Biodiversity UPSC

Biodiversity

• The term ‘biodiversity’ refers to ‘the variety and variability among living organisms and the ecological complexes in which they occur.’

• It can be defined as ‘the totality of genes, species and ecosystems of a region’.

Levels of Biodiversity

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 sur-vive drastic changes and thus carry on desirable genes. 

• The survival of individuals ensures the survival of the population. 

• The genetic diversity gives us beautiful butterf l ies, roses, parakeets or coral in a myriad hues, shapes and sizes.

Species diversity: 

• It refers to the variety of living organisms on earth. 

• Species dif f er from one another, markedly in their genetic makeup, do not inter-breed in nature. 

• Closely-related species however have in common much of their hereditary characteristics. For in-stance, about 98.4 per cent of the genes of humans and chimpanzees are the same.

• It is the ratio of one species population over total number of organisms across all species in the given biome. 

• ‘Zero’ would be inf i nite diversity, and ‘one’ repre-sents only one species present. 

Ecosystem/ Community diversity: 

• This 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 around the world. Corals, grasslands, wetland, desert, mangrove and tropical rain forests are examples of ecosystems.

• Change in climatic conditions is accompanied by a change in vegetation as well. Each species adapts itself to a particular kind of environment. 

• As the environment changes, species best adapted to that environment becomes predominant. Thus the variety or diversity of species in the ecosystem is influenced by the nature of the ecosystem.

Measurement of Biodiversity

Species Richness

It represents the number of different species in a given habitat or region.

Species Evenness

It is the measure of relative abundance of different species in the area.

Indices Used by Ecologists to Measure Diversity

Alpha Diversity

Refers to the diversity of organisms sharing the same community or habitat. A combination of species richness and evenness is used to represent diversity within a community or habitat

Beta Diversity

Indicates diversity between communities. Species frequently change when habitat or community changes. There are differences in species composition of communities along environmental gradients like latitudinal gradients, moisture gradients thereby increasing dissimilarity between communities.

Gamma Diversity

Refers to the diversity of the habitats over the total landscape or geographical area.

Gradients of Biodiversity:

• Biodiversity is not uniform on earth. It varies with change in latitude or altitude. Biodiversity increases, when we move from high to low altitude (i.e. from poles to the equator).

• Biodiversity in tropics is higher compared to temperature region which has severe climate.

Eg:- Decrease in number of ant species along the latitudinal gradient (from low to high altitude).

• Similarly, the species diversity decreases from lower to higher altitude on a mountain.

Benefits of Biodiversity

1. Source of food and Improved Varieties:

Human food is entirely obtained from living world. We have several thousand species of edible plants, but only less than 20 plant species are cultivated to produce about 85% of the world’s food. The rest 15% of world's food is produced by animals. Improved varieties of crop plants and domestic animals are the backbone of modern agriculture, and wild relatives of crop plants and useful animals are essential for regular production of high yielding and disease resistant varieties.

2. Drugs and Medicines:

Biodiversity has many medicinal uses. A number of substances with therapeutic properties are obtained from plants. For example, Morphine, used as an analgesic is obtained from Chinchonaledgeriana tree.

3. Aesthetic and cultural benefits:

Biodiversity provides a good deal of fun and recreation. Ecotourism, bird watching, wildlife, gardening etc are some examples of aesthetics rewards of biodiversity. Biodiversity is also related to our cultural and religious beliefs. Plants and animals are considered to be symbols of aesthetic rewards of our cultural heritage. For example, Ocuimus sanctum (Tulsi) is considered sacred and worshiped by many people in India.

4. Ecosystem Services

Biodiversity is essential to keep natural cycles going and making the ecosystem a self sustaining unit. 

Some of the services are:

(i) Maintenance of gaseous composition of the atmosphere.

(ii) Climate control by forests and oceanic systems.

(iii) Natural pest control.

(iv) Formation and protection of soil.

(vi) Nutrient cycling etc.

Threats to Biodiversity

1. Destruction of Habitats: 

a primary threat to biodiversity. In many parts of the world, natural habitats, which protect natural flora and fauna are being converted to human settlements, crop-lands, dams, and mining sites.

2. Habitat Fragmentation: 

the process where a large, continuous area of habitat is divided into two or more fragments. It limits the dispersal and colonisation potential of species and also reduces the foraging abilities of animals.

3. Disturbance and Pollution: 

Natural as well as man-made disturbances such as fire, tree fall, defoliation, release of radiation, oil spill in water bodies, eutrophication/nutrient enrichments etc affect communities adversely.

Environment pollution also moves up the food chain an further affects the rest of the species in the food web.

4. Introduction of exotic species: 

Introduction of exotic/alien species may cause significant loss to the biological communities. These species, if successful in the new area, may kill or eat native species to the point of extinction, or may alter the habitat that many natives are no longer able to persist.

Modes of Conservation

In-Situ Conservation

It refers to the conservation of biological diversity in their natural habitats through protection of total ecosystem.

Protected Areas:

• These areas of land and/or sea especially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources. The protected areas are managed through legal or other effective means.

National Parks:

• An area which is strictly reserved for the welfare of wildlife and where activities such as forestry, grazing or cultivation are not allowed.

• Private ownership right and habitat manipulation are not permitted in a national park.

Wild Life Sanctuaries:

• An area which is reserved for the conservation of animals only.

• Operations such as harvesting of timber, collection of minor forest products and private ownership rights are allowed provided they do none affect the animals adversely.

• There are around 500 Wildlife Sanctuaries in India.

Conservation Reserves and Community Reserves:

Conservation Reserves:

• Protected areas of India which typically act as buffer zones to or connector and migration corridorsbetween established national parks, wild life sanctuaries, and reserved and protected forests of India

• First introduced in the Wildlife (Protection) Amendment Act of 2002.

• There are 65 conservation reserves with J&K highest with 34 conservation reserves.

Community Reserves:

Similar to Conservation reserves but area held by private individuals/groups

Biosphere Reserves:

The Man and Biosphere (MAB) program of UNESCO formulated the concept of Biosphere Reserves in 1975, which deals with the conservation of ecosystems and the genetic resources contained therein.

There are 18 biosphere reserves in India of which 11 are part of the UNESCO MAB program. 

Core Zone: 

It comprises an undisturbed and legally protected ecosystem.

Buffer Zone:

It surrounds the core area, and is managed toaccommodate a greater varieties of resource use strategies, and research and educational activities.

Transitional Zone: 

It is the outermost part of the Biosphere reserve. It serves as an area of active cooperation between reserve management and the local people, wherein activities like settlements, cropping, forests and recreation and other economic uses continue in harmony with conservation goals.

Sacred Forests or Lakes:

There has been traditional practice in India to maintain sacred forests and lakes to protect biodiversity. The sacred forests/lakes are protected by tribal communities and local peoples due to religious sanctity accorded to these forests.

Eg : Khecheopalrilake in Sikkim has been declared sacred by the people to save aquatic life from degradation.

Ex-situ conservation

It refers to conservation of biodiversity at places away from their natural habitat. These include botanical gardens, zoos, genetic resource centres, pollen grains, DNA banks etc.

Seed Gene Banks/Germplasm Banks: 

Are the easiest way to store germplasm of wild and cultivated plants in low temperature in cold rooms at ultra low temperature called cryopreservation.

Botanical garden : 

Botanical garden refers to the scientifically planned collection of living trees, shrubs, herbs, climbers and other plants from various parts of the globe.

Zoo : 

Zoo is an establishment, whether stationary or mobile, where captive animals are kept for exhibition to the public and also aims to conserve endangered animals through captive breeding programmes.

Biodiversity hotspots :

• A biodiversity hotspot is a bio-geographic region with a significant reservoir of biodiversity that is under threat from humans

• Norman Myers wrote about the concept

Criteria:

• Must contain at least 05% or 1500 species of vascular plants as endemics.

• It has to have lost at least 70% of its primary vegetation.

At world level:

▪ There are 35 Biodiversity hotspots throughout the world.

▪ These sites support nearly 60% of the world’s plant, bird, mammal, reptiles and amphibian species with a very high share of endemic species.