Definition

Biodiversity or  biological diversity, refers to the variety and variability of life forms on Earth. It encompasses the diversity of species, their genetic variation within species, and the variety of ecosystems in which they live.  It also refers to the interrelatedness of genes, species, and ecosystems and their interactions with the environment. Animal species make up more than 70% of all known species, while plants (including algae, fungi, bryophytes, gymnosperms, and angiosperms) make up no more than 22% of the total. In terms of taxonomic diversity, insects make up more than 70% of all animal species, making them the most diverse group. India is home to around 7% of all known species. The Amazon rainforest is home to the world's greatest biodiversity. 

Levels of biodiversity

 LEVEL OF BIODIVERSITY

Biodiversity is often described at three levels:

1. Ecosystem Diversity:  This refers to the variety of ecosystems present in a region or on the planet. It includes different types of habitats, communities, and ecological processes that interact within and between ecosystems.

2. Species Diversity:  This refers to the variety and abundance of different species within a given area. It includes the number of species present (species richness) as well as their relative abundance (species evenness).

3. Genetic Diversity:  This refers to the variation of genes within species. It includes the diversity of alleles, genotypes, and genetic traits present within populations of a species. Genetic diversity is crucial for the adaptation and evolution of species over time.

Values of biodiversity

The value of biodiversity extends far beyond its intrinsic worth; it provides numerous benefits to human societies and the planet as a whole. 

A. Ecosystem Services: Biodiversity plays a crucial role in providing ecosystem services that support human well-being. These services include:

Pollination

Nutrient Cycling: Biodiverse ecosystems efficiently recycle nutrients, such as carbon, nitrogen, and phosphorus, which are essential for soil fertility and plant growth.

Climate Regulation: Forests, oceans, and other ecosystems help regulate the Earth's climate by sequestering carbon dioxide and influencing weather patterns.

Water Purification: Wetlands, forests, and other ecosystems filter and purify water, helping to maintain clean freshwater sources for drinking and irrigation.

Flood Control: Mangroves, wetlands, and other coastal ecosystems act as natural buffers against storm surges and flooding, protecting human communities and infrastructure.

Erosion Control: Vegetation and root systems stabilise soil, reducing erosion and preserving soil fertility.

B. Genetic Resources: Biodiversity provides a vast array of genetic resources that are essential for agriculture, medicine, and industry. Wild plant and animal species serve as sources of genetic material for crop breeding, pharmaceutical discovery, and biotechnological innovation.

C. Economic Benefits: Biodiversity supports economic activities such as agriculture, forestry, fisheries, and ecotourism, providing livelihoods for millions of people worldwide. Healthy ecosystems contribute to economic resilience and sustainable development.

D. Cultural And Recreational Value: Biodiversity enriches human cultures and traditions, providing inspiration for art, music, literature, and spiritual practices. Natural landscapes and wildlife habitats also offer opportunities for recreation, tourism, and outdoor activities.

E. Resilience and Adaptation: Biodiversity enhances ecosystem resilience and adaptive capacity, helping ecosystems and human communities withstand and recover from environmental changes, disturbances, and disasters.

F. Scientific and Educational Value: Biodiversity provides valuable opportunities for scientific research, education, and discovery. Studying diverse species and ecosystems enhances our understanding of ecological processes, evolutionary dynamics, and the interconnectedness of life on Earth.

Preserving biodiversity is essential for maintaining these values and ensuring the long-term health and sustainability of ecosystems and human societies. Conservation efforts, sustainable management practices, and policies that prioritize biodiversity protection are critical for safeguarding these benefits for current and future generations.

Hot spots of biodiversity

• Biodiversity hotspots are geographical areas that exhibit a notable abundance of diverse species, including numerous species that are unique to that specific location and a substantial number of species that are at risk of extinction.  The notion of biodiversity hotspots was initially introduced in the late 1980s and has since served as a valuable means of identifying regions that require heightened conservation efforts.
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• Only 2.5 per cent of the Earth’s land surface is taken up by the 36 hotspots that exist today, yet they are home to about 43 per cent of the world’s bird, mammal, reptile, and amphibian species, as well as more than half of its plant species.
• The hotspots provide essential ecosystem services to humans, including clean water, pollination, and climate regulation.
• These spectacular locations also have some of the world’s greatest human population densities, yet the relationship between people and biodiversity is not simply one of more people causing more environmental consequences. Human activity, not human density, is responsible for a large portion of human-biodiversity impacts.
• Conservation in hotspots encourages the long-term management of these vital natural resources while also supporting economic growth, which lessens the causes of violent conflict.
  What is the criteria of Biodiversity Hotspots?
  
• To qualify as a biodiversity hotspots, a region must meet two criteria- according to Conservation International-
• a) It must have at least 1,500 vascular plants as endemics which is to say, it must have a high percentage of plant life found nowhere else on the planet. A hotspot is irreplaceable.
• b) It must have 30% or less of its original natural vegetation and must be threatened.
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Biodiversity hotspots of India

• Biodiversity hotspots of India
  
• In India, there are four areas which qualify the criteria for biodiversity Hotspots-
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• Himalayan Hotspot
• It is the dwelling place of the highest mountains on Earth, such as Mt. Everest. These mountains ascend abruptly, giving rise to a wide array of ecosystems that vary from grasslands and forests in lower regions to meadows at higher altitudes where trees cannot grow.  It’s remarkable that even vascular plants have been found flourishing at elevations exceeding 6,000 meters.  This hotspot is a crucial habitat for many significant bird and mammal species, including vultures, tigers, elephants, rhinos, and wild water buffalo.
• Indo- Burma Hotspot
• Encompassing over 2 million sq. kms. of tropical Asia, the Indo-Burma region continues to unveil its rich biological treasures. In the past 12 years alone, six significant mammal species have been discovered like the large-antlered muntjac, the Annamite muntjac, etc.  This area is also home to a remarkable number of unique freshwater turtle species, many of which are facing the threat of extinction due to excessive harvesting and extensive loss of their natural habitats. 
• Furthermore, the bird population in Indo-Burma is incredibly diverse, boasting nearly 1,300 distinct species, including endangered ones like the white-eared night-heron, the gray-crowned crocias, and the orange-necked partridge.
• Sundaland Hotspot
• The breath-taking plants and animals of the Sundaland Hotspot are being negatively impacted by the rapid expansion of industrial forestry in these islands and the international trade of animals, such as tigers, monkeys, and turtle species, for food and medicine in other countries.  The population of orangutans, which can only be found in this hotspot, is experiencing a significant decline. Additionally, the islands of Java and Sumatra are home to some of the last remaining habitats of two rhino species in Southeast Asia.  Similar to many tropical regions, the forests in the Sundaland Hotspot are being cleared to make way for commercial activities. Rubber, oil palm, and pulp production are three major factors that are severely affecting the biodiversity in this region.
• Western Ghats- Sri Lanka Hotspot
• The forests in the Western Ghats and Sri Lanka have been severely impacted due to the increasing population and the resulting demand for timber and agricultural land. 
• The remaining forests in the Western Ghats are highly fragmented, and in Sri Lanka, only 1.5 % of the original forest remains. 
• The pressure from the growing population is also affecting the outskirts of protected areas, where illegal activities such as farming, logging, and poaching take place. 
• The unique combination of the yearly monsoons and the mountainous terrain in this area has created a hotspot that is home to a diverse range of plants, reptiles, and amphibians, many of which are found nowhere else in the world. 
• Sri Lanka alone may have as many as 140 species of amphibians that are endemic to the region. 
• Additionally, the Western Ghats and Sri Lanka are home to significant populations of Asian Elephants, Indian Tigers, and the endangered Lion-tailed Macaque. 
• The region also boasts a remarkably high level of freshwater fish endemism, with over 140 native species.
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  Biodiversity hotspots teach us a crucial lesson i.e., understanding biodiversity  requires taking into account various factors such as human population, agricultural techniques, military activities, and political systems. Biodiversity is intricately linked with human influences. Similarly, comprehending human economic, social, and political systems is impossible without considering the diverse life forms that sustain us.

Threats to biodiversity

Biodiversity faces numerous threats, many of which are caused or exacerbated by human activities. These threats can lead to the loss of species, genetic diversity, and ecosystems, with significant consequences for the environment and human societies. Some of the main threats to biodiversity include:

1. Habitat Destruction And Fragmentation: One of the leading causes of biodiversity loss is the destruction, degradation, and fragmentation of natural habitats due to activities such as deforestation, urbanization, agriculture, mining, and infrastructure development. Loss of habitat reduces available space for species, disrupts ecological processes, and isolates populations, leading to declines in biodiversity.

2. Climate Change:  Rising temperatures, changing precipitation patterns, and extreme weather events associated with climate change pose significant threats to biodiversity. Climate change can alter habitats, disrupt ecosystems, and shift species distributions, leading to range shifts, changes in phenology, and increased risks of extinction for vulnerable species.

3. Overexploitation and unsustainable harvesting: Unsustainable exploitation of natural resources, including overfishing, illegal logging, poaching, and hunting, can deplete populations of species and disrupt ecosystems. Overexploitation can lead to declines in biodiversity, loss of ecosystem services, and cascading ecological effects.

4. Invasive Species: Invasive alien species introduced to new environments can outcompete native species, disrupt ecosystems, and alter ecological processes. Invasive species can spread rapidly, causing declines or extinctions of native species and disrupting ecosystem functioning.

   
   

   
   
5. Disease Outbreaks:  Infectious diseases can spread among wildlife populations, leading to population declines, localised extinctions, and altered species interactions. Disease outbreaks can be exacerbated by factors such as habitat destruction, climate change, and human activities.
6. Global Trade And Transport: International trade and transport of goods can facilitate the spread of invasive species, diseases, and pathogens across borders, increasing the risks to biodiversity. Globalisation can also drive demand for wildlife products, leading to overexploitation and illegal trade in endangered species.
7. Land Use Change and Agricultural Expansion: Conversion of natural habitats for agriculture, including croplands, pasturelands, and monoculture plantations, can result in habitat loss, fragmentation, and degradation. Agricultural expansion often involves clearing forests, draining wetlands, and using pesticides and fertilizers, leading to biodiversity loss and ecosystem degradation.
8. Pollution:  Pollution from various sources, including industrial activities, agriculture, urbanisation, and waste disposal, can contaminate air, water, and soil, posing threats to biodiversity. Pollution can harm species directly through toxicity or indirectly through habitat degradation, altered food webs, and ecosystem disruption.

Addressing these threats to biodiversity requires concerted efforts at local, national, and global levels, including conservation measures, sustainable land management practices, policy interventions, public awareness campaigns, and international cooperation. Protecting and preserving biodiversity is essential for maintaining ecosystem services, sustaining livelihoods, and ensuring the health and resilience of ecosystems and human societies.

Causes of species extinction

The abusive and unsustainable use of natural resources not only harms the health of the planet, it also wipes out entire species so that they disappear for ever. The frenetic loss of biodiversity means that a million plants and animals are currently under threat.

Species endangerment and extinction have three major anthropogenic causes—overhunting or overharvesting; introduction of nonnative species, including the spread of disease; and habitat degradation or loss.

Over 99 % of organisms that used to live on earth do not exist any more. In general terms, species become extinct for the following reasons:

Demographic and Genetic Phenomena

First of all, species with small populations face a greater risk of extinction. Also, natural selection does its job by keeping beneficial genetic traits and eliminating poor ones. There are animals with a good gene pool that is robust and more adaptable to unforeseen exogenous circumstances, and others that are weaker.

Destruction of Wild Habitats

Man is a direct cause of the extinction of species: out of the 8 million existing, 1 million are in danger due to overexploitation of resources on land and at sea. In addition, one fifth of the surface of the Earth has been degraded —the forests are home to over 80 % of terrestrial species— and marine debris  and acidification are wreaking havoc in the oceans.

Introduction of Invasive Species

The introduction of exotic and invasive species artificially, intentionally or accidentally into habitats where they do not belong can also alter the biodiversity of ecosystems. These new inhabitants displace the native species, which, in the worst cases, die and become extinct. According to the UN, in Europe, one out of every three species is in danger of extinction for this reason.

Climate Change

The rising global temperature and sea levels  have a negative effect on biodiversity. According to the WWF, half of the plant and animal species in the richest natural areas of the world could suffer local extinction by the end of the century due to climate change. Even without exceeding the 2 °C limit set by the Paris Agreement 25 % of their species could disappear.

Hunting and Illegal Trafficking

The black market, which moves between €8 billion and €20 billion a year, threatens over 300 species that are already on the verge of extinction. According to the World Wildlife Crime Report, published by the United Nations Office on Drugs and Crime (UNODC), over 30,000 elephants, 100 tigers and 1,000 rhinoceroses are slaughtered each year.

Endangered and threatened species

Endangered and threatened species are categories used to classify species based on their risk of extinction. These classifications are typically determined by organisations such as the International Union for Conservation of Nature (IUCN) and governmental agencies based on specific criteria related to population size, habitat loss, and other threats. Here's a breakdown of what these terms mean:

ENDANGERED SPECIES

Endangered species are those that are facing a very high risk of extinction in the wild. This means that the population size of the species has declined significantly, and its habitat is being destroyed or degraded to the extent that it may not survive without intervention.

Endangered species are typically characterised by small population sizes, restricted ranges, and significant threats such as habitat loss, poaching, pollution, climate change, and disease.

Examples of endangered species include the giant panda, tiger, blue whale, orangutan, and black rhinoceros.

THREATENED SPECIES

Threatened species include both endangered species and species that are classified as vulnerable. These species face a high risk of extinction in the wild, but their populations are not yet as critically low as those of endangered species.

Threatened species may have larger populations or more widespread distributions than endangered species, but they still face significant threats that could lead to their extinction if not addressed.

Threatened species are often prioritised for conservation efforts to prevent them from becoming endangered.

Examples of threatened species include the African elephant, snow leopard, cheetah, polar bear, and leatherback sea turtle.

Both endangered and threatened species are considered priorities for conservation efforts to prevent their extinction and restore their populations and habitats. Conservation strategies may include habitat protection, restoration, captive breeding and reintroduction programs, anti-poaching measures, public education and awareness campaigns, and international cooperation to address global threats such as climate change and illegal wildlife trade.

Red data book

The Red Data Book, also known as the Red List, is a comprehensive record of species that are categorised as threatened, endangered, or vulnerable to extinction. It is compiled and periodically updated by the International Union for Conservation of Nature (IUCN), a global organization dedicated to assessing the conservation status of species and ecosystems.

The primary purpose of the Red Data Book is to provide authoritative information on the conservation status of species, serving as a valuable resource for conservationists, policymakers, researchers, and the general public. It helps identify species at risk of extinction, prioritize conservation efforts, and inform decision-making processes related to biodiversity conservation and management.

The Red Data Book classifies species into different categories based on the level of threat they face. These categories include:

Extinct(EX): Species that are believed to have become extinct, with no known individuals remaining.

Extinct in the wild(EW): Species that survive only in captivity or cultivation, with no known populations remaining in their natural habitat.

Critically Endangered(CR): Species facing an extremely high risk of extinction in the wild, with very small populations and severe declines in numbers or range.

Endangered(EN): Species facing a very high risk of extinction in the wild, with significant declines in population size or range.

Vulnerable (VU): Species facing a high risk of extinction in the wild, with moderate declines in population size or range.

Near Threatened(NT): Species that are close to qualifying for a threatened category but do not currently meet the criteria.

Least Concern(LC) : Species that are not currently considered threatened with extinction, with widespread and abundant populations.

Data Deficient(DD)  : Species for which there is insufficient information to assess their conservation status accurately.

The Red Data Book provides detailed assessments for thousands of species across various taxonomic groups, including mammals, birds, reptiles, amphibians, fishes, invertebrates, plants, and fungi. It plays a critical role in guiding conservation efforts, raising awareness about the plight of threatened species, and mobilizing support for their protection and recovery.

List of threatened flora and fauna in India

India is home to a rich diversity of flora and fauna, but many species are threatened due to habitat loss, poaching, pollution, climate change, and other human activities. Here is a list of some threatened flora and fauna species in India:

THREATENED FAUNA

1. Bengal Tiger (Panthera tigris tigris): Endangered
2. Indian Elephant (Elephas maximus indicus): Endangered
3. Indian Lion (Panthera leo persica): Endangered
4. Snow Leopard (Panthera uncia): Endangered
5. Greater One-Horned Rhinoceros (Rhinoceros unicornis): Vulnerable
6. Indian Wild Dog (Cuon alpinus): Endangered
7. Asiatic Lion (Panthera leo persica): Endangered
8. Red Panda (Ailurus fulgens): Endangered
9. Gharial (Gavialis gangeticus): Critically Endangered
10. Indian Pangolin (Manis crassicaudata): Endangered
11. Ganges River Dolphin (Platanista gangetica gangetica): Endangered
12. Great Indian Bustard (Ardeotis nigriceps): Critically Endangered
13. Nilgiri Tahr (Nilgiritragus hylocrius): Endangered
14. Indian Vulture (Gyps indicus): Critically Endangered
15. Himalayan Musk Deer (Moschus chrysogaster): Vulnerable

THREATENED FLORA

1. Red Sanders (Pterocarpus santalinus): Endangered
2. Pitcher Plant (Nepenthes khasiana): Endangered
3. Kurinji Flower (Strobilanthes kunthianus): Vulnerable
4. Madagascar Periwinkle (Catharanthus roseus): Vulnerable
5. Silent Valley Lily (Lilium mackliniae): Endangered
6. Similipal Orchid (Dendrobium ramosii): Endangered
7. Giant Himalayan Stinging Nettle (Girardinia diversifolia): Vulnerable
8. Blackbuck Thorn (Sarcopoterium spinosum): Vulnerable
9. Neela Kurinji (Strobilanthes kunthiana): Endangered
10. Dwarf Horse Chestnut (Aesculus indica): Endangered
11. Great Indian Rhododendron (Rhododendron arboreum): Vulnerable
12. Kadam Tree (Neolamarckia cadamba): Vulnerable
13. Bentinckia Palm (Bentinckia condapanna): Endangered
14. Blue Vanda (Vanda coerulea): Endangered
15. Indian Sandalwood (Santalum album): Vulnerable

This is not an exhaustive list, and there are many more species in India that are threatened with extinction. Efforts to conserve and protect these species are essential to ensure their survival and maintain India's rich biodiversity.