Biodiversity

• The term coined by Walter G. Rosen in 1985.

• Biodiversity is all the different kinds of life found in one area—the
variety of animals, plants, fungi, and even microorganisms like
bacteria that make up our natural world.
• According to International Union for Conservation of Nature (IUCN)
and UN Environment Programme (UNEP) “the totality of genes,
species and ecosystems in a region” is termed as “Biodiversity”.
• Three levels of Biodiversity includes:
1. Genetic Diversity
2. Species Diversity
3. Community or Ecosystem Diversity
Genetic Diversity:

 Every species on Earth is related to every other

species through genetic connections.

 The more closely related any two species are, the

more genetic information they will share, and the
more similar they will appear.

 An organism’s closest relatives are members of its

own species, or organisms with which it has the
potential to mate and produce offspring.
Species Diversity:

 Species diversity is the variety of species within

a habitat or a region.

 Species are the basic units of biological

classification and thus the normal measure of
biological diversity.

 Species richness is the term that describes the

number of different species in a given area.

 The world total is estimated at five to 10 million

species, though only 1.75 million have been
named scientifically so far.
Community/ Ecosystem Diversity:
 An ecosystem consists of organisms from many
different species living together in a region and their
connections through the flow of energy, nutrients and
matter.

 Those connections occur as the organisms of different

species interact with one another.

 The ultimate source of energy in almost every

ecosystem is the sun.
Keystone Species
 Keystone species is a species whose addition to or loss from an ecosystem
leads to major changes in the occurrence of at least one other species.

 Certain species in an ecosystem is considered more important in

determining the presence of many other species in that ecosystem.

 All top predators (Tiger, Lion, Crocodile, Elephant) are considered as

keystone species because they regulate all other animal population
indirectly.

 Hence top predators are given much consideration in conservation.

 If keystone species is lost, it will result in the degradation of the whole

ecosystem.

 For example, certain plant species (ebony tree, Indian-laurel) exclusively

depends upon bats for its pollination. If the bat population is reduced, then
regeneration of particular plants becomes more difficult.
 Foundation species

Foundation species is a dominant primary producer in an

ecosystem both in terms of abundance and influence. Example:
kelp in kelp forests and corals in coral reefs.

 Flagship species

▪ A flagship species is a species chosen to represent an

environmental cause, such as an ecosystem in need of
conservation.

▪ These species are chosen for their vulnerability,

attractiveness or distinctiveness in order to engender support
and acknowledgement from the public at large.

▪ Example: Indian tiger, African elephant, giant panda of China,

the leatherback sea turtle, etc.
 Measuring Biodiversity

 Alpha Diversity: number of species in a single community.

Here, species richness is high.

 Beta Diversity: the degree to which species composition

changes along an environmental gradient.

 Gamma Diversity: applies to a larger geographical scale. It

is the rate at which additional species are encountered as
geographical replacements within a habitat type in different
localities.
 Biodiversity in Tropics

i. The tropics have stable climate.

ii. Tropical communities are older than temperate ones. This

allows them greater degree of specialization and local
adaptation to occur.

iii. Favourable conditions for growth and reproduction (warm

temperature and high humidity).

iv. Species richness is high.

v. In plants interbreeding rates are high which leads to high

genetic variability.

vi. Tropical areas receive much more solar energy. Thus much
more productive.
 Mega-biodiversity

 The term megadiverse country refers to any one of a

group of nations that harbor the majority of Earth's
species and high numbers of endemic species.

 The World Conservation Monitoring Centre (WCMC) of

the United Nations Environment Program has
identified a total of 17 mega-diverse countries:

 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.
Characteristics of the megadiverse
countries

 In accordance with the World Conservation Monitoring

Centre, for a country to be considered mega-diverse, it
must:

i. Have at least 5,000 endemic plants.

ii. Have marine ecosystems within its borders.

 Geographic position: most are in tropical areas, where

there is a large diversity of species.

 Diversity of countries: the complexity of mountain scenery

brings forth the diversity of atmospheres, soils and
climates.
 Isolation: the progressive separation of islands and
continents has allowed the development of unique flora
and fauna.

 Size: the larger the size, the greater the diversity of

scenery and species.

 Evolutionary history: some of the countries are on

intersection between two biogeographic regions,
producing a mixture of fauna and flora with different
histories.

 Culture: the domestication of plants and animals has

contributed to the natural wealth.
 Biodiversity of India
 In terms of species richness, India ranks 7th in mammals, 9th in
birds and 5th in reptiles.
 In terms of endemism of vertebrate groups, India’s position is
10th in birds with 69 species, 5th in reptiles with 156 species
and 7th in amphibians with 110 species.
 India’s share of crops is 44% as compared to the world average
of 11%.
 India Represents:
 2 ‘Realms’
 5 Biomes
 10 Bio-geographic Zones
 25 Bio-geographic provinces
 Realms
 Biogeographic realms are large spatial regions within which
ecosystems share a broadly similar biota.

 A realm is a continent or sub-continent sized area with unifying

features of geography and fauna & flora.

 The Indian region is composed of 2 realms. They are:

1. the Himalayan region represented by Palearctic Realm and

2. the rest of the sub-continent represented by Indomalayan Realm

 In world, 8 terrestrial biogeographic realms are typically

recognized.

Nearctic Realm, Palaearctic Realm, Africotropical Realm, Indomalayan

Realm, Ocenaia Realm, Australian Realm, Antarctic Realm and
Neotropical Realm
 Biomes of India
 The term biome means the main groups of plants and
animals living in areas of certain climate patterns.

 It includes the way in which animals, vegetation and soil

interact together. The plants and animals of that area have
adapted to that environment.

 The 5 biomes of India are:

1. Tropical Humid Forests

2. Tropical Dry or Deciduous Forests (including Monsoon

Forests)

3. Warm deserts and semi-deserts

4. Coniferous forests and

5. Alpine meadows.
 Biogeographic zones of India
• India contributes 2.4% of the
total land area of the world.
• India contributes 8% to the
known global biological
diversity.
• India has been divided into 10
biogeographic zones
 Trans-Himalayan Region: Ladakh, Jammu & Kashmir, North Sikkim, Lahaul and Spiti
areas of Himachal Pradesh. wild sheep and goat, Snow Leopard and the migratory
Black necked Crane.

 Himalayan Zone: richest areas in terms of habitats and species. Bharal, Ibex, Markhor,
Himalayan Tahr, and Takin. Other rare and endangered species restricted to this zone
include Hangul and Musk Deer.

 Indian Desert Zone: Wolf, Caracal, Desert Cat, and birds of conservation interest viz.,
Houbara Bustard and the Great Indian Bustard.

 Semi Arid Region: a transition zone between the desert and the dense forests of
Western Ghats. This semi-arid region also has several artificial and natural lakes and
marshy lands. Sambar, Chital, Lion (Gujarat), Caracal , Jackal, wolf.

 Western Ghats: Nilgiri Langur, Lion Tailed Macaque, Grizzled Giant Squirrel, Malabar
Civet, Nilgiri Tahr, and Malabar Grey Hornbill.

 Deccan Plateau: forests are deciduous in nature. Chital, Sambar, Nilgai, and
Chousingha, Barking deer, and Gaur (Antilope), Elephant, Wild Buffalo, Swamp Deer.
 Gangetic Plain: Rhino, Elephant, Buffalo, Swamp Deer, Hog-Deer and Hispid Hare.

 North East Region: the transition zone between the Indian, Indo-Malayan and Indo-
Chinese bio-geographical regions as well as being a meeting point of the Himalayan
mountains and peninsular India, biodiversity hotspot (Eastern Himalaya).

 Coastal Region: sandy beaches, mangroves, mud flats, coral reefs and marine
angiosperm pastures make them the wealth and health zones of India. The coastline
from Gujarat to Sundarbans is estimated to be 5,423 km long. A total of 25 islets
constitute the Lakshadweep, which are of coral origin, and have a typical reef lagoon
system, rich in biodiversity. However, the densely populated Lakshadweep islands
virtually have no natural vegetation.

 Andaman and Nicobar Islands: Tropical moist evergreen forests zones in India. The
islands house an array of flora and fauna not found elsewhere. These islands are
centers of high endemism and contain some of India’s finest evergreen forests and
support a wide diversity of corals. In India, endemic island biodiversity is found only
in the Andaman and Nicobar Islands. Some of the endemic fauna of Andaman &
Nicobar islands include Narcondam hornbill, South Andaman krait etc.