Download Loss in Biodiversity

Biodiversity
McNeely (1988) defined
“Biodiversity is a comprehensive
word for the degree of nature’s variety,
including both the number and
frequency of ecosystem, species and
genes in a given assemblage.”
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Level of Biodiversity
• 3 level of biodiversity are
considered:
1. Genetics diversity
2. Species diversity
3. Ecosystem diversity
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• 1.4 million species of flora, fauna
and microbes have been examined,
named and classified.
• Scientists estimate total species
diversity 5-30 million species on
earth that have not yet been
explored.
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Value of Biodiversity
• Biodiversity at all levels contribute and
sustain human life and economic
activity
• Biodiversity provides ‘biological
wealth’
• Species is directly useful to humans,
such as food, medicines, fuel,
construction materials, and other
utilitarian needs.
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But, these species currently
used are only a tiny fraction of
total species diversity.
????
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Species diversity values
• Species have use values such as:
– raw materials
– foods
– fiber plants
– medicines
– bioenergy
– natural pesticides
– scientific and educational materials
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Table 18-2
Modern Drugs from Traditional Medicines. These Drugs Were Discovered
by Traditional Healers and Developed by Pharmaceutical Researec.
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Genetic diversity value
•I t
i s
f o c u s i n g
o n :
– Genetic resources
– Commercial products (Agricultural or
pharmaceutical products)
– Genetic modification
– Genetic engineering
• It is difficult to provide the monetary
values.
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Ecosystem diversity value
• It provides lots of services to the
whole earth which might be valued
relative to its services:
– food production
– energy supply
– water supply
– aesthetics
– etc.
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Biodiversity in Thailand
• In 1961, forest covered more than half of
Thailand’s land area.
• The forest cover dropped to 28% after 3
decades.
• Thailand located between the IndoMalayan and Asian continental
biogeographical region.
• Thailand has been rich in biodiversity
(genetics, species and ecosystems)
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Biodiversity loss in Thailand
• The significant biodiversity loss is
related to the loss of:
– Terrestrial forests
– Coastal mangrove forests
– wetlands
• Even 16% of total land area of the
country will be declared as ‘Protected
area’ but still have pressure of
deforestation.
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• What is different between
deforestation,
reforestation and
afforestation?
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• Deforestation = the act/process of
changing forest land to non-forest
land.
• Reforestation = the act/process of
changing previously deforested
lands back to forest land.
• Afforestation = the act/process of
creating forest land where it
‘historically’ did not exist.
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• Reforestation programs are being
implemented but the rate of reforestation
is far below the deforestation rate.
• Deforestation rate has slowed from 0.9%
per year before 1989 to 0.4%
per year
just after ban logging.
• Thailand lost >50%of mangrove forest
between 1961 (372,000 ha) and 1993
(168,000 ha).
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• The decline of mangrove is due
to the combined effect of
aquaculture (32%), timber and
firewood clear-felling, salt
ponds, etc.
• Marine biodiversity (sea grass
and coral reefs) are affected by...
– Household & industrial wastes
– Sedimentation
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• Fisheries catch increases at a rate of
4.3% per year.
• Fishing yields decline because of
– over-harvesting of marine fisheries
about tenfold.
– over-capitalisation of fisheries sector
stimulated by open access
– poor enforcement of regulations
– input subsidies on fuel and fishing
gear
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