Bio-diversity Condition in the Watershed

Chapter 4 Bio-diversity Condition in the Watershed

4.1 Introduction

Eastern Nepal is very rich in biodiversity due to humid climate, altitudinal variation and drainage with many streams and tributaries of rivers. On the basis of vegetation, forest of Nepal is divided mainly into three zones viz. Tropical and Sub-tropical, Temperate and Alpine and Sub-alpine zones. Tropical and sub-tropical zone include Terai, Siwalik Hills, Dun Valley and the southern slope of Mahabharat range. They are below 2100 m. elevation and domi- nated by various deciduous trees and shrubs.

Shardu watershed area falls on the tropical and sub-tropical zone and is dominated by broadleaf Quercus forest and Karam forest at different elevations. Vegetation study of Sardu watershed area was carried out by the process of “Rapid Biological Assessments” (Primack, 1998 where it is not possible to collect and report all of kind plants and animal species), however, attempt has been made to include all the common species found in the watershed.

4.2 Floral Diversity

The upper region of the watershed area is dominated by Quercus lantana (Banjha) and Macaranga indica (Maledo) tree plant and Nephrolepis cordifolia (Pani amala) and Hedychium sp. (Saro) shrub and grass plants. The lower region is covered with Trewia nudiflora (Pithari) and Adina cordifolia (Karam) tree plants and Lantana camara (Banmara) and Woodfordia fructicosa (Dhaero) shrub plants.

From the Rapid Biological Assessment and information collected from the local people, members of community forest user groups and foresters the table below of the flora and fauna of Sardu watershed area was prepared.

Table 4.1 reveals that the watershed is Table 4.1: Floral Diversity in the Watershed rich in floral diversity. The Sardu watershed area has 147 species of

Plant Types

No. of Species

vascular plants. There are 130 species

Vascular Plants

belonging to dicotyledons, 12 species of Dicotyledons 130

Monocotyledons 12

monocotyledons and 8 species of

Pteridophyta 8

pteridophytes. On the basis of their uses,

Medicinal Plants

there are 28 medicinal plants, 29 edible

Edible Plants (vegetable/pickles/fruits)

plants (vegetable/pickle/fruits) and 20

Timber Plants

timber plants listed. The details are in the

Source: Field Survey, 2009

annexes (6, 7 and 8).

The main functions of the vegetations of the watershed area are as follows: • Vegetation makes the soil moist and covers it and prevents excessive evaporation of the

soil water; • It reduces the hit force of the rain water and prevents natural soil erosion and keeps the

soil particles intact; • Plant’s root binds the soil; • Vegetation regenerates new layer of soil from its dead parts; • It provides basic need of livelihood to the local people; • Plants purifies water; • It maintains ecosystem and food web by providing clean water, food, fiber and habitat for

species and communities; and • It increases water percolation capacity of soil by aerating soil particles.

Besides the wild vegetation there are numerous cultivated plants in the form of vegetables and crop which play an important role for the sustainability of ecosystem of the watershed area. The landscape is not apt for paddy production because of steep lands and gravel soil. Therefore, main agriculture productions are maize, millet and vegetables like radish, cabbage, Indian mustard (Rayo) and ginger. The common crop and cultivated plants (41 in numbers)

are listed in the Annex 8. At the lowland region, Rorippa nastrurtium (Sim sag) is cultivated. It is the main source of income of denizens of that area.

4.3 Fauna Diversity

During the study period the different kinds Table 4.2: Fauna Diversity in the Watershed of fauna were found and those are listed below (Table 4.2) on the basis of their class. Sardu

Animal Types No. of Species

watershed area does not have dense forest and Mammals 8 is not a suitable habitat for big wild animals and

Birds 26 birds. However, these animals are chief

Reptiles 14 components of the ecosystem of the watershed

Amphibians 5 area. The list of fauna available in the watershed

is given in Annex 9.