A Presentation By Mr. Allah Dad Khan Visiting Professor the University of Agriculture Peshawar allahdad52@gmail.com

4. Threats to
Biodiversity and
Ecosystems

5. Desertification
Desertification process is the result of poor land
management which can be aggravated by climatic
variations. Converting wild lands to agriculture
often involves ploughing the soils which leads in
temperate regions to an average decline in soil
organic matter between 25 and 40 per cent over
twenty five years.

6. Deforestation
Forest ecosystems contain as much as 80 percent
of the world’s terrestrial biodiversity and provide
wood fiber and biomass energy as well as critical
components of the global cycles of water, energy
and nutrient. Forest ecosystems are being cleared
and degraded in many parts of the world.
The direct cost of deforestation is reflected in the
loss of valuable plants and animal species.

9. Habitat Loss
Habitat loss occurs when natural environments are transformed or modified to serve
human needs. It is the most significant cause of biodiversity loss globally. Common types
of habitat loss include cutting down forests for timber and opening up land for agriculture,
draining wetlands to make way for new development projects, or damming rivers to make
more water available for agriculture and cities. Habitat loss can also cause fragmentation,
which occurs when parts of a habitat (the local environment in which an organism is usually
found) become separated from one another because of changes in a landscape, such as
the construction of roads.
Fragmentation makes it difficult for species
to move within a habitat, and poses a major challenge for species requiring large tracts of
land such as
the African forest elephants living in the Congo basin. Though some habitat loss is
necessary to meet
human needs, when natural habitats are changed or modified with little concern for
biodiversity the
results can be very negative.

19. Global Climate Change
Carbon dioxide released from burning fossil fuels and biomass,
deforestation, and agricultural practices contributes to greenhouse
gases, which prevent heat from escaping the earth’s surface. With
the increase in temperature expected from increasing greenhouse
gases, there will be higher levels of air pollution, greater variability in
weather patterns, and changes in the distribution of vegetation in
the landscape. Some species will not be able to adapt to these
changes in the environment and will become extinct. However, it is
expected that many plant and animal species will attempt to
disperse to higher latitudes and altitudes as the temperature
increases. Therefore, any barriers in the landscape, such as
highways and urban areas that prevent movement to more
hospitable environments, will result in loss of biodiversity.

20. Habitat Fragmentation
Ecosystem conversion and ecosystem degradation
contributes to habitat fragmentation. Habitat loss from
exploitation of resources, agricultural conversion, and
urbanization is the largest factor contributing to the loss of
biodiversity. The consequent fragmentation of habitat results
in small isolated patches of land that cannot maintain
populations of species into the future

21. Alterations in ecosystem
composition
Such as the loss or decline of a species, can lead to a loss of
biodiversity. For example, efforts to eliminate coyotes in the canyons of southern
California are linked to
decreases in song bird populations in the area. As coyote populations were
reduced, the populations of
their prey, primarily raccoons, increased. Since raccoons eat bird eggs, fewer
coyotes led to more
raccoons eating more eggs, resulting in fewer song birds.

22. Pollution
Atmospheric and hydrologic pollution have far-reaching negative effects on
biodiversity. Pollution from burning fossil fuels such as oil, coal and gas can
remain in the air as particle pollutants or fall to the ground as acid rain. Acid
rain, which is primarily composed of sulfuric and nitric acid, causes
acidification of lakes, streams and sensitive forest soils, and contributes to
slower forest growth and tree damage at high elevations. In addition,
chemical pollutants such as pesticides and herbicides leach into soils and
watersheds. Some fish species, such as salmonids, require small freshwater
streams to spawn. Polluted streams result in the abandonment of traditional
spawning areas and ultimately in the loss of salmon populations. Species’
sensitivity to pollution is variable. However, many species are vulnerable to
the indirect effects of pollution through the concentration of toxic chemicals in
top predators of food chains and disruption of predator-prey interactions.

23. Over Exploitation
Overexploitation, or unsustainable use, happens when biodiversity is removed faster than
it can be replenished and, over the long term, can result in the extinction of species. For
example:
1. The once-plentiful cod fishery off the coast of Newfoundland, Canada has all but
disappeared because of overfishing; • freshwater snakes in Cambodia are declining
from hunting pressure;
2. Encephalartos brevifoliolatus, a cycad, is now extinct in the wild after being
overharvested for use in horticulture;
3. •Overexploitation, especially when combined with destructive harvesting practices, is
a major cause of biodiversity loss in certain ecosystems.

24. :
Marine Environment
Oceans play a vital role in the global environment. Covering
70 per cent of the earth’s surface, they influence global
climate, food production and economic activities. Despite
these roles, coastal and marine environment are being
rapidly degraded in many parts of the globe.
In coastal areas, where human activities are concentrated,
pollution, over-exploitation of resources, development of
critical habitats such as wetlands, and mangroves, and
water-flow from poor land-use practices have led to drastic
reductions in near shore fisheries production and aquatic
biodiversity.

25. :
Increasing Wildlife Trade
According to Nick Barnes, “Trade is another cause
of biodiversity depletion that gives rise to conflict
between North and South.” Global trade in wildlife
is estimated to be over US $ 20 billion annually.
Global trade includes at least 40,000 primates,
ivory from at least 90,000 African elephants, 1
million orchids, 4 million live birds, 10 million reptile
skins, 15 million furs and over 350 million tropical
fish.

26. Alien Species
The introduction of invasive alien species can be
either intentional, as with the introduction of new
crop or livestock species, or accidental such as
when species are introduced through ballast water
or by stowing away in cargo containers. Some of
the main vectors (carriers) for IAS are trade,
transport, travel or tourism, which have all
increased hugely in recent years. .

27. Overgrazing
The effect of livestock grazing on pasturage
negatively impacts wild animals leading to decrease
in population size, break up of habitat and increase
in poaching. Recently there has been a tremendous
increase in the number of livestock in Mongolia and,
especially, in more aggressive grazers such as
Cashmere goats. The related demand for pasture
lands represents one of the main threats to the
habitat of wild ungulates such as the Altai mountain
sheep and Saiga antelope and gradually to the
population size

28. Disease
Arrivals of pathogens that are favored by the
introduction of exotic species, pollution and the
destruction of habitats

29. Human Population
In the year 1800, there were fewer than 1 billion
people on earth, and today there are about 6.8 billion.
Even without the vast increases in per capita
resource use that have occurred during this period,
the pressures on biodiversity would have increased
during this time period simply based on population
growth. While the impacts that each human has on
biodiversity varies widely depending on the types and
amounts of resources that he or she uses (as in the
I=PAT equation), overall, increasing populations have
lead to increasing threats to biodiversity.

30. Intensive Farming
Intensive farming practices; extensive use and
concentrations of chemical and/or biological
pesticides. often large areas of land are planted with a
single crop (monocultures) which greatly reduces the
level of biodiversity in that area

31. What are the major issues in biodiversity?
1) All the species of biota are not totally mapped. Some may even be lost
before their existence is known.
2) Majority of citizens, bureaucrats, law makers do not understand the
importance of biodiversity.
3) Some of the scientists take too much of time to identify samples of biota
sent to them, with the result, the scientists working at the field level get
disinterested in their work.
4) Use of inorganic fertilizers is so great, that they are responsible in loss of
diversity in agriculture fields.
5) Culture of commercial crops leads to loss of biodiversity.
6) Introduction of new species of biota from overseas, leads to loss of
biodiversity.

32. How can we protect Biodiversity?
There Are are three approaches to manage and conserve biodiversity.
The ecosystem approach aims to safeguard existing populations of species in
their native habitats. It emphasizes to establish legally protected wildlife reserves
and wilderness areas. Moreover, it focuses on the elimination or reduction of the
populations of non-native species. Many biologists support this approach by stating
that the protection and conservation of ecosystems is the best way to conserve
biological diversity and ecological integrity. The only drawback is that fully or
partially protected wildlife sanctuaries will require more than 6% of the world's land
area which seems to be unfeasible as human population is expected to double in
the next 40 years.
The species approach aims to legally protect endangered species by identifying
them, preserving their habitats, propagate them in captivity, and reintroduce them
into sustainable habitats.
The wildlife management approach aims to use laws to regulate hunting,
reinforce harvest quotas and develop species population management plans. It
also emphasis on the introduction of international treaties to protect migrating
species such as waterfowl.

33. Conclusion
Though biodiversity loss is occurring at a rapid rate,
examples from all over the world show that people
are beginning to make choices and take actions
that benefit biodiversity. However, we need more
action if further biodiversity loss is to be averted. It’s
important to carefully consider the choices you make
and their impacts, and to encourage other groups such
as businesses and governments to do the same. The
rest of this guide will help inform you about issues to
consider, steps you can take and examples of positive
action for biodiversity.

34. IUCN Lists of Species Threatened
At threat of extinction are
1 out of 8 birds
1 out of 4 mammals
1 out of 4 conifers
1 out of 3 amphibians
6 out of 7 marine turtles
75% of genetic diversity of agricultural crops has been lost
75% of the world’s fisheries are fully or over exploited
Up to 70% of the world’s known species risk extinction if the global
temperatures rise by more than 3.5°C
1/3rd of reef-building corals around the world are threatened with
extinction
Over 350 million people suffer from severe water scarcity