Q.23. What are the major causes of threats of
biodiversity? Discuss the strategies and
conservation of biodiversity. (AKTU. - 2013-14)
Ans. Threats To Diversity: -
The Earth and its biodiversity are
dynamic and ever changing. As such extinction of species is a natural
phenomena. Fossil record reveals that all species have a definite life span and
it is bound to extinct after that. But the cause of concern is the rate at
which species extinct in present day context as compared to earlier undisturbed
state.
It has been estimated that in earlier times, the rate
of extinction, in general, through natural evolution was just one species over
a span of 60-70 years (400 yeas for mammal species and 200 years for bird
species) which gradually has increased to an alarming situation due to
consistent interference of human
activity as is evident from the figures given below:
It has been estimated that
over the next half century. tropical deforestation will be the single largest
cause of species extinction. At the current rate of deforestation, about 5-10%
of closed tropical forest species will become extinct perdecade by 2050 AD i.e.
an unimaginable rate of about 100 species a day. It is also to be emphasized
here that with extinction of one species, the dependent speices, which could be
even 10 to 20, will also become endangered.
Conservation Of
Biodiversity: -
In order to
retain the capabilities of life supporting system it is essential to save and
maintain species and ecosystems ultimately for survival of human race. Efforts
have been made to save biodiversity both by ex-situ and in-situ conservation.
Ex-situ Conservation: -
It refers to conservation of species in suitable
locations outside their natural habitat. The need to conserve species in
ex-situ arise when its population is so fragila/fragmented that its survival in
wild may no longer be possible or in other words a threatened or endangered speices.
Suitable location in field
(1) Botanical/zoological gardens, aquarium and reserarch centres.
(2) Field Gene Banks: These are the places where
collections of growing plants have been assembled including as many individual
of species as possible in order to maintain the widest practicable range of
biodiversity.
(3) Seed Banks: These are most efficient and effective
method of ex-situ conservation of plants whose seeds are suitable for long term
storage. Since seed represents a wide range of genetic viability, its storage
ensures conservation of genetic diversity. A seed could remain viable for 5-25
years at -50C but it could be viable for hundred years if preserved at - 200C.
(4) In Vitro (in Glass): It refers to storage under laboratory
conditions. The meristem tips, buds and stem tips are kept under low
temperature (-30 to 120C) for slow growth
and long storage.
Insitu Conservation: -
The preservation
of species in its natural eco-system is called in-situ conservation. It is
being done by declaring the area as ‘protected area’ with emphasis either to
save the entire area or an endangered species. As a consequence, protected
areas are being identified and maintained of natural conservation of species by
individual countries in the world. In Indian context, we have protected area
network of biosphere, national park and sanctuaries with objective to save
entire specified area and tiger reserves, elephant and crocodile projects etc.
to save particular endangered species. Brief details of each type of protected
area in Indian context are as under:
Biosphere Reserves:-
A
biosphere reserve has two distinguished zones, namely, core zone and buffer
zone. The internal area or the core zone of biosphere reserve is simply
protected as such with almost no or very little human interference (R & D
permitted) whereas buffer zones
are open for research, education, tourism, sustainable agriculture, beneficial
and ecological sound development programmes.
National Park and Sanctuaries:-
Our
country has good network of protected areas under the category of National
parks and Sanctuaries. At present, we have 80 national parks and 441
sanctuaries covering about 14.87 million hectare area which is over 4% of the
total geopraphical area of the country (MOEF (2),1955). Both these areas are
being declared under legal arena of Wildlife (Protection) Act, 1972, whereas
biosphere reserve is without any legal declaration. Similar to core area of
biosphere reserve, the biotic interference and tourism activity are not allowed
in national park area whereas we can have biotic interence and tourism
activities of certain extent in sanctuary area.
Tiger Reserves: -
The objectives behind setting up of tiger reserves in India are as
follows:
(1) To maintain a viable population of tigers in India for
scientific, economic, cultural and ecological values.
(2) To preserve for all time, areas of such biological importance
as a natural heritage for benefit, education and enjoyment of people.
The programme of tiger reserves was started
in 1973 with tiger population dwindling around 270.
Project Elephant:-
The objective was to ensure long term
survival of viable population of elephants and tackling problemtic elephant
populations causing serious depredation and also restoring lost and degraded
habitats of elephants.
Similar was the objective of
setting up crocodile breeding project through captive breeding in Hyderabad but
has still not come in operation.