- According to IUCN (2004), the total number of plant and animal species described so far is slightly more than 1.5 million.
- Estimates place the global species diversity at several million.
- A large proportion of the species waiting to be discovered are in the tropics.
- More than 70 per cent of all the species recorded are animals, while plants (including algae, fungi, bryophytes, gymnosperms and angiosperms) comprise no more than 22 per cent of the total.
- Among animals, insects are the most species-rich taxonomic group, making up more than 70 per cent of the total.
- The number of fungi species in the world is more than the combined total of the species of fishes, amphibians, reptiles and mammals.
- The largely tropical Amazonian rain forest in South America has the greatest biodiversity on earth.
- Biodiversity is the variety of plant and animal life in the world or in a particular habitat.
- Biodiversity is measured by two major components: species richness, and species evenness.
- It is the measure of the number of species found in a community.
- Species evenness is a measure of the relative abundance of the different species making up the richness of an area.
- Example: The sample forest A has 4 tigers, 5 deer and 6 rabbits and sample forest B has 1 tiger, 6 deer and 8 rabbits. Both samples have the same richness (3 species – species richness) and the same total number of individuals (15). However, the sample forest A has more evenness than the sample forest B.
- Low evenness indicates that a few species dominate the site.
- It refers to the diversity within a particular area or ecosystem and is usually expressed by the number of species (i.e., species richness) in that ecosystem.
- It is a comparison of diversity between ecosystems, usually measured as the change in the amount of species between the ecosystems.
- It is a measure of the overall diversity for the different ecosystems within a region.
- Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species.
- A single species might show high diversity at the genetic level (E.g. Homo sapiens: Chinese, Indian American, African etc.).
- India has more than 50,000 genetically different strains of rice and 1,000 varieties of mango.
- Genetic diversity allows species to adapt to changing environments. This diversity aims to ensure that some species survive drastic changes and thus carry on desirable genes.
- Species that differ from one another in their genetic makeup do not interbreed in nature.
- Closely-related species have in common much of their hereditary characteristics. For instance, about 98.4 per cent of the genes of humans and chimpanzees are the same.
- It is the ratio of one species population over total number of organisms across all species in the given biome. ‘Zero’ would be infinite diversity, and ‘one’ represents only one species present.
- Species diversity is a measure of the diversity within an ecological community that incorporates both species richness (the number of species in a community) and the evenness of species.
- In general, species diversity decreases as we move away from the equator towards the poles.
- With very few exceptions, tropics (latitudinal range of 23.5° N to 23.5° S) harbour more species than temperate or polar areas.
- Bioprospecting: nations endowed with rich biodiversity explore molecular, genetic and species-level diversity to derive products of economic importance.
- A stable community means that there is not much variation in productivity from year to year; it is either resistant or resilient to occasional disturbances (natural or human-made) and is resistant to invasions by alien species.
- Ecological diversity refers to different types of habitats. A habitat is the cumulative factor of the climate, vegetation and geography of a region.
- It includes various biological zones, like a lake, desert, coast, estuaries, wetlands, mangroves, coral reefs etc.
- At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like Norway.
- There are more than 200000 species in India of which several are confined to India (endemic).
- Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere.
- A particular type of animal or plant may be endemic to a zone, a state or a country. The extreme opposite of endemism is cosmopolitan distribution.
- Keystone species is a species whose addition to or loss from an ecosystem leads to major changes in the occurrence of at least one other species.
- Certain species in an ecosystem is considered more important in determining the presence of many other species in that ecosystem.
- All top predators (Tiger, Lion, Crocodile, Elephant) are considered as keystone species because they regulate all other animal population indirectly.
- Hence top predators are given much consideration in conservation.
- If keystone species is lost, it will result in the degradation of the whole ecosystem.
- For example, certain plant species (ebony tree, Indian-laurel) exclusively depends upon bats for its pollination. If the bat population is reduced, then regeneration of particular plants becomes more difficult.
- Foundation species is a dominant primary producer in an ecosystem both in terms of abundance and influence. Example: kelp in kelp forests and corals in coral reefs.
- A flagship species is a species chosen to represent an environmental cause, such as an ecosystem in need of conservation.
- These species are chosen for their vulnerability, attractiveness or distinctiveness in order to engender support and acknowledgement from the public at large.
- Example: Indian tiger, African elephant, giant panda of China, the leatherback sea turtle, etc.
- India is recognized as one of the mega-diverse countries, rich in biodiversity and associated traditional knowledge.
- India has 23.39% of its geographical area under forest and tree cover.
- With just 2.4% of the land area, India accounts for nearly 7% of the recorded species even while supporting almost 18% of the human population.
- In terms of species richness, India ranks seventh in mammals, ninth in birds and fifth in reptiles.
- In terms of endemism of vertebrate groups, India’s position is tenth in birds with 69 species, fifth in reptiles with 156 species and seventh in amphibians with 110 species.
- India’s share of crops is 44% as compared to the world average of 11%.
- Two ‘Realms’
- Five Biomes
- Ten Bio-geographic Zones
- Twenty-five Bio-geographic provinces
- Biogeographic realms are large spatial regions within which ecosystems share a broadly similar biota.
- A realm is a continent or sub-continent sized area with unifying features of geography and fauna & flora.
- The Indian region is composed of two realms. They are:
- the Himalayan region represented by Palearctic Realm and
- the rest of the sub-continent represented by Malayan Realm
- In world, Eight terrestrial biogeographic realms are typically recognised. They are
- Nearctic Realm
- Palaearctic Realm
- Africotropical Realm
- Indomalayan Realm
- Ocenaia Realm
- Australian Realm
- Antarctic Realm
- Neotropical Realm
- The term biome means the main groups of plants and animals living in areas of certain climate patterns.
- It includes the way in which animals, vegetation and soil interact together. The plants and animals of that area have adapted to that environment.
The five biomes of India are:
- Tropical Humid Forests
- Tropical Dry or Deciduous Forests (including Monsoon Forests)
- Warm deserts and semi-deserts
- Coniferous forests and
- Alpine meadows.
- Biogeography deals with the geographical distribution of plants and animals.
- Biogeographic zones were used as a basis for planning wildlife protected areas in India.
- There are 10 biogeographic zones which are distinguished clearly in India. They are as follows:
- Western Ghats
- Deccan Peninsula
- Gangetic plain
- North-east India
- Bio-geographic Province is an ecosystematic or biotic subdivision of realms.
- India is divided into 25 bio geographic zones.
|Biogeographic Zones (10)||Biogeographic Provinces (25)|
- The west Himalayas have low rainfall, heavy snowfall (temperate conditions).
- In the east Himalayas, there is heavy rainfall, snowfall only at very high altitudes.
- Lower altitudes conditions are similar to the tropical rain forests.
- Flora: Natural monsoon evergreen and semi-evergreen forests; dominant species are sal, silk-cotton trees, giant bamboos; tall grassy meadow with savannahs in terai.
- Fauna: Elephant, sambar, swamp deer, cheetal, hog deer, barking deer, wild boar tiger, panther, hyena, black bear, sloth bear, Great Indian one-horned rhinoceros, wild buffalo, Gangetic gharial, golden langur.
- Flora: Natural monsoon evergreen and semi-evergreen forests; rhododendrons; dwarf hill bamboo and birch forests mixed with alpine pastures.
- Fauna: Tibetan wild ass (kiang) (Don’t confuse this with Asiatic wild ass which in found in Kutch region), wild goats (thar, ibex) and blue sheep; antelopes (Chiru and Tibetan gazelle), deers (hangul of Kashmir stag and shou or Sikkim stag, musk deer); golden eagle, snow cocks, snow partridges; snow leopard, black and brown bears; birds like Griffon vultures.
Q. What is the difference between the antelopes Oryx and Chiru?
- Oryx is adapted to live in hot and arid areas whereas Chiru is adapted to live in steppes and semi-desert areas of cold high mountains.
- Oryx is poached for its antlers whereas Chiru is poached for its musk.
- Oryx exists in western India only whereas Chiru exists in north-east India only.
- None of the statements a, b, and c given above is correct.
- They are both antelopes.
- Flora: Oaks, magnolias, laurels and birches covered with moss and ferns; coniferous forests of pine, fir, yew and junipers with an undergrowth of scrubby rhododendrons and dwarf bamboos; lichens, mosses, orchids, and other epiphytes dominant (due to high humidity and high rainfall).
- Fauna: Red panda, hog badgers, forest badgers, crestless porcupines, takins etc.
- It has two zones.
- peninsular India and its extension into the drainage basin of the Ganges river system, and
- desert region of Rajasthan-the Thar of Indian desert region.
- It is home to tropical moist deciduous to tropical dry deciduous and scrub vegetation depending upon the variation in rainfall and humidity.
- Flora: Sal in north and east extensions (higher rainfall) and teak in southern plateau are dominant trees.
- West Ghats have evergreen vegetation (flora and fauna similar to evergreen rainforests of northeastern of India. In dry areas of Rajasthan and Aravalli hills, trees are scattered, and thorny scrub species predominate. The forests give way to more open savannah habit.
- Fauna: Elephant, wild boar, deers (cheetal or axis deer), hog deer swamp deer or barasinga, sambar, muntjak or barking deer, antelopes (four-horned antelope, Nilgiri, blackbuck, chinkara gazelle), wild dog or dhole, tiger, leopard, cheetah, lion, wild pig, monkey, striped hyena, jackal, gaur.
- Thar desert of Rajasthan has unique flora and fauna.
- Flora: Thorny trees with reduced leaves; cacti, other succulents are the main plants.
- Fauna: Animals are mostly burrowing ones. Among mammals’ rodents are the largest group.
- The Indian desert gerbils are mouse-like, rodents, other animals are, Asiatic wild ass, black buck, desert cat, caracal, red fox; reptiles (snakes, lizards and tortoise) well represented.
- Desert lizards include agamids and geckos. Among birds, the most discussed is Great Indian Bustard.
- Distributed in areas of Western Ghats and northeast India.
- Flora: Extensive grasslands interspersed with densely forested gorges of evergreen vegetation known as sholas occur in the Nilgiris (an offshoot of Western Ghats). Sholas also occur in Annamalai and Palani hills.
- The rain forests of the Western Ghats have dense and lofty trees with much species diversity. Mosses, ferns, epiphytes, orchids, lianas and vines, herbs, shrubs make diverse habitat. Ebony trees predominate in these forests.
- Fauna: It is very rich with all kinds of animals. There are wild elephants, gaur and other larger animals.
- Most species are tree dwellers. The most prominent are hoolock gibbon (only ape found in India), golden langur, capped langur or leaf monkey, Assam macaque and the pig-tailed macaque, lion-tailed macaque, Nilgiri langur slender loris, bats, giant squirrel, civets, flying squirrels, Nilgiri mongoose, spiny mouse.
- Flora: These are home for tropical rain forests. Mangroves are distributed in the coastal areas.
- Fauna: Among mammals, bats and rats; Andaman pig, crab-eating macaque, palm civet and deers (spotted deer, barking deer, hog deer, sambar).
- Among marine mammals, there are dugong, false killer whale, dolphin.
- Among birds are rare one is Narcondum hornbill, white-bellied sea-eagle.
- Salt-water crocodile, a number of marine turtles, coconut crab, lizards (the largest being water monitor), 40 species of snakes including cobra, viper, voral and sea snake, python, etc. are present.
- Sunderbans are the delta of the Ganges where both the Brahmaputra and the Ganges join and drain into the Bay of Bengal.
- Flora: Various species of mangroves.
- Fauna. In the higher regions of mangroves, there are spotted deer, pigs, monitor lizard, monkeys. The most interesting animal of Sunderbans is the Royal Bengal Tiger.
- Biodiversity hotspots are regions with high species richness and a high degree of endemism.
- The British biologist Norman Myers coined the term “biodiversity hotspot” in 1988 as a biogeographic region characterized both by exceptional levels of plant endemism and by serious levels of habitat loss.
- Conservation International (CI) adopted Myers’ hotspots and in 1996, the organization made the decision to undertake a reassessment of the hotspots concept.
- According to CI, to qualify as a hotspot a region must meet two strict criteria:
- It must contain at least 1,500 species of vascular plants (> 0.5% of the world’s total) as endemics – which is to say, it must have a high percentage of plant life found nowhere else on the planet. A hotspot, in other words, is irreplaceable.
- It has to have lost at least 70% of its original habitat. (It must have 30% or less of its original natural vegetation). In other words, it must be threatened.
- In 1999, CI identified 25 biodiversity hotspots in the book “Hotspots: Earth’s Biologically Richest and Most Endangered Terrestrial Ecoregions”.
- In 2005 CI published an updated titled “Hotspots Revisited: Earth’s Biologically Richest and Most Endangered Terrestrial Ecoregions”.
- The 35 biodiversity hotspots cover 2.3% of the Earth’s land surface, yet more than 50% of the world’s plant species and 42% of all terrestrial vertebrate species are endemic to these areas.
- In 2011, the Forests of East Australia region was identified as the 35th biodiversity hotspot.
- Himalaya: Includes the entire Indian Himalayan region (and that falling in Pakistan, Tibet, Nepal, Bhutan, China and Myanmar).
- Indo-Burma: Includes entire North-eastern India, except Assam and Andaman group of Islands (and Myanmar, Thailand, Vietnam, Laos, Cambodia and southern China)
- Western Ghats and Sri Lanka: Includes entire Western Ghats (and Sri Lanka).
- Sundalands: Includes Nicobar group of Islands (and Indonesia, Malaysia, Singapore, Brunei, Philippines).
Eastern Himalayas, which was originally part of the Indo-Burma Biodiversity Hotspot and included Bhutan, north-eastern India and southern, central and eastern Nepal.
In 2004, a hotspot reappraisal classified the region as part of two hotspots: Indo-Burma and the newly distinguished Himalaya.
List of Biodiversity hotspots in India given in Geography notes must be ignored. The info given here is the most accurate.
Q. Consider the following statements: 
- Biodiversity hotspots are located only in tropical regions.
- India has four biodiversity hotspots, i.e., Eastern Himalayas, Western Himalayas, Western Ghats and Andaman and Nicobar Islands.
Which of the statements given above is/are correct?
- 1 only
- 2 only
- Both 1 and 2
- Neither I nor 2
Answer: d) neither
- The Himalaya Hotspot is home to important populations of numerous large birds and mammals, including vultures, tigers, elephants, rhinos and wild water buffalo.
- Indo-Burma holds remarkable endemism in freshwater turtle species, most of which are threatened with extinction, due to over-harvesting and extensive habitat loss.
- The spectacular flora and fauna of the Sundaland Hotspot are succumbing to the explosive growth of industrial forestry in these islands and to the international animal trade that claims tigers, monkeys, etc.
- Faced with tremendous population pressure, the forests of the Western Ghats and Sri Lanka have been dramatically impacted by the demands for timber and agricultural land.
- The region also houses important populations of Asian Elephants, Indian Tigers, the Lion-tailed Macaque, Niligiri tahr, Indian Giant squirrel, etc.
- World Heritage Sites means “Sites any of various areas or objects inscribed on the United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage List”.
- The sites are designated as having outstanding universal value under the Convention concerning the Protection of the World Cultural and Natural Heritage.
- This Convention, which was adopted by the UNESCO in 1972 (and enforced in 1975) provides a framework for international cooperation in preserving and protecting cultural treasures and natural areas throughout the world. The first list of World Heritage state was published in 1978.
- The convention defines the kind of sites which can be considered for inscription of the World heritage list (ancient monuments, museums, biodiversity and geological heritage,), and sets out the duties of the State Parties in identifying potential sites and their role in protecting them.
“Natural heritage sites are restricted to those natural areas that
- furnish outstanding examples of the Earth’s record of life or its geologic processes.
- provide excellent examples of ongoing ecological and biological evolutionary processes.
- contain natural phenomena that are rare, unique, superlative, or of outstanding beauty
- furnish habitats or rare endangered animals or plants or are sites of exceptional biodiversity”.
- There are ten criteria for cultural heritage and natural heritage.
- Nominated sites must be of “outstanding universal value” and meet at least one of the criteria below.
- The United Nations declared 2010 to be the International Year of Biodiversity.
- It is a celebration of life on earth and of the value of biodiversity for our lives.
“Biodiversity is variety of life on earth
Biodiversity is life.
Biodiversity is our life”.
- It was first started by UNESCO in 1971.
- Later introduced in India in 1986.
- Studying the effects of human interference and pollution on the biotic and abiotic components of ecosystems.
- Conservation the ecosystems for the present as well as future.