What is Biodiversity

There are generally three levels of biodiversity: genetic, species and ecosystem. These levels are all interrelated yet distinct enough that they can be studied as three separate components.

Genetic Diversity

Genetic diversity is the variety of genes within a species. Each species is made up of individuals that have their own particular genetic composition.
This means a species may have different populations, each having different genetic compositions.
For ex. India has more than 50,000 genetically different strains of rice, and 1,000 varieties of mango.

Species Diversity

Species diversity is the variety of species within a habitat or a region.
For ex. Some habitats, such as rainforests and coral reefs, have high number of species residing in them.

Ecosystem diversity

It is the variety of ecosystems in a given place. An ecosystem is a community of organisms and their physical environment interacting together.
An ecosystem can cover a large area, such as a whole forest, or a small area, such as a pond.
For ex India, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like Norway.

How Many species are there?

The IUCN Red List tracks the number of described species and updates this figure annually based on the latest work of taxonomists. In 2021 it listed 2.13 million species on the planet.

In this pool of recorded species of animals, insect forms majority of share. If we look at the breakdown across a range of taxonomic groups – 1.05 million are insects; over 11,000 are birds; over 11,000 are reptiles; and over 6,000 are mammals.

One important fact that should be kept in mind is the number of fungi species in the world is more than the combined total of the species of fishes , amphibians, reptiles and mammals.

One of the most widely-cited figures comes from Camilo Mora and colleagues; they estimated that there were around 8.7 million species on Earth today.

Although India has only 2.4 per cent of the world’s land area, its share of the global species diversity is an impressive 8.1 per cent. That is what makes our country one of the 12 mega diversity countries of the world.

Nearly 45,000 species of plants and twice as many of animals have been recorded from India.

Along with species richness, India also possesses high rates of endemism.

In terms of endemic vertebrate groups, India’s global ranking is tenth in birds, with 69 species; fifth in reptiles with 156 species; and seventh in amphibians with 110 species.

Endemic-rich Indian fauna is manifested most prominently in Amphibia (61.2%) and Reptilia (47%).

India is also recognized as one of the eight Vavilovian centers of origin and diversity of crop plants, having more than 300 wild ancestors and close relatives of cultivated plants, which are still evolving under natural conditions.

Biogeographic zones in India

India is a diverse country with varied biogeographic zones that encompass a wide range of ecosystems and biodiversity. The major biogeographic zones of India are as follows:

Trans-Himalayan Zone

This zone includes the high-altitude regions of Ladakh, Lahaul-Spiti, and parts of Jammu and Kashmir.
It is characterised by alpine meadows, barren landscapes, and sparse vegetation.

Himalayan Zone

This zone extends along the entire length of the Himalayan mountain range and includes states like Uttarakhand, Himachal Pradesh, and parts of Jammu and Kashmir.
It features diverse ecosystems ranging from sub-tropical forests in the lower regions to coniferous forests, alpine meadows, and glaciers at higher elevations.

Desert Zone

The desert zone covers the arid regions of Rajasthan, Gujarat, and parts of Haryana and Punjab.
It comprises the Thar Desert and features xerophytic vegetation, sand dunes, and saline lakes.

Semi-Arid Zone

This zone encompasses areas with a semi-arid climate, including parts of Rajasthan, Gujarat, Maharashtra, and Madhya Pradesh.
It features shrub-lands, dry deciduous forests, and grasslands.

Western Ghats

The Western Ghats, running parallel to the western coast of India, constitute a hotspot of biodiversity.
This zone includes tropical evergreen forests, moist deciduous forests, grasslands, and wetlands.

Deccan Plateau

The Deccan Plateau covers central and southern India, including parts of Maharashtra, Karnataka, Andhra Pradesh, and Tamil Nadu.
It consists of dry deciduous forests, scrublands, and extensive agricultural lands.

Gangetic Plain

This zone encompasses the fertile plains of the Ganges and Brahmaputra rivers, extending across states like Uttar Pradesh, Bihar, West Bengal, and Assam.
It features alluvial soils, wetlands, and diverse vegetation.

Coastal Zone

The coastal zone covers the coastal areas of India, including mangrove forests, estuaries, beaches, and coral reefs.
It is rich in marine biodiversity and supports unique ecosystems.

Northeastern Himalayan Region

This zone includes the states of Arunachal Pradesh, Sikkim, and parts of Assam and Nagaland.
It features a diverse range of habitats, including subtropical forests, montane forests, and alpine meadows.

Eastern Ghats

The Eastern Ghats stretch along the eastern coast of India, covering states like Odisha, Andhra Pradesh, and Tamil Nadu.
This zone comprises dry deciduous forests, scrublands, and hilly terrain.

Islands

The Lakshadweep Islands are a group of coral islands located in the Arabian Sea. This zone is characterised by coral reefs, lagoons, and marine ecosystems with rich biodiversity.
Andaman and Nicobar Islands: The Andaman and Nicobar Islands are a chain of islands located in the Bay of Bengal. They are home to diverse ecosystems, including tropical rainforests, mangroves, coral reefs, and endemic species.

Levels of Biodiversity

Levels of Biodiversity

What is Biodiversity