Eastern Himalayan Alpine shrub and meadows

• Category: Grassland, Tundra, and Human Biomes.
• Geographic Location: Asia.
• Summary: The Eastern Himalayan Alpine Shrub and Meadows biome features spectacular flora that developed between the snowfields and tree lines; it is threatened by changes in land use and climate.

The Eastern Himalayan Alpine Shrub and Meadows biome lies between the tree line and snowline, spreading across parts of India, Nepal, Bhutan, and Myanmar. As one proceeds to higher elevations, tree life is abruptly replaced by a magnificent combination of shrubs and meadows, before reaching the permanent snow-covered areas.

Separated from the western part of the Himalaya Mountains range by the Kali Gandaki River, the eastern altitudinal belt holds an area of outstanding biodiversity and high endemism (home to species found nowhere else on Earth). In fact, the Eastern Himalayas Alpine Shrub and Meadows are home to more than 7,000 species of plants, three times more than the rest of the Himalayas, making it perhaps the most important alpine area in the world, and an obvious conservation priority.

Biota

Since the mid-1800s, expeditions have been made to this area and other parts of the Himalayas in search of new species and medicinal plants. As a result of such voyages, many plant species were introduced to the gardens of the Western world. It is estimated that approximately one-quarter of the popular garden plants found throughout the world originated in this region.

During spring and summer, this habitat explodes with purple, blue, and pink flowers, as several types of rhododendrons and alpine herbs bloom on the steep hills of these massive mountain ranges. Representative plants include Alchemilla, Anenome, Gentiana, Impatiens, Viola, and many other herbaceous plants, as well as a range of full-size and dwarf rhododendrons.

Altitude, topography, and aspect encourage a high rate of endemism, and create a broad range of unique local environmental conditions to which different plant forms have evolved and adapted. Among the most significant adaptations is the so-called vegetation dwarfing, in which as altitude increases, shrub species of rhododendron reduce their height and radically change their appearance. Vegetation dwarfing is associated with maintaining environmental conditions on a range that allows metabolic efficiency at lower temperature. Even though this adaptation allows many species to be distributed on a wider range along the altitudinal gradient, most of the Himalayan alpine shrubs and herbs are restricted to a narrow altitudinal belt of about 656 feet (200 meters) in total.

This restriction hinders their ability to adapt to long-term environmental changes, making the Eastern Himalayan Shrubs and Meadows biome particularly vulnerable to climate change. Small shifts in temperature and precipitation patterns could have dramatic effects on plants and animals adapted to live at a certain altitude. Ongoing changes in climatic conditions may result in massive species loss in mountain ecosystems.

In addition to altitudinal effects, species distribution is determined by particular microclimatic conditions. The eastern Himalayas receive the influence of the southwestern monsoon from September to May, but this general condition varies significantly across the mountain range. The intricate topography that characterizes this region creates local weather conditions with great variations in rainfall patterns, for example. While some areas receive as much as 118 inches (3,000 millimeters) of rainfall per year, others average a mere 12 inches (300 millimeters). This topographic effect is further marked by slope aspect: North-facing slopes receive considerably less sunlight than their southern counterparts, developing far more humid conditions and longer periods of snow cover. This results in starkly different vegetation communities, and also affects the distribution of fauna.

Besides being significant for their plant biodiversity, these shrubs and meadows are important parts of the altitudinal migration routes of many large carnivores. Throughout the year, alpine shrubs and meadows serve as bridges that connect lower areas of evergreen broadleaf or subalpine coniferous forest with permanent snow-cover zones. This connection allows the movement of wildlife between ecosystems, helping maintain their integrity. These mountain grasslands are crossed by big mammals such as snow leopards, wolves, and even Asiatic black bears, all of which chase takins, goats, and blue sheep along the abrupt hills.

Human Impacts

The eastern Himalayas are rich not only in terms of plant diversity, but also in habitation by diverse ethnic groups. The region combines Buddhists, Hindus, Animists, and Christians—members of groups that have always had a spiritual connection with nature. These ethnic groups value many areas of the Himalayas as sacred sites. The cultural complexity of the eastern Himalayas represents a huge challenge to establishing successful conservation initiatives, however.

At first glance, the Eastern Himalayas Alpine Shrubs and Meadows biome may seem well-preserved, given that its extent has been relatively stable during the past few decades. In reality, it is undergoing extremely destructive degradation processes that seriously threaten this distinctive area. Livestock grazing and trampling by yaks have deleterious effects on shrub growth and regeneration. Collection of fuelwood and plant extraction for medicinal purposes affect the survival of many shrubs and alpine plant populations. On top of these more localized environmental problems are the effects of climate change on mountain ecosystems. According to researchers in the 2020s, rising temperatures throughout the Eastern Himalayas, especially in the winter and spring, have caused the treeline, which is the highest elevation where trees can grow, to move higher. This higher treeline has led to the encroachment of shrub and tree species into the alpine meadow areas.

Several protected areas have been established to conserve the habitats of the tallest—and youngest—mountain range in the world. Of particular importance are Sagarmatha National Park, home of Mount Everest; and the Annapurna Conservation Area, created in the 1990s with the objective of conserving rhododendron biodiversity. Even though 20 percent of the overall area is under protection, these measures have had limited success in stopping the depletion of most Himalayan ecosystems. One of the biggest problems is the lack of local biodiversity across the Himalayas, because most of the protected areas are concentrated on the Nepal side, restricting conservation to a particular zone. Recent efforts have been directed toward creating landscape connectivity through biological corridors and transboundary management initiatives.

Large-scale planning, involving mainly the governments of Nepal, India, and Bhutan, is crucial for preserving the area, as well as guaranteeing resources for the rural and urban people who depend on it. These efforts have proved to be effective only in combination with local stewardship components. Since 2000, key programs such as the Sacred Himalayan Landscape and the Transboundary Biodiversity Conservation Initiative, led by the International Center for Integrated Mountain Development, have promoted regional development and biodiversity conservation through integrating local spiritual beliefs and practices into sustainable management of the natural resources of this breathtaking place and fragile ecosystem.

Bibliography

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