An Assessment of Land Use Land Cover Changes and Restoration Perspectives of The Mbam Watershed of Adamawa Plateau
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Land Use Land Cover Change (LULCC) often degrades important ecosystem services of watersheds such as soil and water quality, biodiversity, microclimates, methane emissions, and Carbon sequestration. Also, LULCC contribute to climate change, and increase vulnerability of natural resources to certain natural hazards.
This work was aimed at developing the structure of the hydrological system of the Mbam watershed, It also assess the trend in land use land cover change over a period of two decades, determine the drivers of land cover change and perspectives for restoration.
Participatory field observation including; ground truthing, key informants’ interview, focus group discussion, transect walks were done and GPS coordinates of all land use types collected.
Data collection was done around the Mayo Banyo Division. Analysis of data and obtained was accomplished through the use of software packages such as ENVI (Version 5.2), ARCGIS (version 10.4), and SPSS statistical package.
Remote sensing techniques were used to analyze satellite images – Landsat MSS of 2000 and Landsat TM of 2020 scenes to trace spatial and temporal land use/cover changes.
The structure of the hydrological system of the Mbam watershed was produced, the structure exhibits a dendritic drainage pattern which looks like the branching pattern of tree roots, land use land cover changes were assessed from 2000 to 2020, forest cover reduced to 40.6%, grassland slightly reduced to 13.2%, water bodies reduced to 0.88%.
However, the 42.62%, followed by built-up areas 0.67%, Further, the study established that, the underlying drivers to these changes were high population growth, poverty.
Other causes were; overgrazing, bushfires, agricultural intensification. As a result of such changes, households have opted for diverse livelihood strategies, Ecosystem restoration to adapt the impacts of land use/cover changes and law enforcement to protect unsustainable land use.
At the end of this study, there’s a high perspective for ecosystem restoration as most of the community members are in support of ecosystem restoration. Participatory land-use planning, tree planting, and agroforestry.
The study recommends that, more studies should be done on the hydrology of Adamawa Plateau since limited information exists.
Key words: Land use/cover changes, watershed, ecosystem Restoration, forest, Mbam Watershed
Globally, land use/cover change has been notorious since 1950s due to rapidly growing human population that increased demand for food, fresh water, timber, fibre and fuel. (Kangalawe and Lyimo, 2010).
These changes also contribute to climate change (of various scale), an increased vulnerability of certain natural hazards (floods, droughts, fires), (Megersa & Degefa, 2019).
These changes have currently become a global concern due to the negative impacts associated with them such as soil degradation, loss of biodiversity, and wetland degradation.
Drivers of change are manifold and can be directly linked to human activities such as population growth, economic development, and globalization (Näschen et al., 2019) and these activities are said to have transformed the geographical environment (Adhikari et al., 2016).
The United Nations announced 2021–2030 as the ‘Decade on Ecosystem Restoration’ to fast-track the restoration of severely degraded landscapes worldwide.
Similarly, Target 15.3 (achieving land cover change neutrality) of the Sustainable Development Goals 2030, promotes prioritization and acceleration of land restoration activities (Cowie et al., 2018; ADB, 2019).
Estimating historical LULCC trends is essential in assessing the rate at which change occurs and the problems that result, which can lead to better predictions of future impacts and issues that might occur (Adhikari et al., 2016).
Globally, Scientists recently warned that 24 billion tons of fertile soil were being lost per year. If this trend continues, 95 per cent of the Earth’s land areas could become degraded by 2050 (WWF., 2007).
Consequently, 3.2 billion people are affected by the land cover change, though the world population is projected to increase by about 35 percent to 9.7 billion in 2050 therefore more pressures on natural resources.
However, rapid population 2 growth, economic development and industrialization have led to the unprecedented transformation of freshwater ecosystems and consequent biodiversity loss (WWF, 2007) According to the U.N. FAO, 22.7% of Africa is forested, Africa lost an average of 3,740,950 ha or 0.50% per year.
In total, between 1990 and 2010, Africa lost 10.0% of its forest cover.
Between 2010 and 2020, the continent lost 3.9 million hectares of forest area per year, compared to 3.4 million hectares between 2000 and 2010. Worse, « the rate of net loss of forest area has increased in Africa in each of the periods concerned since 1990.
A phenomenon that affects the Congo Basin, the second green lung of the planet after the Amazon (FAO, 2020). Its continuous disappearance could exacerbate the insecurity of freshwater and food supplies for some of Africa’s most vulnerable populations (WRI, 2019).
Forests and trees play crucial roles in hydrological processes in watersheds. Forested mountain and upland watersheds supply an estimated 70% of the world’s accessible freshwater resources for domestic, agricultural, industrial and ecological needs (FAO, 2021).
Freshwater systems are also habitats for diverse fauna and flora which provide an important source of food and fiber that sustain incomes and livelihoods, particularly for rural communities in developing countries.
However, the ten most endangered rivers are: the Salween, La Plata, Danube, Rio Grande, Ganges, MurrayDarling, Indus, Nile, Yangtze and Mekong.
Today, 41% of the world’s population live in river basins under water stress, consequently, the threats to freshwater ecosystems are immense.
Physical alteration, habitat loss, degradation, water extraction, overexploitation, pollution and the introduction of invasive species threaten the planet’s freshwater ecosystems and their associated biological resources.
Consequently, more than 20% of the world’s 10,000 freshwater species have become extinct, threatened or endangered in recent decades.
Unfortunately, the demand for water itself is rapidly 3 increasing as well, thus, there is an ever-increasing need and urgency for improved management of freshwater ecosystems (WWF, 2007).
In Cameroon, the destruction of the remaining forests is heavy, even within reserved lands. Fires and commercial exploitation of the forests result in the degradation of 200,000ha of forest per year. Overgrazing is degrading the semiarid northern rangelands (Cameroon- environment Nations encyclopaedia, 2020).
In Cameroon, agriculture has been tagged the main driver of these changes, thus, transforming initial forestlands into agrarian lands (Tchindjang et al., 2020).
Consequently, forest loss in Cameroon is 0.01 % between 1990 and 2000, and forest degradation rate has multiplied by 9 between 2000 and 2005 (Tchatchou et al., 2015).
Adamawa plateau is the major watershed in Cameroon since several of these river systems originate either from its northern (the Bénoué and the Logone) or its southern slopes (the Sanaga and the Kadeï).
The flora is rich in montane forests and locally these forests are crucial for maintaining a year-round water supply for local communities and are the headwaters of several major rivers such as Djerem, Vina, Benue and Mbam.
In this light, the Mbam River is the main tributary to the Sanaga River, However, ecological studies have found that causes of rapid degradation of the rare Afromontane ecosystems are largely anthropogenic: over grazing, uncontrolled bush fires, commercial hunting, deforestation for farming, chemical fishing, firewood extraction, and commercial bark harvesting (BLI, 2003). These activities have led to the change in the land cover of the area.
1.2 Statement of the Problem
Land cover change is one of the world’s most pressing environmental problems. Forests cover 30% of the Earth’s land area and host 80% of its biodiversity. They provide subsistence and income to about 25% of the world’s population.
The world’s forests are 4 in serious danger through deforestation and forest degradation with a forest area of 1.3 million square kilometers lost between 2000 and 2016; this is the equivalent of approximately 800 football fields of forest lost every hour (European Union Commission, 2020).
Approximately 80% of global deforestation is caused by the expansion of land used for agriculture. Urban expansion, infrastructure development and mining are also factors driving deforestation (European Union Commission, 2020).
Besides rainfall, Cameroon has considerable water resources. In the well-watered southern region, which has metamorphic and igneous rocks, the waters are mostly surface water, while in the semi-arid less watered north, they are mostly groundwater, owing to the permeability of the sedimentary rocks.
Cameroon has a dense network of rivers most of which arise from the Adamawa Plateau the number one watershed in Cameroon.
The Plateau is at the Centre of the country and the water that originates there flow north and southwards. Today, Cameroon’s major catchment areas and river courses have been modified significantly through land use intensification.
Such transformations have disrupted the regular flow pattern of most rivers in this part of the country and this has equally affected other human activities depending on it.
Even though Adamawa Plateau is the number one water tower of Cameroon, not much work has been done on the hydrology of the watersheds of this landscape especially that of Mbam watershed. Consequently, this work will identify and map out the hydrological system of the Mbam watershed.
Adamawa Plateau harbors the rare montane forest. Locally these forests are crucial for maintaining a year-round water supply for local communities and are the headwaters of several major rivers.
Mbam River is the main tributary to the Sanaga river which is used for hydroelectricity generation. And since the country is experiencing problems in electricity, it only means the water in the Mbam River has reduced.
This could be as a 5 result of the degradation of the rare Afromontane ecosystem of Adamawa Plateau. Ecological studies have found that causes of rapid degradation of the rare Afromontane ecosystems are largely anthropogenic: overgrazing, uncontrolled bush fires, commercial hunting, deforestation for farming, chemical fishing, firewood extraction, and commercial bark harvesting (BLI, 2003).
And these activities have turn to cause changes in land cover, but unfortunately, in Adamawa Plateau, information on LULC changes is scanty.
Therefore, assessing the land cover dynamics will give information on the state of degradation of the watershed and a perspective to the conservation of the rare Afromontane ecosystem of Adamawa Plateau. Consequently, solving the electricity problems in the country.
The anthropogenic activities causing harm to the health of the ecosystem and consequently to the Mbam watershed are driven by some major factors, in this work, The drivers of these changes in the land cover are identified and some measures to address them are identified which could therefore lead to a perspective for ecosystem restoration.