**Abstract**

This study aimed at determining ecosystem services and conservation dynamics of three protected forests in Nigeria. Using simple sampling technique, 24 plots with 25 m<sup>2</sup> were established in these protected forests to facilitate data collection. A total of 370 individual trees per hectare, disproportionately distributed between 53 different species in 25 families, were encountered in Omo biosphere reserve (BR) while 381 stems in 63 species in 24 families in strict nature reserve (SNR) and Okomu national park (NP) recorded 352 individual stems, 59 species, and 25 families. The three protected forests had high tree species diversity index (Shannon-Wiener diversity index of 3.19 for Omo BR, 3.90 for Akure SNR, and 3.45 for Okomu NP). The values for basal area (36.63, 72.39, and 32.47 m<sup>2</sup> ), volume (427.08, 929.05, and 366.71 m<sup>3</sup> ), above-ground biomass (153.20, 316.73, and 353.92 ton), below-ground biomass (30.64, 63.35, and 190.04 ton), and total carbon stock (70.78, 91.92, and 212.35 ton) for Omo BR, Akure SNR, and Okomu NP, respectively. This study serves as baseline information for management of protected forests in Nigeria and it shows the potential of *in-situ* conservation for the dynamism of the ecosystem services.

**Keywords:** biodiversity, conservation, *Celtis zenkeri*, ecosystem services, *in-situ*, national park, protected forest

## **1. Introduction**

Nigeria as one of the developing countries of the world has high population density and high biodiversity forest associated with tropical rainforest ecosystem. Nigeria as tropical rainforest is known for large diverse forest ecosystems with lots of *in-situ* conservation methods such as forest reserves (FR), strict nature reserves (SNR), biosphere reserves (BR), national parks (NP), and enrichment plantation (EP), they

contribute to biodiversity reservoir of the world. Forest ecosystems in Nigeria are very important for biodiversity conservation, ecosystem functions, watershed protection, mitigation of climate change, economic sustainability, habitats for wild animals, and nutrition and enhancement of rural livelihoods [1]. The tropical rainforest is the most diverse of the terrestrial ecosystems, containing more flora and fauna species than any other biome, which are important source of biodiversity, food, and carbon storage [2]. Tropical rainforest has the ability to accommodate 70% of animal and plant species, which serves as a reservoir of biodiversity [1, 3]. Carbon sequestration, production of oxygen and Ozone layer protection are part of many services that the forest delivers as ecosystem services for the goods of the environment [4, 5].

Over 60% of the population residing in rural areas depend on forest and other biomass resources for fuel-wood and timber and non-timber forest products for their energy needs and livelihood. Forests are repository of the biodiversity, gene pool resources and sequester carbon dioxide, and they also provide a lot of other environmental services [1]. They play a vital role in sustaining the life of people which are crucial for food, water, forest resources and livelihood security. This is ensured through better management practices and sustainable utilization of forestlands. Forest vegetation covers protect watersheds, conserve species diversity, serve as habitat for wildlife, and contribute to good quality environment [6]. More than half of the world's species diversity can be found in the tropics according to a study by [7]. However, this critically important role of tropical forests is being threatened by deforestation. The effects of deforestation on the environment are numerous. There is overwhelming evidence and consensus that the high rate of tropical deforestation is one of the major causes of climate change [8, 9]. Deforestation contributes to climate change by reducing forest vegetation cover and increasing surface temperature. An estimated 20 to 25% of global emissions stem from deforestation, predominantly in the tropics [8]. Strategies to drastically reduce the rate of deforestation and restoration of degraded forests must be urgently developed in order to save the tropical forests and humans from the catastrophic effects of climate change. The forest is regulator of the micro and macro environment as carbon stock and carbon sequestration [5]. Furthermore, forest vegetation covers protect watersheds and species diversity, serves as biodiversity reservoir and conservation, habitat to wildlife and thus contributes to effective ecosystem functioning and good quality ecosystem. In addition, healthy forest vegetation cover plays important role in climate change mitigation by sequestering carbon dioxide from the atmosphere.

Tropical forests are predominantly located in developing countries and are often subject to activities such as logging and conversion to agriculture [10]. Nigerian rainforest ecosystems occupy 95,372 km<sup>2</sup> (9.7%) of the country's land mass. It is the most densely populated part of Nigeria and source of the bulk of the country's timber needs [11]. The protected forest is a specific term to denote forests with some amount of legal and constitutional protection in certain countries, besides being a generic term to denote forests where the habitat and resident species are legally accorded protection and are protected from any further depletion. Protected areas provide habitat for the country's endangered, rare and endemic plant and animal species. There are seven strict nature reserves, one biosphere reserve, 160 constituted forest reserves and six national parks in Nigeria. There are no known studies on the Phytosociological characteristics, ecosystem services and conservation dynamics of these protected forests. The method adopted by the government to promote ecosystem sustainability makes the forest play essential role in carbon sequestration and function effectively as climate change regulator. Thus, an increase in carbon sequestration can be achieved

*Phyto-Sociological Attributes, Ecosystem Services and Conservation Dynamics of Three… DOI: http://dx.doi.org/10.5772/intechopen.106433*

through conservation and effective management of these protected forests. This study essentially provides information on structure, species diversity, biomass, and carbon stock as ecosystem services and function to the environment. This, therefore, represents an important contribution to ecosystem-wide carbon cycle and amount of carbon dioxide that can be sequestered annually from the atmosphere by these protected forests.
