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LAND USE AND LANDCOVER DYNAMICS IN UKWUANI LOCAL GOVERNMENT AREA, DELTA STATE, NIGERIA
The Researcher- International Journal of Management Humanities and Social Sciences Jan-June 2018, 3(1) 1
LAND USE AND LANDCOVER DYNAMICS IN UKWUANI
LOCAL GOVERNMENT AREA, DELTA STATE, NIGERIA
WEJE, Ikezam Innocent1 TPL. OSANEBI, Nathaniel Nwabueze
2
Abstract
The world has witnessed and is still witnessing increase in land cover changes occasioned by
increased demand for land space to meet man’s diverse need but not without its consequences.
Using ArcGIS, this work x-rayed the issue of land cover changes in Ukwuani Local
Government Area (LGA) of Delta State, Nigeria using satellite imageries for three different
periods (1987, 2000 and 2018) at 28 meters resolution. The result shows disparity in the land
cover in the area for the different periods under review. The study recommends for the use of
strategic planning and systematic monitoring of forest to reduce the rate of land cover changes
and land conversion in the area. There is also the need for proper management of the forest
resources by the government through the implementation of sustainable forest management
policies and programmes. This will help in the development of the areas and at the same time
curb the socio-economic problems associated with sustained land cover changes in the study
area.
Key Words: deforestation, development, degradation, environment, forest
management, forest resource, socio-economic;
;
1. Introduction
Man-environment relation is both dependent and inter-independent and always in a
continuous interaction with each other. The environment provides a range of services; life
support, source of raw material and sink for wastes product, on which lays the sustenance of the
earth system. In view of these essential services exploitation of its resources ought to proceed in
a sustainable manner.
1 Department of Urban & Regional Planning, Rivers State University, Port Harcourt 2 Ministry of Urban Development, Town Planning Department, Asaba, Delta State, Nigeria
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Land cover refers to the physical and biological cover over the surface of land, including
water, vegetation, bare soil, and/or artificial structures. Land use describes the use that land is
put including all human activities such as agriculture, forestry and building construction that alter
land surface processes including biogeochemistry, hydrology and biodiversity (Encyclopedia of
the Earth,2018).Changes in land use and land cover date to prehistory and are the direct and
indirect consequence of human actions to secure essential resources (Encyclopedia of the
Earth,op cit). This may first have occurred with the burning of areas to enhance the availability
of wild game and accelerated dramatically with the birth of agriculture, resulting in the extensive
clearing (deforestation) and management of Earth’s terrestrial surface that continues today.
Again as the world go through rapid urbanization and industrialization this has
encouraged the concentration of human populations within urban areas and the depopulation of
rural areas, accompanied by the intensification of agriculture in the most productive lands and
the abandonment of marginal lands.
Forests cover about 30% of the planet, but man’s relation with the environment
especially through deforestation that results in the clearing of earth's forests on a massive
scale, resulting in damage to the quality of the land and change in land cover of an area. One
of the areas where man-environment relation can be easily seen is in the area of\ exploitation of
forest and forest it resources to make room for man’s socio-economic growth. These activities
takes diverse forms which may include the clearing of forests for agriculture, commercial and
construction purposes, the grading of the topography for transport routes and garden, the change
in drainage pattern, the channeling of stream segments, the construction of culverts and dams,
the disposal of wastes on various parts of the landscape, among others(Onibokun, et al 1985).
Generally speaking, the world has witnessed and is still witnessing increase in land cover
changes occasioned by increased demand for land space to meet man’s diverse need but not
without its consequences. Papkin, (1993) opines that millions of tons of soil are lost every year
as a result of deforestation. Though deforestation is a global phenomenon, its rate appears to be
more pronounced in the developing countries of the world where the quest for socio-economic
growth is on the ascendency with little or no regard paid to the sustainability of this all
important resource-forest. The problem is made worse as countries in the less developed nations
make effort to deliberately increase the tempo of socio-economic growth as a way to ‘catch up’
LAND USE AND LANDCOVER DYNAMICS IN UKWUANI LOCAL GOVERNMENT AREA, DELTA STATE, NIGERIA
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with development pace of the developed nations. The resulting scenario is increased degradation
of forest through the total clearance and change of use.
In Nigeria for example, the exploitation of resources as it relates to communities’ socio-
economic life has left so much to be desired. Apart from the forest reserved areas that are under
restriction, other areas are at the mercy of continuous exploitation and over use. This situation
has led to incessant deforestation which at this present time threatens the socio-economic life of
the people. More worrisome is the fact that, in most cases, deforestation activities are carried out
by the people who in one way or the other; destroy the forest through bush fire, excessive
cultivation for agriculture, urbanization, logging, collection of fuel-wood etc.
The consequences of unsustainable use of forests resources are grave with attendant
negative impact on the environment. The most dramatic impact is loss of habitat for millions of
species. Deforestation drives climate change. Forest soils are moist, but without protection
from sun-blocking tree cover, they quickly dry out. Trees also help perpetuate the water
cycle by returning water vapor to the atmosphere. Without trees to fill these roles, many former
forest lands can quickly become barren deserts.
Removing trees deprives the forest of portions of its canopy, which blocks the sun’s
rays during the day, and holds in heat at night. This disruption leads to more extreme
temperature swings that can be harmful to plants and animals. Trees also play a critical
role in absorbing the greenhouse gases that fuel global warming. Fewer forests means
larger amounts of green house gases entering the atmosphere—and increased speed and
severity of global warming.
Apart from the negative impacts of deforestation noted above, this phenomenon has
other wide range of effects on the socio-economic lives of the people. For example, with the
setting in of deforestation, comes a corresponding decrease in the productivity of the soil
through nutrient leaching, laterization, desiccation and outright erosion. Soil is exceedingly
fragile wherein nearly all of human food, fiber, energy and industrial crops are cultivated and
on which all our livestock are reared. Its disappearance causes flooding, siltation of rivers
and streams, the entrophication of fish and losses in agricultural production systems which,
in turn, affect the socio-economic activities of the people, leading to or aggravating
unemployment, scarcity of forest resources, emigration, civil unrest, crime, poverty, and
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food shortage amongst others. This study is an assessment of land cover changes in Ukwuani
Local Government Area (LGA) of Delta State, Nigeria, with a view highlighting the changes
in land cover of the area over time.
Ukwuani is one of the LGAs in Delta state, Nigeria geographically located between
latitude 5o21’N and 6
o12’N and longitude 5
o48’E and 6
o10’E. It is bounded in the north by
Ndoka-West, in the south by Iliologbo (Isoko-North Local Government Area) and West by
Edo State, South – West by Abraka (Ethiope-East) Local Government Areas as indicated in
figure 1.
The area of study is predominantly dominated by clayey and loamy soil types. The loamy
soils are present in areas close to the bank of the rivers and the streams. While the sand loamy
soils are relatively found distance away from the rivers. The soil condition in the study area
varies from one location to another. The climate of the study area is humid sub equatorial with a
long wet season lasting from March to October that alternates with a shorter dry season that last
from November to February
LAND USE AND LANDCOVER DYNAMICS IN UKWUANI LOCAL GOVERNMENT AREA, DELTA STATE, NIGERIA
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Fig.1: UKWUANI LGA SHOWING THE COMMUNITIES.
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The vegetation of the study area consists of rain forest type. The forest consists of many trees
which include iroko, mahogany, obeche, opepe, ebony, abura among others.
Lots of studies have been done on land cover changes. One of the areas that have
attracted the attention of scholars is on what actually constitute ‘deforestation’ and ‘forest’
Under the United Nations Forest Convention on Climate (UNFCC), deforestation is the “direct
human induced conversion of forested land to none forested land” while forest as an area of
land “with tree crown cover more than 10% to 30% with the potential to reach a minimum height
of 2 to 5m at maturity in situ” (IPCC, 2000).
The first authoritative estimate of global losses of tropical forests to conversion,
extrapolated from partial data, concluded that 11.4 million hectares were disappearing each year
in the early 1980’s (IUCN, 2002). The use of satellite imagery, backed by site checks, has
pushed up estimates for the late 1980s from 17 million to 20 million hectares a year.
The UN estimates that the world lost 94 million hectares of forest in the twentieth century and
assumes that developing countries lost 130 million hectares while the industrial world gained 36
million hectares as abandoned agricultural areas. The yearly loss of natural forests was
16million hectares – 94% in the tropics.
Deforestation heightened the country’s reliance on plantations and imports. Earth Policy
Institute, (2002) estimates that in Indonesia, forest loss averages 2 million hectares a year. In
Asia, it declined by 4 million hectares. Deforestation in tropical areas exceeds 13 million
hectares a year. About 40% of the world’ forests will be gone within 10 to 20 years. The
estimate stated that global wood production has raised to 50% most from primary and secondary
growth forests. About 1.8 billion cubic meters, is burned each year in developing counties while
about 290 million hectares of forest are protected from logging, but threatened by illegal
exploitation. (Earth Policy Institute, op cit).
Illegal logging has reduced incentives to invest in sustainable forestry. Plantations cover
less than 5% of forested area, but account for 20% of wood production. Unfortunately,
governments grant concessions to logging companies’ contingent on their planting of
replacement trees, but they leave the land bare and move to new area. In Indonesia, 9 million
hectares have been allocated but only 2 million have been replanted. A Satellite Survey found
that 88% of the key areas are sparsely populated and offer a starting point for preservation.
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Reduced consumption of virgin wood is a key to saving the world’s trees (Earth Policy Institute,
2002).
Miller (1994) worked on forest destruction, cultural extinction and fuelwood crisis,
stated that about 56% of the world’s tropical forests have been cleared or damaged and the
annual rate of loss rose by 50% between 1981 and 1991. Using Satellite Scan Miller (1994)
opines that forests are varnishing at a rate of at least 170,000 square kilometres per year –
equivalent to about 37 city blocks per minute or almost two football fields per minute.
Daubenmire (1947), worked on direct effects of fire on vegetation, pointed out that if fire
is very hot, leaf, mould; the upper part of the humus containing the plants are destroyed. He also
pointed out that rainfall interception is eliminated when losses are not increased proportionately.
The soil moisture content may rise for lack of plants to use up the water. From the work of
Daubenmire (1947), it is clear that uncontrolled fire can trigger off soil erosion and total
destruction of plant species. The study only addressed one factor of deforestation – fire. He
failed to consider the other factors responsible for deforestation such as agriculture, logging,
population, urbanisation and effect it has on the socio – economic life of the people.
2. Materials and Methods
This study adopted the time-series research design since its objective is to examine the
land cover dynamics in Ukwuani LGA of Delta State, Nigeria and to project the likely changes
in land cover changes in the area in the next thirteen (13) years (2006-2018).
To achieve this satellite imagery of Nigeria for three periods (1987, 2000 and 2018) at 28
meters resolution was used to analyze the changes. The study area (Ukwuani) was extracted out
of the Nigerian satellite imagery by cutting in a polygon shape, the relevant portion for each of
the three satellite imagery were extracted using ArcGIS software. The extracted satellite imagery
was geo-referenced using image to image rectification. The selected features and the coordinates
of X and Y were applied for the geo-referencing. The coordinate system used for the geo-
referencing of the attribute data is the Decimal-Degree (geographic coordinate systems).
The study area (Ukwuani L.G.A) was cut out from the satellite images of 1987, 2000 and
2018 in ArcGIS and they were exported to Idrisi, band by band for image processing operations.
The bands of the Satellite images of 1987and 2000, and 2018 were classified using User Defined
classification utility module in Idrisi to classify into three classes (Forest, no data and others).
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To analyze these temporal images of 1987 ,2000 and 2018; cross-tabulation model was used to
evaluate the changes in the two different years to their locations in relation to the entire Local
government area (Ukwuani L.G.A) and also projecting for the next 13 years
3. Result and Discussions
Tables 1 and 2 below are the results of the land use change analysis emanating from this
work. From table 1 the total forests cover of Ukwuani in 1987 was 77,948 square meters and
the remaining 389,449 square meters were covered by other land uses such as agricultural land
use, settlement, and industrial land uses. The total land area in 1987 amount to 467,397 square
meters. The investigation revealed that the forest which was 77,948 square meters in 1987 has
reduced to 14, 988 square meters in 2000. The total forest land lost to other land uses amount to
approximately 62,960 square meter (77,948-14,988)m2 and the total land areas gained by other
land uses amounted to approximately 63,765 square meter (453,214-389,449}m2. Plate 1 is a
schema showing land use change of Ukwuani LGA for the period 1987-2000.
Table 1: Change Detection Analysis from 1987 – 2000.
Classification 1987 Class % Forest
change in
1987
2000
Class
% Forest
change in
2000
Rate of
change
to other
uses
2 = Forest 77,948 16.68% 14,988 3.20% 1.02%
1 = Other land uses 389,449 453,214
Total 467,397 468,202
Source: Field work, 2018
The percentage of land covered by forest in 1987 was 16.68% and the percentage land
covered by forest in 2000 was 3.20%. Therefore, the percentage change of forest cover between
1987 to 2000 amount to approximately 13.68% (16.68 – 3.20} % in 13 years. The result revealed
that 13.68% of forest areas have been lost to other land uses within the study period. The rate of
change of forest to other land uses between the 1987 – 2000 is approximately 1.02% per year.
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Plate 1. CLASSIFIELD IMAGE OF THE STUDY AREA IN 1987
Source: Field work, 2018
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Table 2 is the change detection analysis of the forest of the study area from 2000 to 2018
for Ukwuani area. The result indicated that the areas covered by forest which was 77,948 square
meter has reduced to 25,226 square meters in 2018 and the areas covered by other land uses
increased from 389,449 square meters in 2000 to 442,234 square meter in 2018. The total forest
land lost to other land uses amount to approximately 52,785 square meter while the total land
area gained by other land uses amount to approximately 52,785 square meter (44, 2234 –
389,449) m2.
The percentage of land covered by forest in 2000 amounted to 16.68% and the percentage of
land covered by forest in 2018 amounted to 5.40%. Thus, the percentage change of forest cover
between 2000 to 2018 amount to approximately 11.28% (16.28 – 5.40) . The land cover change
rate (to other land uses) from 2000 to 2018 is approximately 1.88% per year. Plate 2 is the land
use classification of the study area in 2000 while plate 3 is the one for 2018 respectively.
Table 2 Change Detection Analysis from 2000 – 2018.
Classification 2000 Class 2017 class % forest
covered in
2018
Rate of
change
between
200-2018
Rate of
change to
other
uses(per
yr)
2 = Forest 14,988 25,226 5.40% 11.28% 1.88%
1 = Other land uses 453,214 442,234
Total 468,202 467,460
Source: Field work, 2018
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Plate 2: CLASSIFIELD IMAGE OF THE STUDY AREA IN 2000
Plate 3: CLASSIFIELD IMAGE OF THE STUDY AREA IN 2018
Source: Field work, 2018
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Source: field work, 2018
4. Conclusion and Recommendations
The analysis made in this work reveals that there is significant variation in the land cover
in the study area within the period under investigation. The result of the study has a lot of
planning implications if the present rate of land cover changes is left unabated. One implication
of the rapid land cover changes in Ukwuani LGA is its likely impact on the socio-economic
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activities and wellbeing of the people. The loss of economic trees, scarcity of fertile land,
accentuates the problem of unemployment, which further impoverishes the people.
In view of the above urgent measures such as strategic planning and systematic
monitoring of the forest and evaluation of the forest resources is a only a desideratum.
There is also the need for proper management of the forest resources by the government through
the implementation of sustainable forest management policies and programme. This will help in
the development of the areas and at the same time curb the socio-economic problems associated
with sustained land cover changes in the study area.
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