Nepal has a monsoon climate, with the wet season starting in June when heavy rains of the south-west monsoon arrive. The High Himalaya range blocks the northwards passage of the moist airs, increasing rainfall in Nepal and keeping the areas beyond in deep rain shadow. These same mountains also act as a barrier to the cold fronts sweeping across from central Asia, protecting Nepal and northern India and giving them warmer winters. The high mountains, deep river valleys and lowland plains combine with the effects of the summer monsoon and dry winter to form bewildering array of habitats in what is a relatively small country: Nepal is smaller than the UK, and barely larger than the 'boot' of Italy. Existing checklists for Nepal record some 6000 species of flowering plants (about 4 times as many the UK) and about 530 ferns. However, botanical exploration has really only extended beyond the capital Kathmandu since the 1950's, and botanical experts estimate that over 6600 species will be listed for Nepal when the poorly known remote regions are fully explored.
Nepal is a narrow, rectangular country at the heart of the Himalaya. Bounded by the cold, arid Tibetan Plateau to the north, and the hot, humid Indian plains to the south, Nepal is famous for its culture and spectacular mountain scenery. Eight of the world's ten highest peaks are found within its borders, including the highest point on earth, Sagarmatha, 8,848 m (Mount Everest, 29,028 ft). Nepal is also home to an amazing diversity of plants: from stunted alpines battling with the harsh environments of the frozen mountains, to mighty trees of the steamy lowland jungles down at around 60 m, and all within 150 km (see Fact File for country statistics).
Botanically Nepal forms a transition zone between the plants of the western Himalaya (including western Asiatic and Mediterranean elements) and the eastern Himalaya (with many Sino-Japanese elements). Adding variety to the mix are Tibetan Plateau (Central Asiatic) plants from the north and humid tropical species of the lowland plains (Terai) from the Gangetic plains of India and further a field into Indochina. Central to this is the Himalayan range itself, a unique series of mountain chains formed by geologically recent mountain building events. These young massifs contribute to the diversity of plants, and have provided barriers to and corridors through which plants migrated during the ice ages.
It is estimated that 246 flowering plant species are endemic to (only found in) Nepal (Shrestha & Joshi, 1996). Nepal's importance to world conservation is further highlighted by the international recognition of the Himalayan Region as one of the World's top 20 hottest global biodiversity hotspots: a region for which Nepal is a major component. Like most of the Himalaya (Bhutan is the exception), much of Nepal has been greatly modified by man over the last four to five thousand years, and little of the original forest remain. Conservation is a high priority for HM Government of Nepal, both locally and internationally, and Nepal is signatory to the Convention on Biological Diversity (CBD). The formulation and implementation of successful conservation measures depends upon accurate and well-communicated information on plant diversity. Floras (a comprehensive account of all the plants found within a country) provide the fundamental knowledge needed for this, but, unlike surrounding countries, Nepal does not have a Flora. The Flora of Nepal project is addressing this urgent need with Nepalese botanists working with an international team of scientists on the production of a Flora of Nepal.
Since ancient times, the people of Nepal have depended upon plants and plant products as a mainstay of everyday life. Today, almost 90% of Nepalese rely on subsistence agriculture, with plants performing a vital role as arable crops, fodder, fruit and vegetables, fuel, building materials and medicines. Nepal is a multiethnic and multilingual country, with more than 60 different ethnic groups speaking about 75 languages. As one would expect, associated with this is a great diversity in plant lore. However, with increasing urbanisation and uptake of modern medicines and agricultural practices, much of this indigenous knowledge is now dwindling and largely only retained by village elders. There is real danger that this will be lost to future generations, and ethnobotanists are busy documenting the wealth of indigenous knowledge for posterity. So far over 1500 plants (1434 flowering plants, 65 ferns and their allies, and 8 conifers and their allies) have been recorded as having at least one use, including more than 650 used as food plants and over 1000 species of wild plants used for medicine.