Biodiversity Hotspots In India

Biodiversity hotspots

A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is under threat from humans. To qualify as a biodiversity hotspot on Myers 2000 edition of the hotspot-map, a region must meet two strict criteria:

1.     it must contain at least 0.5% or 1,500 species of vascular plants as endemics

2.     it has to have lost at least 70% of its primary vegetation.

Around the world, at least 25 areas qualify under this definition, with nine others possible candidates. These sites support nearly 60% of the world's plant, bird, mammal, reptile, and amphibian species, with a very high share of endemic species. Three regions that satisfy these criteria exist in India and are described below.

The Western Ghats and Sri Lanka

                                                       

 The Lion tailed macaque is a flagship species of the Western Ghats

About the region: The Western Ghats are a chain of hills that run along the western edge of peninsular India. Their proximity to the ocean and through orographic effect, they receive high rainfall. These regions have moist deciduous forest and rain forest. The region shows high species diversity as well as high levels of endemism. Nearly 77% of the amphibians and 62% of the reptile species found here are found nowhere else. Sri Lanka, which lies to the south of India, is also a country rich in species diversity. It has been connected with India through several past glaciation events by a land bridge almost 140 kn wide.

How the biodiversity of Western Ghats originated is a still a puzzle. The region shows biogeographical affinities to the Malayan region. More recent phylogeographic studies have attempted to study the origin of Western Ghats using molecular approaches. There are also differences in taxa which are dependent on time of divergence and geological history. Along with Sri Lanka, this region also shows some faunal similarities with the Madagascan region especially in the reptiles and amphibians. Examples include the Sibynophis snakes, the Purple Frog and Sri Lankan lizard genus Nessia which appears similar to the Madagascan genus Acontias.  Numerous floral links to the Madagascan region also exist.  An alternate hypothesis that these taxa may have originally evolved out-of-India has also been suggested.

Biogeographical quirks exist with some taxa of Malayan origin occurring in Sri Lanka but absent in the Western Ghats. These include insects groups such as the zoraptera and plants such as those of the genus Nepenthes.

Biodiversity: There are over 6000 vascular plants belonging to over 2500 genera in this hotspot, of which over 3000 are endemic. Much of the world's spices such as black pepper and cardamom have their origins in the Western Ghats. The highest concentration of species in the Western Ghats is believed to be the Agasthyamalai Hills in the extreme south. The region also harbors over 450 bird species, about 140 mammalian species, 260 reptiles and 175 amphibians. Over 60% of the reptiles and amphibians are completely endemic to the hotspot. Remarkable as this diversity is, it is severely threatened today. The vegetation in this hotspot originally extended over 190,000 square kms. Today, its been reduced to just 43,000 sq. km. In Sri Lanka, only 1.5% of the original forest cover still remains.

The Eastern Himalayas

                                

 The Indian Rhinoceros is one of the 45 species of globally threatened mammals found in the Eastern Himalayas.

About the region: The Eastern Himalayas is the region encompassing Bhutan, northeastern India, and southern, central, and eastern Nepal. The region is geologically young and shows high altitudinal variation. Together, the Himalayan mountain system is the world's highest, and home to the world's highest peaks, which include Mount Everest and K2. To comprehend the enormous scale of this mountain range, consider that Aconcagua, in the Andes, at 6962 metres is the highest peak outside Asia, whereas the Himalayan system includes over 100 mountains exceeding 7200 metres. Some of the world's major river systems arise in the Himalayas, and their combined drainage basin is home to some 3 billion people (almost half of Earth's population) in 18 countries. The Himalayas have profoundly shaped the cultures of South Asia; many Himalayan peaks are sacred in Hinduism, Buddhism and Sikhism.

Geologically, the origin of the Himalayas is the impact of the Indian tectonic plate traveling northward at 15cm per year to impact the Eurasian continent, about 40-50 million years ago. The formation of the Himalayan arc resulted since the lighter rock of the seabeds of that time were easily uplifted into mountains. An often-cited fact used to illustrate this process is that the summit of Mount Everest is made of marine limestone.

Biodiversity: The Eastern Himalayan hotspot has nearly 163 globally threatened species including the One-horned Rhinoceros (Rhinoceros unicornis), the Wild Asian Water buffalo (Bubalus bubalis (Arnee)) and in all 45 mammals, 50 birds, 17 reptiles, 12 amphibians, 3 invertebrate and 36 plant species. The Relict Dragonfly (Epiophlebia laidlawi) is an endangered species found here with the only other species in the genus being found in Japan. The region is also home to the Himalayan Newt (Tylototriton verrucosus), the only salamander species found within Indian limits.

There are an estimated 10,000 species of plants in the Himalayas, of which one-third are endemic and found nowhere else in the world. Five families - Tetracentraceae, Hamamelidaceae, Circaesteraceae, Butomaceae and Stachyuraceae - are completely endemic to this region. Many plant species are found even in the highest reaches of the Himalayan mountains. For example, a plant species Ermania himalayensis was found at an altitude of 6300 metres in northwestern Himalayas. A few threatened endemic bird species such as the Himalayan Quail, Cheer pheasant,Western tragopan are found here, alongwith some of Asia's largest and most endangered birds such as the Himalayan vulture and White-bellied heron

                    

    The Saola, a bovine, is one of the world's rarest mammals. It was discovered in Vietnam only in 1992

The Himalayas are home to over 300 species of mammals, a dozen of which are endemic. Mammals like the Golden langur, The Himalayan tahr, the pygmy hog, Langurs, Asiatic wild dogs, sloth bears, Gaurs, Muntjac, Sambar, Blue sheep, Takin, the Gangetic dolphin, wild water buffalo,swamp deer call the Himalayan ranged their home. The only endemic genus in the hotspot is the Namadapha flying squirrel which is critically endangered and is described only from a single specimen from Namdapha National Park.

Indo-Burma

About the region: The Indo-Burma region encompasses several countries. It is spread out from Eastern Bangladesh to Malaysia and includes North-Eastern India south of Brahmaputra river, Myanmar, the southern part of China's Yunnan province, Lao People’s Democratic Republic, Cambodia, Vietnam and Thailand. The Indo-Burma region is spread over 2 million sq. km of tropical Asia. Since this hotspot is spread over such a large area and across several major landforms, there is a wide diversity of climate and habitat patterns in this region.

Biodiversity: Much of this region is still a wilderness, but has been deteriorating rapidly in the past few decades. In recent times, six species of large mammals have been discovered here: Large-antlered muntjac, Annamite muntjac, Grey-shanked douc, Annamite striped rabbit, Leaf deer, and the Saola. This region is home to several primate species such as monkeys , langurs and gibbons with populations numbering only in the hundreds. Many of the species, especially some freshwater turtle species, are endemic. Almost 1,300 bird species exist in this region including the threatened white-eared night-heron, the grey-crowned crocias, and the orange-necked partridge. It is estimated that there are about 13,500 plant species in this hotspot, with over half of them endemic. Ginger, for example, is native to this region. 

 Reasons for biodiversity loss in hotspots

There are four main reasons why species are being threatened in these biodiversity hotspots

1.     Habitat destruction: As recently as 30 years ago, most of the regions in these biodiversity hotspots were inaccessible and remote. Now, due to better infrastructure, contact of these areas with humans has increased. Activities such as logging of wood, increased agriculture, increased human habitation has led to destruction of forests and pollution of rivers. These factors are causing species ranges to reduce and habitats to become choppy. The government planned to establish habitat corridors, but these plans have not yet materialized in most areas. Activities such as mining, construction of large dams, highway construction has also caused significant destruction of habitats.

2.     Resource mismanagement: Increased tourism without proper regulation has led to pollution and environmental degradation. Prime example are pilgrimage destinations like Rishikesh and hill stations like Dehradoon. These spots, once nestled in the pristine ranges of the Himalayas, are now dirty commercial destinations. Places like Dehradoon are even experiencing a construction boom so large that illegal immigrants from Bangladesh are also flocking there. Religious destinations in the Himalayas, where devotees flock in millions now, are also hot destinations for medicinal plant trade, which has threatened plant life in the area.

3.     Poaching: Large mammals such as the tiger, rhinoceros and the elephant once faced the distinct possibility of complete extinction due to rampant hunting and poaching. However, efforts by conservationists since the 1970s has helped stabilize and grow these populations. Still, the trade in tiger hide, elephant tusks, tiger teeth, rhinoceros horn remains profitable and rampant.

4.     Climate change: Although dire IPCC predictions of Himalayan glaciers melting by 2035 have been retracted, there is no doubt that several Himalayan glaciers are melting. In the Western Ghats, studies have shown that the deciduous and the evergreen forests of Karnataka are the most at risk. Climate change may significantly affect the temperatures, rainfalls and water tables in the Western Ghats, according to an assessment by the Government of India.