loss of biodiversity; biodiversity conservation; hotspots, endangered organisms, extinction

• Natural (or) background extinction is a slow process of replacement of existing species with the better adapted species due to alternate evolution, predators and diseases.
• Earth have experienced 5 mass extinctions
  Examples: Extinction of marine invertebrates in permian period
                     Extinction of dinosaurs and numbers of other species between Cretaceous and tertiary period
• Anthropogenic extinctions are abetted by human activities like settlements hunting are exploitation and habitat destruction. The primary cause of the loss of biodiversity is not direct human exploitation but the habitat destruction that inevitably results from the expansion of human populations and human activities.
• The world is facing accelerated rates of species extinctions, largely due to human interference. The four major causes - The Evil quartet
  ⇒ Habitat loss and fragmentation
  ⇒ over exploitation
  ⇒ Alien species invasions
  ⇒ Co - Extinction
• Other factors : Disturbance and degradation, pollution, intensive agriculture and forestry.
• Klater hyacinth was introduced in Indian waters to reduce pollution. Later It has clogged water bodies including wetlands at many places resulting in death of several aquatic plants and animals.
• Biodiversity conservation mean protection, upliftment and scientific management of biodiversity to maintain it at its optimum level.
• Three main reasons to conserve the biodiversity:
  → Narrow utilitarian [food, fibres, drugs]
  → Broad utilitarian [climate regulation, flood / erosion control (etc)]
  → Ethical utilitarian
• Conservation strategies are broadly of 2 types - in situ and Ex situ
• In situ conservation means on site conservation. It is conservation and protection of the whole ecosystem and its biodiversity at all levels in order to protect the threatened species. There are hotspots and protected areas.
• Hotspots are areas with high density of biodiversity which are also the most threatened ones. A hotspot in an area which faces serious threat from human activities and support a unique biodiversity with representatives of evolutionary processes of speciation and Extinction.
• India's 3 hot spots
  → Indo-Burma
  → Himalayas
  → Western ghats - Sri Lanka.
• Protected areas are ecological / biogeographical areas where biodiversity along with natural and cultural resources in protected, maintained and managed through legal or other effective measures.
• They are delimited on the basis of bio diversity Eg. cold desert, hot desert, Wetland, saline swampy areas, mangroves, Temperate forests.
• Protected areas include national parks, sanctuaries and biosphere reserves.
• National parks are large areas of scenic and national beauty maintained for scientific, educational and recreational use they are not usually used for commercial extraction of resources.
• First national park of India → Jim corbett National park (famous for Tigers) Yellowstone park (USA)
  Royal park (Sydney, Australia)
  Gir National park → Gujarat [Asiatic lion]
• Sanctuaries are the tracts of land with or without lake where wild animals / fauna can take refuge without being hunted.
• Other activities collection of forest products, timber harvest, private ownership of land, land filling.
• Biosphere reserves are multipurpose protected areas which are meant for preserving genetic diversity in representative ecosystems of various natural biomes and unique biological communities by protecting wild populations, traditional lift style of tribals and domesticated plant / animals genetic resources.
• Creation of biosphere reserve was initiated in 1975 under MAB programme of UNESCO
• Zones of Each biosphere :
  ⇒ core / Natural zone : No human activity ; undisturbed ; legally protected
  ⇒ Buffer zone : Surrounds core area ; Limited human activity ⇒ strategies, research, education.
  ⇒ Transition zone : [manipulation zone] ⇒ outermost; active co-operation is present between reserve management and local people for activities like settlements, cropping, recreation, forestry and other economic uses without disturbing ecology.
• The importance of biosphere are restoration, conservation, development, monitoring Education and research.
• Ex - situ conservation is the conservation outside the habitats which includes offsite collections and gene banks.
• Offsite collections are live collections of wild and domesticated species is botanical gardens, zoological parks, arboreta.
• Currently, there are more than 1500 botanical gardens and Arboreta having more than 80,000 species.
• Many of them have seed banks, tissue culture facilities, which have well managed captive breeding programmes.
• Gene banks are institutes that maintain stocks of viable seeds, live growing plants, tissue culture and frozen germplasm with the whole range of genetic variability.
• 
• Plants with recalcitrant seeds are grown in orchards where all possible strains and varieties are maintained eg; Litchi, oil palm, rubber tree etc.
• Preservation at -196°C (liquid nitrogen) can maintain tissue culture, embryos, animal cells / tissues, spermalazoa indefinitely which is called cryopreservation

Levels of Biodiversity:

• Biodiversity is of 3 types Alpha, Beta and Gamma diversity.
• Alpha (α) diversity ⇒ Calculated by the combination of species richness and evenness (or) equitability
            ↓ evenness (or) equitability
  No. of species in given community
• β - diversity ⇒ between community diversity
                    ⇒ The greater the difference (or) turnover of species between the habitats, greater the β - diversity
• Gamma diversity ⇒ regional diversity
                          ⇒ representation of total species richness in all habitats found within a region (or) landscape
• Species diversity is the diversity in number and richness of species of region. The no. of species per unit area is called species richness. Number of individuals of different species represent species evenness (or) species equitability.
• Western ghats have greater amphibian species diversity as compared to eastern ghats.