Biodiversity

Reasons for conserving biodiversity fall into three categories: 1. **Narrowly utilitarian:** Direct economic benefits — food (cereals, pulses, fruits), firewood, fibre, construction material, industrial products (tannins, lubricants, dyes, resins, perfumes), and products of medicinal importance. More than 25 per cent of drugs currently sold worldwide are derived from plants; 25,000 species of plants contribute to traditional medicines used by native peoples. 2. **Broadly utilitarian:** Indirect benefits through ecosystem services — pollination, oxygen production (Amazon forest produces 20% of Earth's atmospheric oxygen), climate moderation, pest control, flood control, soil formation. 3. **Ethical:** Every species has intrinsic value. We have a moral duty to care for their well-being and pass on our biological legacy in good order to future generations. **Two approaches to conservation:** **In-situ conservation (on-site):** Protecting the whole ecosystem so that biodiversity at all levels is protected — "save the entire forest to save the tiger." This is the preferred approach for most species. *Biodiversity hotspots:* To address the conflict between development and conservation, conservationists identified "biodiversity hotspots" — regions with very high levels of species richness and high degree of endemism (species confined to that region and not found anywhere else). Initially 25 hotspots were identified; subsequently nine more were added, bringing the total to **34 biodiversity hotspots** worldwide. These hotspots are also regions of accelerated habitat loss. Three of the 34 hotspots cover India's exceptionally high biodiversity regions: - Western Ghats and Sri Lanka - Indo-Burma - Himalaya Although all biodiversity hotspots together cover less than 2 per cent of Earth's land area, the number of species they collectively harbour is extremely high. Strict protection of these hotspots could reduce the ongoing mass extinctions by almost 30 per cent. *India's in-situ conservation network:* - 14 biosphere reserves - 90 national parks (earlier text says 110) - More than 448 wildlife sanctuaries - Sacred groves (in Khasi and Jaintia Hills in Meghalaya, Aravalli Hills of Rajasthan, Western Ghats regions of Karnataka and Maharashtra, Sarguja, Chanda and Bastar areas of Madhya Pradesh). In Meghalaya, the sacred groves are the last refuges for a large number of rare and threatened plants. **Ex-situ conservation (off-site):** Threatened animals and plants are taken out from their natural habitat and placed in special settings for protection and special care. Methods: - Zoological parks, botanical gardens, wildlife safari parks - Cryopreservation — gametes of threatened species preserved in viable and fertile condition for long periods - In vitro fertilisation — eggs can be fertilised in vitro - Tissue culture propagation of plants - Seed banks — seeds of different genetic strains of commercially important plants kept for long periods **International initiatives:** - Convention on Biological Diversity (CBD) — signed at the Earth Summit in Rio de Janeiro, 1992; called upon nations to take appropriate measures for conservation and sustainable utilisation - World Summit on Sustainable Development, Johannesburg, 2002 — 100 countries pledged commitment to achieve by 2010 a significant reduction in current rate of biodiversity loss

The biological wealth of our planet has been declining rapidly, and the accelerated finger clearly points to human activities. The IUCN Red List (2004) documents the extinction of 784 species (including 338 vertebrates, 359 invertebrates, and 87 plants) in the last 500 years. Colonisation of tropical Pacific Islands by humans led to extinction of more than 2,000 species of native birds. Recent extinctions include the dodo (Mauritius), quagga (Africa), thylacine (Australia), Steller's Sea Cow (Russia), and three subspecies (Bali, Javan, Caspian) of tiger. The current species extinction rates are estimated to be **100 to 1,000 times faster** than in pre-human times. Ecologists warn that if present trends continue, nearly half of all species on earth might be wiped out within the next 100 years. From Earth's fossil history, there have been five episodes of mass extinction — the present is considered the **sixth extinction**, distinguished from earlier episodes by its much faster rate driven by human activities. Currently, 12 per cent of all bird species, 23 per cent of all mammal species, 32 per cent of all amphibian species, and 31 per cent of all gymnosperm species face the threat of extinction. More than 15,500 species worldwide are facing the threat of extinction. **The Evil Quartet — four major causes of biodiversity loss:** 1. **Habitat loss and fragmentation:** The most important cause. The most dramatic examples come from tropical rain forests. Once covering more than 14 per cent of Earth's land surface, rain forests now cover no more than 6 per cent. The Amazon rain forest (called the "lungs of the planet") is being cut and cleared for cultivating soybeans or conversion to grasslands for beef cattle. When large habitats are broken into small fragments, mammals and birds requiring large territories and animals with migratory habits are badly affected. 2. **Over-exploitation:** When "need" turns to "greed," it leads to over-exploitation of natural resources. Many species extinctions in the last 500 years (Steller's sea cow, passenger pigeon) were due to over-exploitation by humans. Many marine fish populations around the world are now being over-harvested. 3. **Alien species invasions:** When alien species are introduced (intentionally or accidentally), some become invasive and cause decline or extinction of indigenous species. Examples: - Nile perch introduced into Lake Victoria (East Africa) led to extinction of more than 200 species of cichlid fish - Invasive weed species in India: carrot grass (Parthenium), Lantana, water hyacinth (Eichhornia) - African catfish Clarias gariepinus (illegal introduction for aquaculture) poses threat to indigenous catfishes in Indian rivers 4. **Co-extinctions:** When one species becomes extinct, plant and animal species associated with it in an obligatory way also become extinct. Example: When a host fish species becomes extinct, its unique assemblage of parasites also meets the same fate. A co-evolved plant-pollinator mutualism — extinction of one inevitably leads to extinction of the other. **Effect of biodiversity loss on ecosystems:** - Decline in plant production - Lowered resistance to environmental perturbations like drought - Increased variability in certain ecosystem processes (plant productivity, water use, pest and disease cycles)

Biodiversity refers to the sum total of diversity that exists at all levels of biological organisation. The most important levels are genetic, species, and ecosystem diversity. **Three levels of biodiversity:** 1. **Genetic diversity:** Diversity within a species at the genetic level over its distributional range. Example: India has more than 50,000 genetically different strains of rice, and 1,000 varieties of mango. The medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges shows variation in potency and concentration of the active chemical (reserpine). 2. **Species diversity:** Diversity at the species level. Example: The Western Ghats have greater amphibian species diversity than the Eastern Ghats. 3. **Ecological diversity:** Diversity at the ecosystem level. India, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows, has greater ecosystem diversity than a Scandinavian country like Norway. **Global species diversity:** According to IUCN (2004), the total number of plant and animal species described so far is slightly more than 1.5 million. A more conservative scientific estimate by Robert May places global species diversity at about 7 million. More than 70 per cent of all recorded species are animals; plants (including algae, fungi, bryophytes, gymnosperms and angiosperms) comprise no more than 22 per cent. Among animals, insects are the most species-rich taxonomic group, making up more than 70 per cent. The number of fungi species is more than the combined total of fishes, amphibians, reptiles, and mammals. **India's biodiversity:** Although India has only 2.4 per cent of the world's land area, its share of global species diversity is 8.1 per cent. This makes India one of the 12 **megadiversity countries** of the world. Nearly 45,000 species of plants and twice as many species of animals have been recorded from India. **Patterns of biodiversity:** 1. **Latitudinal gradients:** Species diversity decreases as we move away from the equator towards the poles. Tropics (latitudinal range of 23.5°N to 23.5°S) harbour more species than temperate or polar areas. Colombia (near equator) has nearly 1,400 species of birds; New York (41°N) has 105; Greenland (71°N) has only 56. India has more than 1,200 species of birds. The Amazonian rain forest in South America has the greatest biodiversity on earth — more than 40,000 species of plants, 3,000 of fishes, 1,300 of birds, 427 of mammals, 427 of amphibians, 378 of reptiles, and more than 1,25,000 invertebrates. Explanations for tropical species richness: (a) Tropics had more evolutionary time due to long undisturbed history; (b) Relatively constant and predictable tropical environments promote niche specialisation and greater diversity; (c) More solar energy available in tropics contributes to higher productivity and indirectly to greater diversity. 2. **Species-Area relationships:** Observed by Alexander von Humboldt. Within a region, species richness increases with increasing explored area, but only up to a limit. The relationship follows a rectangular hyperbola; on a logarithmic scale, it is a straight line: log S = log C + Z log A. The value of Z (regression coefficient) lies between 0.1 and 0.2 for smaller regions regardless of taxonomic group. For very large areas like continents, Z values are in the range 0.6 to 1.2. **Importance of species diversity to ecosystems:** Communities with more species tend to be more stable. David Tilman's long-term ecosystem experiments showed that plots with more species showed less year-to-year variation in total biomass, and increased diversity contributed to higher productivity. Paul Ehrlich's rivet popper hypothesis: like rivets holding an airplane together, loss of too many species (particularly key species driving ecosystem functions) makes the ecosystem dangerously unstable.

India's plant diversity reflects its varied geography — from the Himalayas to coastal mangroves, from desert xerophytes to rainforest epiphytes. India has approximately 45,000 plant species. The country's marine diversity includes rich coral reef, mangrove, and seagrass ecosystems.

The Indian elephant (Elephas maximus indicus) is one of three recognized subspecies of the Asian elephant, primarily native to mainland Asia. It holds significant ecological importance as a megaherbivore shaping its diverse habitats across grasslands and various forest types. For UPSC Prelims, understanding the Indian elephant is crucial due to its status as India's National Heritage Animal, its endangered conservation status (IUCN Red List), and the government's flagship conservation initiative, Project Elephant (1992). Questions often revolve around its classification, distribution (especially in India), threats, and conservation efforts.

The Lion-tailed Macaque (*Macaca silenus*), locally known as wanderoo, is an Old World monkey species endemic exclusively to the Western Ghats of South India. It is easily recognized by its distinctive black fur, a striking silver or gray mane that frames its hairless black face, and a lion-like tuft at the tip of its tail. This primate is highly significant for UPSC Prelims due to its classification among the rarest and most threatened primates globally. It serves as an indicator species for the health of the tropical moist evergreen and monsoon forests of the Western Ghats, facing severe threats primarily from habitat fragmentation and loss driven by human developmental activities.

The Kharai is a unique dromedary camel breed native to the Kutch district of Gujarat, famously known as the ‘swimming camel’ or 'Dariyataru'. It is uniquely adapted to the salt marsh ecosystems, demonstrating the rare ability to swim several kilometers in the sea to reach mangrove grazing grounds. Its name is derived from the Gujarati word 'khara', meaning salty. This distinct adaptation, along with its close association with traditional pastoral communities and its status as one of India's officially recognized camel breeds, makes the Kharai camel a significant concept for UPSC. It highlights themes of biodiversity, ecological adaptation, traditional knowledge systems, and conservation challenges posed by habitat loss due to industrialization.

The Malabar large-spotted civet, scientifically known as *Viverra civettina*, is a critically endangered viverrid species endemic to the Western Ghats of India. Its conservation status is a major concern due to its extremely low population, estimated to be fewer than 250 mature individuals. This species is highly relevant for UPSC Prelims Environment and Biodiversity sections, particularly regarding endemic Indian fauna, IUCN Red List classifications, and conservation challenges in biodiversity hotspots like the Western Ghats. Its elusive nature and failure to be recorded in recent surveys highlight the urgent need for robust conservation strategies for such an indicator species.

The Gangetic Dolphin (*Platanista gangetica*), also known as the Ganges River Dolphin, is a unique freshwater toothed whale native to the Indian subcontinent. It holds the significant status of India's National Aquatic Animal. Belonging to the genus *Platanista*, this cetacean is distinctly adapted to murky riverine environments. While historically considered one species (*P. gangetica*), recent genetic and morphological evidence in 2021 led to its reclassification as one of two distinct species, alongside the Indus River Dolphin (*Platanista minor*). For UPSC Prelims, the Gangetic Dolphin is a high-yield topic due to its critical conservation status ('Endangered' on the IUCN Red List), its role as an indicator species for river health, and the various anthropogenic threats it faces. Its unique biological adaptations, taxonomic journey, and its status as a protected species under Indian law make it a recurring subject in Environment and Biodiversity questions.

The Great Indian Bustard (*Ardeotis nigriceps*) is a critically endangered large ground bird, among the heaviest of flying birds, endemic to the dry grasslands and shrublands of the Indian subcontinent. It is a flagship species for grassland ecosystems, characterized by its distinct horizontal body, long bare legs, and a contrasting black cap on a pale head. Its conservation status is of paramount importance for UPSC Prelims due to its drastic population decline, with only an estimated 150 individuals surviving as of 2018. Protected under Schedule I of the Indian Wild Life (Protection) Act, 1972, the GIB's plight underscores critical environmental issues like habitat loss, poaching, and the impact of infrastructure development on India's biodiversity.

The Honeybee Waggle Dance is a sophisticated form of communication employed by successful honeybee foragers to convey critical information about vital resources to other members of their colony. It involves a specific figure-eight pattern dance performed inside the hive. This remarkable animal behaviour falls under ethology and is a prime example of complex non-human communication, making it significant for UPSC Prelims in understanding biodiversity, ecological interactions, and animal adaptations. Through the waggle dance, bees communicate the precise direction and distance to patches of flowers yielding nectar and pollen, water sources, or potential new nest-site locations. This ability to share spatial information efficiently is crucial for the colony's survival and resource acquisition, highlighting the intricate social structure and cooperative foraging strategies within bee colonies, which directly impacts pollination and agricultural productivity.

The Great Indian Hornbill (*Buceros bicornis*), also known as the Great Pied Hornbill or Concave-casqued Hornbill, is one of the larger and heaviest Asian hornbill species found across the Indian subcontinent and Southeast Asia. Predominantly frugivorous, its diet also includes small mammals, reptiles, and birds, making it a crucial component of its forest ecosystem. This species holds significant ecological and cultural importance in India, which is highly relevant for UPSC Prelims. It is currently listed as 'Vulnerable' on the IUCN Red List since 2018, highlighting its conservation priority. Recognised as an important seed disperser for numerous forest tree species, it also holds the distinction of being the official State Bird of both Kerala and Arunachal Pradesh, reflecting its deep cultural value in tribal traditions.

Biodiversity is the variety of life on Earth, including all organisms, species, and populations, the genetic variation among them, and their complex communities and ecosystems. As defined by