Biodiversity

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Biodiversity [pdf]

Biodiversity is a term used to describe the enormous variety of life on Earth. It is a measure of variation at the genetic, species and ecosystem level. Terrestrial biodiversity is usually greater near the equator, which is the result of the warm climate and high primary productivity. Mountains have high range of species at the low altitude as they can support larger number of species due to climatic condition.

There are three levels of biodiversity:

1. Genetic diversity– It is concerned with the variability of genes within a particular species. Genetic diversity allows species to adapt to changing environments and survive drastic changes. This ensures survival of the population.
2. Species diversity– It refers to the variety of living organisms on Earth.
3. Ecosystem diversity– It refers to different types of habitats like grasslands, desert, mangroves etc.

Biodiversity is measured using species richness. Species richness is the number of different species represented in an ecological community, landscape or region.

1. 1. Alpha diversity– It refers to diversity within a particular area or ecosystem.
   2. Beta diversity– It is a comparison of diversity between ecosystems.
   3. Gamma diversity– It is a measure of overall diversity for the different ecosystems within a region.

As per World Wildlife Fund’s (WWF) Living Planet Report, species extinction rate is 100-1000 times higher than a few hundred years ago. There are several constrains in biodiversity conservation like:

1. 1. Low priority for conservation in policies.
   2. Exploitation of biodiversity for monetary gains.
   3. Limited knowledge regarding biodiversity and its importance.
   4. Unplanned urbanization resulting in destruction of wetlands, deforestation etc.

Considering the threats to biodiversity, there are two modes of conservation of the same:

1. In-situ conservation– It aims to enable biodiversity to maintain itself within the natural habitats in which it is found. E.g., National parks, sanctuaries, Biosphere reserves, reserved forests and protected forests.
2. Ex-situ conservation– It aims at conserving biodiversity outside the areas where they naturally occur. E.g., Seed banks and botanical gardens.

Reintroduction of Gangetic gharial in Chambal river flowing through Uttar Pradesh, Rajasthan and Madhya Pradesh where it had become extinct is an example of Ex-situ conservation.

5.1 Indian Biodiversity

With just 2.4% of the land area, India accounts for nearly 7% of the recorded species. The varied climatic, edaphic and topographic conditions have resulted in a wide array of ecosystems and habitats in India with enormous biodiversity.

5.1.1 Landscape Biodiversity

A landscape is a “mosaic of heterogeneous landforms, vegetation types and land uses.”

1. Realms: Realm is a continent or subcontinent sized area with unifying feature of geography, flora and fauna.

The Indian region is composed of two realms-

1. The Himalayan region represented by Palearctic Realm.
2. Rest of subcontinent represented by Malayan Realm.
3. Biomes: A biome is a collection of plants and animals that have common characteristics for the environment they exist in. They can be found over a range of continents. The five biomes of India are Tropical Humid Forests, Tropical Dry or Deciduous Forests, Warm Deserts or Semi-deserts, Coniferous Forests and Alpine Meadows.
4. Biogeographic Zones: Biogeography deals with the geographical distribution of plants and animals. The Himalayan range is very rich in species diversity due to confluence of different bio-geographical zones.

Picture Credits: Wikipedia

4. Biogeographic provinces– It is an Eco systematic or biotic subdivision of realms.

5.1.2 Fauna

India accounts for about 6.45% of the faunal species known world-wide.

1. Vertebrates: These are animals with backbones and spinal columns.

2. In-vertebrates: These animals do not have backbones. More than 98% animal species in the world are invertebrates.

5.1.3 Flora 

India represents about 11% of the world’s known floral diversity.

Insectivorous plants specialize in trapping insects. They have several attractions to lure insects like bright colours and sweet secretions. They hunt for insects despite having normal roots as they are usually found in nutrient poor soils. As a result, they have to hunt in order to replenish themselves.
Some of the insectivorous plants found in India are Drosera/Sundew, Aldrovanda/Pitcher plants, Nepenthes, Utricularia/Bladderworts and Pinguicula/Butterworts. Insectivorous plants have great medicinal properties like treating cholera, urinary tract infections, blisters. Some are also capable of curdling milk.

are species whose introduction and/or spread outside their natural past or present distribution threatens biological diversity.

important medicinal plants of India are as follows:

5.1.4 IUCN Red Data Book 

IUCN Red Data Book contains the complete list of threatened species, including both plants and animals. The pink pages in this book include the critically endangered species. Green pages are used for species that were formerly endangered but have now recovered to a point where they are no longer threatened.

Picture Credits: IUCN

is a science-based network of more than 7500 volunteer experts from almost every country of the world.

5.1.5 Schedule Animals of Wildlife Protection Act 1972 (WPA)

Wildlife Protection Act consists of 6 schedule lists, which give varying degrees of protection. Poaching, smuggling and illegal trade of animals listed Schedule 1 to Schedule 4 are prohibited.

1. Schedule 1 and part II of Schedule 2
   1. Animals listed under these have absolute protection.
   2. Examples of animals listed in Schedule 1 include lion tailed macaque, great Indian bustard, black buck, rhinoceros, dugong etc.
   3. Animals under Schedule 2 are dhole, flying squirrel etc.
2. Schedule 3 and Schedule 4
   1. These animals are also protected but the penalties for offenses against them are lower.
   2. Schedule 3 animals include hyena, nilgai, barking deer, hog deer etc.
   3. Schedule 4 animals include vultures etc.
3. Schedule 5
   1. Animals under Schedule 5 are called “vermin” and can be hunted.
   2. Mice, rat, common crow and flying fox are few examples
4. Schedule 6
   1. Cultivation, collection, extraction and trade of plants and its derivatives listed in Schedule 6 are prohibited.
   2. Plants under this include Red Vanda, Blue Vanda, Kuth, Pitcher plant, Laddies Slipper Orchid and Beddomes Cycad

Pointers for prelims

. Some of the important ones facing extinction include:

Bird Conservation:

Integrated Development of Wildlife Habitats (IDWH) is a Centrally Sponsored Scheme where government provides financial and technical assistance to State/UT governments for wildlife conservation. The Scheme has following components:

5.1.6 Animal Diversity of India

Duck-billed platypus and some species of anteaters are few exceptions as despite being mammals, they lay eggs rather than giving birth to young ones. All of them are found only in Australia and New Guinea.

5.1.7 Marine Organisms

1. Plankton: It refers to both microscopic plants like algae (phytoplanktons) and animals like crustaceans and protozoans (zoo-planktons) found in all aquatic ecosystems except certain swift moving waters.
   1. Locomotory power of planktons is limited and their distribution is largely controlled by water current.
2. Phytoplankton: Phytoplankton are the autotrophic components of the plankton community and a key part of ocean and freshwater ecosystems. All phytoplankton have chlorophyll and carry out photosynthesis. Thus, they also act as a Carbon Sink by removing CO₂ naturally during photosynthesis.
   1. Common kinds of phytoplankton are cyanobacteria, protists and green algae.
   2. They are present throughout the lighted regions of all the seas and oceans including the Polar Regions and their total biomass is greater than that of total plants on land. However, their distribution is limited to the uppermost layers of the oceans where light intensity is sufficient for photosynthesis.
   3. The highest concentration of phytoplanktons is found at higher latitudes, while the tropics and subtropics have 10 to 100 times lower concentrations.
3. Zooplanktons: They are the animal component of the planktonic community. They are heterotrophic, meaning they cannot produce their own food and must consume instead other plants or animals as food. In particular, this means they eat plankton.
   1. Examples of zooplankton include tiny flagellates and giant jellyfish.
4. Sea-grass: They are marine flowering plants that resemble grass in appearance. They grow in shallow coastal waters with sandy or marshy bottoms and require comparatively calm areas. Sea-grass beds serve variety of purposes like:
   1. Reducing wave energy.
   2. Filtering sediments and nutrients from water.
   3. Controlling erosion.
   4. Serves as habitat for marine fauna.
5. Seaweeds: They are microscopic algae, meaning that they have no differentiation of true tissues such as roots, stems and leaves. Functions of seaweeds include:
   1. They are important as food for humans.
   2. They are used as a drug for goitre treatment.
   3. Commercial products like agar-agar, alginates and iodine can be extracted from them.
   4. Biodegradation of seaweeds can produce methane.
   5. They serve as indicators of marine pollution.
   6. Other general functions are similar to sea-grass.