- 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.
B) Species richness
- It is the measure of the number of species found in a community.
C) Species evenness
- 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.
D) Alpha diversity
- It refers to the diversity within a particular area or ecosystemand is usually expressed by the number of species (i.e., species richness) in that ecosystem.
E) Beta diversity
- It is a comparison of diversity between ecosystems, usually measured as the change in the amount of species between the ecosystems.
F) Gamma diversity
- It is a measure of the overall diversity for the different ecosystems within a region.
G) Genetic diversity
- 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.
H) Species diversity
- 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.
I) Stable community
- 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.
J) Ecological diversity
- 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.
L) Keystone species
- 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, and 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.
M) Foundation species
- 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.
N) Flagship species
- 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.
BIODIVERSITY OF INDIA
- 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.
- India’s share of crops is 44% as compared to the world average of 11%.
A) India Represents
- 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
- Palaearctic Realm
- Africotropical Realm
- Indomalayan Realm
- Ocenaia Realm
- Australian Realm
- Antarctic Realm
- Nearctic Realm
- Neotropical Realm
C) Biomes of India
- 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.
D) Bio-geographic Zones
- Biogeography deals with the geographical distribution of plants and animals.
- There are 10 biogeographic zones which are distinguished clearly in India.
- They are as follows:
- Western Ghats
- Deccan Peninsula
- Gangetic plain
- North-east India
E) Bio-geographic provinces
- Bio-geographic Province is an ecosystematic or biotic subdivision of realms.
- India is divided into 25 bio geographic zones.
WILDLIFE DIVERSITY OF INDIA
A) Himalayan mountain system
- 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, Great Indian one-horned rhinoceros, wild buffalo, Gangeticgharial, golden langur.
Western Himalayas (High altitude region)
- 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 leopard, black and brown bears; birds like Griffon vultures.
- Flora: Oaks, magnolias, laurels and birchescovered 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.
B) Peninsular India
- 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), tiger, leopard, cheetah, lion, wild pig, monkey, striped hyena, jackal, gaur.
C) Indian desert
- 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.
D) Tropical rain forest region
- 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. Ebonytrees 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, Nilgirilangur slender loris, bats, giant squirrel, civets, flying squirrels, Nilgiri mongoose, spiny mouse.
E) Mangrove swamps of Sundarbans
- 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.
- 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.
F) Andaman and Nicobar Islands
- 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.
- Biodiversity hotspotsare 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:
- 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 hotspotscover 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 Australiaregion was identified as the 35th biodiversity hotspot.
A) Biodiversity hotspots in India
WORLD HERITAGE SITES
- 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 theConvention 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.
A) “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.
MAN AND BIOSPHERE PROGRAMME (MAB PROGRAMME)
- 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.
- Conservationthe ecosystems for the present as well as future.
B) The main objects of MAB programme are to:
- Conserve representative samples of ecosystem.
- Provide long term in situ conservation of genetic diversity.
- Provide opportunities for education and training.
- Provide appropriate sustainable managements of the living resources.
- Promote infer national co-operation.