EVS online class: 3rd Sem
by
Dr. Sangeeta Bansal
Department of Environmental Studies
PGDAV College, Delhi University
9th November 2023
Major Threats to Biodiversity
1. Habitat Destruction: Billions of forests and grasslands have been lost due to deforestation
and desertification for expanding agriculture, human settlements and development projects.
The forests are disappearing at the rate of 0.6% per year and it is estimated that 20-25% of
the global flora will be lost with in few years due to this forest loss.
2. Habitat Fragmantation: Dividing the natural habitats in small segments or scattered
patches either by development projects or activities or by natural calamity like floods.
3. Poaching: Illegal trade of wildlife products via killing prohibited endangered animals. Like
Killing of tigers for bones and skin; elephants for tusks/ivory ; Rhinos for horns, Musk deer
for perfumes and Bears for gall bladder used in medicines
The cost of elephant tusks can go up to $ 100 per kg
The leopard fur is sold at rate of $ 100,000 in Japan.
Major Threats to Biodiversity
4. Biological Invasions: Intentional or unintentional introduction of individuals of species to
its non-native area but with similar climate, which causes economical/ecological damage to
the new environment. The introduced species are called as invasive or non-native or exotic
or alien species.
Domestic Invasions : Dogs and Livestock
Invasions of Exotic Species: Parthenium hysterophorus (Congrass Grass), Lantana camara
(Flowering hedge plant), Eichhornia crassipes (Water hyacinth), Lantana Eupatorium and
Spotted dear.
5. Biodiversity degradation by pollution and climate change : Continuously declining
population of corals due water pollution and global warming.
6. Man-wild conflicts: Due to the human population expansion and shrinking of natural
habitats, there is an increased competition between man and wild animals for food and
space leading Man-wild conflicts.
• In India, man-animal conflict is seen across the country in a variety of forms, including
monkey menace in the urban areas, crop raiding by ungulates and wild pigs, destruction
by elephants, and cattle and human killing by tigers and leopards.
• In India, data from the MoEFCC indicates that over 500 elephants and 200 tigers were
killed between 2014-2015 and 2018-2019, most related to human-elephant/tiger
conflict. During the same period, 2,361 people were killed as a result of conflict with
elephants or tigers.
The most important causes include:
• Lack of wilderness in the periphery of protected areas particularly buffer zones
• Land use changes into intensified canal fed farms promoting herbivores and predators
into human landscape for food and cover, thus coming directly in contact with people
• Conversion of elephant migration corridors into tea and coffee plantations
• Damage of crops by Nilgai and wild boar causing serious economic loss
• Rising deforestation and wildlife habitat loss
Remedial Measures
• Each PA should maintain ecologically sensitive buffer zones between farmlands,
human settlements that are close to the National parks and sanctuaries
• Restoration of wildlife corridors
• Combat deforestation
• Resettlement and rehabilitation of people who live inside the core areas of
National Parks and tiger reserves
• Crop and livestock damage and loss of human life due to wildlife must be
prevented and compensated by the country by good amount
• Eliciting local participation and public awareness for management of PAs by
enhancing alternative income by capacity building, education and skill
development programs, ecotourism, and eco-restoration of degraded land
outside the PA
• Current Mass extinctions: Unlike previous extinction events caused by natural
phenomena, the current mass extinction is the phenomena of extinction driven
by human activity, primarily (though not limited to) the unsustainable use of land,
water and energy use, and climate change and environmental pollution.
• At the end of the last Ice Age in North America, about 12,000 years ago, at least
60 species are known to have gone extinct. For the area that is now New York
State, this meant the loss of species such as mammoth, mastodon, stag-moose,
giant beaver, and giant ground sloth.
• Currently, which is the 6th extinction, Cheetahs became extinct in India primarily
because of habitat loss and hunting for their distinctive spotted coats. An Indian
prince, the Maharaja Ramanuj Pratap Singh Deo, is widely believed to have killed
the last three recorded cheetahs in India in the late 1940s.
• The Dodo is a lesson in extinction. Found by Dutch soldiers around 1600 on an
island in the Indian Ocean, the Dodo became extinct less than 80 years later
because of deforestation, hunting, and destruction of their nests by animals
brought to the island by the Dutch.
• According to a 2020 analysis, the sixth mass extinction of wildlife on Earth is
accelerating with more than 500 species of land animals on the brink of
extinction that will likely be lost within the next two decades.
