A sky island in the clouds
Natma Taung, also known as Mount Victoria, is a peak of ecological isolation. Rising 3,053 meters (10,016 feet) above sea level, it is the highest point in the Chin Hills of western Myanmar. This mountain and its surrounding 723-square-kilometer national park are a "sky island," a high-altitude environment separated from other mountain ranges by vast, low-elevation landscapes with dramatically different climates. The mountain's geology is part of the Arakan-Yoma Range, a belt of mountains uplifted in the Miocene Epoch that runs north to connect with the Himalayas.
The elevation gradient creates distinct forest types. The lower slopes, up to 800 meters, contain Dipterocarp forest and bamboo. As elevation increases, the vegetation transitions to pine forests on drier ridges above 1,800 meters and temperate evergreen forests dominated by oaks (Quercus) and laurels between 2,000 and 2,900 meters. Above 2,700 meters, the oak forest thins and species of Rhododendron become a major component of the landscape. The summit itself is a cold, windswept alpine meadow. This vertical zonation of habitats provides a multitude of niches for life to specialize and adapt.
A Pleistocene laboratory for evolution
The unique plants of Natma Taung are living relics of the Pleistocene epoch, which lasted from about 2.6 million to 11,700 years ago. During this period, Earth experienced repeated glacial cycles, or ice ages. While glaciers did not cover Natma Taung, these global climate shifts had a deep effect on its vegetation. As the climate cooled, temperate forests like those in the Himalayas spread south and down the slopes of mountains. During warmer interglacial periods, these forests retreated upwards, leaving small, isolated populations of plants stranded on high-altitude refuges like Natma Taung.
This isolation was the engine of speciation. Separated from their parent populations in the Himalayas, the plants on Natma Taung began to diverge, adapting to the specific local conditions. Molecular phylogenetic studies, which analyze DNA to reconstruct evolutionary relationships, show that many of Natma Taung's endemic species arose during these cycles of isolation.
Examples of these unique plants include Potentilla montisvictoriae, Himalaiella natmataungensis, and Roscoea australis, which are found on the mountain and nowhere else on Earth. Several rhododendron species are also prominent, including Rhododendron burmanicum and the brilliant red-flowered Rhododendron arboreum. The presence of plant species once thought to be endemic to India or China, such as Boehmeria manipurensis and Microtoena delavayi, further shows the mountain is a biogeographic crossroads.