Rajasthan Board RBSE Class 10 Science Notes 19 Biodiversity and its Conservation
- The variety of living beings found on earth is called biodiversity.
- As per ‘Technology Assessment Report, 1987’ by the USA, biodiversity is defined as follows:
- “The variety, differences and ecological complexity found among creatures is called biodiversity.”
Levels of Biodiversity:
There are three levels of biodiversity, viz. species diversity, genetic diversity and ecosystem diversity.
The total number of species of plants and animals in a given region is called species diversity of that region. Species diversity is considered as the most common meaning of biodiversity. This is taken as a unit of measurement for balance of any ecosystem.
The variation among members of a single species because of genes is called genetic diversity. This type of diversity is seen in different population groups of a species or even among different members of a population.
Each ecosystem has its unique geographical and environmental features. Such features are responsible for diversity among creatures in a particular region. This type of diversity is called ecosystem diversity. In other words, the differences in geographical and environmental conditions in different ecosystems are called ecosystem diversity.
According to Millennium Ecosystem Assessment, there are 5 to 30 million species on earth but out of which only 1.7 to 2 million species have been identified till date. The distribution of biodiversity is uneven on earth. The equatorial region is rich in biodiversity.
Biodiversity of India:
India comprises just 2.4% land area of the world but it has about 7-8% of the total biodiversity of the world. India has almost all types of ecosystem, e.g. grasslands, tropical rain forests, temperate forests, coral reefs, river valleys, islands, desert, etc. Due to this, India is among the 17 countries with Mega Biodiversity.
To be eligible to be categorized as biodiversity hotspot, a region must fulfill following criteria:
- It should have more than 0.5% of total endemic species of the world. It should have at least 1500 endemic species.
- At least 70% of original habitat of the region should have been destroyed, i.e. is under threat because of human activities.
Biodiversity Hotspots of India
- Eastern Himalayas Biodiversity Hotspot: Assam, Arunachal Pradesh, Sikkim and some areas of West Bengal come under this biodiversity hotspot. This hotspot is spread over 750,000 square km. There are about 10,000 species, out of which 3,160 are endemic species.
- Western Ghats Biodiversity Hotspot: The Western Ghats is along the western coast of Indian peninsula. This is spread over 160,000 square km. There are 5916 species of plants and animals in this hotspot, out of which about 50% are endemic species.
- Indo-Burma Biodiversity Hotspot: This region is spread over China, India, Myanmar, Vietnam, Thailand, Cambodia and Malaysia. This is spread over 2,373,000 square km. This huge hotspot is home to 13500 species of plants, 433 species of mammals, 1266 types of amphibians and 1262 types of fish.
- Endemic Species: A species which is found only in a particular region, i.e. in a limited area is called endemic species.
Importance of Biodiversity
- Economic Value: Biodiversity has immense economic value. We get food, fuel, fodder, timber, industrial raw materials, etc. directly from biodiversity. We are able to get different types of food, like rice, wheat, pulses, vegetables, fruits, etc. because of biodiversity.
- Medicinal Value: Herbs are being used as cure for many diseases since ancient times. As per one estimate, about 40% of the medicines are obtained from plants.
- Environmental Value: Biodiversity has immense environmental value. Biodiversity helps in conservation of food chain, regulation of nutrient cycle and in clearing environmental pollution.
- Social, Cultural and Spiritual Value: Some tribal societies exist even today which fully depend on nature for their needs. Some trees, like peepal, banyan, mango, tulsi, amla, banana, etc. have special place in our culture.
Threats to Biodiversity
Following are the reasons of threat to biodiversity:
- Habitat Loss: Because of growing population, we are destroying these habitats so that we can do farming and other activities to fulfill our needs.
- Habitat Fragmentation: The natural habitat of wildlife was earlier spread over huge areas. But construction of roads, rail lines, gas pipeline, canals, electricity transmission lines, farms, etc. has fragmented the habitats. It has badly affected the life of wild animals and they are always at risk of some accident.
- Climate Change: Human activities are also causing significant changes in climate. Increased emission of greenhouse gases has increased the temperature of earth.
- Environmental Pollution: Environmental pollution has adverse effect on plants and animals. Industrial waste pollutes land and water and destroys many plants and animals.
- Over Exploitation of Natural Resources: We have indulged in over exploitation of these resources for commercial interests. It has resulted in increased risk for many species.
- Commercial Practices in Agriculture and Forestry: Farmers now grow a selected type of seeds and rear certain selected breeds of cattle. This practice has drastically reduced genetic diversity of crops and cattle. Monoculture is being practiced to grow plants to feed the demand for paper, matchboxes, plywood and raw materials. Growing a single variety of plants by destroying the natural forest is called monoculture. The practice of monoculture is reducing biodiversity.
- Invasion of Foreign Species: Sometimes, intentional or non-intentional introduction of a foreign species endangers the existence of indigenous species. This creates an imbalance in the whole ecosystem.
- Superstition and Ignorance: Sometimes, superstition and ignorance also threaten a particular
species. People in rural parts of Rajasthan believe that Goira (Monitor Lizard) has poisonous breath. Hence, people instantly kill a Goira whenever they see one.
Conservation of Biodiversity:
Many efforts are on to save endangered species at local, national and international levels.
The United Nations constituted International Union for Conservation of Nature in 1968. This organization studied different species of plants and animals for four years and came with a book named ‘Red Data Book’. A comprehensive list of endangered species, their habitat and their current population was included in this book.
- Extinct Species: A species which is not longer found alive in any part of the world is called extinct species. Examples: Dodo, dinosaur, rainia plant, etc.
- Endangered Species: A species which is on the verge of extinction and can become extinct if timely action is not taken is called endangered species. Examples: Cheetah, tiger, gingko bioloba, sarpagandha, rhino, etc.
- Vulnerable Species: A species whose number is falling drastically and which is at risk of becoming endangered is called vulnerable species. Examples: yak, nilgiri langur, red panda, cobra, black bug, etc.
- Rare Species: A species which is found in limited geographical area and has a small population is called rare species. Examples: red wolf, Hainan Gibbon, Java Rhino, etc.
- Insufficiently Known Species: We have insufficient knowledge about some species and they cannot be kept under any specific category. Such species is called insufficiently known species.
India is one of the signatories to Convention on Biodiversity (CBD). In context of this, the Union Government enacted the Biodiversity Act 2002. This act has three main goals which are as follows:
- Conservation of biodiversity
- Sustainable use of biodiversity
- Equitable distribution of bio-resources to ensure their reach to maximum number of people
Under the Biodiversity Act 2002, there is a provision for a three-tier organization. National Biodiversity Authority works at national level, State Biodiversity Board is in states and Biodiversity Management Committees work at local level.
National Green Tribunal was constituted on 2nd June 2010 to bring all the laws related to environment, forest, water, air and biodiversity, under one umbrella.
Type of Biodiversity Conservation
- In-situ Conservation: The conservation which is carried out in natural habitat and with human intervention is called in-situ conservation.
- Ex-situ Conservation: In this method, a plant or animal is kept in an artificial habitat for conservation purpose.