The term Biodiversity refers to the variety of life forms, from genes to species to broader scale of ecosystems. In other words, it means variety and variability among living organisms, their genetic differences and the ecosystems in which they live. This living wealth of earth is the outcome of millions of years of evolutionary history.

The diverse weather and physio-geographic features contribute to rich faunal and floral biological diversity in UP. The habitats range from natural forest and semi natural thorn scrub to alluvial grasslands, diverse agricultural ecosystems to fragile wetlands.
 
Biodiversity has been viewed in many ways depending upon the perspectives of people from different spheres. In many instances, it has also been referred to “life” or “wilderness”. The distribution of biodiversity is uneven on the earth because of the different environmental conditions.

Levels of Diversity

Biodiversity is often considered at three fundamental levels - genetic, species and ecosystem level.

1. Genetic diversity: It refers to genetic differences within each species i.e. differences at the level of genes. For example, varieties of crops, strains of microbes or breeds of livestock. According to an estimate there are 10 billion different genes distributed across the world’s living organisms. More genetic diversity within a species means greater variability and adaptability of individuals to environmental conditions. Lesser genetic diversity on the other hand leads to uniformity and thus greater susceptibility to environmental changes. Monocultures (genetically similar crops or trees) are known to be more susceptible to environmental changes compared to mix-cultures (genetically different crops or trees) because of little genetic diversity in them. The genetic variations can be measured using a variety of DNA-based and other techniques.
2. Species diversity: It refers to the variety of species of animals, plants or microorganisms found on the earth. Biodiversity term is mostly considered as a synonym to species diversity. It is very important level of biodiversity since it is easier to work with it and the species can be seen with the naked eyes unlike genetic diversity that can be worked out only in the laboratories. There is a wide difference in the various estimates for the total number of species found on this earth (this varies from 5 to 100 million). However, so far nearly 1.7 million species have actually been described. Species diversity can be measured in a number of ways. Most of these ways can be classified into three groups of measurements - species richness, species abundance and taxonomic diversity.
3. Ecosystem diversity: It includes various types of ecosystems and the diversity of habitats and ecological processes occurring therein. Examples of various ecosystems are coral reefs, tropical rain forests or temperate rain forests and these are based on the major communities. The measurement of biodiversity within an ecosystem is a difficult task because of their complex nature.

 
Importance of Biodiversity

Biodiversity is very important as it provides a number of valuable services to us. These are:

Ecological Services

Biodiversity provides us various ecosystem services that sustain our life. Some of these services are as under:
Conservation and Protection of Water:

In the water catchments and riparian areas vegetation act as a buffer and helps in maintaining movement and storage of water within biosphere (atmosphere, lithosphere and hydrosphere), and regulates runoff (water that moves on the land especially along a slope, instead of entering into soil).

Protection and Conservation of Soil:

Plants protect soil cover by binding the soil particles and also help in its formation. Litter (dead and decaying leaves and other parts of the plants) adds organic matter to soil and hence enhances its fertility.

Climate Moderation:

Vegetation stabilizes the climates in the local areas and has a cooling effect on the environment.

Maintenance of Ecosystem Integrity:

Biodiversity protects ecosystem integrity by regulating oxygen and carbon dioxide balance, nutrient and mineral cycling.

Biodiversity as a Source of Food

Biodiversity is a direct source of food (cereals, vegetables, fruits, etc.) and contributes substantially to the economy of the country. Though a number of plant species (nearly 5000) can be utilized as a source of food yet only a few of them are nutritionally important and thus managed on commercial scale. Crops like wheat, rice and maize are widely used as staple food. Human existence is greatly dependent upon plants as source of food. Likewise, some animal species are also used as food source

Medicinal Value

People have since long used biological resources as source of medicine. Plants and microbes are the source of a number of drugs used to treat not only common ailments but also some of the serious diseases like cancer. In India, a number of herbs are used in traditional medicine. For example, basil (Tulsi) known as sacred herb is widely used to treat cold and fever, congestion and joint pain in India.

Wood and Non-timber Products

Wood, a primary source of fuel and fibre, is a basic commodity used worldwide. It is harvested from a number of trees like teak, shisham, eucalypts (safeda), deodar, sal, etc. Besides, a number of non-wood products like turpentine oil, dyes, tannins, etc. are also obtained from the forest trees.

Social Benefits

In addition, biodiversity provides a number of social benefits such as: use in research and education, for recreational and aesthetic purposes, and it is also an important component of our traditional culture as some trees and animals are worshipped.

Causes of Biodiversity Loss

Rapid biodiversity loss worldwide could be attributed to the following reasons:

Habitat loss, Deterioration and Fragmentation

A number of species have lost their habitat (place where a species lives) because of increased human interference like construction of dams, roads, railway tracts or bridges across natural ecosystems, mining activity or industries. Habitat fragmentation due to deforestation or any other biotic stress has caused much harm to precious biodiversity.

Deforestation rate is increasing due to burgeoning population and this has destroyed the natural homes of species. In fresh water ecosystems, construction of dams has destroyed large habitat of hundreds of aquatic flora and fauna. Likewise, in marine ecosystems, the coastal development has affected the communities, particularly species rich ecosystems like coral reefs.

Exotic Species

Exotic species are those which have been introduced either purposely or entered accidentally in some environmentally distinct zone from the other geographically different areas. These have caused much harm to native plant communities than expected and enhanced the extinction (loss of species) rate. The phenomenon is more common on the islands or isolated ecosystems. A number of example exist world over when an introduced species has become a serious pest or problem. For example, Lantana camara introduced as an ornamental hedge in India has now become a serious invader of forests. The example of accidental entry is the Congress grass (Parthenium hysterophorus) that is now a major problematic weed in India, Australia and other parts of the world. A number of reasons such as fast growth, rapid colonization, better and efficient resource utilization, wider adaptability and the absence of natural enemies in the invaded areas.

Overexploitation

Some of the species have become threatened and even gone extinct due to their over exploitation by the humans for their food, feed or some other beneficial purpose. In fact, a number of ecosystems have got damaged both in terms of number and variety of species that these are beyond repair in the near future.

Environmental Pollution

Air, water, and soil pollution is one of the major reasons for biodiversity loss in the modern era. Modernization, urbanization, increasing population, and changing life style are some of the prime reasons for the increased levels of pollution in the natural environment. It has not only affected the number of existing species but has also caused the loss of a variety of species that could not tolerate the increased pollutant levels in the atmosphere and have gone extinct. Excessive use of synthetic chemicals as herbicides, pesticides and insecticides has polluted the soil and water environment and greatly threatens the diversity and richness of the species. Due to increased industrialization, the intensity of the acid rain has increased and greatly affected the natural vegetation and the forests in different regions of the world.

Global Warming

Climate change due to global warming is another reason for the depletion of natural biodiversity in the recent times. The increase in the earth’s temperature has already shown its impact in terms of depletion of forest resources in many parts of world. For example, temperate or the Taiga forests are reducing in size whereas tropical / sub-tropical forests are slightly increasing. Additionally, the temperature rise also alters the tolerance limit of the species and greatly changes the structure and ecosystem function. The increased global temperature would result in melting of ice caps and rising of sea levels. It would result in submerging of many islands and inundation of coastal areas thereby greatly affecting the biodiversity of such regions.

Commercialization of Agriculture and Forestry

During the last century there has been a great change in the agricultural practices and the forest operation. Of late, agriculture has shifted from low-input traditional systems involving crop rotations into highly commercialized monocultural practices that utilize high yielding varieties, monocultural operations and use of harmful synthetic chemicals and fertilizers. It has resulted in the depletion of the biodiversity base not only of the plant species in such intensive ecosystems but also affected the animals and other species dependent upon them. Likewise, to meet the increased demand of the timber natural forest has been cut. In order to maintain the forest cover, a number of fast growing tree species have been promoted but in monocultural or pure strands. It has resulted in formation of large areas of plantations / forests that have only one type of species and resulted in loss of other useful species that naturally occurred in the natural forests or exist in the mix-culture type of forests.