Nepal is a land of geographical extremes, ranging from near sea level elevations in the southern Terai (Nepal’s plains) to the world’s highest mountains in the north.
The country contains a variety of landscapes and ecosystems: treeless pastures and dense fir forests of the high valleys, oak and rhododendron woods of the middle hills, and tall sal forests of the south.
Along the southern borders of Nepal are preserved lowland jungles and grasslands that once covered this part of the sub-continent. Here one can see birds and mammals found nowhere else. Although animal habitat has been somewhat depleted as a result of agriculture, deforestation and other causes, through Nepal’s extensive and effective park and reserve system, the country still has more varied flora and fauna than any other area in Asia.
Nepal’s flora and fauna can be divided into four regions:
1. Tropical Deciduous Monsoon Forest (up to 1000m): This includes the Terai plains and the broad flat valleys or Duns found between hill ranges. The dominant tree species of this area are Sal (Shorea robusta), sometimes associated with Semal (Bombax malabricum), Asna (Terminalia termentosa), Dalbergia spp. and other species. Tall coarse two-metre high elephant grass originally covered much of the Dun valleys but has now been largely replaced by agricultural settlement.
This tropical zone is Nepal’s richest area for wildlife, with gaurs, wild buffalo, four species of deer, tiger, leopard and others. Rhinoceros, swamp deer and hog deer are found on the grasslands and two species of crocodile and the Gangetic dolphin inhabit the rivers.
2. Subtropical Mixed Evergreen Forest (1100m-2400m): This includes the Mahabharat Lekh, which rises to a height of about 2400m and comprises the outer wall of the Himalayan range. Great rivers such as the Karnali, Narayani, and Sapta Koshi flow through this area into the broad plains of the Terai. This zone also includes the so-called ‘middle hills’, which extend northwards in a somewhat confusing maze of ridges and valleys to the foot of the great Himalayas.
Among the tree species characteristic of this region are Castenopsis Indica in association with Schima wallichii, and other species such as Alnus Nepalensis, Acer oblongum and various species of oak and rhododendron, which cover the higher slopes where deforestation has not yet taken place.
Orchids clothe the stems of trees and gigantic climbers smother their heads. The variety and abundance of the flora and fauna increase progressively with decreasing altitude and increasing luxuriance of the vegetation.
This zone is generally poor in wildlife. The only mammals, which are at all widely distributed, are wild boar, barking deer, serow, goral and bears. Different varieties of birds are also found in this zone.
3. Temperate Evergreen Forest (2500m-4000m): Northward, on the lower slopes and spurs of the great Himalayas, oaks and pines are the dominant species up to an altitude of about 2400m - above which dense conifer forests including Picea, Tusga, Larix and Abies-spp are found. The latter is usually confined to higher elevations with Betula typically marking the upper limit of the tree line.
At about 3600 to 3900m, rhododendron, bamboo and maples are commonly associated with the coniferous zone. Composition of the forest varies considerably with coniferous predominating in the west and ericaceous in the east.
The wildlife of this region includes the Himalayan bear, serow, goral, barking deer and wild boar, with Himalayan tahr sometimes being seen on steep rocky faces above 2400m. The red panda is one of the ‘more interesting’ of the mammals found in this zone; it appears to be fairly distributed in suitable areas of the forest above 1800m. The rich and varied avifauna of this region includes several spectacular and beautiful pheasants, including the Danfe pheasant, Nepal’s national bird.
4. Subalpine and Alpine Zone (More than 4000m): Above the tree line, rhododendron, juniper scrub and other woody vegetation may extend to about 4200m. This continues up to the lower limit of perpetual snow and ice at about 5100m.
The mammalian fauna is sparse and unlikely to include any species other than Himalayan marmots, mouse hare, tahr, musk deer, snow leopard and occasionally blue sheep. In former times, the wild Yak and great Tibetan sheep could also be seen in this region and there is a possibility that some of them may still be survived in the areas like Dolpa and Humla. Yaks are the only livestock, which thrives at high altitude. They serve both back and draught animals. Birds like lammergeyer, snow-cock, snow-partridge, and bunting, with redstarts and dippers often seen along the streams and rivulets.
With this wonderful flora and fauna, Nepal has been known to be the paradise for wildlife, animals and bird lovers and it is the best destination for the naturalists and foresters.