1.3. Floral composition

and South America, Central and West Africa, Indo-Malaya and Australia [1]. They are storehouses of a range of food resources for a wide variety of fauna species as well as for human

Tropical rainforests are the most diverse in the vegetation structure and composition (Figure 1) that supported a diversity of fauna species such as birds, reptiles, mammals, amphibians, and invertebrates, which directly or indirectly depend on them for their survival and existence. They are rich in habitat diversity and provide a variety of resources for the avian species, such as food, habitat, and shelter [6]. Tropical rainforest is vital ecosystem, i.e., it provide crucial ecosystem services such as raw materials, reservoirs of biodiversity, soil protection, sources of

Tropical rainforest covers less than 10% of the land area of the Earth, representing the largest biological diversity reservoir, i.e., >50% of known plant species grow in tropical rainforest. Despite being rich in fauna diversity, every year, huge areas of tropical rainforests are being lost and degraded due to human interference [10–15]. It has been stated that 25–50% of the world's tropical rainforest has been lost and degraded due to the land-use change such as

beings, raw material for buildings, and medicines [2, 3] and affect the climate [4, 5].

12 Tropical Forests - The Challenges of Maintaining Ecosystem Services while Managing the Landscape

timber, medicinal plants, carbon sequestration, and watershed protection [7–9].

1.1. Ecological importance of tropical rainforest

1.2. Threats to tropical rainforest

Figure 1. Aesthetic view of tropical rainforest.

Tropical rainforests are the most rich tree species forest on the Earth and encompasses of broad-leaved trees with large buttress, and covered with climbers, epiphytes, and hemi-epiphytes. They have multi-layered canopy, i.e., upper, middle, and dense understory vegetation composition and are rich in diversity of flora and fauna, especially birds, mammals, reptiles, amphibians, and invertebrates [41–44]. Tropical rainforest is blessed with an enormous variety of flora species. The vegetation species composition of rainforests encompasses of four distinct layers of trees, namely; emergent, upper canopy, understory, and forest floor.

#### 1.3.1. Emergent vegetation layer

Emergent or sunlit layer is dominated by broad-leaved, hardwood and evergreen. The trees may attain the height from 30.48 to 76.2 m and a trunk size up to 4.48 m around. The winds and sunlight are major environmental factors, which play a significant role (such as pollination and seed dispersal) in the tropical rainforest management ecosystem. The emergent layer is rich in the fauna species, such as birds (hummingbirds, macaw, harpy eagle, etc.), mammals (i.e., monkeys, bats, etc.), snakes, and insects such as butterflies, moths, etc. The birds and insects play a crucial role in the pollination of tropical rainforest plant species. The microclimate of this layer often fluctuates from time to time depending upon temperature and wind speed.
