BIODIVERSITY
v Biodiversity
is the variety and differences among living organisms from all sources,
including terrestrial, marine, and other aquatic ecosystems and the ecological
complexes of which they are a part.
v It is
virtually synonymous with “Life on earth”.
v Biologists
most often define "biological diversity" or "biodiversity"
as the "totality of genes, species, and ecosystems of a region".
v The
biodiversity found on Earth today consists of many millions of distinct
biological species, which is the product of nearly 3.5 billion years of
evolution.
1 Levels of Biodiversity
1) Genetic diversity
v It is a
level of biodiversity that refers to the total number of genetic
characteristics in the genetic makeup of a species.
v It is
distinguished from genetic variability, which describes the tendency of genetic
characteristics to vary.
2) Species diversity
v It refers
to the variety of species within a region.
v Species
diversity is an index that incorporates the number of species in an area and
also their relative abundance.
v It is
generally a much more useful value than species richness.
3) Community and Ecosystem diversity
v Ecosystem
diversity refers to the diversity of a place at the level of ecosystems. This
has 3 perspective:
v Alpha
Diversity: Within community diversity. Alpha diversity refers to the diversity
of organisms sharing the same Community/Habitat.
v Gamma
Diversity: Diversity of the habitat over the total landscape or geographical
area is called gamma diversity.
2 Values of Biodiversity
Food:
About 80,000 edible plants and about 90% of present day food crops have been
domesticated from wild.
Drugs
& Medicines: About 75% of world’s population depends on plants or plant
extracts.
Fuel:
Forests have been used since ages for fuel wood. Fossil fuels are also products
of Biodiversity.
Social
Value: Many of the plants like Tulsi, Lotus, Peepal etc are considered holy and
sacred.
v About 2.1
million species have been identified till date, while many more species are
believed to exist.
v According
to UNEP estimate, approximately 9.0 – 52 million of species exist on Earth
v India’s
position is 10th in the world & 4th in Asia in terms of Plant diversity.
HOT- SPOTS OF BIODIVERSITY
v A
biodiversity hotspot is a biogeographic region with a significant reservoir of
biodiversity that is threatened with destruction.
v An area
is designated as a hot spot when it contains at least 0.5% of plant species as
endemic.
v There are
25 such hot spots of biodiversity on a global level, out of which two are
present in India.
v These
are: Indo- Burma (earlier The Eastern Himalayas) ,The western Ghats & Sri
Lanka..
v These hot
spots covering less than 2% of the world’s land area are found to have about
50% of the terrestrial biodiversity.
Criteria for determining hot-spots
v No. of Endemic Species i.e. the species which
are found no where else.
v Degree of
threat, which is measured in terms of Habitat loss.
E.g. Indo- Burma (Eastern Himalayas) Hotspot
v The
hotspot includes all of Cambodia, Vietnam & Laos, and nearly the entire
areas of Thailand, Myanmar & Bhutan as well as part of Nepal, far eastern
India and extreme southern China.
v In
addition, it covers several offshore Islands including Mainan Islands in the
south China Sea and Andaman & Nicobar Islands in Indian Ocean.
v Indo-Burma
is one of the most threatened biodiversity hotspots, due to the rate of
resource exploitation and habitat loss.
E.g. Western Ghats and Sri Lanka
v Western
Ghats and Sri Lanka, also known as the “Sahyadri Hills” encompasses the montane
forests in the southwestern parts of India and on the neighboring Islands of
Sri Lanka.
v The
entire extent of hotspot was originally about 1,82,500 square kms, but due to
tremendous population pressure, now only 12,445 square Km or 6.8% is in
pristine condition.
v The
important populations include Asian elephant, Indian tigers and the endangered
lion tailed macaque.
THREATS TO BIODIVERSITY
v Extinction
is a natural event and, from a geological perspective, routine.
v In last
century, human impact has been so severe that thousands of species and
varieties are becoming extinct annually.
v Some of
the main causes are:
v Habitat
loss, degradation, fragmentation.
v Habitat
loss & degradation are major causes of species extinction, affecting 89% of
all threatened birds, 83% of mammals & 91% of all threatened plants
assessed globally (IUCN, 2000)
v The main
causes of habitat are agriculture activities, Mining, development of human
settlement, industry etc.
v According
to ICUN, UNEP report, more than 50% of wildlife habitat has been destroyed in
49 out of 61 old world tropical countries.
POACHING OF WILDLIFE
v Poaching
is another threat that has emerged in recent decades as one of the primary
reason for decline in number of species.
v Wildlife
is sold and traded in many countries for live specimens, folk medicines, furs,
Skin, and other products such as Ivory, horns etc amounting to millions of
dollars.
MAN – WILDLIFE CONFLICTS
v The
conflict between man and wildlife started with the evolution of man, but
intensity increased due to the activities of modern man
v Due to
the lack of stable food and disruption of movement, wild animals came out of
forest area and attack the agricultural field and humans and in turn got killed
by the humans.
1 Introduction of Exotic species
v Organisms introduced into habitats where they
are not native are termed as exotics.
v They can
be thought of as Biological Pollutants and are considered to be among the most
damaging agents of habitat alteration and degradation the world.
2 Climate change
A changing
global climate threatens species and ecosystems.
v The
distribution of species (biogeography) is largely determined by climate.
v Climate
change may simply shift these distributions but, for a number of reasons,
plants and animals may not be able to adjust.
ENDANGERED SPECIES
v According
to The International Union of Conservation of Nature and Natural Resources
(IUCN), the species that considered in imminent danger of extinction and whose
survival is unlikely, if factors causing their decline continue to operate.
v Out of
about 47,000 species of plants in our country, 7000 are endemic
v India
contains 172 species of animals considered globally threatened by IUCN, or 2.9%
of the world’s total number of threatened species.
v These
include 53 species of mammals, 69 birds, 23 reptiles and 3 amphibians
v As many
as 3,000- 4,000 higher plants may be under high degree of threat in India
v Thus
Indian subcontinent has about 62% endemic flora, restricted mainly to
Himalayas, khasi Hills & Western Ghats.
v Sapria
himalayana, Uvaria lurida, Napenthes khasians etc. are some endemic flora of
our country.
v A large
number out of a total of 81,000 species of animals in our country is endemic.
About 62% amphibians and 50% lizards are endemic to western Ghats.
v Golden
monkey, Niligiri Langur, Indian Wolf, Red Fox, Himalayan Brown Bear, Great
Indian One Horned Rhinoceros, White Winged Wood Duck, Black Necked Crane,
Indian Pea Fowl, Gharial, Indian egg eating Snake, Indian Salamandar etc. are
some examples of endemic animal species of India.
CONSERVATION OF BIODIVERSITY
v The
convention on Biological Diversity held in June, 1992 stressed the need of the
conservation of Biodiversity for sustainable development and perpetuation of
human beings on earth.
v Conservation
is defined as “ the management of human use of the biosphere so that it may
yield the greatest sustainable benefit to the present generation while
maintaining its potential to meet the needs and aspirations of the future
generations”.
v The two
basic approaches to wildlife conservation in protected habitats are:
1) In- situ
conservation 2) Ex- situ conservation.
1 In- situ conservation
v It simply
means conservation of species in its natural ecosystem or even in man made
ecosystems.
v This
strategy emphasizes protection of total ecosystem through a network of
“protected area”.
v Protected
Areas: an area of land and/or sea specially dedicated to the protection and
maintenance of biological diversity and managed through legal effective means.
v There are
different categories of protected areas which are managed with different
objectives. These include; Biosphere reserves, National parks, Wild Life
Sanctuaries etc.
v At
present we have 11 major biosphere reserves, 80 National parks, 420 wildlife
sanctuaries in our country covering 4% of the geographic area.
v The JIM
CORBETT National Park was 1st national park established in India.
What is
Difference among Biosphere reserves, National parks, Wild Life Sanctuaries ?
Examples of Biosphere reserves of India:
1. Nilgiri-
5,520 sq.km
2. Nanda
Devi- 5,860.69 sq. km
3. Manas –
2837 sq. km
4. Gulf of
Mannar – 10,500 sq. km
5. Great
Nicobar – 885 sq. km
6. Panchmarhi
– 4,926.28 Sq Km Examples of some National park in India
1. Kaziranga- Assam, Gir National Park- Gujarat,
Periyar – Kerala, Sariska – Rajasthan Examples of some Wild Life Sanctuaries of
India:
1. Ghana
Bird sanctuaries
2. Hazaribagh
sanctuaries
3. Abohar
wild life sanctuaries
4. Jaldapara
wild life sanctuaries
5. Mudamalai
wild life sanctuaries
2 Ex- situ conservation
v It is
defined as “the conservation of component of biological diversity (Sample of
genetic diversity, particularly of endangered species) outside their natural
habitats”.
v It
involves maintenance and breeding of endangered plant and animal species under
partially or wholly controlled conditions. E.g. Zoos, Botanical Gardens,
Aquaria, Nurseries, DNA bank, Seed bank, Gene bank etc.
v There are
more than 1500 Botanical gardens in the world containing more than 80,000
species.
v There are
more than 800 zoos around the world with about 3,000 species of mammals, birds,
reptiles and amphibians.
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