Left

Formatted: Left

Formatted: Centered

Formatted: Left

Formatted: Left

Formatted: Centered

Formatted: Left

Formatted: Left

Formatted: Centered

Formatted: Left

Formatted: Left

Formatted: Centered

Formatted: Left


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implies that more areas with gentle slopes (


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Land tenure system: Before the 1975 land reform, land in Ethiopia was the property of a few

landlords. This was also the case in the Upper Dijo River catchment area. Of the sample

households, 65% were petty landowners (gebar) and 14% were tenants (chisegna). Both gebar

and chisegna did not own any land. After the 1975 land reform, local people who were petty

landowners and tenants were ensured of their right to use their landholdings.

Figure 4: Causes and consequences of land use and land cover changes and farmers

responses. (The green arrow indicates positive change however; the red arrow indicates negative

change).

The 1975 land reform, which resulted in the change in ownership of land by a few landlords to

ownership distributed among many peasants, has probably adversely influenced the pattern of

Populationpressure

Increase demand for:

Fuelwood

Food Othernecessities

Expansion ofcroplandstowards

forest, shruband marginal

lands

Destruction ofremnant forests

& shrubs

Land degradation: soilerosion, decline in soil fertilityand expansion of bare land

Destruction offorests;

Use of cropresidues &

animal dung forfuel wood

Destruction offorests

The 1975land reform

Landredistribution

Emergence of newhouseholds

Increase demandfor food, fuel wood

& shelter;Illegal landtransactions

Conversion offorest areas tocropland and

settlement areas

Farmingsystem

Traditionalfarm

implementsmaresha &kember

Cutting oftrees

Reduction incrop yields

Extensification orintensification of

cropland

Destructionof remnant

forests

Increase thevalue added

to land

Improve-ments in

soilmanage-ment


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land use and land cover changes in the area. The redistribution of landownership resulted in the

emergence of new households, which in turn led to increased demands for food and hence

cropland and other basic necessities. As a result, forest areas were converted to cropland and

areas for settlements (Fig. 4). Thus, the 1975 land reform resulted in problems of land

consolidation, expansion of cropland and the destruction of natural forests in the area. The

latter has resulted in increased amounts of bare land and changes in soil properties. Moreover,

the land tenure system which prevailed after the 1975 land reform gave peasants use rights

only. In response, the local people have engaged in illegal land transactions in the form of

weled aged (illegal way of transferring land to another person), which has resulted in the

reduction of landholding size and allows land to be used by rich peasants. This has aggravated

the level of poverty among the people.

Landholding size: Table 7 shows the average landholding size per household in the study

area. In 2004 the average landholding size in the study area was nearly 0.7 ha (2.8 timad) andthe holdings ranged from 0.13 ha to 2.5 ha. However, there were slight variations within the

sample transects. The average landholdings were 0.74 ha in Transect 1, 0.86 ha in Transect 2,

0.55 ha in Transect 3, and 0.63 ha in Transect 4. The average holding size was less than 1 ha.

Thus, the holding sizes were very small, which indicates high population pressure on existing

land resources.

Per capita landholdings in 2004 were 0.09 ha in Transect 1, 0.12 ha in Transect 2, 0.08 ha in

Transect 3, and 0.09 ha in Transect 4. The difference in per capita holdings between transects

was due to variations in population size and the total area of the transects.

Table 7: Distribution of households and landholding size in 2004.

Number of respondentsHousehold size

Tr. 1 Tr. 2 Tr. 3 Tr. 4 Total area

5 4 5 9 7 25

68 7 17 18 9 51

9 9 14 12 9 44

Total 20 36 39 25 120

Landholding (ha)


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0.5 10 13 25 13 62

0.51 8 15 10 11 43

>1 2 7 4 1 14

Total 20 36 39 25 120

A total 93% of respondents reported that their holdings had decreased over the previous threedecades, for several reasons: 48% of the respondents reported that the 1975 land reform and its

consequent land redistribution was one of the main factors, while 23% attributed the decrease

to soil erosion and gully expansion, and 17% to increased population pressure. A few

respondents (12%) claimed that part of their landholding had been snatched by Keble Peasant

Association leaders and transferred to others in the form of weled aged. In contrast, a few of

the respondents indicated that their holdings had increased during the previous three decades.

When asked where the extra land had come from, many of them replied that they had bought it

informally from other holders. According to a local official,10

this traditional way of

transferring land to another person has aggravated the level of poverty in the area. In addition,

it may further complicate the problems of implementing the new land certification process,

which has implemented by the countrys main regions started in 2003 modelled in an effort in

Tigray during the late 1990s.

Land fragmentation: Another problem related to the land tenure system was fragmentation of

land. In the study area the number of plots held by a person ranged from one to five plots, and

the average was two. However, there was no variation within transects. With regard to travel

time on foot, the average distance from any given homestead to all plots was approximately 13minutes. However, slight variations among transects were observed: travel time was 11.8

minutes in Transect 1, 13.89 minutes in Transect 2, 11.54 minutes in Transect 3, and 16.21

minutes in Transect 4.

Land fragmentation is a constraint to land management and the intensity of cultivation. This

was clearly observed in the study area, where peasants planted enset around their homesteads

and invested more in their enset fields compared to farm plots located further away. They

10 Ato Tale Geta, Team Leader, Silte Wereda Extension and Communication Office


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added manure and crop residues to enset fields and gave more attention and care. According to

the respondents, they did not add manure and crop residues to land used for growing annual

crops. Hence, soil fertility is expected to decrease more rapidly in such plots which are located

further away from homesteads.

FARMING SYSTEM

Crop production: A further influential factor that has led to the changes in the pattern of land

use and land cover is the traditional nature of the farming system in the area. The farming

system is a mixed type, where both crop farming and livestock production are carried out on a

subsistence basis. The subsistence nature of the farming system has contributed to the pattern

of land use and land cover change through the cutting of trees in order to prepare traditional

farm implements such as maresha (traditional ploughs), kember (a part oftraditional ploughs)

and hand hoes, and also the expansion of croplands towards forest areas and grazing lands to

increase yields to feed the growing population (Fig. 4). The expansion of croplands hasresulted in the destruction of natural forests. Similarly, the expansion of croplands into grazing

lands has led to a decline in livestock production. Today, most of the lands which are suitable

for crop production are already cultivated. Hence, the only option to increase crop production

is to use croplands more intensively. Due to shortage of land, peasants are compelled to shift

from extensification to intensification by increasing labour and other inputs. However,

peasants do not have access to fertilizers due to their prohibitively high prices. Moreover, they

use their available supplies of manure and crop residues on enset fields and as feed for

livestock rather than applying these to land used for growing annual crops. As a result, there is

no return of organic matter to restore the fertility of land used for growing annual crops. This

has resulted in declining soil fertility and a drop in agricultural productivity.

Livestock production: As in all other parts of the country, livestock are an integral part of the

cropping system in the study area. The total number of livestock of the sampled households

was 376, equivalent to three livestock per household. Cattle accounted for 78%, sheep and

goats for 11.4%, and horses, donkeys and mules for 10.6%. In terms of Tropical Livestock

Unit (TLU),11 the total number of livestock of the sampled households was 237. The average

11 TLU (Tropical Livestock Unit) is equivalent to 250 kg live animal weight.


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holdings of households were 2.15 TLU in Transect 1, 2.13 TLU in Transect 2, 1.74 TLU in

Transect 3, and 1.98 TLU in Transect 4.

Oxen are the major source of drought power in the study area. However, nearly 44% of the

households did not have any oxen and of those who did possess oxen, 51% had only one ox per

household and 5% had only two oxen per household. This has created serious problems for the

efficiency of farming activities in the area.

With regard to the trend in livestock numbers, as many as 82% of the respondents reported that

livestock numbers had decreased in the area, while 8.5% of the sample households reported an

increase in numbers; the remaining 9.5% reported that there had been no change in numbers of

livestock. Approximately half (52%) of respondents indicated that the main reason for the

decrease in the numbers of livestock per households had been shortage of animal feed, while

approximately 30% attributed the decrease to the death of livestock due to animal diseases,14% attributed it to the selling of cattle due to poverty, and the remaining 4% claimed it was

due to other problems such as seasonal shortages of labour.

According to 57% of the respondents the main factor behind the shortage of livestock feed was

the expansion of cropland (Plate 1), 22% claimed it was the expansion of gullies, while 21%

claimed that drought was the major cause.

Plate 1: Expansion of cropland towards grazing land.

Sources of energy: Fuel wood and cattle dung have been the most important energy sources

(biofuels) in rural Ethiopia in general and in the Upper Dijo River catchment in particular; 60%


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of the respondents confirmed that fuel wood was most important, while 35% confirmed that

cattle dug was most important. A few respondents (5%) told that they used crop residues as

energy sources. However, such usage was not found to be significant because peasant

households often use crop residues for animal feed rather than energy sources (Fig. 4).

IMPL ICATIONS OF LAND USE AND LAND COVER CHANGES

Land use and land cover changes degrade or enhance the lands capacity for sustained use and

regaining its natural cover. Specifically, changes in land use and land cover have a significant

influence on soil resources and biodiversity.

Implications for soil degradation: Table 8 shows that the sand fraction was higher in open

grassland and lower in cropland and degraded land in the study area. In contrast, the clay

fractions were found to be highest in degraded lands and croplands and lowest in open

grassland and soils from reference sites. Hence, the general trend in soil texture in conjunction

with the pattern of land use and land cover change is not in agreement with the findings of

Woldeamlak & Stroosnijder (2003) who reported low clay content in cultivated soils. This is

due to the fact that the soil samples taken from degraded and cultivated lands by Abyiot (2005)

were unfortunately all on vertisols, particularly on depositional sites, which are rich in clay

content. Further, the absence of natural forest cover in the area may have affected the results.

Table 8: Soil properties (030 cm) of four land use and land cover types.

Land use/cover types

Soil properties Cropland aOpen

grassland aDegraded

lands a

Reference

sites * Average

Clay 43.75 30.00 55.00 39.00 41.94

Silt 33.39 36.25 22.5 33.00 31.30

Sand 22.86 33.75 22.5 28.00 26.8

pH 1:1 H2O 5.52 6.37 6.075 6.15 6.03

Total N (%) 0.197 0.23 0.11 0.23 0.193

Available P (ppm) 7.1 4.5 4.2 6.37 5.54

Organic C (%) 3.228 3.275 1.365 3.689 2.889


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C/N ratio 17.27 14.32 12.085 15.83 14.88

SOM (%) 5.57 5.65 2.36 6.4 4.995

K+((c mol(+)/kg)) 1.322 1.359 1.226 3.107 1.754

Notes:

Cropland refers to annual crops,

* References are sites which include farm boundaries and holy sites which are believed to have not suffered fromland use or land cover change.aSoil sample results obtained by Abyiot Legesse (2005)

The total nitrogen (N) content of the soils showed differences among different land use and

land cover types. It was highest in control and open grassland soils (0.23%) and lowest in

degraded soils (0.1%) (Table 8). An LSD test revealed that degraded soils significantly

differed from all others in terms of total N, and in general degraded lands were found to have a

low total N. This may be due to soil erosion and leaching. The same result was obtained by

Wakene & Heluf (2004).

The soil organic matter (SOM) content was found to be highest in reference soils (Table 8).

When compared with soils from reference sites, the soils under crop, open grass and degraded

lands had average SOM contents of 87%, 88% and 37% of soils from the reference sites,

respectively. It seems that human influences have resulted in a drop in SOM content. This

finding is in line with those of Mulugeta (2004) and Woldeamlak & Stroosnijder (2003).

However, the ANOVA and LSD test did not show significant variation in SOM among

different land use and land cover types. This may be due to the absence of natural forests and

the subsequent widespread soil degradation due to erosion by runoff in the study area.

The available phosphorous (P) content ranged from 4.2 ppm in degraded land to 7.1 ppm in

cropland (Table 8). The highest concentration of available P was observed in croplands, which

could be due to the effect of application of chemical fertilizers, especially DAP (diammonium

phosphates)on croplands. This result is in line with the findings of Woldeamlak & Stroosnijder

(2003), but contradicts those of Wakene & Heluf (2004). However, the available P content of

the soils had statistically significant differences among the different land use and land cover

types.


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The potassium (K+) content of the soils varied among the different land use and land cover

types. It was highest in reference soils (3.11 (C mol (+)/kg)) and lowest in degraded soils (1.23

(C mol (+)/kg)) (Table 8). This result is similar to that of Wakene & Heluf (2004), who

reported a higher K+ content from virgin land than from cultivated and abandoned lands.

However, the ANOVA did not show a significant variation in K+ among the different land use

and land cover types. This is in agreement with the findings by Woldeamlak & Stroosnijder

(2003), who reported insignificant difference in K+ among different land uses.

The differences in the pH of soils under different land use and land cover types were small

(Table 8). Cropland soils were moderately acidic (pH = 5.52), while open grassland, degraded

and reference soils were slightly acidic (pH ranged from 6.08 to 6.37). However, the trend of

soil acidity for cultivated lands showed that intensive cultivation and continuous use of acid-

forming inorganic fertilizers had accentuated the level of soil acidity. Soil pH directly affects

plant growth through the effect of the hydrogen ions, and indirectly through the effects on

nutrient availability (Woldeamlak & Stroosnijder 2003).

Implications for biodiversity loss: The natural vegetation and tree species of the Upper Dijo

River catchment have been under threat. Focus group discussions confirmed that Kosso

(Hagenia abyssinica), Sobla, Kulkual (Euphorbia abyssinica), Wadesha, Korch (Erythrina

brucei), Gulo (Ricinus communis), and Mesena are some of the most severely threatened

species of trees, which are on the verge of extinction. Even Sembelet (Hyparrhenia) and

Sendedo(Pennisetum) are becoming severely threatened due to excessive and unwise use for

thatching as well as for manufacturing traditional artefacts. In addition, Sigeda(Oleaceae) and

Zigba (Podocarpus falcatus) trees are becoming extinct in the study area. Regarding food

crops, peas (Pisumsativum) and lentils (Lens culinaris) are avoided by peasants due to their

vulnerability to attacks by pests and monkeys.

Generally, land use and land cover change have resulted in soil degradation, the removal of

topsoil, leading to loss of soil fertility, and the depletion of biodiversity, which in turn leads to

irreversible deterioration of natural resources. These findings are in line with those of empirical

studies by Mulugeta (2004) and Woldeamlak & Stroosnijder (2003).


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FARMERS RESPONSES12

Response to the scarcity of fuel wood: The scarcity of wood for fuel and other uses has

forced people to plant eucalyptus trees. All of the sample households had planted eucalyptus

trees around their homesteads, along and inside gullies, and on degraded lands (Plate 2).

Further, the local official13 reported that 250 ha of land in Anshebeso and Arat Berkebeleshad

beenplanted with eucalyptus trees.

Eucalyptus trees have grown widely and have become the dominant tree type in the area. The

respondents in the focal group discussions indicated that the main reason for preferring

eucalyptus trees was their fast growth and tolerance of environmental stress. However, the

peasants suggested that the eucalyptus trees have adverse effects on the ecology, especially on

water resources by causing desiccation, and consequently the land may not be used

productively in other ways. For this reason the peasants in the study area do not expand their

croplands into the eucalyptus tree plantations, but keep reasonable distances in between.

Plate 2:Eucalyptus trees planted by farmers in badly degraded lands.

Despite their adverse impact, eucalyptus tree plantations have continued to expand rapidly. The

respondents associated this with the trees role in controlling the expansion of gullies. It was

reported that many people plant trees to stop the expansion of gullies into their cropland and

grazing areas and thereby they also met their household needs for fuel wood and other

12 The responses refer to the conservation measures taken by farmers to alleviate the adverse effects of land use

and land cover change on their livelihood and the environment.13 Ato Tale Geta, Team Leader, Selti Wereda Extension Communication Office.


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necessities. In response the question where do you plant trees? the farmers (household heads)

answered along and inside gullies.

Farmers participation in soil and water conservation: The respondents were aware of the

problems of soil erosion that existed in the area and tried to tackle these by applying some

conservation measures. Almost all (98%) of the respondents used soil and stone bunds while

only 2% used check dams to alleviate the problem of soil erosion in the area.

Soil fertility management systems: As a consequence of the study area being very densely

populated, access to new land has become very limited. Hence, there is growing pressure on

the limited resources. This has forced farmers to cultivate marginal lands, discontinue the

practice of fallowing, and stop the use of crop residues to maintain soil fertility. As a

consequence, land management is necessary to prolong cultivation periods and feed the

growing population. In this respect, the peasants in the study area have employed a variety ofmeasures, including improving the fertility status of the soils (95% of respondents) and

changing the land use type (5% of respondents).

Most of the respondents were engaged in improving soil fertility, using different methods to

maintain the fertility levels of the soils: 53% used artificial fertilizers, 37% used manure, and

10% used crop rotation and other methods such as fallowing. Most of the farmers mainly

applied manure to enset fields, while for cereal crops they used commercial fertilizers and

practised crop rotation. Hence, the decline in soil fertility is accelerated on plots that are

located further away from homesteads. This finding is in agreement with that of Tilhun et al.

(2001) who reported that homestead plots in the Gununo area in Southern Ethiopia are given

continuous applications of manure, compost, household waste, and ash.

CONCLUSIONS AND RECOMMENDATIONS

This study has revealed that the recent advancements in spatial technology, namely remote

sensing and GIS, could provide powerful tools for evaluating land use and land cover changes

at catchment levels. Heterogeneous data types, specifically aerial photography and satellite

images, provided valuable data for this study. Using these advanced technologies together with


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field-based detection, quantified changes in land use and land cover were calculated for the

study area in the Upper Dijo River catchment between 1972 and 2004. The general trend

observed was a decrease in shrub-grassland at a rate of 21.5 ha per year and a decrease in

riverine trees at a rate of 16.3 ha/yr. A corresponding increase was observed in bare land/open

grassland (24.8 ha/yr), cropland and settlement areas (12.5 ha/yr), and tree plantations (2.8

ha/yr). The decrease in riverine trees and shrub-grassland partly reflects the considerable

degradation of natural vegetation in the area.

The current ecological problems of the Upper Dijo River catchment and the associated land use

and land cover changes can be related partly to the livelihoods of the local population, i.e.

socio-economic conditions and access to agricultural, public and institutional services, and to a

certain extent the population growth. In the Upper Dijo River catchment, as in much of rural

Ethiopia elsewhere, the local people live in abject poverty. Further, the area is one of the most

densely populated areas of the country, with an average of 7.8 persons per household. Landand livestock form the basis of peoples livelihood. However, landholdings per household have

been declining and today the rate is 0.7 ha/household. This is due to the growing and unabated

population pressure. In addition, the productivity of land has declined over time. However,

neither Malthusian nor Boserupian assertions can completely account for the relationship

between the people and the environment in the study area. This is due to both land degradation,

mainly the expansion of bare land (in line with Malthusian perspectives), and environmental

recovery, which has resulted from household tree plantation activities (in support of Boseupian

perspectives).

The change in land tenure and growing fragmentation of land following the 1975 land reform

has accentuated the changes in the pattern of land use and land cover. In this respect, however,

it is not land redistribution, as in other parts of the country, but rather it is the illegal

transactions of land from person to person (weled aged) which has aggravated land

fragmentation and poverty levels in the area. Hence, demographic factors alone are not

responsible for environmental degradation. Non-demographic factors have strongly influenced

the dynamics of the environment in the area too.


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The land use and land cover change and associated problems observed in the area have

environmental implications at local, regional, national, and international levels because the

consequences of degradation have no boundaries. In this regard, soils in open grasslands

showed higher sand content, but lower available N, P, K+, and soil organic matter (SOM)

compared to soils in the reference sites. This is a major threat to the agricultural sector of the

study area. Moreover, the biodiversity of the area is highly threatened.

There is a trend towards more people, more trees in the study area, which is in line with the

reports made by Muluneh (2003; and unpublished data, 1994) and Woldeamlak (2002), but in

contrast to the findings of Kebrom & Hedlund (2000), Gete (1997) and Belay (2002). This

trend may be a result of the ongoing community afforestation programme and private

initiatives to check the expansion of gullies around croplands. The household level tree

planting practice is a praiseworthy initiative because it could have ecological advantages.

However, the increase in tree plantation coverage does not imply a favourable change towardssustainable land use and land cover because most of the newly planted areas are planted with

eucalyptus trees (to check the expansion of gullies) which are known to have numerous

negative ecological effects.

The following recommendations are made:

The people in the study area are confronted with problems of poverty and resource

degradation which require solutions which integrate development and conservation

measures. Hence, further development and environmental planning in the locality

should take into account the direction and magnitude of land use and land cover change

patterns. In addition, solutions to the problems of land use and land cover change

should include improving the productivity of the agricultural sector through technical

intervention, creating off-farm employment opportunities for the population, and

reducing human and livestock population pressure on the land. The local people must

be involved in all development activities and resource conservation in order to ensure

sustainability.


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Although the area of land under tree plantation has increased, the general trend in land

use and land cover change in the area has not benefited soil fertility. For this reason,

multipurpose agro-forestry should be introduced that can satisfy the need for wood,

livestock fodder, soil fertility improvement, and soil and water conservation.

As the study area is located in the Great Rift Valley system, where relatively recent

rock formations and major and minor faults are found, physical factors such as

physiographic location, age of rock formation and fault lines have influenced the area

along with the human factors. However, to date no study of the impact of these physical

factors on the local environment and the livelihoods of the people has been conducted.

This gap invites further investigations into the impact of physical factors on the patterns

of land use and land cover change and also the associated problems of the environment

and the livelihoods of the people in the study area.


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Briassoulis, H. 2000. Analysis of Land Use Change:Theoretical and Modeling Approaches.

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Crummey, D. 1998. Deforestation in Wollo: Process or illusion?J ournal of Ethiopian Studies

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Gete, Z. 1997. Land Use/Land Cover Maps (of 1957 and 1982) of Dembecha Area, Gojam,Ethiopia. Centre for Development and Environment, University of Berne, Berne.

Kebrom, T. & Hedlund, L. 2000. Land cover changes between 1958 and 1986 in Kalu District,

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