BIODIVERSITY

Biodiversity is all the different kinds of life found in one area i.e., the variety of animals, plants, fungi and even microorganisms like bacteria that make up the natural world. Each of these species and organisms work together in ecosystems like an intricate web, to maintain balance and support life.

Biodiversity is the variety of life on earth, including organisms, species and populations; the genetic variation among these and their complex assemblages of communities and ecosystems.

Definition

Biodiversity is defined as the variability among living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species and of ecosystems.

Biodiversity is not distributed evenly on Earth, it is usually greater in the tropics because of the warm climate and high primary productivity in the region near the equator. These tropical forest ecosystems cover less than 10% of the earth’s surface and contain about 90% of the world’s species.

1. Levels of Biodiversity

Biodiversity is considered to exist at three levels: genetics, species and ecosystems.

Genetic diversity

• It is concerned with the variation in genes within a particular species.
• Genetic diversity allows species to adapt to changing environments.
• This diversity aims to ensure that some species survive drastic changes and thus carry on desirable genes.
• The survival of individuals ensures the survival of the population.
• genetic diversity gives us beautiful roses, butterflies, and corals in different shapes, hues and sizes, butterflies.

Species Diversity

• Species diversity refers to the variety of living organisms on earth.
• Species differ from one another, markedly in their genetic makeup, and do not interbreed in nature.
• Closely related species have many common hereditary characteristics. For instance, 98.4% of the genes of humans and chimpanzees are the same.
• Species diversity is defined as the number of different species present in an ecosystem and the relative abundance of each of those species.
• It is the ratio of one species' population over a total number of organisms across all species in the given biome.
• Zero would be infinite diversity and one represents only one species present.

Ecological diversity

• Ecological diversity refers to the different types of habitats. A habitat is the cumulative factor of the climate, vegetation and geography of a region.
• There are several kinds of habitats in the world. Corals, wetlands, grasslands, deserts, mangroves and tropical rainforests are good examples of this.
• Change in climatic conditions is accompanied by a change in vegetation. Each species adapts itself to a particular kind of environment.
• As the environment changes, species best adapted to that environment become predominant. Thus the variety or diversity of species in the ecosystem is influenced by the nature of the ecosystem.

Biodiversity is measured by two major components :

Species Richness, Species Evenness.

Species Richness

Species richness is the number of different species found in a given ecosystem. It is the most common type of biodiversity index. When the number of species in a particular location is high, it is considered that species richness is high.

It is of three types

1. Alpha diversity- It refers to the diversity within a particular area or ecosystem and is usually expressed by the number of species in that ecosystem.
2. Beta diversity- It is a comparison of diversity between ecosystems, usually measured as the change in the amount of species between the ecosystems.
3. Gamma diversity- It is a measure of the overall diversity of the different ecosystems within a region.

Species Evenness

Species evenness measures the proportion of species at a given like low evenness indicates that a few species dominate the site.

Food Web

• The building blocks of living organisms like plants, animals, and humans are identical and are made up of carbon, oxygen, nitrogen and hydrogen. These elements are found in the environment like air, water, and soil.
• Only green plants can absorb nitrogen from soil through their roots and use sunlight, and water to produce energy by a process called photosynthesis, hence known as producers.
• Consumers are the organisms that depend on other organisms for their food. The chain that links consumers to producers is called the food chain or food web.
• Every single creature is found in the food web. There are several food chains and they can be complex or simple depending on the environment.
• The importance of every creature in the web of life is evident. Tampering with the food chain only produces negative results, leading to the destruction of the species.
• Every time a species becomes extinct, the chain is broken and many species including humans, move closer to extinction.

2. Biodiversity provides several natural services for human beings.

Biological services

• Medicinal resources and pharmaceutical drugs.
• Wood products
• Food
• Ornamental plants
• Diversity in genes, species, ecosystems
• Breeding stocks

Ecosystem services

• Recovery from unpredictable events.
• Protection of water resources.
• Maintenance of ecosystems.
• Soil formation, and protection.
• Contribution to climate stability.
• Nutrient storage, and recycling.

Social Services

• Cultural values
• Research, education, monitoring
• Recreation and tourism.

3. Loss of biodiversity

Loss of biodiversity occurs when either a particular species is destroyed or the habitat essential for its survival is damaged. The latter is more common as habitat destruction is an inevitable fallout of development.

The extinction of species takes place when they are exploited for economic gain or hunted for sport or food. Extinction of species may also occur due to environmental reasons like ecological substitutions, biological factors and pathological causes which can be caused either by nature or by humans.

Natural Causes

• Lack of pollination and diseases.
• Floods
• Earthquakes
• Landslides
• Rivalry among species

Anthropogenic causes

• Conversion of rich biodiversity sites for human settlement and industrial development.
• Extension of agriculture.
• Uncontrolled commercial exploitation
• Hunting & poaching
• Filling up of wetlands.
• Destruction of coastal areas
• Habitat destruction.

4. Conservation of Biodiversity

Conservation of biological diversity leads to the conservation of essential diversity and preserves the continuity of food chains.

Different Modes

Ex-situ Conservation

• Conserving biodiversity outside the areas where it naturally occurs is known as ex-situ conservation.
• In ex-situ conservation, animals are reared or plants are cultivated in zoological parks or botanical gardens. Reintroduction of an animal or plant into the habitat from where it became extinct is another form of ex-situ conservation.
• Seed banks, botanical gardens, and horticultural and recreational gardens are important centres for ex-situ conservation.
• For instance, the Gangetic gharial was reintroduced in the rivers of Uttar Pradesh, Madhya Pradesh and Rajasthan where it became extinct.

In-situ Conservation

• Conserving the plants and animals in their natural habitat is known as in-situ conservation.
• The established natural habitats are- National Parks, Sanctuaries, Biosphere reserves, Reserved forests, and Protected forests.

Limitations in biodiversity conservation

• Exploitation of living natural resources for monetary gain.
• Low priority for conservation of living natural resources.
• Unplanned urbanization and uncontrolled industrialization.
• Values & knowledge about the species and ecosystem are adequate.

Zoological park

• A zoo is an establishment, whether stationary or mobile, where captive animals are kept for exhibition to the public & includes a circus, and rescue centres but doesn’t include an establishment of a licensed dealer in captive animals.
• The main purpose of zoos was entertainment, over the decades, zoos have been transformed into centres for wildlife conservation and environmental education.
• Apart from saving individual animals, zoos have a role to play in species conservation also.

Botanical gardens

• A botanical garden refers to a scientifically planned collection of living trees, shrubs, herbs, climbers and other plants from different parts of the world.
• The main purpose of the botanical garden is to study the taxonomy as well as the growth of plants.
• To study the introduction and acclimatization process of exotic plants, botanical gardens are necessary.
• These gardens act as germ-plasm collections.
• They also help in the development of new hybrids.
• It augments conserving rare and threatened species.

The Red Data Book

• Species judged as threatened are listed by various agencies and by some private organizations. The most cited of these lists is in the Red Data Book.
• It is a volume of information on the status of many kinds of species.
• This volume is continually updated and is issued by the International Union for Conservation of Nature (IUCN) located in Morges, Switzerland.
• “Red” symbolizes the danger that the species of plants & animals presently experience throughout the world.
• The Red Data Book was first issued in 1966 by IUCN’s special Survival Commission as a guide for the formulation, preservation and management of species listed.
• Information about endangered mammals, and birds is more extensive than other groups of animals, plant coverage is also given to less prominent organisms facing extinction.
• The pink pages in this book include the critically endangered species. As the status of the species changes, new pages are sent to the subscribers.
• Green pages are used for those species that were formerly endangered but have now recovered to a point where they are no longer threatened.
• with time, the number of pink pages continues to increase. There are a few green pages.

IUCN Classification

Extinct(Ex)

A taxon is extinct when there is no doubt that the last organism dies. A taxon is presumed Extinct when exhaustive surveys in known and expected habitat, at proper durations, throughout its historic range have failed to record an individual.

Extinct in the Wild(EW)

A taxon is considered Extinct in the Wild, when it is known only to survive in cultivation, in captivity or as a naturalized population, outside the past range.

Critically Endangered

• A taxon is Critically Endangered when the best available evidence indicates that it meets any of the criteria for Critically Endangered.
• If the population of a species is reduced by more than 90% over the last 10 years and if the matured organisms are less than 50, it is considered as the species is endangered.
• If the quantitative analysis shows the probability of extinction in the wild in at least 50% in their 10 years, it is considered as critically endangered.

Endangered

• A taxon is endangered when the best available evidence indicates that it meets any of the criteria for endangered.
• If the population size is reduced by 70% over the last 10 years and the population size is estimated to number less than 250 mature individuals, the species is considered endangered.
• If the quantitative analysis shows the probability of extinction in the wild at least 20% within 20 years, it is considered as endangered.

Vulnerable(VU)

• A taxon is vulnerable when the evidence indicates that it meets any of the criteria for vulnerable like-
• Reduction in population by less than 50% over the last 10 years.
• Species population is estimated to number fewer than 10,000 mature individuals,
• The probability of extinction in the wild is at least 10% within 100 years.

Near Threatened(NT)

A taxon is near threatened when it has been evaluated against the criteria but does not qualify for critically endangered, endangered, or vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category shortly.

Least Concern(LC)

A taxon is of Least Concern when it is evaluated against the criteria and does not qualify as critically endangered, vulnerable, endangered, or near threatened. Widespread and abundant taxa are included in this category.

Data Deficient(DD)

• A taxon is data deficient when there is inadequate information to make a direct, indirect assessment of its risk of extinction based on its distribution and population status.
• A taxon in this category may be well studied and its biology is well known, but appropriate data on abundance and distribution is lacking.
• Data deficient is not a category of threat.
• Listing of taxa in this category indicates that more information is required and acknowledges the possibility that future research will show that threatened classification is appropriate.

Not Evaluated(NE)

A taxon is not evaluated when it is not been evaluated against the criteria.