Biodiversity and sustainable development | Environmental Geography | Principle Of Geography

 

Environmental Geography

Principle Of Geography

Geography Complete Study Material

(Paper - I)

Biodiversity and Sustainable Development

Biodiversity

          A wide variety of living organisms including plants, animals and micro-organisms with whom we share this planet earth makes the world a beautiful place to live in. Living organisms exist almost everywhere from mountain peaks to the ocean depths; from deserts to the rainforests. They vary in their habit and behaviour, shapes, sizes and colour. The remarkable diversity of living organisms form an inseparable and significant parts of our planet however, the ever increasing human population is posing serious threats to bio-diversity.

Types of Biodiversity

         Sum total of all the variety of living organisms on earth constitute biodiversity. Biological diversity is usually considered at three different levels – a) genetic diversity i.e. at genetic level , b) species diversity i.e. at the level of species, and c) ecosystem diversity i.e. at the level of ecosystem.

(a) Genetic diversity 

              Each species, varying from bacteria to higher plants and animals, stores an immense amount of genetic information. For example, the number of genes is about 450-700 in mycoplasma, 4000 in bacteria (eg. Escherichia coli) , 13,000 in Fruit-fly (Drosophila melanogaster); 32,000 – 50,000 in rice (Oryza sativa); and 35,000 to 45,000 in human beings (Homo sapiens sapiens). This variation of genes, not only of numbers but of structure also, is of great value as it enables a population to adapt to its environment and to respond to the process of natural selection. If a species has more genetic variation, it can adapt better to the changed environmental conditions. Lower diversity in a species leads to genetic uniformity of genetically similar crop plants. This homogeneity is desirable in producing uniform quality of grain. But genetic uniformity restricts adaptability of a species to environmental stress as all the plants have same level of resistance.

             With the above background, genetic diversity refers to the variety of genes contained within species of plants, animals and micro-organisms. New genetic variation in individuals occurs by gene and chromosomal mutation, and in organisms with sexual reproduction may be spread across the population by recombination. For instance, two brothers differ in their structure, although their parents are the same. The differences could be in alleles (different variants of the same gene), in entire gene (the traits determining particular characteristics) or in chromosomal structure. The amount of genetic variation (gene pool) present in an inter-breeding population is shaped or decided by the process of natural selection. Selection leads to certain genetic attributes being preferred and results in changes in the frequency of genes within this pool. This forms the basis of adaptation among the living organisms. India has high genetic diversity and is regarded as a Vavilov’s centre of high crop genetic diversity – so named after the Russian agro-botanist N I Vavilov, who identified eight such centres of origin of cultivated plants around the world in the 1950s.

(b) Species diversity 

              Species diversity refers to the variety of species within a geographical area. Species diversity can be measured in terms of: 

(a) Species richness – refers to the number of various species in a defined area.

(b) Species abundance – refers to the relative numbers among species. For example, the number of species of plants, animals and microorganisms may be more in an area than that recorded in another area. 

(c) Taxonomic or phylogenetic diversity – refers to the genetic relationships between different groups of species. 

            Kinds of species that are present in an area is also important. When taxonomically unrelated species are present in an area, the area represents greater species diversity as compared to an area represented by taxonomically related species. At the global level, an estimated 1.7 million species of living organisms have been described to date and many more are yet to be discovered. It has been currently estimated that the total number of species may vary from 5 - 50 millions. Species diversity is not evenly distributed across the globe. The overall richness of species is concentrated in equatorial regions and tends to decrease as one moves from equatorial to polar regions. In addition, biodiversity in land ecosystems generally decreases with increasing altitude. The other factors that influence biodiversity are amount of rainfall and nutrient level in soil. In marine ecosystems, species richness tends to be much higher in continental shelves.

(c) Ecosystem diversity 

          It refers to the presence of different types of ecosystems. For instance, the tropical south India with rich species diversity will have altogether different structure compared to the desert ecosystem which has far less number of plant and animal species. Likewise, the marine ecosystem although has many types of fishes, yet it differs from the freshwater ecosystem of rivers and lakes in terms of its characteristics. So such variations at ecosystem level are termed as ecosystem diversity.

          As stated above, ecosystem diversity encompasses the broad differences between ecosystem, and the diversity of the habitats and ecological processes occurring within each ecosystem type. India has very diverse terrestrial and aquatic ecosystems ranging from ice-capped Himalayas to deserts, from arid scrub to grassland to wetlands and tropical rainforests, from coral reefs to the deep sea. Each of these comprises a great variety of habitats and interactions between and within biotic and abiotic components. The most diversity-rich are western-ghats and the north-eastern region. A very large number of species found in these ecosystems are endemic or found in these areas only in India i.e. they are found no where else except in India. The endemics are concentrated mainly in north-east, western-ghats, north-west Himalaya, and Andaman and Nicobar Islands. About 33% of the flowering plants recorded in India are endemic to our country. Indian region is also notable for endemic fauna. For example, out of recorded vertebrates, 53% freshwater fish, 60% amphibians, 36% reptiles and 10% mammalian fauna are endemic.

CONSERVATION OF BIODIVERSITY 

           Conservation is the planned management of natural resources, to retain the balance in nature and retain the diversity. It also includes wise use of natural resources in such a way that the needs of present generation are met and at the same time leaving enough for the future generations. Conservation of biodiversity is important to:-

• prevent the loss of genetic diversity of a species, 

• save a species from becoming extinct, and 

• protect ecosystems damage and degradation.

Important Point:

• Biodiversity refers to the totality of genes, species, and ecosystems of plant, animals or micro-organisms in a region. Study of biodiversity has become very important recently after realising the value of biodiversity for our survival. It has many medicinal, commercial, economic and scientific uses. 

• Wild relatives of cultivated crop plants are the source of genes for disease resistance and several other attributes required for crop improvement. 

• Biodiversity also provides valuable services like water conservation, clean air, soil conservation and improvement of soil fertility, pollution break-down, aesthetic needs and so on. 

• The total number of species on earth is estimated to range from 5-100 million, but only about 1.8 million species have so far been described. 

• India is very rich in biodiversity and is one of 12 megadiversity countries globally recognized. In India, 70 % of the country’s area has been surveyed and around 45,000 species of microorganisms and plants; and 81,000 species of animals have been described till date. 

• Biodiversity has 3 levels - i) genetic, ii) species, and iii) community or ecosystem. Species are distinct units of diversity and each species plays a specific role in a ecosystem. 

• The diversity within a species often increases with environmental variability. Species diversity refers to the variety of species within a region. In ecosystem biodiversity, the biodiversity increases from polar regions towards the equator, and from high elevations to low elevations. 

• Habitat loss and fragmentation, over-exploitation, environmental pollution, climate change and introduction of exotic species pose major threat to biodiversity. It is estimated that 14,000-40,000species are being lost every year from the tropical forests alone. 

• The IUCN Red list is the world’s most comprehensive inventory of the global conservation status of threatened plant and animal species. 

• It is important to ensure the conservation of landscapes, ecosystems, species and genetic resources failing which it will create survival crisis for mankind. 

• Conservation strategies include in-situ (on-site)and ex-situ (off-site) approaches. 

• Habitat protection is the main in-situ approach. The Protected Area Network for habitat protection includes national parks, wildlife sanctuaries, biosphere reserves, sacred groves or sacred forests. 

• Ex-situ conservation is doen by setting up botanical gardens, zoos, gene banks and seed banks, cryopreservation and preservation of germplasm.

Sustainable Development

          In United Nations Conference on Environment and Development (the “Earth Summit”) held in Rio de Janerio in year 1992, the world leaders signed Framework Convention on Climate Change and Biological Diversity. The “Rio Summit” adopted Rio Declaration for achieving Sustainable Development in the 21st Century. It is here that the concept originated.

          Development requires resources for the production of goods and services. The resources are basically provided by nature and thus known as natural resources. We must learn to respect nature and use the resources in a judicious and responsible manner, failing which we will deprive our future generations from these natural resources thereby endangering their life on this planet. Population growth coupled with unplanned and ruthless exploitation of natural resources in the name of development is the root cause of our present state of environment. Economic development is absolutely necessary for the welfare of people even though it causes damage and destruction of our environment. With economic development increasing use of natural resources is inevitable. Also with the increasing population these are bound to be tremendous increase in the use of resources. But the million dollar question is how do we use our resources? Can we use them so efficiently that we are able to conserve them, save them, use alternate and non-conventional resources and allow them (resources) to regenerate so that we do not run out of their stock? We have to hand over the earth with its environment clean and intact to our future generations. We owe this responsibility to them. So it is binding in us not to exploit our environment beyond its carrying capacity.

        The concept of carrying capacity will become clear, by using the familiar example of any transport vehicle like a car or a bus. What is the carrying capacity of a car? It is the maximum number of people, it can carry without breaking down in the middle of a journey. If the number of passenger or people travelling in a car become more than its capacity to carry, then it would run slowly and may even break down in the middle of the road. Thus carrying capacity is the maximum pressure or load that a system can with stand before breaking down.

        Similarly environment also has a capacity to bear the pressure of continual use. Its carrying capacity would be in terms of maximum amount of natural resources drawn from it and maximum amount of pollution discharged into it. If too much resources are extracted or used up than it can afford to give or too much pollutants are discharged into it than it can absorb, then it is severely damaged. Once damaged and destroyed beyond repair, it loses its ability to get back to its pure or usable or harmless state. Thus the carrying capacity of the environment may be defined as maximum load or pressure or use that the environment can withstand by economic or other human activities. Nature is finite and we have almost reached a critical point beyond which ecological decline would lead to disaster.

Important Point:

• Economic development is necessary for the welfare of people but it should not be at the cost of environmental degradation. 

• Carrying capacity is the maximum pressure or load that a system can withstand or take up before breaking down. 

• Carrying capacity of the environment may be defined as maximum use of human activities that the environment can tolerate. 

• Sustainable development is “development that meets the needs of the present taking care of the needs of future generations”. 

• Human activities like agriculture, industrialization etc. affect sustainability of biosphere. 

• Human activities meant to improve the quality of life are usually accompanied by environmental degradation. 

• Rapid growth of population coupled with demand and needs of man for material comforts has put tremendous pressure on earth and its environment.

• Most dangerous consequence of population is poverty. Poverty is a major threat to human health and environment. 

• One method of eliminating poverty is by taking care of equitable i.e. far and just distribution of resources. 

• Resource is anything useful or can be made useful to humans to meet their needs and wants. 

• Resources that belong to no one in particular become common property. Examples air, water, rivers, forest, oceans, mountains etc. 

• People are apathetic and careless for them or their maintenance. 

• Each of us must treat the common natural resources with same amount of care as one treats the personal things. 

• Privately owned industries, agricultural land, houses, building, offices, gardens etc. are cared for and looked after by the owners. 

• Ecological foot print is a measure of area of earth required per person (to produce resources) and waste production. 

• Ecological foot print of most people in developed countries is large because of the half amount of consumption of natural resources. 

• There is need to conserve and manage the resources for posterity. 

• In order to improve the environment it is important to act and encourage other for conservation of natural resources.