Biodiversity and Conservation

The Earth is home to an astonishing variety of living things, from microbes to blue whales. This variety is called biodiversity. It is the planet's life-support system: it keeps ecosystems working and provides food, medicine and clean air. Yet species are vanishing faster than ever before. Understanding what biodiversity is, why it is being lost, and how it can be saved is one of the most important themes in environmental study.

Biodiversity forms the very basis of human existence because of the free services that living systems provide. These ecosystem services are easy to overlook, yet human life depends on all of them together:

• Soil formation: organisms slowly break down rock and dead matter into fertile soil.
• Prevention of soil erosion: plant roots and ground cover hold the soil in place against wind and rain.
• Recycling of waste: decomposers such as bacteria and fungi return nutrients to the soil and water.
• Pollination of crops: bees, birds and other animals fertilise the plants that feed us.

Biodiversity exists at three levels:

• Genetic diversity: the variety of genes within a single species, such as the thousands of varieties of rice or the different strains of a medicinal plant.
• Species diversity: the variety of species in a region.
• Ecosystem diversity: the variety of ecosystems (forests, wetlands, deserts, coral reefs) in an area.

India is one of the world's megadiverse countries, holding a large share of global species on a small share of the land.

A biodiversity hotspot is a region that is both very rich in species (especially species found nowhere else, called endemic) and under serious threat of destruction. Hotspots cover a tiny part of the Earth but hold a huge fraction of its species. Protecting them is therefore a priority.

India has parts of four recognised hotspots:

• The Himalayas
• The Western Ghats (and Sri Lanka)
• The Indo-Burma region
• Sundaland (the Nicobar Islands)

Species are not spread evenly across the planet. Two broad gradients shape where life is richest.

• Latitudinal gradient: biodiversity is normally greater at lower latitudes, near the equator, than at higher latitudes, near the poles. The tropics receive more solar energy, enjoy a more stable climate over time and offer more complex habitats, so more species can coexist.
• Altitudinal gradient: along a mountain slope, biodiversity is normally greater at lower altitudes than at higher altitudes. Conditions grow harsher and colder higher up, so fewer species survive.

Both gradients point the same way: warmth, energy and stable conditions allow more species to pack into a region.

Living things are sorted into broad groups, and a few distinctions are worth fixing in mind.

• Pioneer colonisers: lichens (a partnership of a fungus and an alga) and mosses (small non-flowering plants called bryophytes) can survive on bare rock with no soil. They are often the first life on a fresh surface. Ferns and mushrooms generally need soil.
• Marine mammals versus fish: the sea cow (dugong) and the sea lion are mammals that breathe air and suckle their young. The sea horse, despite its name, is a bony fish.

A few signature facts about animals around the world are tested often.

• Where species belong: the indri, a large lemur, lives only in Madagascar, not Brazil. The elk is native to North America and Europe, not Indonesia. The bonobo, a great ape, lives in the Democratic Republic of Congo, not Madagascar.
• Big cats: lions have no fixed breeding season and breed all year. Cheetahs, unlike most other big cats, cannot roar; they chirp and purr. Male leopards do mark their territory by scent, so they are not an exception to this habit.
• Poisonous groups: poisonous species exist among butterflies, fish and frogs alike. Poison dart frogs, puffer fish carrying tetrodotoxin and several toxic butterflies are all real examples.

India's plant and animal life is vast, and exams test specific names, ranges and traits. The points below group the most testable facts.

Native versus introduced plants. Many familiar crops are not Indian in origin.

• Native to India: red sanders (Pterocarpus santalinus), a tree endemic to the dry deciduous forests of the Andhra Pradesh hills, not to rain forests.
• New World introductions: cashew, papaya, pineapple and guava came from the Americas, brought by the Portuguese in the sixteenth and seventeenth centuries. Tobacco, cocoa (cacao) and rubber were also domesticated in the New World and carried to the Old World.

Plant forms and vegetation zones.

• Plant habits: cassava is a woody shrub, ginger is a herb with a pseudostem, and Malabar spinach is a herbaceous climber. Mint is a perennial herb, not an annual shrub.
• Deciduous trees shed their leaves in the dry season. Mahua and teak are deciduous; jackfruit is evergreen.
• Himalayan vegetation includes oak, rhododendron, juniper, silver fir, spruce and Taxus (Himalayan yew). Sandalwood belongs to the Deccan and South India, and mahogany is a tropical American timber, so neither is Himalayan.

Useful and notable plants.

• Lemon grass yields citronella oil, a natural mosquito repellent.
• Neem oil is a biopesticide and has pharmaceutical uses, but neem seeds are not a source of biofuel or hospital detergents.
• Cluster bean (guar) gives guar gum, used to thicken fluid for shale gas extraction.
• Himalayan nettle (Girardinia diversifolia) is a sustainable source of textile fibre.
• Sea buckthorn controls soil erosion, resists desertification and is nutritious; it thrives in cold high altitudes but is not a biodiesel or timber source.
• Taxus (yew) yields the anti-cancer drug taxol and is listed in the Red Data Book of threatened species.
• Dalbergia is the genus of rosewood and sheesham.
• The pitcher plant is insectivorous, trapping insects in fluid-filled leaves.
• Gucchi, a prized morel, is a fungus that grows wild in Himalayan forests and cannot be commercially cultivated.

Endemic and native animals, and their ranges.

• The Asiatic lion survives in the wild only in Gir, India. The one-horned rhinoceros is found in India and Nepal. The double-humped (Bactrian) camel is native to Central Asia, not India.
• The lion-tailed macaque is endemic to the Western Ghats of Tamil Nadu, Kerala and Karnataka. The red panda lives in the Eastern Himalayas. The slow loris lives in the dense forests of the North East.
• Pangolins, the scaly, toothless anteaters, are found in India. The Hoolock gibbon is the only ape native to India.
• Star tortoise, monitor lizard and pygmy hog are native to India; the spider monkey is a New World primate and is not. Black-necked crane, flying squirrel and snow leopard occur in India; the cheetah went extinct here in the 1950s.
• The Indian wild ass lives in the sandy, saline Little Rann of Kutch, where it has no predators but loses habitat. The Kharai camel of Kutch swims in tidal creeks and grazes on mangroves. The saltwater crocodile lives in the Andaman and Nicobar Islands, and shrew and tapir occur in the Malabar Western Ghats. The gharial, a fish-eating crocodilian, is best seen in the Chambal River.

Distinctive animal traits.

• An Indian elephant herd is led by a female (matriarch), and the gestation period can reach 22 months. Karnataka has the highest elephant population among Indian states, and India holds the largest Asian elephant population, about 20,000 to 25,000 animals.
• The king cobra is the only snake that builds a nest; being egg-laying (oviparous), it guards its eggs until they hatch. Its diet is mainly other snakes, making it ophiophagous.
• In many spiders, the female kills the male after mating, a behaviour called sexual cannibalism.
• Hedgehogs and pangolins roll into a ball to protect their soft parts. Indian squirrels are omnivorous and store food in the ground, but they nest in trees rather than burrows.
• The oyster is a filter feeder. Certain ants, such as leafcutters, cultivate fungi for food.

Birds and the national aquatic animal.

• The Gangetic river dolphin is India's national aquatic animal, declared so in 2009.
• Ceylon frogmouth, coppersmith barbet, gray-chinned minivet and white-throated redstart are all birds. The golden mahseer is a fish, not a bird. The flying fox is a fruit bat, and the langur is a monkey, not an ape.
• The Great Indian Hornbill lives in the evergreen forests of the Western Ghats and the North East. The common myna follows cattle to catch insects disturbed by their movement.

Endangered species.

• Great Indian Bustard, musk deer, red panda and Asiatic wild ass are all endangered. Gharial, leatherback turtle and swamp deer (barasingha) are endangered too, as are the crocodile and the Asian elephant.
• The musk deer lives in high-altitude Himalayan forests, such as Askot Wildlife Sanctuary and Gangotri National Park.
• The oryx is an antelope of hot, arid deserts; the chiru (Tibetan antelope) lives on the cold, high steppes of the Tibetan plateau.
• Marsupials, the pouched mammals, are not naturally found in India. They are characteristic of Australia.

Seas and coasts hold some of the richest and most fragile habitats on Earth.

• Coral reefs grow mostly in warm tropical waters. Australia, Indonesia and the Philippines together hold more than a third of the world's reefs, and reefs host more animal phyla than tropical rainforests. India's reefs lie in the Andaman and Nicobar Islands, the Gulf of Mannar, the Gulf of Kachchh and Lakshadweep; the Sundarbans, a mangrove delta, has none. The Great Barrier Reef off Australia is the largest reef in the world. Biorock (mineral accretion) technology passes a low current through steel frames in the sea to grow limestone and restore damaged reefs.
• Ocean acidification, driven by rising carbon dioxide, dissolves the carbonate shells of calcareous plankton and corals and harms animals whose larvae are planktonic.
• Phytoplankton anchor the ocean as a carbon sink and form the base of marine food chains; they do not control the density of seawater.
• The dugong, or sea cow, is a herbivorous marine mammal of the order Sirenia. It is protected under Schedule I of the Wildlife (Protection) Act, 1972, and lives in select areas such as the Gulf of Mannar and the Andaman Sea, not along the whole coast.
• Mangroves are specialised forests of tropical and subtropical coasts. Their dense, interlocking roots anchor them against storms and tides, stabilise the shoreline and buffer wave energy, which is why they shielded coasts during the 2004 tsunami. Notable sites include Achra-Ratnagiri in Maharashtra, Coondapur in Karnataka, Pichavaram in Tamil Nadu and Vembanad in Kerala.
• The Olive Ridley turtle nests in huge numbers on the coast of Odisha, at Gahirmatha and Rushikulya.

Species are being driven to extinction mainly by human activity. The major causes are often called "the evil quartet":

• Habitat loss and fragmentation: the biggest cause. Forests and wetlands are destroyed for farming, cities and industry.
• Over-exploitation: hunting, fishing and harvesting species faster than they can recover.
• Invasive alien species: foreign species that, once introduced, out-compete and wipe out natives.
• Co-extinctions: when one species dies out, others that depend on it (such as its parasites or partners) go too.

The loss matters because every species has a role. A poorer web of life is less stable and less able to provide the services people rely on.

Some species matter far out of proportion to their numbers. A keystone species is one whose presence disproportionately determines whether many other species in an ecosystem persist. Remove it and the whole community can unravel. Being a keystone is not the same as being abundant: a keystone species can be quite rare yet still hold an ecosystem together. This idea also helps fix two related terms. Sympatric species live in the same geographic area, while allopatric species are kept apart by a geographic barrier such as a mountain or sea.

Not every cause fits the evil quartet. India's vultures crashed in number within a few years, one of the fastest declines recorded for any bird. The cause was diclofenac, a painkilling veterinary drug given to cattle. When a treated animal died, the vultures that fed on the carcass suffered fatal kidney failure. The drug, not invasive species, food scarcity or disease, drove the collapse, which is why diclofenac was banned for veterinary use.

Conservation is of two broad kinds. In-situ conservation means protecting species in their natural homes, by safeguarding whole ecosystems. Its main tools are:

• National parks: strictly protected natural areas.
• Wildlife sanctuaries: protected areas where some regulated human activity may be allowed.
• Biosphere reserves: large areas that protect ecosystems while also allowing research and sustainable local life.

Protecting the habitat protects all the species living in it at once. This is why in-situ conservation is considered the best approach.

Exams test the better-known parks by name and by what each one protects.

• Desert National Park: spread across two districts of Rajasthan, it is a stronghold of the Great Indian Bustard, one of the country's most endangered birds.
• Kanha National Park (Madhya Pradesh): home to the hard-ground barasingha, a sub-species of swamp deer saved here from near extinction.
• Valley of Flowers National Park (Uttarakhand): lies wholly in the temperate alpine zone, famed for its high-altitude flower meadows.
• Namdapha National Park (Arunachal Pradesh): its great altitude range gives it a climate that shifts from tropical at the base to near-arctic on the heights.
• Keibul Lamjao National Park (Manipur): the only floating swamp national park, set on the matted vegetation of Loktak Lake, it protects the Sangai, the brow-antlered deer.
• Indravati National Park: lies in the Bastar region of Chhattisgarh.
• Indira Gandhi Wildlife Sanctuary and National Park (Tamil Nadu): the Anamalai reserve also known as Top Slip.
• Among the union territories, the Andaman and Nicobar Islands hold the most national parks.

Tiger reserves are a special class of protected area, and PYQs test which sites qualify and where they sit.

• Nagarjunasagar-Srisailam (Andhra Pradesh and Telangana) holds the country's largest Critical Tiger Habitat.
• Bandipur, Manas and the Sundarbans are tiger reserves. Bhitarkanika, a mangrove and saltwater-crocodile habitat in Odisha, is not.
• Sathyamangalam (Tamil Nadu) is a vital corridor linking the Eastern and Western Ghats. It sits in the Cauvery basin along with Nagarhole and Wayanad. Papikonda, by contrast, lies on the Godavari, not the Cauvery.
• State matches worth fixing: Dampa is in Mizoram, Gumti in Tripura, and Saramati is a peak in Nagaland.

Specific reserves and wetlands are tested by location, river and component.

• Agasthyamala Biosphere Reserve spans the southern Western Ghats, taking in the Neyyar, Peppara and Shendurney wildlife sanctuaries and the surrounding forests.
• Gulf of Mannar, Nilgiri, Nanda Devi and the Sundarbans are among the Indian biosphere reserves inscribed in the UNESCO World Network of Biosphere Reserves. Great Nicobar and Nanda Devi are also biosphere reserves; the Gulf of Kachchh is not, being a marine protected area instead.
• The Gulf of Kachchh holds India's first marine sanctuary, later raised to a marine national park.
• Pakke, also called Pakhui, Wildlife Sanctuary lies in Arunachal Pradesh.
• Kuno (Kuno-Palpur), in Madhya Pradesh, was prepared as the site to translocate Asiatic lions from Gir.
• Bundala, a biosphere reserve and Ramsar wetland, lies in Sri Lanka, not India.
• Nokrek sits in the Garo Hills of Meghalaya, Loktak in Manipur and Namdapha in Arunachal Pradesh.

Wetlands and their rivers carry their own recall:

• Harike wetland forms at the confluence of the Beas and Sutlej rivers. Keoladeo (Bharatpur) and Kolleru are other major wetlands.
• Sambhar Lake in Rajasthan is India's largest inland saline wetland.
• Gujarat has the largest wetland area of any Indian state.
• Corbett lies on the Ramganga, Kaziranga on the Brahmaputra, and Silent Valley on the Kunthi river.

Ex-situ conservation means protecting species away from their natural homes, used especially for species too threatened to survive in the wild. Its methods include:

• Zoological parks (zoos) and botanical gardens, which keep living animals and plants.
• Seed banks and gene banks, which store seeds and genetic material.
• Cryopreservation, freezing gametes or tissue at very low temperatures for the long term.

Ex-situ methods can even breed threatened species and release them back into the wild.

Several global bodies and treaties guide how nature is protected. Their exact nature is often tested.

• IUCN (International Union for Conservation of Nature) is an independent union, not an organ of the United Nations. It runs thousands of field projects worldwide and publishes the Red List, also called the Red Data Book, which lists species by their risk of extinction (threatened species). The Red List does not catalogue endemic species by hotspot or protected sites.
• CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) is an agreement between governments. It is legally binding on the states that join, but it supplements rather than replaces their national laws.
• BirdLife International is a global partnership of conservation organisations. It identifies Important Bird and Biodiversity Areas (IBAs). The concept of biodiversity hotspots, however, came from the ecologist Norman Myers, not from BirdLife.
• Wetlands International is an independent non-governmental organisation, not an intergovernmental body of Ramsar signatories. It builds field knowledge and advocates better wetland policies. The Ramsar Convention is the treaty on wetlands of international importance.
• The Montreux Record is a register kept under the Ramsar Convention. A wetland is placed on it when its ecological character has changed, is changing or is likely to change because of human interference.

India protects biodiversity through a layered framework of laws and bodies.

• The Biological Diversity Act, 2002 created a three-tier system: the National Biodiversity Authority (NBA) at the centre, State Biodiversity Boards, and local Biodiversity Management Committees (BMCs).
• BMCs are key to meeting the goals of the Nagoya Protocol, the agreement on sharing the benefits of genetic resources. They help decide access and benefit sharing and can levy collection fees on access to biological resources in their area.
• The NBA checks biopiracy and protects indigenous and traditional genetic resources. Its approval is required before anyone files for intellectual property rights based on Indian biological resources. The NBA does not supervise research on genetically modified crops; that work falls to the GEAC under the environment ministry.
• Several older central laws also bear on biodiversity: the Import and Export (Control) Act, 1947 and the Customs Act, 1962 regulate trade in wildlife products, the Mining and Mineral Development (Regulation) Act, 1957 affects habitats, and the Indian Forest Act, 1927 governs forest biodiversity.
• The Animal Welfare Board of India is headquartered in Chennai.

Beyond single laws, a set of international agreements and initiatives shapes biodiversity policy.

• The Convention on Biological Diversity (CBD) is the central global treaty, and India is a signatory. The Cartagena Protocol under it deals with the safe handling and cross-border movement of living modified organisms, that is, genetically modified organisms.
• TRAFFIC is a joint programme of the WWF and IUCN, not a bureau of the UN Environment Programme. Its mission is to ensure that trade in wild plants and animals does not threaten the conservation of nature.
• TEEB (The Economics of Ecosystems and Biodiversity) is an initiative hosted by the UN Environment Programme. It draws attention to the economic value of biodiversity and helps decision-makers recognise, demonstrate and capture the value of ecosystems.

Damaged land can sometimes be brought back to life with the help of natural partnerships.

• Mycorrhiza is a symbiosis between fungi and plant roots. Mycorrhizal biotechnology is used to rehabilitate degraded sites because the fungi extend the root network and so help plants resist drought and increase their absorptive area, tolerate extremes of pH, and resist disease.