Biodiversity

The sum total of all the variety of living organisms makes Biodiversity. The term Biodiversity was first coined by E.O. Wilson in the year 1985. It includes all the species on the Earth, i.e. different plants, animals, organisms and their genes, water ecosystems, terrestrial ecosystem, marine ecosystem, etc. It is important for our existence as it provides fundamental building blocks for several goods and services and provides healthy environment to lead happy and healthy life.
 

Definition of Biodiversity

It is defined as “the variety and variability of living organisms and the ecological complexes in which they exist.”  

In other words, the term biodiversity refers to the occurrence of several ecosystems, different organisms, their species, along with the entire range of variants adapted to different environment, climate, etc.; along with their processes and interactions. Thus, biodiversity consist of genetic variability and diversity of life forms such as microbes, plants, animals, etc. living in the wide range of ecosystem.

Following image explains the biodiversity in an area. It includes plants and animals at one place. Plants like food and cash crops, intercropping, kitchen crop, trees, etc. and animals like farm animals, birds and insects.

Genetic Diversity – It includes variation in the type and number of genes; and chromosomes present in different species. The magnitude of diversity increases with the increase in environmental parameter and size of the habitat.

Following image shows the genetic diversity of bananas – 

Importance of Genetic Diversity

• It helps in evolution or speciation of new species.

• Genetic diversity is important for productivity and development of agriculture.

• It is important in adaptation to change as per the change in surroundings.

Species Diversity – It describes the richness and variety of species in a particular region. It is defined as “the number of species per unit area.” The richness of species explains the extent of biodiversity and provides several methods for comparing different sites. The richness of species depends on the conditions of climate.

Following image shows the species diversity of butterflies in a particular ecosystem:

Ecosystem Diversity – It describes the interaction and assemblage of species living together and the physical environment of that area.  Ecosystem diversity relates to biotic communities, habitats and ecological processes in the entire biosphere. This diversity is also referred as landscape biodiversity because it consists of size and placement of different ecosystems.

Example of Ecological Diversity – The landscapes such as mountains, grasslands, deserts, display ecosystem diversity. This diversity is due to tropic levels, diversity of niches and several ecological processes (i.e. food webs, nutrient cycle, role of dominant species, energy flow, and several other biotic components).
 

Patterns of Biodiversity

Latitudinal Gradients – The diversity is not uniform, rather it is present in the form of uneven distribution. For majority of groups and animal, latitudinal gradient pattern can be observed. Usually, the diversity of species decreases as we move away from equator, towards the poles. Therefore, tropics harbor has more species as compared to polar or temperate areas. Colombia, located near equator, has around 1400 species, while New York at 41 degree north has 105 species, and Greenland, at 71 degree north has 56 species.
 

Species – Area Relationships – Every area has different species of plants and animals. It is important to note that the relation between species richness with area of wide variety of taxa (birds, plants, freshwater fishes and bats) turns out to be rectangular hyperbola.

Figure on the right shows the species area relationship. It is important to note that on log scale the relationship becomes linear and is described by the following equation –

Log s = log C + Z log A

Where,

S = Species richness

A = Area

Z = slope of the line (regression coefficient)

C = Y - intercept

Importance of Biodiversity

Biodiversity is important because it helps in preventing the extinction of species. It allows the organisms to adapt according to the environment and provide wider range of material and food for survival. It is the biodiversity that provides vast genetic pools that helps in preserving existence of life on earth.

Rain forest comprises of around 50% of entire world. Animal and plant species and biodiversity of these forest helps in regulating the weather pattern of earth. Biodiversity prevents against erosion and drought and regulates the chemical composition of the soil. It helps in determining the reproductive season of different animals as well as the growth cycle of plants.

Biodiversity helps in maintaining equilibrium in the environment and also defines the manner in which different organisms interact with each other. It helps in maintaining the balance by recycling and storage of nutrients, stabilizing climate, forming and protecting soil, combating pollution and thereby maintaining eco-balance. It is threatened by climatic change, overexploitation of natural resources, habitat loss and pollution. Loss of biodiversity weakens the connection between various species in the ecosystem. 
 

Reasons of Loss of Biodiversity

The biodiversity of earth is in danger and we, human beings are the most dangerous cause of destruction. According to Edward Wilson, HIPPO is the major cause of destruction. HIPPO stands for “Habitat destruction, Climate change, Invasive species, Pollution, Human overpopulation and Over-harvesting.”

Habitat destruction is one of the major causes of loss of biodiversity and this is caused due to Global warming, Over population, Deforestation and Continuously increasing pollution. Especially physically large species are affected in this category. According to the experts, by the year 2050, around thirty percent of the species will extinct.

Even if the small element of the ecosystem breaks down, it results in threatening of the entire ecosystem. Invasive species grows which are limited due to several natural barriers. Since these barriers are affected; invasive species invade the ecosystem, resulting in the destruction of the native species. Species are also threatened by genetic pollution via gene swamping and uncontrolled hybridization.

Over-exploitation is another factor that is resulting in the loss of Biodiversity. It includes the activities like over hunting, over fishing, illegal trade of wildlife and excessive logging. Global warming is also an important factor that is affecting biodiversity. Thus, it is clear that biodiversity is mandatory for the well-being of life on earth but several human activities are resulting in loss of it. It is important to take preventive action on the urgent basis in order to prevent biodiversity of our planet.

Following image shows the causes and consequences of loss of biodiversity. According to it, activities like pollution, over harvesting, habitat alteration, population growth, globalization, global climate change are the factors that are resulting in loss of biodiversity. As a result of this loss, we are facing loss of ecosystem services like loss of food sources, loss of tourism and recreation, loss of sources of medicines, etc. This, on the other hand, is resulting in economic loss, negative health impacts and social disruption.

Conservation of Biodiversity

We are aware of the fact that biodiversity is continually being depleted due to various reasons. But in order to reap the benefits of biodiversity, it is important to adequate actions for the perseverance of biodiversity. We need to prevent destruction and degradation of the habitats by maintaining biodiversity at the optimum level. There are three main objectives of Conservation of Biodiversity –

1. To preserve the species diversity

2. Make the sustainable utilization of species and ecosystem

3. Maintain the important ecological process and life supporting systems
 

Why should we conserve Biodiversity?

It is important to conserve biodiversity because of its several benefits it offers that are essential to live. It provides biological resources, ecosystem services, social and spiritual benefits.

Biological Resources – It includes any product that is harvested from the nature. These resources come under category like herbs, medicines, fibers, oil, wood, food, etc. Under one category like food around 7,000 species are involved and we are mainly dependent on 12 major crops. Similarly, for medicines, we are dependent on plants like aspirin comes from willows, the medicine for the treatment of malaria is produced from Cinchona tree, etc. Fibers are used in making clothing, ropes, webbing, sacking, netting, etc. These are made from plants like Agave plant, cotton plant, flax plants, Corchorus plant, etc.

Ecosystem Services – It includes those processes that support human life. For example, decomposition of waste, pollination, renewal of soil fertility, water purification, etc. are some of the processes which are very important for mankind and are carried out by biodiversity. But rapid increase in pollution, cutting down of trees and decrease in the forest area has disrupted the natural environment and we need to depend of artificial services in order to carry out above mentioned services of ecosystem.

Social and Spiritual Benefits – Conservation implies protection of nature. The biodiversity effects cultural development as well. In different areas, different cultures are dominant and influence diet, language, occupation and various other types of activities. Uniqueness of each habitat can be seen in terms of variation in plants, animals. Even during travelling, we observe and enjoy biological diversity.
 

Strategies for the Conservation of Biodiversity

• It is important to focus on conservation of all type of food, timber plants, forage, agricultural animals, livestock, microbes, etc.

• The entire organism which is economically important should be identified and conserved.

• Perseverance process needs to be prioritized and critical habitats of each and every species need to be identified and safeguarded.

• The international trade of wildlife needs to be regulated followed by sustainable utilization of available resources.

• Hunting and poaching of wildlife need to be prevented and it is important to focus on the development of reserves and protected areas.

• We need to control the emission of pollutants and this can be done by increasing the awareness of biodiversity amongst the people.

• Different habitat of migratory birds should be protected by multilateral agreement and it is important to first focus on endangered species.

• Efforts need to be made to set up more and more national parks, wild life sanctuaries, etc. in order to safeguard genetic diversity. Useful animals, plants and wild relatives need to be maintained both in the form of natural habitat and zoological botanical gardens.

Hot Spots

“Hot Spots refer to the area with high density of diversity or mega diversity which are threatened at present.” There are around 16 hot spots, out of which two are located in India by the name Western Ghats and North-East Himalayas. These hot spots are determined on the basis of four factors –

• Degree of expectation

• Degree of endemism

• Number of species diversity

• Degree of threat to habitat as a result of fragmentation and degradation.
   

Watch this Video for more reference
 

Frequently Asked Questions

Q1. Define Species Equitability.

“The number of individuals of different species with in a region represents species evenness or species equitability.”

Q2. Define Endemic Species.

“The product species richness and species evenness give species diversity of a region. When a species is confined entirely to a particular area, it is termed as endemic species.”

Q3. What are the different types of community diversities?

According to Whittaker, community diversity is of three types –

• α – Diversity – It represents the diversity of species in a given area and depends on the evenness and richness of species.

• β – Diversity – It explains the range of diversities due to replacement of species. These ranges of species are derived due to the presence of several niches, environmental conditions and microhabitats.

• ϒ – Diversity – It explains the diversity in the entire geographical area or total land escape.

Q4. What are basic conservation strategies?

All the conservation efforts are categorized under two heads –

• In-Situ (on – site) – This include conservation of plants and animals within their protected area or natural habitat.

• Ex-Situ (off – site) – This include conservation outside their natural habitats like zoo, botanical gardens, national parks, seek bank, gene bank, cryopreservation etc.

Following figure shows the scheme of biodiversity conservation management system, in which two types of strategies, i.e. In-Situ and Ex-Situ are explained. In-Situ comprise of protected areas like national parks, sanctuary and biosphere reserve while ex-situ include seed bank, gene bank, cryopreservation, sacred plant, home garden, botanical garden, zoological parks, aquaria, arboreta, etc. 

 Q5. Why tropics have greater account of biological diversity?

According to several biologists and ecologists, there are several reasons that tropics have greater account of biological diversity. Firstly, speciation, a function of time, unlike temperate zones is subjected to glaciations in the past and therefore, tropical latitudes have remained undisturbed for millions of years. Therefore, has good diversification of species. Secondly, environment in tropics is less seasonal as compared to temperate zones and constant temperature promotes niche specialization and greater species diversity. Lastly, on tropics, more solar energy is present that contributes to higher productivity and thereby greater diversity.

Q6. What is the importance of species diversity to the Ecosystem?

According to ecologists, the communities with more species tend to be more stable as compared to the communities with lesser species. So, species diversity is important to the ecosystem.

Q7. What is meant by stability for a biological community?

The community should not show much variability and this is referred as stability. The species in community must be either resistant or resilient to occasional disturbances. Added to this, it must also resist to any alien species.