Understanding Biodiversity

• Biodiversity refers to the number, variety, and variability of life forms in a geographic region, including terrestrial and aquatic.
• Biodiversity is a product of millions of years of evolution.
• It covers diversity within species, between species, and variations among ecosystems.

Importance of Biodiversity

• Biodiversity provides supporting ecosystem services like photosynthesis, soil formation, and habitat.
• Provisioning services include food, clean water, fish, and wood.
• Biodiversity contributes to regulating services such as pollination, temperature control, flood control, water purification, and carbon storage.
• Cultural services include aesthetic value, recreation, education, and clean air.

Ecological Role of Biodiversity

• All species contribute at least one function in an ecosystem.
• These functions regulate species balance, diversity, and health.
• Examples of these functions include biomass production, atmospheric oxygen creation, soil formation, water purification, flood control, and climate regulation.

Economic Role of Biodiversity

• Food, specifically crop biodiversity or agro-biodiversity, is a key factor.
• Goods include timber, paper, and medicines.
• Genetic resources: Biotechnology and genetic engineering use genes to make new crops and medicines.
• Species can give scientists insight into how life evolved.

Cultural, Social, Aesthetic Role

• Biodiversity promotes education, recreation, tourism, and exploration.

World Biodiversity Day

• World Biodiversity Day is on May 22nd.

Megadiverse Countries

• Megadiverse countries include Australia, Brazil, China, Colombia, Ecuador, United States, Philippines, India, Indonesia, Madagascar, Malaysia, Mexico, Papua New Guinea, Peru, Democratic Republic of Congo, South Africa, and Venezuela.
• A main criterion for megadiverse countries is endemism at the level of species, genera, and families.
• A megadiverse country must have at least 5,000 species of endemic plants and border marine ecosystems.

Factors Determining Diversity

• Habitat stress is a factor.
• Geographical isolation is a factor.
• Dominance by one species is a factor.
• Availability of ecological niches is a factor.
• Geological history is a factor.
• The Edge effect is a factor.

Species Diversity

• Species diversity refers to the number of plant and animal species in a community or ecosystem.
• It varies between ecosystems.
• Tropical rainforests and coral reefs have high species diversity.
• Isolated islands have low species diversity.
• An estimated 8.7 million total species exist on Earth, with 6.5 million on land and 2.2 million in oceans.
• Areas rich in species diversity are called 'hotspots'.
• 1.8 million species have been identified and described.
• 86% of land and 91% of sea species are yet to be discovered.

Species Richness vs Evenness

• Species Richness refers to the total number of species.
• Species Evenness refers to the relative abundance of species.
• Species Dominance refers to the most abundant species.

Genetic Diversity

• Genetic diversity is the variation in genetic composition of individuals in a population, community, or species.
• No two members of the same species are genetically identical.
• High genetic diversity increases the ability of populations and species to survive major environmental changes.
• The diversity in wild species forms the 'gene pool'.
• Modern biotechnology also manipulates genes to develop better types of medicines and a variety of industrial products.
• Loss of genetic diversity within a species is called "Genetic erosion".

Ecosystem Diversity

• Ecosystem diversity deals with variations in ecosystems within a geographical location and its impact on human existence and the environment.
• Types of ecosystems include forests, grasslands, deserts, marine, and wetlands.
• Examples in India: humid tropical Western Ghats, hot desert of Rajasthan, cold desert of Ladakh, icy mountains of Himalayas, and coasts of peninsular India including coastal region of Orissa.

Keystone Species

• Keystone species determine the survival of other species and are mostly top-level predators.

Sentinel/Indicator Species

• Sentinel/indicator species act as indicators of danger to human life, providing advance warning.
• They are used for food monitoring, health assessments, and epidemiological studies.
• Domestic canaries were used to detect gas in coal mines.

Species Extinction

• Biological extinction is the complete and irreversible disappearance of a species, which can be local or ecological.
• Background extinction is the gradual disappearance of species.
• Mass extinction involves over 65% of all species becoming extinct.
• A mass extinction event 225 million years ago eliminated 95% of marine species
• A mass extinction event 65 million years ago eliminated the dinosaurs
• Reasons for extinction include global cooling, predation, and asteroid/comet hits.

The IUCN Red List

• The IUCN Red List of Threatened Species uses criteria to evaluate the extinction risk of species and subspecies.
• Goals: provide information on the status of species, highlight importance of threatened biodiversity, influence policy, and guide conservation.

Threatened Species

• A threatened species faces threats to its survival and is potentially at risk of extinction.

Vulnerable Species

• A vulnerable species has a population that has declined by at least 50% or 30%, where the decline is known or unknown, respectively.

Endangered Species

• Endangered species are those with populations declined ≥70% (cause known), or ≥50% (cause unknown).

Biodiversity Hotspots

• Biodiversity hotspots contain at least 1,500 species of vascular plants found nowhere else and have lost at least 70% of their primary native vegetation.
• Hotspots in India include the Himalayas, Western Ghats, Indo-Burma region, and Sundaland (including Nicobar group of Islands).

India's Biodiversity

• India has approximately 45,000 plant species and 81,000 animal species.
• 18% of plant species are endemic.
• There are 166 crop species and >30,000 rice varieties.

Biogeographic Classification of India

• Biogeographic zones: Trans Himalayan, Himalayas, Desert, Semi-Arid, Western Ghats, Deccan Peninsula, Gangetic Plain, North-East India, Islands, and Coasts and Lakshadweep Islands.

Threats to Biodiversity

• Habitat loss, degradation, and fragmentation occur due to volcanic eruptions, wildfires, droughts, severe storms, conversion of forest to agricultural lands, dam construction, and human settlements.
• Effects: Species are divided into smaller populations, become more vulnerable to predators and competitors, fragmentation limits species dispersal, and migratory birds lose seasonal habitats.
• The slide refers to Serengeti national park habitat fragmentation.
• Commercial hunting, poaching, and man-wildlife conflicts are all threats.
• Invasive species become "invasive" when introduced outside their natural areas and displace native species.
• Overexploitation of bio resources is a threat.
• Pollution is a threat.
• Climate change is a threat.

Convention on Biological Diversity

• The Convention on Biological Diversity (CBD) entered into force in December 1993.
• CBD objectives: conservation of biodiversity, sustainable use of components, and fair sharing of benefits from the utilization of genetic resources.

Conservation Measures

• Protect species/ecosystems through in-situ conservation (on-site) and ex-situ conservation (off-site).
• In-situ: National parks, Biosphere Reserves, Wildlife Sanctuaries.
• Ex-situ: Seed banks, Zoos, Botanical gardens, Aquariums.
• Prevent and control forest fires.
• Burning of grasslands must be controlled.
• Eliminate excessive cutting of trees and only harvest mature trees.
• New seedlings should replace harvested trees.
• Use erosion-resistant grasses like Cynodon dactylon to improve soil fertility.
• Manage insects and diseases affecting trees.
• Conserve endangered and endemic species in natural forests ("guardians of diversity").
• Implement effective methods to minimize water, soil, and air pollution.
• Stop improper land degradation due to mining.
• Intensify efforts to curb poaching.
• Restore species that can be restored.
• Implement educational programs to promote knowledge of conservation and preservation of wildlife.