Biodiversity: Definition, Types, Causes & Significance


What is Biodiversity?

Type of Biodiversity:

Genetic diversityA species can exhibit significant genetic diversity across its distributional range. A notable example is the medicinal plant Rauwolfia vomitoria, which displays genetic variation across various Himalayan ranges.India boasts over 1,000 different types of mangoes and a staggering 50,000 distinct genetic variations of rice.
Species diversityThe diversity of the flora and fauna at the species level. For instance, the Eastern Ghats have a lesser amphibian species diversity than the Wester Ghats.
Ecological diversityIt refers to the diversity of different biological communities or ecosystems like rain forests, deserts, mangroves, corals etc.India, for instance, with its wetlands, estuaries, alpine meadows etc. has a bigger diverse ecosystem than a Scandinavian country. 

Measurement of Diversities:

Alpha DiversityDiversity within a particular area or ecosystem is represented by alpha diversity. The number of species in an ecosystem, also known as species richness, indicates its level of biodiversity.
Beta DiversityIt is a difference of diversity between ecosystems, usually measured as the change in amount of species among the ecosystems.
Gamma DiversityIt measures overall diversity for the different ecosystems within a region.

Terminology Related to Species:

Flagship Species

  • A species is chosen to serve as a representative, symbol or ambassador for a specific habitat, issue, campaign or environmental cause. 
  • The examples are Giant panda, Indian tiger, Golden lion, African elephant, Asian elephant etc. 

Keystone Species

  • Species that cause significant changes in the abundance or occurrence of at least one other species when they are added to or removed from an ecosystem. 
  • These species play a role in the structure, functioning or productivity of a habitat or ecosystem.
  • Predators like Tiger, Lion, Crocodile, Elephant etc. are part of it.

Priority Species

  • A priority species indicates a significant threat within an ecoregion, and conserving this species will greatly help in addressing the broader threat. 
  • It is also important to note that this species plays a vital role in the economic or spiritual welfare of the people living in that ecoregion.

Indicator Species:

  • An indicator species or a group of species is selected to represent and provide information about the condition of an ecosystem or a specific process occurring within that ecosystem.
    • Crayfish as indicators of freshwater quality.
    • Lichens are indicators of air quality (sensitive to sulphur dioxide).

Foundation Species

  • Like Corals serve as the dominant primary producers in an ecosystem, exhibiting both abundance and influence.

Charismatic Species

  • Certain charismatic megafauna captures the attention of the general public and are often utilized by environmental activists to promote conservation efforts that extend beyond the scope of these particular species.
  • The examples are Giant panda, Barasingha (Bhoorsingh from Kanha National Park), The Bengal Tiger and Blue Whale are examples.

Umbrella Species

  • It acts as an umbrella for conservation attempts and programs. Conservation of umbrella species would extend protection to other species as well.
  • To conserve tigers, endeavours have been undertaken to preserve the populations of wild tigers, which in turn helps protect other species inhabiting the same ecosystems, such as leopards, monkeys, hares, boars, and more.

Invasive/Alien Species

  • Species that occur outside their natural range and threaten native plants and animals or other aspects of biodiversity by altering and utilising the components of the ecosystem in which they are introduced.
  • The examples are Goat weed, Calotropis/Madar, Swallow wort, Water Hyacinth, Alternanthera paronychioides etc.

Significance of Biodiversity:

  • Species of various types play important roles in ecosystems. Each organism not only meets its own needs but also provides benefits to other organisms in the environment. 
  • They capture, store, and utilize energy, produce and break down organic materials, participate in water and nutrient cycles, and contribute to gas fixation in the atmosphere. 
  • Additionally, they help regulate the climate, promote soil formation, reduce pollution and protect land, water, and air resources
  • These functions of biodiversity are crucial for maintaining ecosystem functions and stability.

Loss of Biodiversity

  • The loss of biodiversity refers to the loss of species, ecosystems, or genes. The planet’s biological wealth is decreasing rapidly. 
  • Over the past 500 years, the IUCN Red List has recorded the extinction of 784 species, including 338 vertebrates, 359 invertebrates, and 87 plants
  • According to the Living Planet report, in the last 20 years, there have been the disappearance of more than 30 species.
  • The current rate of species extinction is between 100 and 1000 extinctions per 10,000 species over a span of 100 years. 
  • The report measures the abundance of biodiversity, shows a consistent downward trend. On average, populations of monitored species have declined by 58% since 1970. 

Causes for Loss of Biodiversity:

  • Over-exploitation of species
  • Introduction of alien species
  • Habitat loss and fragmentation
  • Global climate change
  • Natural causes like floods, earthquakes and other natural disasters etc.

Biodiversity and its conservation are now vital environmental issues of international concern as more and more people around the world begin to realise the critical importance of biodiversity for well- being and survival on this planet.


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