An introduction to Biodiversity: Definition, Levels, Measures, Services, Threats and Conservation Methods.

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In this article, we will learn the following

  1. What is Biodiversity?
  2. What are the different levels of Biodiversity?
  3. How do we measure Biodiversity?
  4. What are the different services provided by Biodiversity?
  5. What are the main causes of Biodiversity Loss?
  6. What are the different methods of Biodiversity Conservation?

Biodiversity is our most valuable but least appreciated resource”- E.O. Wilson

What is Biodiversity?

Biological Diversity (abbreviated as Biodiversity) is the variety of all life forms-unicellular fungi, protozoa, bacteria, and multicellular organisms such as plants, animals, their genes and the ecosystems of which they are a part of.

It is the very existence of life on planet Earth. It exists both on land and in water- from high altitudes to deep ocean trenches.

The term “biodiversity” was popularised by socio-biologist Edward Wilson in 1988. He came to be popularly known as the Father of Biodiversity.

What are the different levels of Biodiversity?

The variety of life forms – Biodiversity- is considered to exist at three different levels. These are Genetic, Species and Ecosystem

Genetic Diversity:It is the variation in genes within a species, i.e. between the individuals of species. It is this diversity in genes that allows species to adapt themselves in changing environments and adapt to diseases.

For example: India has more than 50,000 genetically different strains of rice, and 1,000 varieties of mango!!!

Species Diversity: It is the variety of living organisms- the number of species of plants and animals on Earth.

For example: A Tiger and a cat!! Both of them belong to the same genus but are different species.

Latitudinal Variation in Biodiversity

The diversity of plants and animals is not uniform on Earth. In general, species diversity decreases as we move away from the equator towards the poles.

In general, except few exceptions, tropics (latitudinal range of 23.5° N to 23.5° S) host more species than temperate or polar areas. This is primarily because of three reasons:

•      Firstly, temperate regions have been subjected to frequent glaciations in the past, however, tropical latitudes have remained relatively undisturbed. Thus, it had long evolutionary time for species diversification.

•      Secondly, unlike temperate regions, tropical regions are less seasonal, relatively more constant and predictable. This helps in species diversification.

•      Finally, there is more solar energy available in the tropics, which contributes to higher productivity and indirectly contributes to diversity.

Note: Similarly, along the mountain gradients, biodiversity is normally greater in lower altitudes as compared to higher altitudes.

Ecosystem/Ecological Diversity: It refers to the different habitats, biological communities and ecological processes.

For example: A grassland or a forest or a pond. They are all different ecosystems.

How do we measure Biodiversity?

Biodiversity can be measured and monitored at several spatial scales. It is generally by two major ways:

  1. Species Richness- The number of species fond at a particular site.
  2. Species Evenness: Proportions of species or functional groups present on a site.

Species Richness can again be categorised into:

  1. Alpha Diversity: It is the diversity of species within a particular area or species
  2. Beta Diversity: It is the expression of diversity between habitats.
  3. Gamma Diversity: It is landscape diversity or diversity of habitats within a region.

Let us understand this through a simple diagram:

Alpha Diversity of Site

Alpha Diversity of Site A = 7 species, Site B = 5 species, Site C = 7 species.

Beta Diversity is observed between Site A and C with 10 species that differ between them and only 2 species in common.

Gamma diversity of 3 habitats is 12 species as total diversity.

What are the different services provided by Biodiversity?

Biodiversity provides a wide range of services which are of paramount importance at the local, regional and global level.  In general, the services provided by biodiversity can be classified into Ecosystem Services, Biological Services and Socio-Cultural Services.

  1. Ecosystem Services: These are the services that humans obtain from ecosystems. These include:
  • Maintenance of the water cycle
  • Soil formation, soil protection and maintenance of soil fertility
  • Nutrient Storage and Cycling
  • Degradation of waste, pollution breakdown
  • Carbon sequestration and Regulation of global climate
  • Control of potential pest and disease-causing species
  • Detoxification of soil and sediments, Stabilization of land against erosion
  1. Providing Biological Services: Food, clothing, housing, energy, medicinal resources, are all resources that are directly or indirectly linked to the biological variety present in the biosphere. These are of economic value.

Let us have a look at commonly used modern drugs derived from natural sources

  • Antimalarial drug Quinine is derived from Yellow cinchona
  • Penicillin, a general antibiotic, is derived from Penicillium fungi
  • Morphine, an Analgesic, is derived from Opium poppy
  1. Socio-Cultural Services:

Biodiversity provides us the opportunity for research and education. Also, the sheer aesthetic value of biodiversity has led to tourism and recreational activities.

It also holds importance in human culture- traditions and values.

For example: large number of sacred groves preserved by tribal people in several states of India.

What are the main causes of Biodiversity Loss?

The Global Assessment Report on Biodiversity and Ecosystem Services, released in 2019 by the UN’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), has warned that up to one million species are at risk of extinction!!!

So, let us check what are the major driving forces behind biodiversity loss?

Natural causes: These include floods, earthquakes, forest fires (Example the recent bushfire in Australia), landslides and pathological causes.

Anthropogenic Causes: The fast rate of biodiversity loss is largely attributed to human activities. There are four major causes- Habitat loss and fragmentation, Over-exploitation, alien species invasions and co-extinctions. These factors are often referred to as “The Evil Quartet”.

  1. Habitat Loss and Fragmentation: Habitat loss and fragmentation due to conversion of forest land for agriculture, industrialization, urban development etc. is the most important cause of biodiversity loss. A classic example of habitat loss is the rampant deforestation in Amazon forest in South America.
  2. Over-exploitation: A major reason for species extinction is over-exploitation of natural resources. Example: Overharvesting of fish, especially by trawling has led to serious depletion of fish stocks such as bluefin tuna and Grand Banks cod.
  3. Alien species invasions: the introduction of exotic weeds which are not a part of the natural vegetation leads to extinction of indigenous species. Common examples in India are lantana bushes, Eupatorium shrubs.
  4. Co-extinctions: When a species becomes extinct, the plant and animal species associated with it also becomes extinct- thus-posing a threat to overall biodiversity.

Other human activities such as unsustainable agricultural practices, poaching also lead to significant biodiversity loss.

For example, recently, poachers have killed two extremely rare white giraffes in northeast Kenya leaving just one such animal in the world ☹

Climate Change: Global warming and climate change has also accelerated biodiversity loss. This has also negatively impacted people’s food security and income.

Did you Know?

Bramble Cay melomys, found in the in the eastern Torres Strait of the Great Barrier Reef, Australia, is the first mammal species to be extinct due to anthropogenic climate change!

What are the different methods of Biodiversity Conservation?

Before discussing different methods of Biodiversity Conservation, let us understand the meaning of conservation. In simplest terms, conservation is the careful preservation, protection and efficient use of resources.

There are two major methods of Biodiversity Conservation:

  1. In-situ Conservation (on-site conservation): when the conservation of species is done in their own ecosystem or habitat where they survive, it is called In-Situ conservation.

It is done through establishment of protected areas- such as- National Park (Jim Corbett National Park), wildlife sanctuaries (Wayanad Wildlife sanctuary), Biosphere reserves (Nilgiris Biosphere Reserve), reserved/protected forests, protection of sacred groves, wetlands etc.

  1. Ex-Situ Conservation (off-site conservation): The conservation of species outside their habitat in scientifically managed facilities is termed as Ex-Situ Conservation.

The species are protected in an artificial environment. It can be done through various methods such as:

  • Zoological gardens or Zoos: Delhi Zoo, Alipore Zoo
  • Botanical gardens: Indian Botanical Garden in West Bengal
  • Gene Banks- places where genes of organisms are stored in frozen vaults- i.e. they are cryopreserved
  • Home gardens
  • Aquariums
Biodiversity conservation
Check your Progress with UPSC Previous Year Questions

Q1) Consider the following statements: (2011)

    1. Biodiversity is normally greater in lower latitudes as compared to higher latitudes
    2. Along the mountain gradients, biodiversity is normally greater in lower altitudes as compared to higher altitudes

Which of the following statements is/are correct?

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2

Q2) Which one of the following is not a site of in-situ method of conservation of flora? (2011)

a) Biosphere Reserves

b) Botanical garden

c) National Park

d) Wildlife Sanctuary

Q3) Which of the following can be threats to the biodiversity of a geographical area? (2012)

    1. Global Warming
    2. Fragmentation of habitat
    3. Invasion of alien species
    4. Promotion of vegetarianism

Select the correct answer using the codes given below:

a) 1, 2 and 3 only

b) 2 and 3 only

c) 1 and 4 only

d) 1, 2 and 4 only







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