BIOL1010 - Analysis of Biodiversity Threats, Conservation & Biome

This report provides an overview of biodiversity, its status, and the threats it faces, including habitat degradation, invasive species, and climate change. It highlights the importance of biodiversity for the world's economy and human needs, emphasizing the concern over its decline. The report discusses in-situ and ex-situ conservation methods, including the identification of biological hotspots, development of gene banks, and biotechnological approaches. It further explores the measurement of biodiversity through genetic, species, and ecosystem diversity, detailing the various factors influencing each level. The document also includes a section about selecting a biome based on ecological factors, referencing chapter 36 of a textbook (BIOL1010) and including abiotic and biotic factors to justify the choice.

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Biodiversity-Threats and Conservation
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282 Environ. Sci. & Engg. Vol. 2:Biodiversity and Conservation
1 Department of Horticulture, School of Agriculture, Lovely Professional University,
Jalandhar, Punjab, India.
2 Department of Horticulture, School of Agriculture, Lovely Professional University,
Jalandhar, Punjab, India.
3 Department of Biology, Happy Model School, Varanasi, UP, India.
*Corresponding author: E-mail: [e-mail]
14
Biodiversity-Threats and Conservation
SHAILESH KUMAR SINGH 1*, MADHU SHARMA 2 AND ANJANA PANDEY 3
ABSTRACT
The biodiversity, diversity in life forms, suffers greater threat from
degradation, habitat fragmentation; spreading of invasive species;
indiscriminate use of natural resources; climate change; pollution within
aquatic environment and water flows. Biological resources serve about 40
per cent of the world’s economy and nearly, 80 per cent of the needs of the
people. It provides greater opportunity in the field of medical, research,
education, and economic development. Declining biodiversity is, therefore,
a concern for countless reasons. Preserving species in their habitats is the
in-situ conservation and includes identification of biological hot spots to
protect them as Natural Park/sanctuary/biosphere reserve etc. The ex-situ
conservation includes developing gene banks, zoos and botanical garden,
cryopreservation, artificial propagation of plants, biotechnological approach
etc. Genetic manipulation of the endangered and threatened species can be
the effective tool for maintaining biodiversity.
Key words:Ecosystems, Rainforests, Coral reefs, Convention on Biological
Diversity (CBD), Endangered, Threatened
INTRODUCTION
Biological diversity of the variability in life-forms on the Planet (Earth) is
called as biodiversity. Biodiversity is the existence of various life forms

283Biodiversity-Threats and Conservation
including strength of species of plant, animal and microorganism; the
strength and variability of genes in these taxa is the diverse ecosystems on
the Earth. The Convention on Biodiversity at UN CED (the United Nation
Conference on the Environment and Development), ‘The Earth Summit’ in
1992 had expressed biological diversity as “the variety and variability among
living organisms from all sources and the ecological complexes in which
they occur; this includes diversity within species, between species and of
ecosystem”[1]
. The term biodiversity is supposed to be coined by W.G. Rosen
in 1985[1]. The term biodiversity was applied by socio-biologist Edward
Wilson to describe diversity at all storeys of biological organisation ranging
from intracellular macromolecules to biomes[2]
. Biodiversity is a Greek word
and consists of bios means life and diversity means forms.
BIODIVERSITY STATUS
IUCN [3] has reported global biodiversity of 17, 53, 789 (1.75 million) species
of plant, animals and microbes (Table 1). Taxonomic experts have
approximation of the total number of species range between 3 and 100
millions of species[4]
. Several projects are running at Global level to discover
the new species and the Global Biodiversity Information Facility and
Species, 2000, is one of them. Every year about 15000 of new species are
being discovered.
India, which has merely 2.4 percent of land coverage, is accountable for
1, 42,600 of known species which is about 8.1 percent of global biodiversity[5]
.
Table 1: Diversity or richness of different taxa in the world
Sl. no. Categories Number of species Percentage
1 Higher Plants 2,70,000 15.395
2 Vertebrates 53,239 3.036
2.1 Fishes 26,959 50.64
2.2 Amphibians 4,780 8.98
2.3 Reptiles 7,150 13.43
2.4 Birds 9,700 18.22
2.5 Mammals 4,650 8.73
3 Insects 1,025,000 58.445
4 Fungi 72,000 4.105
5 Molluscs 70,000 3.991
6 Algae 40,000 2.281
7 Crustaceans 43,000 2.452
8 Protozoans 40,000 2.281
9 Nematodes and Worms 25,000 1.425
10 Bacteria (including BGA) 4,000 0.228
11 Viruses 1,550 0.088
12 Others 110,000 6.273
Source: Pradeep’s: A Textbook of Biology for Class XII, Chapter-15: Biodiversity and
Conservation

284 Environ. Sci. & Engg. Vol. 2:Biodiversity and Conservation
The higher contribution in this regard, ranks India among the seventeen
mega-diversity regions of the world. The diversity of various taxa is being
represented in Table 2.
Table 2: Richness or diversity of different taxa in India
Sl. no. Categories Number of species Percentage
1 Angiosperms 17500 13.01
2 Gymnosperms 64 0.05
3 Pteridophytes 1100 0.82
4 Bryophytes 2850 2.13
5 Lichens 2000 1.49
6 Fungi 14500 10.78
7 Algae 6500 4.83
8 Bacteria 850 0.64
9 Mammals 390 0.29
10 Aves 1232 0.92
11 Reptilian 456 0.34
12 Pisces 2546 1.89
13 Protochordate 119 0.09
14 Arthropoda 68389 50.86
15 Mollusca 5070 3.77
16 Protozoa 2577 1.92
17 Other Invertebrates 8329 6.20
Total 134472 –
Source: Pradeep’s: A Textbook of Biology for Class XII, Chapter-15: Biodiversity and
Conservation
India is among the seventeen mega diverse regions of the world. The
mega diversity countries are the countries which accommodate most of the
Earth’s species (70 percent) and so are considered as extremely bio-diverse.
Conservation International had identified 17 mega-diverse countries in
1998[6,7]. The listed mega-diversity countries of the world include (in
decreasing order of Endemic species): Brazil, Indonesia, South Africa,
Colombia, Australia, Papua New Guinea, Mexico, China, Philippines,
Madagascar, India, Malaysia, Venezuela, Peru, Ecuador, United States,
and Democratic Republic of Cango[7]. These countries show high degree of
endemism. A region having very high level of endemic species under threat
from humans is called as ‘Biodiversity Hotspot’. The term hotspot was
introduced Norman Myers in 1988[8-12]
. Atlantic forest of Brazil; Island
and dry deciduous forests of Madagascar; Nicobar Islands group, North-
Eastern Himalayan region and Western Ghats of India are some leading
biological hotspots.
The biodiversity richness of India is due to its geographical location (8º
– 30ºN and 60º– 97.5ºE longitude / latitude) which accounts for diversified
climatic conditions. The Wildlife Institute of India has divided the country
into ten bio-geographical regions. These are:

285Biodiversity-Threats and Conservation
1. Trans-Himalayas (coldest desert)
2. Himalayas
3. Desert
4. Semiarid
5. Western Ghats (covers 4 percent of areas and is most biodiversity
rich region)
6. Deccan Peninsula (covers 42 percent of areas)
7. Gangetic Plain
8. North Eastern region (covers 5.2 percent of areas)
9. Coasts
10. Islands
MEASURMENT OF BIODIVERSITY
There are three inter-related hierarchies of biodiversity. These are:
1. Genetic diversity
2. Species diversity
3. Community or ecosystem diversity
Professor Anthony Campbell[13] added Molecular diversity as 4th level
in the hierarchy of Biodiversity. It is the diversity at the level of molecules
so cannot be isolated from genetic diversity but can be studied separately
to give specific significance.
Genetic Diversity
Genetic diversity denotes the diversity within the species. Living organisms
store a bulk of genetic information in form of nucleic acid (DNA and RNA).
The fragments of nucleic acids which code for a character is called as gene.
These genes are located on locus of chromosomes. The genetic makeup of
any two individuals is not identical so act as source of variation and bring
diversity within the species. The variation in the frequency and nature of
genes; their alleles; and the chromosomes present within the species is
called as genetic diversity.
The genetic differences among the individuals of same species is
accountable for differences in body designs which gives rise the various
intraspecific categories or polymorphs like sub-species, varieties, races,
strains, morphological types, ecological types, biotypes, etc. Some leading
examples of genetic diversity are:
1. India accommodates not less than 50,000 various strains of Oryza
sativa (Paddy) and 1000 varieties of Mangifera indica L. (mango).

286 Environ. Sci. & Engg. Vol. 2:Biodiversity and Conservation
2. There are several races of human like Mongoloid, Negrillo,
Protoaustraloid, etc.
3. Rauvolfia vomitoria (R. serpentina) has medicinal value due to
production of an active chemical called reserpine. The plants
growing in different Himalayan ranges show differences in
potency and concentration of reserpine which is result of genetic
diversity.
Genetic diversity is useful for survival of a species through adaptation
to changing environment. Environment plays a significant role in imparting
genetic diversity through mutations or alteration in the frequency of genes
which results in altered genotypes while through natural selection the most
suitable genotype is favoured to survive in the existing environment. This
accounts for formation of polymorphs in the sympatric populations, races
in allopatric populations and subspecies in the geographically isolated
populations. Thus, genetic diversity helps in speciation or evolution of new
species. Genetic diversity within a species depends on various factors like
number of genes, stability of genes against mutagens, environment and
isolation (geographical and reproductive).
Species Diversity
Species diversity is a degree of diversity that integrates both the number
of species in a group and extent of their relating abundance[14]. It is
measured at the level of species. The species of a genus show unique
biological status of reproductive isolation. The examples of diversity at
species level are:
1. Genus Panthera includes three species viz. P. tigris (tiger),
P. leo (lion) and P. uncia (snow leopard) which are different with
each other.
2. Genus Solanum includes many species including S. melongena
(Brinjal), S. tuberosum (Potato), S. lycopersicon (Tomato) and
S. nigrum (Makoe) which have characteristic differences at species
level.
Species diversity can be expressed as the function of species richness
and species evenness. Species richness can be defined as the number of
species per unit area[15-17]
, whereas, the number of individuals or relative
abundance of different species of a region represents species evenness or
species equitability[16,17]
. Thus, variation in the number of species, types of
species and number of individuals per species of the given area leads to
greater species diversity. Odum et al.[18] suggested that species diversity
can be calculated as the number of species per thousand individuals while
Menhinick[19] expressed it as sum of species in relation to square root of
total number of individuals.

287Biodiversity-Threats and Conservation
Ecological diversity (Community and ecosystem diversity)
The ecosystem diversity refers to the variety of forms in the ecosystem due
to diversity of niches, trophic level and processes like nutrient recycling,
food webs, energy flow, role of dominant and key stone species and various
biotic interactions. Elton[20] reported that diversity helps in producing more
productive and stable ecosystems/communities which can tolerate various
stresses. Tilman[21,22] had confirmed the proposition of Elton by raising
plots with different diversity in minnesota grassland and subjecting them
to various stresses.
Whittaker [15,23,24] proposed three types of diversity to explain
community and ecosystem diversity, namely, alpha (), beta () and gamma
() diversity.
• Alpha diversity: (- index diversity) is the diversity within
community and refers to the species diversity in a given community
or habitat. Alpha diversity is represented by the two indices i.e.,
species richness and species evenness, in the combination.
• Beta diversity: (- index diversity) is the diversity between the
communities and appears in a range of communities due to
replacement of species along the complex-gradient of ecosystem or
habitats within a given geographical region. It is due to the presence
of different microhabitats, niches and differences in environmental
conditions. The- diversity is observed along altitude gradient,
moisture gradient or gradient of any other environmental factors.
Greater the heterogeneity in the habitats or between communities,
there will be greater-diversity.
• Gamma diversity: (- index diversity) refers to diversity present in
range of communities and is represented by diversity of habitats or
ecosystems over a total landscape or geographical area. Whittaker[23]
proposed that- diversity can be measured as the ratio between
regional diversity or-diversity and the average- diversity such
that =/±.
Reice[25] had reported that more perturbations and heterogeneity results
in more biodiversity which in turn make the ecosystem more stable and
sustainable. Tropical rain forest and coral reefs have fragile environment
and vulnerable habitats which accounts for the maximum biodiversity in
these regions even there is little seasonal changes of temperature and
moisture. In 1807, German naturalist and geographer Alexander von
Humboldt while exploring the South American forests reported that species
richness was increased within the region as area of exploration was
increased but only up to a certain extent[26]
. A rectangular hyperbola is
obtained when the species richness of a wide variety of Texas was plotted
against the explored area. The mathematical expression of this relation is
S = CAZ, where, S is species richness, A represents area explored, Z is

288 Environ. Sci. & Engg. Vol. 2:Biodiversity and Conservation
regression coefficient and C is a constant for the given species. The
logarithmic scale gives straight line for the above expression.
log S = log C + Z log A
Where, log C is intercept on Y-axis (species richness) and Z is slope of
graph line representing the regression coefficient between species richness
and area of exploration (Figs. 1a & b).
The value of regression coefficient (Z) has been reported as 0.1 to 0.2 for
different taxonomic group in different regions but for a very large area like
a continent this value ranges from 0.6 to 1.2. In 1960s, Robert Mac Arthur
and E.O. Wilson had also justified the A. von Humboldt hypothesis by
testing species- area relationship on several animals and plants and they
had reported the value of Z between 0.2 to 0.4[26]
.
SIGNIFICANCE OF BIODIVERSITY
A rich biodiversity is essential for ecosystem as well as survival of human
race. Significance of biodiversity can be explained in many ways:
Ecosystem Productivity
Biodiversity strengthen the ecosystem productivity where all species have
been assigned their own specific role by the nature. Ecosystem with high
biodiversity like tropical rain forest are more productive than ecosystem
with lower biodiversity like temperate forests. Tilman et al.[27] have
confirmed that increased biodiversity contributes to higher productivity.
The natural services that can be provided by a healthy ecosystem or
biodiversity can be categorised as:
1. Ecosystem services
Fig. 1: Species area relationship a) Geometric; b) Logarithmic

289Biodiversity-Threats and Conservation
2. Biological resources
3. Social benefits
• Ecosystem services: The ecosystem services refers to the services
provided by an ecosystem due to presence of a healthy biodiversity.
These services are water and energy resource conservation, genesis
of soil and its protection, nutrient storage and recycling, pollution
control, climate regulation, ecosystem maintenance, recovery from
natural calamities or non-predictable events, photosynthesis,
pollination through animals, decomposition of wastes, biological
control of diseases, insects and pests.
A healthy and biodiversity rich ecosystem serves as the buffer against
natural disasters including flood, drought and landslides and thereby
regulate the climates. According to UN CBD[28]
, “Biodiversity and
healthy ecosystems can provide important natural buffers against
natural disasters such as floods, drought and landslides.” The poor
or sick people of rural communities are more dependent upon
ecosystems biodiversity and are more vulnerable to the impact of
disasters. Therefore, sustainable management of biodiversity is
essential source of health promoting resources and management of
post crisis life.
• Biological resources: A healthy biodiversity acts as the source of
biological resources to human like food, medicinal resources,
pharmaceutical drugs, wood products, ornamental plants, breeding
stocks, population reservoirs, future resources etc. Thousands of plant
and animal species are known to be edible.
• Social benefits: A healthy biodiversity serves the purpose of
research, education and monitoring; recreation and tourism; and
social and cultural values. The animals, plants and microbes are being
used for many biological and medical research like study about the
physiological processes, effect of drugs or poisons, new surgical
techniques and space studies. The biodiversity of gardens, zoological
parks, aquaria, national parks and sanctuaries are very rewarding,
pleasure and nice pursuit. They also serves the tourism of a place.
Green vegetation, beautiful foliage and flowers, graceful beasts, birds
song, colourful fishes or birds, all provide grandeur to the biosphere.
Wildlife is a cultural asset of a country. It is an inspiration for poets
to compose poems and songs and for artists to make paintings and
sculptures. The wide variety of organisms existing today is the product
of organic evolution and will serve for future speciation. A species
once lost is lost forever. So, it would be unethical to let any species to
disappear along the passage of time. G.H. Brundtland, Prime Minister
of Norway, had stated, “We must consider our planet to be a loan
from our children, rather than being a gift from our ancestors. As
caretakers of our common future, we have responsibility to seek
scientifically sound policies, nationally as well as internationally. If

290 Environ. Sci. & Engg. Vol. 2:Biodiversity and Conservation
the long term viability of humanity is to be ensured, we have no other
choice”[29,30]
.
Ecosystem Stability
Biodiversity is essential for stability of an ecosystem. Any destruction in
the part of an ecosystem does not degrade it but the ecosystem is resilient
and is able to restore itself after sometimes as confirmed by David Tilman[31]
through long term ecosystem experiment using outdoor plots. Tilman and
Dowing[32] reported a crucial role of biodiversity in maintenance of
ecosystem to environmental shocks. Thus, ecosystem is a self-sustainable
unit of biosphere and its sustainability depends on strength of biodiversity.
The ecosystem which bears greater diversity of species tends to be more
sustainable in comparison to those with lesser diversity.
All organisms are components of food chain at different trophic level
and interact with the abiotic environment to keep natural cycles continuous.
This makes the ecosystem a self-sustaining unit. Biodiversity is essential
for maintenance and health of ecosystem through the occurrence various
checks, controls, negative and positive feedbacks, critical links and keystone
species. Killing or disappearance of even few species may have a
destabilizing impact. Paul Ehlrich had proposed a rivet popper hypothesis
for justifying the effect of decrease in biodiversity on the ecosystem.
Biodiversity and Human Health
According to UN CBD[28] report, “Biodiversity is the foundation for human
health. By securing the life sustaining goods and services the conservation
and sustainable use of biodiversity can provide significant benefits to our
health. In contrast, the continuing loss of biodiversity on a global scale
represents a direct threat to our health and well-being. Without a global
environment that is healthy and capable of supporting a diversity of life,
no human population can exist.” The Millennium Ecosystem Assessment
and the Intergovernmental Panel on Climate Change report states that
the global environment and the sustainability of the ecosystem affects the
human well-being.
According to UN CBD[28] report, “Genetic diversity in food system
provides the foundation of crop development and food security, and promotes
resistance and resilience to environmental stresses including pests and
diseases of crops and livestock. Diet based on diversity of food species
promote health, and can help to protect against diseases by addressing the
problem of micronutrients and vitamin deficiencies.”
“Studies on wild life anatomy, physiology and biochemistry helps in
developing human medicine”[28]
. There are several species which are used
for various medical research. Examples[33]
:

291Biodiversity-Threats and Conservation
i. Bears are being used for studies on osteoporosis, cardio- vascular
disorders, renal diseases and diabetes.
ii. Sharks are being used for studies on osmoregulation and immunology.
iii. Cetaceans are being used for studies on respiration and treatments
for divers suffering from decompression sickness.
iv. Horse- shoe Crabs are being used for studies on optometry/
ophthalmology and molecular biology.
Biodiversity also provides the raw materials for development of
traditional and modern medicine which ensures the health improvement
of the human. Examples[33]
:
i. Pain killers- Zinconitide from cone snail toxin.
ii. Cardiac drugs- Lanoxin from Digitalis plants.
iii. Anti-cancer drugs- Taxol from Taxus trees and Hycamtin from
Camptotheca trees.
iv. Diabetes treatment- Exanitide from Heloderma lizards.
According to UN CBD[28] report, “Biodiversity loss and ecosystem change
can increase the risk of emergence or spread of infectious diseases in
animals, plants and human”. The outbreaks of SARS (Severe Acute
Respiratory Syndrome), Ebola disease, Marburg, HVPS (Hantavirus
Pulmonary Syndrome), avian influenza and malaria are result of human
influence over biodiversity and the wildlife or change in land use pattern.
Thus, the access to “green-space” results in better health development,
reduced illness and better recovery of patient in comparison to the
completely urbanized atmosphere. The Co-operation on Health and
Biodiversity (COHAB, Galway, Ireland) Initiative is an international
programme to address the gaps in awareness, policy and action on the
links between human health and well-being and the conservation of
biological diversity (http://www.cohabnet.org).
Keystone Species and Biodiversity
The term ‘Keystone Species’ was introduced by Robert T. Paine in 1969[34]
.
Two basic criteria of keystone species have been proposed by Mills et al.[35]
:
i. The presence of keystone species is crucial in maintaining the
organization and diversity of their ecological communities.
ii. These species are exceptional, relative to the rest of the community,
in their importance.
Thus, within biological communities, a set of species is so significant or
crucial that determines the stability of a wide range of other species in the
community, is called as ‘Keystone Species’[36,37]
. These species determine
or regulate the ecosystem functioning, like nutrient cycling or energy flow,
of a community so need special conservation strategies and efforts. The

292 Environ. Sci. & Engg. Vol. 2:Biodiversity and Conservation
loss of such species will accelerate the rate of extinctions of other species
in the community. Thus, the keystone species are special focus or priority
during the effort to maximise biodiversity safeguard[37-40]
. Cox et al.[41]
justified the significance of these species and argued for need of their
targeted protection for sustainability of the ecosystem. Rohlf[42] suggested
a primary focus should be given for management of each and every keystone
species in order to manage the whole communities of the ecosystem.
Carroll[43] stated that management of keystone species is essential to
support population of other species in reserves. Conway[44] proposed
the necessity of keystone species sustainability and stability of
ecosystem structure and functioning. The leading examples of keystone
species[35] are:
1. Enhydra lutris (sea otters) regulates the Strongylocentrotus spp. (sea
urchins) density which feed over kelps, the giant alga[45,46]
.
2. Solenopsis geminate (Fire ants) exclusion increases the number of
arthropods which are harmful to agriculture[47]
.
3. Humming bird pollinators[48]
.
4. Terborgh[37] proposed the palm nuts, figs and nectars as keystone
resources because of their extreme significance for fruit and nector
eating species of tropical forest like the primates, squirrels, rodents,
and many birds.
5. Caster canadensis (North American beavers) make dams which can
change hydrological and biogeochemical factors of the region to alter
the productivity[49]
.
6. Cornitermes cumulans (Brazilian termites) make bulky, rich and
distinctively designed mounds which has wide range of obligate
users[50]
.
7. Sea urchins grazing prevents the transition from encrusting algae
dominated community to a large, fleshy algae dominated one[51]
.
8. Thomomys bottae (Pocket gophers) maintain mountain meadow
communities[52]
.
9. Pisaster ochraceus (sea star) exclusion resulted in loss of almost half
of the resistant diversity of the ecosystem[36,53]
.
10. Loxodonta africana (the African elephants) is the keystone species
for Savana and forest ecosystems[54]
.
11. Oculina arbuscula (Compact ivory bush coral) creates new habitats
to avail shelter for above 300 invertebrate’s species of North and South
Carolina in the United States[55]
.
THREATS TO BIODIVERSITY
Environment New Service report released in August 1999 states, “the
current extinction rate is now approaching 1000 times the background rate