Aquatic Ecosystem System

Nepal’s biodiversity is a reflection of its unique geographic position, wide altitudinal variations and diverse climatic conditions that result in five main physiographic zones (from tropical to nival) within a short horizontal span. Situated in the central Himalaya, about 86% of the total land area is covered by hills and high mountains, and the remaining 14% comprises the flat lands of the Terai that are less than 300m in elevation. The latest physiographic data indicates that Nepal harbours 29% forest area, 10.6% shrub land and degraded forest, 12% grassland, 21% farmland, 2.6% water body, and 7% of uncultivated inclusions. The country is part of a biodiversity hotspot and lies at a transition zone comprised of six floristic regions. There are six biomes occurring in Nepal, including as many as 35 forest types and 118 ecosystems which have been classified on the basis of altitudinal, climatic variations and vegetation types.

The mountain ecosystem in Nepal comprises a high number of endemic species occurring in subalpine and alpine zones. Nepalese rangelands have high biodiversity and are estimated to cover nearly 12% of the country’s total area, providing habitat for various flowering plants, including endemic species and wildlife as well as globally threatened species. In addition, these grasslands also sustain domestic livestock which is an important source of local livelihoods. About 21% of the total land area of Nepal is used for agriculture. Principal cereal crops grown are paddy (53.6%), maize (23.0%), wheat (19.5%) and millet (3.3%). Likewise, major cash crops include sugarcane (51.3%), potato (45.3%) and oilseed (3.1%). Similarly, horticultural diversity includes over 100 high-yielding varieties of various fruit crops. There is also a great diversity in indigenous livestock breeds in Nepal. The cattle population totals 7.2 million, in addition to 5.1 million buffaloes, 9.5 million goats, among other livestock.

The wetlands of Nepal comprise about 2.6% of the country’s area and are rich in biodiversity, supporting habitat for 172 species of plants, 193 species of birds and 185 species of freshwater fishes. Wetland sites of international importance show wide disparity in distribution at altitudinal zones. A total of 9 Ramsar sites covering 31,555 ha have been designated and, of these, approximately 68.2% of the wetland sites are located in the Terai, followed by 31.6% in the High Himalaya, whereas the Mid Hills remain poorly represented with less than 1%.

 

Table 1.4: Ecoregions:Distribution and conservation status in Nepal
Symbol Ecoregion type Distribution and Altitude (m) Conservation Status
IM0115 Himalayan subtropical broad-leaved forest Nepal,Bhutan,India (500-1000) Critical/Endangered
IM0301 Himalayan subtropical pine forest Nepal,Bhutan,India,Pakistan(1000-2000) Vulnerable
IM0401 Eastern Himalayan  broad-leaved forest Nepal,Bhutan,India (1500-3000) Stable/Intact
IM0403 Western Himalayan  broad-leaved forest Nepal,India,Pakistan (1500-3000) Critical/Endangered
IM0501 Eastern Himalayan subalpine conifer forest Nepal,Bhutan,India (3000-4000) Vulnerable
IM0502 Western Himalayan subalpine conifer forest Nepal,India,Pakistan (1500-3000) Vulnerable
IM0701 Tarai-Duar savannah and grassland Nepal,Bhutan,India (<500) Critical/Endangered
PA1003 Eastern Himalayan alpine shrub and meadows Nepal,Bhutan,India,China,Myanmar (4000-5000) Relatively stable/Intact
PA1021 Western Himalayan alpine shrub and meadows Nepal,India, (3700-4400) Relatively stable/Intact
IM-Indo Malayan;PA-Palearctic

 

Table 1.5:Major groups and forest types in Nepal (after Stainton 1972)
Major groups Forest types
Tropical and Subtropical Sal forest,Tropical deciduous riverine forest,Tropical evergreen forest,Subtropical evergreen forest,Terminalia forest,Dalbergia sissoo-Acacia catechu forest,Subtropical deciduous hill forest,Schima-Castanopsis forest,Subtropical semi-evergreen hill forest,Pinus roxburghi forest
Temperate and Alpine Broad – leaved Quercus leucotrichophora-Quercus floribunda forest,Quercus semecarpifolia forest,Castanopsis tribuloides-Castanopsis hystrix forest,Quercus glauca forest,Lithocarpus pachyphylla forest ,Aesculus-Juglans-Acer forest,Lower temperate mixed broad-leaved forest,Upper temperate mixed broad-leaved forest,Rhododendron forest,Betula utilis forest
Temperate and Alpine Conifer Abies spectabills forest,Tsuga dumosa forest,Pinus wallichiana forest,Picea smithiana forest,Abies pindrow forest,Cedrus deodara forest,Cupressus torulosa forest,Larix forest
Minor Temperate and Alpine associations Alnus woods,Populus cliata woods,Hippophae scrub,Moist alpine scrub,Dry alpine scrub,Juniperus wallichiana forest

 

Wetlands of International Importance in phytogeographic regions
Highlands-West Highlands – Centre Highlands-East
Phoksundo Lake (494 ha) Gosainkunda and Associated Lakes (1030 ha) Gokyo and Associated Lakes (7770 ha)
Rara Lake (1583 ha)
Midhills-West Midhills-Centre Midhills-East
Maipokhari (98 ha)
Tarai and Siwaliks-West Tarai and Siwaliks-Centre Tarai and Siwaliks-East
Ghodaghodi Lake (2563 ha) Beeshazari and Associated Lakes (3200 ha) Koshi Tappu (17500 ha)
Jagdishpur Reservoir (255 ha)

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