A biodiversity hotspot is a biogeographic region with significant levels of biodiversity that is threatened with destruction. For example forests are considered as biodiversity hotspots. Norman Myers wrote about the concept in two articles in “The Environmentalist” (1988), & 1990 revised after thorough analysis by Myers and others in “Hotspots: Earth’s Biologically Richest and Most Endangered Terrestrial Ecoregions” and a paper published in the journal Nature.
To qualify as a biodiversity hotspot on Myers 2000 edition of the hotspot-map, a region must meet two strict criteria: it must contain at least 0.5% or 1,500 species of vascular plants as endemics, and it has to have lost at least 70% of its primary vegetation. Around the world, 36 areas qualify under this definition. These sites support nearly 60% of the world’s plant, bird, mammal, reptile, and amphibian species, with a very high share of those species as endemics.
The list of 36 hot spots
North and Central America
- Atlantic Forest4•
- Chilean Winter Rainfall-Valdivian Forests7•
- Tropical Andes1•
- Cape Floristic Region12•
- Coastal Forests of Eastern Africa10•
- Eastern Afromontane28•
- Guinean Forests of West Africa11•
- Horn of Africa29•
- Madagascar and the Indian Ocean Islands9•
- Succulent Karoo13•
- Eastern Himalaya, Nepal, India32•
- Indo-Burma, Indiaand Myanmar19•
- Western Ghats, India21•
- Sri Lanka, Sri Lanka21•
South East Asia and Asia-Pacific
- East Melanesian Islands34•
- New Caledonia23•
- New Zealand24•
- Eastern Australian temperate forests35•
- Southwest Australia22•
- Sundalandand Nicobar islands of India16•
By considering these below said criteria they have assessed the importance of the above said sites.
3)species of endemic plants/ per 100km2
4)species of endemic vertebrates/per 100km2
5)Remaining primary vegetation as a percentage of the original extent.
And they have selected 8 sites as the ‘hottest hot spots’. They are
കെനിയയുടെ(Eastern arc and coastal forest of Tanzania’/Kenya) വെസ്റ്റേൺ (western ghats)ഭാഗത്തു സുൻഡാലാൻഡ്(sundaland) എന്ന സ്ഥലം ഉണ്ടായിരുന്നു .അവിടെ ശ്രീ(sri lanka) എന്ന പെൺകുട്ടി താമസിച്ചിരുന്നു .അവളിത്തിരി മാഡ്(Madagascar) ആയിരുന്നു .ഫിലിപ്പ്(Philippines) എന്ന ചങ്ങായി ഒരു ദിവസം കുറച്ചു കരിമ്പും(Caribbean) കടിച്ചു അവളോട് ചോദിച്ചു “നീ അറ്റ്ലാന്റിക് ഫോറെസ്റ്റ്(Brazil’s Atlantic forest) കാണാൻ ഇൻഡോ(indo-Burma region)”എന്ന് .
The Western Ghats and Sri Lanka is considered as one hot spot.
Sundaland (also called the Sundaic region) is a biogeographical region of Southeastern Asia which encompasses the Sunda shelf, the part of the Asian continental shelf that was exposed during the last glacial period of the Pleistocene, from approximately 110,000 to 12,000 years ago. It includes the Malay Peninsula Malaysia on the Asian mainland, as well as the large islands of Borneo, Java, and Sumatra and their surrounding islands.
The eastern boundary of Sundaland is the Wallace Line, identified by Alfred Russel Wallace as the eastern boundary of the range of Asia’s land mammal fauna, and thus the boundary of the Indomalaya and Australasia ecozones. The islands east of the Wallace line are known as Wallacea, and are considered part of Australasia.
Approximately 60% of the 25,000 species of vascular plants found in Sundaland are endemic. The islands host more than 2,000 species of orchids and are home to the Titan Arum and the Rafflesia, a plant which blooms one of the world’s largest flowers. A large number of species are found only in the Sundaland, including Java hawk-eagles, Bali starlings, Pig-tailed langurs, Slender toads, Komodo dragons, Asian arowanas, and Proboscis monkeys(bekantan). Threatened and endangered animals located in Sundaland include orangutans, Sumatran tigers, and Javan rhinos.
Eastern arc and coastal forest of Tanzania’/Kenya
The Eastern Arc MoAuntains and Coastal Forests region stretches along the Tanzanian and Kenyan coasts from the border with Somalia to the Mozambican border. Previously classified as a biodiversity hotspot itself, this region now lies within two newly classified hotspots: the Eastern Afromontane Hotspot and the Coastal Forests of Eastern Africa Hotspot.
Most of the region is in Tanzania, which takes in the Eastern Arc Mountains and the Rufiji water catchment. However, a narrow hook near the Kenya/Tanzania border follows the Eastern Arc Mountains to their northernmost limits in the Taita Hills in Kenya. The region also extends north to include the forests of the Lower Tana River in Kenya, and includes the Indian Ocean islands of Mafia, Pemba and Zanzibar.
It has been estimated that there are over 2000 plant species in 800 genera in these montane and surrounding forests. At least 800 of these species are believed endemic to this ecoregion The forests are the centres of global endemism for the African violet (Saintpaulia) and Busy Lizzies (Impatiens), also are supported populations of the spectacular Usambara violet (Saintpaulia ionantha), Msambo tree (Allanblackia stuhlmanni), and a large Wild nutmeg (Cephalosphaera usambarensis).
These forests are also home to mammal species, including the endemic Abbot’s duiker (Cephalophus spadix), Angolan black-and-white colobus (Colobus angolensis), forest-dwelling populations of the African buffalo (Syncerus caffer), and Harvey’s duiker (Cephalophus harveyi).
Nillu rat ,purple faced leaf langur, Nolthenius’s long-tailed climbing mouse etc are endemic to sri lanka.
Lemur monkeys like Golden crowned sifaka,golden bamboo lemur are endemic .
Tarsier, Hawksbill turtle, tamaraw and monkey eating eagle are endemic and threatened.
Golden lion tamarin,spider monkeys,maned three toed sloth etc are endemic
Bilogical hot spots in India
Ginger is a native of indo Burma region.
Spread from eastern Bangladesh to Malaysia and includes North eastern India (south of Brahmaputra river),Myanmar,the southern part of china’s Yunnan province,Laos,Cambodia ,Thailand and Vietnam.
New species recently discovered are Large antlered muntjac,annamite muntjac, grey shanked douc,annamite striped rabbit,leaf deer and saola(only in annamite range)
The threatened birds like white eared night heron,the grey crowned crocias and orange necked patridge are seen here.
It is sometimes called the Great Escarpment of India
Has animals like Lion tailed macaque,asian elephant ,Nilgiri Tahr,giant squirrel etc.
Encompasses Nepal,Bhutan and North eastern India.
Himalaya results in a varied ecosystem.Alluvial grasslands and subtropical broad leaf forests in the base,temperate broad leaf forests in the mid hills,conifer forests in the higher hills,alpine meadows above tree line.
Has one horned rhinoceros ,water buffalo,red panda,snow leopard,bharal,muntjac,pygmy hog,Himalayan quail,takin etc.
Hotspot conservation initiatives
Only a small percentage of the total land area within biodiversity hotspots is now protected. Several international organizations are working in many ways to conserve biodiversity hotspots.
- Critical Ecosystem Partnership Fund(CEPF) is a global program that provides funding and technical assistance to nongovernmental organizations and participation to protect the Earth’s richest regions of plant and animal diversity including: biodiversity hotspots, high-biodiversity wilderness areas and important marine regions.
- The World Wide Fund for Naturehas derived a system called the “Global 200 Ecoregions“, the aim of which is to select priority Ecoregions for conservation within each of 14 terrestrial, 3 freshwater, and 4 marine habitat types. They are chosen for their species richness, endemism, taxonomic uniqueness, unusual ecological or evolutionary phenomena, and global rarity. All biodiversity hotspots contain at least one Global 200 Ecoregion.
- Birdlife Internationalhas identified 218 “Endemic Bird Areas” (EBAs) each of which hold two or more bird species found nowhere else. Birdlife International has identified more than 11,000 Important Bird Areas all over the world.
- Plant life Internationalcoordinates several the world aiming to identify Important Plant Areas.
- Alliance for Zero Extinctionis an initiative of a large number of scientific organizations and conservation groups who co-operate to focus on the most threatened endemic species of the world. They have identified 595 sites, including a large number of Birdlife’ s Important Bird Areas.
- The National Geographic Societyhas prepared a world map of the hotspots and ArcView shapefile and metadata for the Biodiversity Hotspots including details of the individual endangered fauna in each hotspot, which is available from Conservation International.