[Answered] Enumerate the causes for the loss of Biodiversity. Explain the in-situ and ex-situ measures of biodiversity conservation.

Biodiversity refers to the number or abundance of different species living within a particular region. Biological diversity encompasses microorganism, plants, animals and ecosystems such as coral reefs, forests, rainforests, desert etc. The biological wealth of our planet has been declining rapidly. The current species extinction rates are estimated to be 100 to 1,000 times faster than in the pre-human times largely due to human activities.

Causes of biodiversity loss:

1. Habitat loss and fragmentation: This is the most important cause driving species to extinction. Besides total loss, the degradation of many habitats by pollution also threatens the survival of many species. Fragmentation of habitats leads to population decline.
2. Over-exploitation: Many species extinctions in the last 500 years were due to overexploitation by humans. Presently many marine fish populations around the world are over harvested, endangering their continued existence.
3. Alien species invasions: When alien species are introduced, some of them turn invasive, and cause decline or extinction of indigenous species.
4. Co-extinctions: When a species becomes extinct, the plant and animal species associated with it in an obligatory way also become extinct.
5. Global warming: Global warming is also becoming a major cause for loss of biodiversity. If the present rate of global warming continues, coral reefs which are biodiversity hotspots will disappear in 20-40 years.
6. Pollution: Pollution alters the natural habitat. Insecticides, pesticides, sulphur and nitrogen oxides, acid rain, ozone depletion and global warming too, affect adversely the plant and animal species.
7. Natural Calamities: Natural calamities such as floods, drought, forest fires, earth-quakes, volcanic eruptions, epidemics etc. are increasing which take a heavy toll of plant and animal life.

Biodiversity conservation measures:

1. In-situ measures: In in situ conservation, the endangered species are protected in their natural habitat so that the entire ecosystem is protected. India has over 600 protected areas, which includes over 90 national parks, over 500 animal sanctuaries and 15 biosphere reserves.
   • National Parks: A national park is an area which is strictly reserved for the betterment of the wildlife and where activities like forestry, grazing on cultivation are not permitted. In these parks, even private ownership rights are not allowed. In national parks, the emphasis is on the preservation of a single plant or animal species.
   • Wildlife Sanctuaries: A sanctuary is a protected area which is reserved for the conservation of only animals and human activities like harvesting of timber, collecting minor forest products and private ownership rights are allowed as long as they do not interfere with well-being of animals. Boundaries of sanctuaries are not well defined and controlled biotic interference is permitted, e.g., tourist activity.
   • Biosphere Reserves: It is a special category of protected areas where human population also forms a part of the system. They are large protected area of usually more than 5000 sq.km.
2. Ex-situ measures – In this approach, threatened animals and plants are taken out from their natural habitat and placed in special settings where they can be protected and given special care. Such strategies include establishment of botanical gardens, zoos, conservation strands and gene, pollen seed, seedling, tissue culture and DNA banks.
   • Seed gene bank: These are cold storages where seeds are kept under controlled temperature and humidity for storage and this is the easiest way to store the germplasm of plants at low temperature. Seeds preserved under controlled conditions remain viable for long durations of time.
   • Gene bank: Genetic variability also is preserved by gene bank under normal growing conditions. These are cold storages where germplasm are kept under controlled temperature and humidity for storage. This is an important way of preserving the genetic resources.
   • Cryopreservation: This is the newest application of technology for preservation of biotic parts. This type of conservation is done at a very low temperature (196°C) in liquid nitrogen. The metabolic activities of the organisms are suspended under low temperature, which are later used for research purposes.
   • Tissue culture bank: Cryopreservation of disease free meristems is very helpful. Long term culture of excised roots and shoots are maintained. Meristem culture is very popular in plant propagation as it’s a virus and disease free method of multiplication.
   • Long term captive breeding: The method involves capture, maintenance and captive breeding on long term basis of individuals of the endangered species which have lost their habitat permanently or certain highly unfavourable conditions are present in their habitat.
   • Botanical gardens: A botanical garden is a place where flowers, fruits and vegetables are grown. The botanical gardens provide beauty and calm environment. Most of them have started keeping exotic plants for educational and research purposes.
   • Animal Translocation: Release of animals in a new locality which come from anywhere else.
   • Zoological Gardens: In zoos wild animals are maintained in captivity and conservation of wild animals (rare, endangered species).

Conservation of biodiversity is a collective responsibility of the entire mankind. Therefore, appropriate measures must be taken for its conservation and sustainable utilization of its benefits. Biodiversity needs to be conserved in order to maintain balance of nature.