Introduction

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Biodiversity is the variety or the variability of life on earth. There exist many different definitions of this term, but according to Oxford Dictionary, “Biodiversity is the variety of plant and animal life in the world or in a particular habitat, a high level of which is usually considered to be important and desirable.” Scientists started using this term at the start of the 20^th century and by the end of the century, it became common and widely popular.

In this article, we will explore the ocean of biodiversity. We will discuss how biodiversity is distributed on the earth and how scientists measure biodiversity. Additionally, in this article, you will read about the importance of biodiversity and its role in human well-being. Lastly, we will talk about the potential threats and also the methods of conservation of life on earth. 

Levels

There are three levels on which we explore biodiversity. These are genetic diversity, species diversity, and ecosystem diversity. 

• Genetic diversity

Genetic diversity refers to the variety of genes on the earth. Diversity is not only in the genes of different species but also in the differential expression of genes which leads to the multiplicity of characteristics and qualities of organisms.  

• Species Diversity

There are millions and millions of species in this world and species biodiversity refers to the variety among them. There are two types of species diversity. Intraspecies diversity is the variation among individuals of the same species. For example, humans have different eye colours. On the other hand, interspecies diversity refers to the diversity of different species. For example, humans have higher diversity than Indus dolphins that are currently facing the threat of extinction. 

• Ecosystem diversity

There are a number of different ecosystems, with different characteristics and features, that exist on the planet. There are deserts, plains, mountains, oceans, and forests, all of them having different natures and a number of different species. This variation & diversity among ecosystems is known as ecosystem biodiversity. 

Distribution

The distribution of life on earth is not the same everywhere. Different areas have different types and numbers of species. Yet, biodiversity is virtually everywhere on the earth. It ranges from big organisms like elephants and whales to tiny little unicellular organisms like bacteria. We will now discuss the spatial and temporal patterns of biodiversity along with some other related information. 

1. Spatial Patterns of Biodiversity

Spatial distribution of biodiversity refers to the arrangement of individual entities in space and their geographic relationship. It includes Biomes, Hotspots, Ecosystems, and Biogeographic realms. The field in which we study the spatial distribution of life forms on earth is called biogeography. 

According to research, terrestrial biodiversity is almost 25 times great than marine biodiversity. In 2011, scientists proposed that there are about 8 and half million species on earth from which only 2 million live in the oceans. Terrestrial biodiversity is mainly present in the forests. According to an estimate, 80 percent amphibian and bird species, 70 percent mammal species, and 60 percent vascular plants are found in the forests. 

Tropical areas and rainforests usually have higher biodiversity, mostly because a wet climate is more suitable for many organisms. On the contrary, biodiversity consistently measures low in the polar regions. The distribution of biodiversity depends not only upon the climate, soil, and geography but human activities also put a lot of influence on its distribution. It is somewhat obvious that the areas with dense human populations have less intact biodiversity than the areas with a lesser human population. 

Another important point is that when we go from the poles to the tropics, there is an increase in biodiversity. There are fewer species in the higher latitudes and more species in the lower latitudes. This phenomenon is called the latitudinal gradient in species biodiversity. 

There are some areas where a high level of endemic species is present. These are called biodiversity hotspots. An example of a biodiversity hotspot is Brazil’s Atlantic Forest. In this area, there are almost 20,000 plant species and 1350 animal species but half of all these species occur nowhere else on the earth. 

2. Temporal patterns of Biodiversity

Temporal refers to time and the temporal patterns of biodiversity refer to the seasonal changes in habitat heterogeneity, dynamics of population, and seasonal disturbances. Understanding the temporal patterns allows the researchers to make an estimate of rates of extinction of species. It has been estimated that there are 0.1 to 1.0 extinctions per million species per year. However, scientists believe that this data underestimate the background extinction rates. According to a report of the World Wildlife Foundation, “biodiversity is being destroyed at a rate unprecedented in human history”. The report claims that almost 68% of the population was destroyed in the recent 50 years.

There is a mismatch between the dynamics of changes in natural ecosystems and how humans respond to those changes. It occurs due to the lags in ecological responses and the difficulty of predicting thresholds. The complex feedbacks between socioeconomic and ecological systems are also responsible for this mismatch. The problem is that understanding thresholds requires long-term records, but having such records is very much difficult mostly because of the wrong periodicity, or they are too localized to provide the essential data to predict threshold behaviour.

Measuring Biodiversity

There are a variety of means to measure biodiversity empirically. Scientists use particular data sets to measure biodiversity. The most common method of measuring and comparing the biodiversity of different places is to count species. There are a lot of species that have not been discovered and examined. Researchers have estimated that it would take about a thousand years to complete just the catalogue of scientific names. 

Usually, we use three indices in the measurement of biodiversity: Alpha diversity, Beta diversity, and Gamma diversity. 

• Alpha diversity is the diversity of life in a particular area. It is usually measured by counting the taxa within that particular ecosystem. 
• On the other hand, beta diversity refers to the diversity between ecosystems. We compare the number of unique taxa in each ecosystem of beta diversity. 
• The third index is gamma diversity which is the measurement of diversity of a region containing a variety of ecosystems. 

Importance

Biodiversity has huge importance in our life. It provides a lot of services that are necessary for human well-being. We categories these services into 4 groups. These are provisioning, regulating, supporting, and cultural services. Following is a brief overview of each of them.

1. Provisioning services 

Biodiversity and ecosystems provide us with food, raw materials, and genetic resources. Humans also get a lot of medical resources such as pharmaceuticals, and test and assay organisms. Greater biodiversity of plants and trees increases the production of fodder and wood. Provisioning services also include ornamental resources such as jewelry and decoration materials. 

2. Regulating services 

Biodiversity plays an integral role in regulating life on earth. Greater diversity of fish increases the stability and quality of fisheries’ yield. Greater diversity of plants increases carbon sequestration and soil nutrient mineralization, and it decreases the disease prevalence on plants. Regulating services of biodiversity also includes the purification of water and air, and waste decomposition. 

3. Supporting services 

These services allow an ecosystem to continue its provisioning services. Some important supporting services are nutrient cycling, habitat provision, primary production, and soil formation. 

4. Cultural services

The main cultural services include the use of nature in paintings, advertising, and folklores. It also provides an environment for recreational activities, and it provides great opportunities for educational research. 

Threats

Biodiversity is experiencing some serious threats mostly due to the activities of humans. With the passage of time, more and more species have become endangered and extinct. IUCN Red List criteria have listed almost 16,000 species as threatened with extinction. There are a lot of different threats, some of which have been described here.

• Farming and Agriculture

Farming and other activities involved in the process have posed some serious threats to biodiversity. Both agriculture and aquaculture are not good for biodiversity because they may result in habitat loss of a variety of species. 

• Development

Residential and commercial development such as housing, industries, recreational areas, shopping areas, hospitals, and schools, etc., are threatening the life of various species.  

• Transportation

Transportation and service corridors are big threats to biodiversity. Wires (electrical & phone wires), Oil & gas pipelines, roads, railway lines, and shopping lanes prove to be very bad for biodiversity.

• Hunting

A lot of species is on the verge of becoming extinct just because of excessive hunting. Humans hunt specific animals to get meat and leather and to show their bravery and skill. Moreover, pest control activities, plant destruction, and wood harvesting play an important role in destroying biodiversity.

• Pollution 

Another big threat to biodiversity is pollution that is increasing day by day. Untreated sewage, non-functioning sewage treatment plants, fertilizers and pesticides, industrial and military toxic chemicals, soil erosion, garbage and solid waste, acid rain, and smog from vehicle emissions are the main culprits that pollute the environment. 

• Climate changes and catastrophes

Apart from human activities, there are some other factors that can destroy or threaten biodiversity. In the past, asteroids have destroyed a lot of species on the earth. Additionally, earthquakes, landslides, avalanches, volcanic eruptions, and tsunamis can sometimes destroy the complete biodiversity of a region.

Climate changes such as heatwaves, cold spells, droughts, thunderstorms, hurricanes, cyclones, tornadoes, and other events can lead to the destruction of a population. 

• Habitat Destruction

Habit destruction is one of the major reasons for the destruction of biodiversity. Human activities, deforestation, global warming, and overpopulation are the main causes of habitat destruction of a lot of species. 

Conservation and Protected Areas

Scientists have adopted a lot of approaches to conserve biodiversity to stop its decline. These approaches include the development of protected areas, collection of genetic materials in gene banks, and improved targeting of pesticides, etc. Protected areas such as national parks and wildlife sanctuaries. Here is an overview of some of them. 

• National Parks

These are large areas (natural or semi-natural) that provide protection to large-scale ecosystems. National parks not only protection to species but allow humans to have a compatible, recreational, and educational environment for scientific research. Usually, governments manage these areas. It is important to note that hunting is banned in these areas.  

• Wildlife Sanctuaries

Wildlife sanctuaries may be owned by governments or individuals. In these areas, hunting and killing are restricted and allowed only under the control of higher authorities. 

• Botanical Gardens

Botanical gardens serve as educational and research centres for the botanist. A botanical garden may consist of a large number and variety of plants, along with special laboratories and lecture theatres. 

Summary

Biodiversity is defined as the variety of plant and animal life on earth or in a particular habitat. Scientists explore biodiversity on three levels. Genetic diversity refers to the variety of genes and gene expression in the same species whereas species diversity is about the variability among species. The third level is ecosystem diversity which refers to variation among different ecosystems. 

The distribution of biodiversity is different in different areas of the world. For example, terrestrial biodiversity is much more than marine biodiversity. Moreover, certain areas such as rainforests and tropical areas have higher biodiversity than the polar regions. Those areas, there exist a high level of endemic species, are called biodiversity hotspots. An example of a biodiversity hotspot is Brazil’s Atlantic Forest. 

Biodiversity and ecosystems provide provisioning, regulating, cultural, and supporting services. Provisioning services include food, raw materials, genetic resources, and medical resources. It is also involved in the purification of water and air, waste decomposition, and carbon sequestration. The cultural services are the use of biodiversity for paintings, folklore, education, and recreational purposes. 

Biodiversity is facing some serious threats such as habitat destruction, increasing human activities, deforestation, and global warming. Climate changes and serious weather conditions such as tornadoes, hurricanes, and other events also threaten biodiversity. There are some areas called protected areas that protect the species and allow scientific research and recreational activities. Some examples of these areas are national parks, wildlife sanctuaries, and botanical gardens. 

References

1. “What is biodiversity?” (PDF). United Nations Environment Programme, World Conservation Monitoring Centre.
2. Gaston, Kevin J. (11 May 2000). “Global patterns in biodiversity”. Nature. 405 (6783): 220–227. doi:10.1038/35012228. PMID 10821282. S2CID 4337597.
3. Field, Richard; Hawkins, Bradford A.; Cornell, Howard V.; Currie, David J.; Diniz-Filho, J. (1 January 2009). Alexandre F.; Guégan, Jean-François; Kaufman, Dawn M.; Kerr, Jeremy T.; Mittelbach, Gary G.; Oberdorff, Thierry; O’Brien, Eileen M.; Turner, John R. G. “Spatial species-richness gradients across scales: a meta-analysis”. Journal of Biogeography. 36 (1): 132–147. doi:10.1111/j.1365-2699.2008.01963.x. S2CID 4276107.
4. Gaston, Kevin J.; Spicer, John I. (22 April 2013). Biodiversity: An Introduction. John Wiley & Sons. ISBN 978-1-118-68491-7.

Young, Anthony. “Global Environmental Outlook 3 (GEO-3): Past, Present and Future Perspectives.” The Geographical Journal, vol. 169, 2003, p. 120.