Abstract

This study seeks to examine the effects of Mangrove exploitation on the physical changes observed on the Tiko Coast. The study relied on historical data and adopts quantitative and qualitative methods, whereby data derived from several primary and secondary sources: Questionnaires, observation, interviews, textbooks, journals, newspapers, government publications, magazines, internet sources, etc, were described, explained, and analyzed within the context of the subject matter under investigation.

The findings reveal that the Tiko inhabitants are mainly involved in Rhizophora/red mangrove and they use both the traditional and modern methods of exploitation. Also, it was found out that mangrove deterioration is caused by land conservation for aquaculture while coastal erosion and increase siltation worsen the situation.

Furthermore, the study reveals that the association between the effect of exploitation and the physical changes in the topography of Tiko is a result of the anthropogenic activities region amongst others.

Thus, the study recommends the delegation of forestry should take serious measures in enforcing the law on mangrove protection and environmental management local framework, by sensitizing the exploiters on the consequences of excessive exploitation of mangrove.

CHAPTER ONE

GENERAL INTRODUCTION

1.1 Background of the Study

Mangroves are complex inter-tidal forests that thrive at the interface between dry land and open seas, in tropical and subtropical regions of the world. This ecosystem is the mainstay of enormous biological and abiotic resources (Adams, 1993; Dame and Kebe, 2000; Tallec and kebe, 2006; Ukwe, Ibe, Nwilo, et al., 2006).

Global mangrove forest cover has however declined by 50% in the last decade attributed to anthropogenic, physical, chemical, and biological disturbances (Farnsworth and Ellison, 1997; Valiela et al., 2001; FAO, 2007; McGowan et al., 2010, UNEP, 2011). Physical deforestation and overexploitation of mangrove forests, due to harvesting of timber products by local communities is widespread in tropical regions throughout the world and is probably as old as coastal settlements (Semesi, 1998; Singh et al., 2010).

Overexploitation (change detection studies have shown that) of mangrove forests has been measured using remote sensing techniques in Kenya (Doute et al., 1981; Gang and Agastiva, 1992; Dahdouh-Guebas et al., 2004; Kairo et al., 2002) and elsewhere.

A number of studies have shown that mangrove deforestation (removal of mangrove vegetation cover) and overexploitation (extractive use of mangrove forest products or habitats) influences the assemblage of mangrove flora (e.g Gang & Agastiva, 1992; Abhuodha & Kairo, 2001; Dahdouh-Guebas et al., 2004) and fauna (e.g. Schrijvers et al., 1995; Fondo and Martens, 1998; Pereira and Goncalves, 2000; Skilleter and Warren, 2000; Khalil, 2001), in Kenya and elsewhere.

These studies have reported a decline in floral and faunal diversity, as a result of human physical disturbance, but few have described the structure of the disturbed forests in any detail. Such basic knowledge is essential to understanding and explaining the impacts of deforestation on mangrove forest functioning as described in some of the above studies and hence the present study.

Africa is richly endowed with mangroves which cover over 3.2million hectares extending from Mauritania to Angola on the Atlantic coast from Somalia to South Africa along the Indian Ocean.

Mangrove covered countries in west and central Africa including Mauritania, Senegal, Gambia, Guinea Bissau, Guinea Conakry, Sierra Leone, Liberia, ivory coast, Sao Tome and Principe, Ghana, Togo, Benin, Nigeria, Cameroon, Equatorial Guinea, Gabon, Congo, democratic republic of Congo and Angola (Ajonina et al., 2008).

The mangrove forest of west-central Africa is critically threatened due to minimal management and policy efforts. Despite the recognized benefits, mangrove forest remains over-exploited. This is because mangroves are marginalized in national and regional political agendas (kjerfve et al 1997; Dodman et al. 2006, UNEP-WCMC, 2007), this is partly caused by insufficient knowledge about the ecological value of mangrove ecosystems, which provide important ecosystem services, such as fish, flood prevention, water regulation, and timber products.

Cameroon mangrove forest found east and west of Mt. Cameroon with smaller formations dispersed along the estuaries of the other rivers. The main stands of trees are the Rio-del Rey and the Cameroon estuary, respectively.

The latter covers an estimated surface area of about 75,000hectares which is approximate 50kmof the coastline while the former covered an estimated area of about 175,000hectares (approximately 60km of the coastline from river Sanaga to the Bimbia estuary). Din et al2017) the floristic composition of Cameroon mangrove is a characteristic of the Atlantic mangrove of West Africa.

Human activities in coastal areas such as physical alteration of the habitat, overexploitation of the resources, and pollution cause significant pressure on the environment. These pressures have steadily increased as the human population increases.

Coastal areas, including mangroves, are characterized by high productivity creating important nurseries for offshore fish, but they are among the most exploited ecosystems. Frequent but low-intensity anthropogenic disturbance such as fuelwood extraction may strongly affect forest structure and species composition in tropical forests.

The assessment of the informal activities carried out by the local populations in the tropical wetland ecosystems is often a determinant to knowing their economic values in developing countries not taking into account these values is the major factor under which political decisions often lead to the overexploitation of these ecosystems (Barbier, 1994)

Tiko, originally called ‘keka’ by the Bakeries, is a town and important port in the southwest region of Cameroon. It is situated along the Bimbia River at the Gulf of Guinea, 12miles (19km) east of Limbe (formerly Victoria). With geographical coordinates404’ 30” N 9021’36” E. The settlement grew as a market town for Douala fishermen, Bakweri farmers, and hunters from Molyko, Bwenga, Bulu, and Bokova.

The core quarters in Tiko are street 1-7, Motombolombo, Downbeach, Longstreet, Likomba, gulf club, Mutengene, Ombe. Tiko has an elevation of64m, with a population of 78,885(2012), the Tiko creeks which harbors large areas of mangrove forests is one of the most depleted ecosystems due to degradation which results in the dynamics and evolution of this ecosystem in relation to the development of the Tiko coast.

1.2 Problem Statement

In general, human activities on mangroves have negative effects on the physical evolution of the coast.

Large expanses of mangrove forests are being depleted in favor of land reclamation for construction purposes, agriculture and aquaculture. As many people seek to settle in the coastal zone, the risk of mangroves in these areas also increases.

Greater pressure is placed on the mangrove environment from both direct impacts (removal of mangrove for water access infrastructure and views) and indirect impacts (such as a change in tidal flow characteristics, pollution, and weed invasion).

Continued loss of mangrove forests will have serious ecological and socio-economic impacts, the impacts of loss are disproportionately felt by communities’ especially coastal communities that rely directly on mangrove products and services for their livelihood. The effects of human activities on mangroves have exceeded those of natural events over the past few decades.

Economic development, rapid population growth, and high population densities in coastal areas are the main drivers for mangrove degradation and loss as a result of wood harvesting, urban settlement and infrastructures, sand extraction, petroleum exploitation, coastal and climate change.

Increasing demands for foreshore development and uninterrupted water views, water frontages are considered to be prime real estate and are often gained by in-filling or clearing mangrove wetlands, mangroves are often illegally cut down, poisoned, or trimmed by owners of waterfront properties to obtain water views and private access to waterways.

Settling along coastal environments leads to trampling by humans. Humans walking through the mangrove forest can trample and cause destruction to mangrove root systems, leading to the death of the trees over time, seedlings can also be destroyed.

The recent rise in clearing projects of mangrove forests along the Tiko coast poses threats, including pressure from rural/urban development, local demands for natural resources, infrastructure, and agricultural development.

1.3 Research Questions

1.3.1 Main Research Question

What are the effects of mangrove exploitation on the physical changes observed on the Tiko coast?

1.3.2 Specific Research Questions

1. What is the state of mangrove exploitation on the Tiko coast?
2. What are the main drivers of coastal dynamics and the evolution of the Tiko coast?
3. What are the impacts of coastal evolution on mangrove ecosystems on the Tiko coast?
4. Following the current trends of evolution of the Tiko coast, what is the future of the mangrove forest in this area?