|Alpine (timberline to
The Alpine Zone is characterized by harsh winters, short summers, shallow stony soils, strong winds and a lack of moisture. Typical plants include the stonecrops and rock jasmines and the drabas, or stoneworts. Delicate red or purple primroses are often seen flowering beside melting snow. In sedge and grass meadows, wildflowers often form spectacular displays. These profusions of color are greatest where snow melt occurs and deeper soils have gathered over the ages. Some species bloom in late summer, especially at higher elevations and on more exposed sites.
In this zone, there are buttercups, anemones, larkspurs, everlasting flowers, asters, dandelions, thistles, saxifrages, cinquefoils, louseworts, geraniums, lilies, gentians, monkshood and the sky blue mykonopsis. The diversity is incomparable. In Nepal, more than 67 species of primrose occur, many of them in the alpine zone; in Bhutan there are liable to be more. Alpine scrub is found along streams and in U-shaped valleys. In Bhutan, relatively lush stands of rhododendron, grasses and sedges prevail.
The animals found in this zone tend to be of Eurasian origin, with pre-existing adaptations to the severe conditions of northern latitudes. Typical mammals include blue sheep, pikas, marmots, red foxes, weasels, voles and mice.
Snow leopard, lynx, wolf and brown bear are also present. A few large birds, such as the snow cock, snow partridge and pigeon, are permanent residents. In summer, there is a dramatic influx of songbirds that breed in the grassy meadows.
Subalpine (narrow transition zone):
Temperate Zone: Below an elevation of 12,000 feet is a pretty continuous forest belt. Conifers such as fir, hemlock, pine, cypress and cedar occupy the higher levels.
Undergrowth is sparse in most places, consisting of rhododendron, a variety of shrubs, and in the east, bamboo. In Bhutan and as far west as central Nepal, a lush temperate evergreen forest grows between elevations of 3,000 to 5,000 feet. Almost pure stands of evergreen oaks are interspersed with laurels, chestnuts, maples, magnolias and other trees that rarely exceed 60 feet in height.
In spring, the forest is ablaze with white magnolia, and white, pink or red rhododendron blossoms. Mosses and lichen clothe every oak, and numerous orchids and other epiphytes add to the "cloud forest" setting. Numerous wildflowers, ferns, and orchids occur, especially in ravines and near streams (especially yellow balsams, purple violets, touch-me-nots, begonias and Solomon's seals).
This truly Himalayan flora and fauna has been little explored, catalogued or described. The large number of species of rhododendron that occur in Bhutan range from trees 45 feet tall to low, creeping shrubs and even epiphytic climbers. Their displays are best seen between late March and early May. The fauna of the temperate zone is diverse and unique. Large mammals include the serow, goral, takin and the Himalayan tahr. At lower altitudes, macaque monkeys forage on the ground; the langur monkey, which spends most of its time in the trees, is found up to the 12,000 foot level. Less frequently seen wildlife includes Himalayan Black Bears (possibly three species), forest leopards, yellow throated martens, red pandas, and a number of small cats. There are numerous small rodents, from wood mice to flying squirrels. Frogs, toads and snakes, few of which are catalogued, also occur. The greatest variety, however, is in the avifauna. The presence of trees, shrubs and ground vegetation provides many foraging niches for birds that would otherwise compete with one another. Laughing thrushes, babblers, and minias flit about the ground and tangled brush, while nuthatches and tree creepers comb conifer branches for food. Tits and warblers forage among the foliage and various woodpecker species work on dead or dying trees.