ABSTRACT

The Tubah Massif of Northern Cameroon is a range of small hills. This region is known to harbor forests with high levels of biodiversity and endemism, but this Massif is botanically poorly known. We assessed tree species diversity, floristic composition and level of endemism of the Tubah forest, comparing it with other sites in Central Africa. Five 1-ha permanent plots within old-growth lowland forests of the Tubah Massif were censused. A total of 2,658 individuals with dbh C 10 cm were recorded, belonging to 293 species, 170 genera and 60 families. The mean number of stems was 532 ± 75 stems have. Taking into account other data available, the list of vascular plants known in the Massif reaches a total of 450 species. We found 47 species of high conservation value, including Cameroon endemics and other rare and threatened species. Species richness and endemism are comparable to those of the richest known sites in Central African forests.

The forests of Tubah were found to be particularly rich in Fabaceae-Caesalpinioideae. Topographic heterogeneity, high precipitation and atmospheric humidity owing to the proximity of the ocean, and permanence of a forest cover during past geological times probably all contribute to explaining the Massif’s high tree diversity and endemism. This study highlights the botanical importance of the poorly studied Tubah forest within the North region of Cameroon, justifying efforts for improved assessment of this value and for the development of suitable national conservation strategies.

Keywords: 1-ha permanent plots  Cameroon  Floristic patterns  Endemic species Tree alpha diversity Tropical rainforest

CHAPTER ONE

• Introduction
  • background of study

The Bambui Wetland is a large wetland complex that covers an area of about 3,000 hectares (7,400 acres). The wetland is fed by rainwater and groundwater. It is surrounded by a dense forest, which helps to protect it from pollution and other threats. The wetland is also home to a number of springs and streams. The Wetland provides a number of important benefits to the local community and to Cameroon as a whole. These benefits include: The Bambui Wetland is located in the Bambui Mountains of the Northwest Region of Cameroon, near the city of Bamenda. It is situated at an altitude of about 2,000 meters (6,500 feet) above sea level.The Bambui Wetland is a Ramsar site, which means that it is recognized as a wetland of international importance. It is one of the most important wetlands in Cameroon and is home to a variety of plant and animal life, including many rare and endangered species. Location:The Bambui Wetland is located in the following coordinates:

• Latitude: 6.083333° N • Longitude: 10.15° E

Despite its high potential for biodiversity conservation, the Tubah Massif has attracted little attention from scientists. In mapping the vegetation of Cameroon, Letouzey (1968, 1985) included this upland area in the ‘‘District atlantique biafre´en’’, characterized by a high number of gregarious caesalpinioid legumes. However, Letouzey’s phytogeographic maps are largely based on prospection and collection of botanical specimens, and very few quantitative inventories were performed. Since then, very little has been published on the Tubah Massif and it has been repeatedly overlooked in nationwide censuses of critical forest sites for biodiversity conservation (Gartlan 1989; Doumenge et al. 2003). However, some recent taxonomic studies, which focused on a small number of families—i.e. Rubiaceae, Begoniaceae and Orchidaceae—have confirmed the high levels of endemism of this area for these taxa (Sosef 1996; Sonke´ et al. 2006a, b, c, 2008a, b; Droissart 2009). As strategies for conserving species and communities focuses as much on species richness and endemism (Myers et al. 2000, Lovett et al. 2000, Kier and Barthlott 2001), more detailed information about the coastal forests of Cameroon, especially on the poorly known Tubah Massif, is necessary. Better data from such unexplored areas would greatly increase the reliability of modeling patterns of tree alpha diversity in African rain forests (Parmentier et al. 2011). Given the ever-increasing threats to local biodiversity in Cameroon, the need to study the Tubah forest has never been greater. In addition to global threats such as climate change, forest destruction for agriculture by local populations and timber exploitation have both heavily impacted the natural vegetation for decades, mainly in the flat lowlands (Letouzey 1985). Other human pressures, such as hunting, have reached alarming rates in the area. Owing to its rugged topography and low population density, the Tubah Massif has so far been relatively preserved from these threats.

Conservation of natural forests and their resources is important in climate change mitigation. However, effective conservation strategies require an understanding of tree species composition and knowledge of the forest stand structure, which will permit the drawing up of a good forest conservation plan [1]. Tropical rain forests are valuable ecosystems and are amongst the most species-rich biome of the world [2]. They harbor over 50% of species on just 7% of the land area [3] with enormous wealth of animals such as insects, amphibians, reptiles, mammals and birds [4]. Ninety percent of primates and 80% of all known insects are found in the tropical rain forests [5]. One hectare of primary forest usually contains about 100 – 500 tree species with individual girths exceeding 10 cm [6]. Over 800 million people depend on tropical forests for fuel, food, and income [7]. For these reasons, tropical forests are undergoing rapid land use changes, including deforestation, as a result of agricultural expansion, commercial logging, plantation development, mining, industry, urbanization, and road building amongst other uses [7] [8] [9]. Cameroon is ranked fourth in Africa for her rich biodiversity [10] and often described as Africa in miniature [11]. Forests cover about 48% of Cameroon’s national territory, approximately 22,500,000 hectares [12]. Most of the forests form part of the Congo basin forest which is the second largest area of dense tropical forest in the world after the Amazon [13]. The Cameroonian forest has been divided into permanent and non-permanent forest estates by the Cameroon government. The permanent forests estates otherwise known as protected areas are considered to be areas belonging to the state [14]. Despite these efforts invested by the administration to protect the forests and its related resources, deforestation has not ceased in both protected and non-protected areas, leading to a continuous change in forest cover and land use. It is estimated that the legal rate of forest change in Cameroon between 2000 and 2005 was −1% to −1.5% per year [15] meanwhile it was −0.9% for the period 1990-2000 [16]. The natural habitat of the Cameroonian Highlands is composed of sub-montane and afromontane forests, with subalpine grasslands on the highest peaks [17]. The Bamenda Highlands is the most diverse and important area in the Cameroon highlands after Mt. Cameroon and Mt. Kupé [4]. Several taxa are endemic to the Bamenda Highlands [17] and particularly to its highest peak at Mt Oku [18]. These highlands are well-known for their richness in plant species diversity, with limited documented works carried out at Tubah sub-division which is one of the Bamenda Highlands forest. However, preliminary plant surveys along- P. Tsitoh, E. E. T. Bechem DOI: 10.4236/oje.2019.98020 275 Open Journal of Ecology side bird surveys conducted revealed that this forest falls amongst the 34 global hotspots [19] and the 218 endemic bird areas [20]. Although these highlands are areas of high endemism and a biodiversity hotspot, the conflicting goal between increase production and sustainable resource management is a call for concern. The high level of anthropomorphic pressure has resulted to savannization of the tropical Montana cloud forests [21] and a dramatic decreasing of biodiversity. The aim of this research was therefore to assess the current state of tree diversity and wetland in the tubah sub division, to develop a comprehensive conservation plan to protect and restore those important ecosystems.

1.2 Problem Statement

Tree Diversity and Conservation of Forested Wetlands in Tubah Sub Division, Cameroon

The Tubah Sub Division in Cameroon is home to a variety of forested wetlands that play a crucial role in maintaining biodiversity, regulating climate, and supporting local livelihoods. These wetlands are characterized by a rich diversity of tree species, which are integral to the ecosystem’s health and functionality. However, these vital ecosystems are increasingly under threat due to human activities such as deforestation, agricultural expansion, and urbanization. These activities lead to habitat fragmentation, loss of biodiversity, and disruption of ecosystem services.

The primary problem addressed in this study is the declining tree diversity in the forested wetlands of Tubah Sub Division and its implications for conservation efforts. The specific issues include:

Loss of Tree Species: There is a noticeable reduction in the number and variety of tree species in these wetlands, which undermines the ecological stability and resilience of the area.

Habitat Degradation: The conversion of wetland areas into agricultural land and settlements leads to the degradation of natural habitats, making it difficult for native tree species to survive and thrive.

Conservation Challenges: Current conservation strategies are inadequate, lacking the necessary focus on preserving tree diversity and ensuring sustainable management practices. There is a need for comprehensive and targeted conservation plans that address the specific needs of the forested wetlands.

Community Engagement: The local communities often rely on these wetlands for their livelihood, leading to overexploitation of resources. There is a lack of awareness and involvement in conservation activities among these communities.

Objectives of the Study

Significance of the Study

Understanding and addressing the decline in tree diversity is crucial for the preservation of forested wetlands in Tubah Sub Division. This study will provide valuable insights into the ecological dynamics of these wetlands and inform the development of more effective conservation strategies. Additionally, it will help to foster a collaborative approach involving local communities, ensuring that conservation efforts are sustainable and beneficial to both the environment and the people who depend on it.

1.3 Research questions

1.3.1 Main Research Question:

How does tree diversity in the forested wetlands of Tubah Sub Division influence the overall health and sustainability of these ecosystems, and what conservation strategies can be implemented to protect and enhance this diversity?

1.3.2 Specific research questions

Specific Research Questions:

Current State of Tree Diversity:

What is the current status of tree diversity in the forested wetlands of Tubah Sub Division?

Which tree species are most prevalent, and which are endangered or declining?