Biodiversity and Its Conservation: Hotspots and Laws

Biodiversity is the variety of life found at every level, from the genes inside a single species to the ecosystems that cover a region. The word was coined in 1985 as a short form of biological diversity and was carried into common use by the biologist Edward Wilson. The subject matters to an examinee for two reasons: it supplies a set of clean definitions, and it carries a long list of dates, conventions and Indian laws that can be asked directly.

The three levels of biodiversity

• Genetic diversity is the variation within a single species, as in the many varieties of rice grown in India or the different medicinal potencies of the same plant growing in different ranges.
• Species diversity is the variety of species in a region, measured by species richness, the plain number of species, and by species evenness, how equally the individuals are spread among them.
• Ecosystem diversity is the variety of habitats in an area, such as forests, grasslands, wetlands, deserts, mangroves and coral reefs.

A different scale of measurement uses three terms introduced by Robert Whittaker: alpha diversity, the diversity within one community or habitat; beta diversity, the change in species composition from one habitat to another; and gamma diversity, the total diversity of a large landscape. Diversity is not spread evenly on the earth. It increases as one moves from the poles towards the equator, so tropical forests hold far more species than temperate ones, and the Amazon rainforest is the richest region of all.

Hotspots, endemism and India

A biodiversity hotspot is a region that is exceptionally rich in species and at the same time seriously threatened. The idea was given by Norman Myers in 1988, and a region qualifies when it holds a large number of endemic plant species and has already lost most of its original vegetation. Endemic species are those found in one geographical area and nowhere else, such as the lion-tailed macaque of the Western Ghats or the Nicobar megapode.

India is counted among the world's megadiverse countries, holding a large share of global species on a small share of the land area, and it is also one of the great centres of crop plant origin.

Why biodiversity is lost

Four causes are grouped together as the evil quartet. Habitat loss and fragmentation is the single largest cause, as forests are cleared, wetlands drained and grasslands ploughed, and the pieces that remain are too small for large animals to survive in. Over-exploitation means taking more than nature replaces, as in overfishing and the hunting of animals for skin, horn or bone. Invasive alien species are organisms brought from elsewhere that crowd out native ones, such as water hyacinth in Indian waterbodies and the African catfish in the rivers. Co-extinction follows when a species disappears and takes with it those that depended on it, such as a parasite or a pollinator.

The Red List and its categories

The International Union for Conservation of Nature, founded in 1948 and based at Gland in Switzerland, maintains the Red List, which places a species in one of a fixed set of categories after assessing its numbers and its range. In descending order of threat these are Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened and Least Concern, with Data Deficient and Not Evaluated for species that cannot yet be placed. The three categories Critically Endangered, Endangered and Vulnerable together are called the threatened categories.

Conservation: in-situ and ex-situ

In-situ conservation protects a species in its natural home, and it is the preferred method because the whole ecosystem is saved along with it. It is carried out through national parks, wildlife sanctuaries, biosphere reserves, conservation and community reserves, and the sacred groves that villages have protected by custom for centuries. A national park has fixed boundaries and no human rights or grazing are allowed inside it, while a sanctuary is meant for a particular species or group and certain regulated activities may continue. A biosphere reserve is a larger unit organised in three zones: an undisturbed core zone, a buffer zone where research and limited use are allowed, and a transition zone where settlements and farming continue. These reserves come under the Man and the Biosphere Programme of UNESCO, begun in 1971, and the Nilgiri Biosphere Reserve, notified in 1986, was the first in India.

Ex-situ conservation protects a species away from its habitat, in zoological parks, botanical gardens, seed banks, gene banks and cryopreservation facilities, and through techniques such as in vitro fertilisation and tissue culture. It is a second line of defence, used when a population has become too small or its habitat too damaged.

Laws and conventions to remember

In India the Wildlife (Protection) Act was passed in 1972 and gives the legal basis for national parks, sanctuaries and the schedules of protected species. Project Tiger began in 1973 and Project Elephant in 1992. The Biological Diversity Act was passed in 2002 and set up a three tier structure, with the National Biodiversity Authority at Chennai, state boards and local biodiversity management committees. Internationally, the Convention on Biological Diversity was signed at the Earth Summit at Rio de Janeiro in 1992 and has three objectives: the conservation of biodiversity, its sustainable use, and the fair sharing of the benefits from genetic resources. Its Cartagena Protocol of 2000 deals with biosafety and its Nagoya Protocol of 2010 with access and benefit sharing. The Ramsar Convention of 1971 protects wetlands and CITES, agreed in 1973, controls international trade in endangered species. The International Day for Biological Diversity is observed on 22 May.