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Biodiversity: why is it
important?
Gwen Raitt
Biodiversity and Conservation
Biology Department
Available at http://planet.uwc.ac.za/nisl/Biodiversity/
BCB 705:
Biodiversity
Some things to consider

The question asked on the title slide assumes that
biodiversity is important, is it?
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Biodiversity has been subject to huge losses (mass
extinctions) before. Why should we worry about it?
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Is our anthropocentric view of biodiversity the only valid
view?

“What sort of world do we want to live in?” (p. 87 Gaston &
Spicer 1998).

“What sort of world are we prepared to pay to live in?” (p. 87
Gaston & Spicer 1998)
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If biodiversity is important, how do we use it sustainably?
Ways of assigning value to
biodiversity

This does not only consider monetary value.
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Non-use Values
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Use Values
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Indirect
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Direct
Intrinsic Value
Non-use values
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Values based on
potential:
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Option Value
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Bequest Value
Values based on
human awareness and
perceptions:
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Existence Value
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Aesthetic Value
Indirect use values
Nutrient
Cycling
Waste
Treatment
Decomposition
Soil
Fertility
Soil Formation & Maintenance
Erosion
Control
Gas Regulation
Climate
Regulation
+ Abiotic
= Habitat
Carbon Sequestration
Air Purification
Natural Organisms
form Ecosystems
Water Purification
Food
Pollination
Water Regulation
Trophic
Levels
Biological
Control
Disturbance
Control
Direct use – indicator of environmental resources
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Organisms may serve as indicators of desired resources. To
illustrate, certain plant species serve as reliable indicators of desired
environmental conditions.
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Some plant species have affinities to certain metals.
Indicator of environmental resources –
dependence and effect

The use of plants as indicators of environmental
resources is dependent on autecological
knowledge of the plant species. Such
knowledge depends on studies of the species in
its natural habitat which requires all the
ecosystem services to maintain it.

Unfortunately the use of the resources indicated
by the plant species tends to be detrimental to
the continued existence of all the native species
in that area.
Direct use – food production

Most of what we eat is produced
by living organisms – either
through agriculture or through
harvesting from the wild.


Subsistence farmers
particularly benefit from
biodiversity.
Food additives
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Aids to food production – e.g. pesticides, insecticides,
fungicides and fertilisers.
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Genetic improvement of domesticated species.
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Non-Use Value = Source of new species for agricultural use.
Food production – effects and dependence
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The survival of species
harvested from the wild is
threatened.

Wild harvesting is dependent on
all the different ecosystem
services to sustain the production
of the harvested species.

Cropland uses space.
Agriculture is dependent on ecosystem services to provide
a suitable environment for the production organisms (plant
and animal). The ecosystem services include biological
control of soil organisms, nutrient cycling, pollination, soil
formation and maintenance, soil fertility and water
purification for plant production and all of the above with
the addition of food sources for animal production.
Direct use – biological control
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The direct use of a natural enemy to control
a pest organism.

See the Invasion Biology Course (chapter 8)
for more detail.
Biological control – dependence
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Biological control makes direct use of the natural biological
control exerted by ecosystems in an unnatural context.
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The biological control agent is dependent on all ecosystem
services that support its host, e.g. nutrient cycling and
habitat. The maintenance of a habitat involves all the other
ecosystem services.
Direct use – medicine

Commercial production of
plants for the extraction of
medicines and direct commercial production of biodiversity derived medicines
are important sources of
medications.
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Traditional medicines (see
picture).
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Animals for product testing
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Non-Use Value = Source of
new medicines
Medicine – dependence
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Agriculturally propagated medicinal species require the ecosystem
services that are required by agriculture.
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Chemical production of medicines is dependent on the water and
air purification and waste treatment services of ecosystems.
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Wild harvesting for traditional or other use is dependent on all the
different ecosystem services to sustain the production of the
harvested species.
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Animal testing of medicines requires a supply of food for the
animals.
Many primate
species are
used to test
drugs.
Direct use – industry
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Raw materials for industrial use include timber, rattans, fibers, oils,
fats, resins, waxes, dyes, fuels, cellulose, latex, cork, lubricants,
poisons, scales, bones, hides and rubber.
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Products include cosmetics, scents, clothing, paper, etc.
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Some species may serve as tools for the extraction of minerals.
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Non-Use Value = Source of new materials for industrial use.
Harvesting Rubber
Lumber
Industry – dependence
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For farmed raw materials (e.g. timber) the
same dependence occurs as in
agriculture: biological control of soil
organisms, nutrient cycling, pollination,
soil formation and maintenance, soil
fertility and water purification for plant
production and all of the above with the
addition of food sources for animal
production.
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Wild harvesting is dependent on
all the different ecosystem services
to sustain the production of the
harvested species.
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All industry is dependent on natural
systems for water and air purification
and waste treatment.
Direct use – bioremediation
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Bioremediation is the use of biological
organisms or their products (e.g. enzymes)
to remove or detoxify contaminants from
hazardous waste and contaminated soil or
water.
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A species of bacteria can breakdown
chlorofluorocarbons (CFCs).
Poplar trees (see picture) are used to
clean contaminated industrial sites.
Bioremediation – dependence
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Bioremediation depends directly on the
ecological services of waste treatment and
water purification.
Direct use – indicator of ecological change
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Changes in the levels of
biodiversity or individual
species ranges may be used to
indicate changes in the ecology.
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Lichen species (see picture)
serve as indicators of air
quality.
Indicator of ecological change –
dependence
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Changes in biodiversity reflect changes in the ecosystem
that have changed the functioning of ecosystem services.
This use of biodiversity relies directly on the organisms to
indicate the condition of the ecosystem of which they are a
part.
Direct use – ecotourism and recreation
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People pay to view biodiversity
in the natural environment.
This is termed ecotourism.
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Recreation
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Gardening
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Camping
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Hiking and Mountain Biking
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Sport
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Fishing
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Hunting
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Falconry
Ecotourism and recreation – dependence
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Ecotourism is dependent on all ecological
services.
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Recreational activities such as gardening
rely on nutrient cycling, soil fertility and soil
formation and maintenance.
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Camping, hiking and mountain biking in
natural areas rely on all ecological services
to maintain the aesthetic appeal of the
environment.
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Sports such as fishing, hunting and falconry
rely on prey species and the ecological
services that sustain them – food sources
and habitats which require all the ecological
services to maintain them.
Direct use – working animals
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Various ‘wild’ animal species
have been trained to aid man.
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Asian elephants are
trained as draught
animals.
Fishing in China and
Southeast Asia
Working animals – dependence
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Farmed working animals require the same inputs as for
agriculture.
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Wild harvesting of animals is dependent on all the
ecosystem services to sustain the organisms for harvesting.
Direct use – cultural
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Biodiversity serves as a source of inspiration for art,
poetry and literature and influences philosophy,
language and religion in many societies.
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Biodiversity may also supply the medium in which
the art is expressed – e.g. canvas for painting and
wood for sculptures.
Cultural – dependence
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In as much as any aspect of biodiversity may provide inspiration,
cultural diversity is reliant on all ecological services to maintain
the source of inspiration.
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Materials for use in art are the products of industry so the
ecological services needed by industry apply – air and water
purification and waste treatment as well as supports for
production.
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Products harvested in the wild for cultural purposes rely on all
ecosystem services to maintain the product.
Direct use – knowledge
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Each species provides unique
information that is lost if the
species becomes extinct. Species,
species interactions and intact
ecosystems are important
research areas.
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Biodiversity provides clues on
evolution, past and present.
Biodiversity presents insights
into how life functions.
Knowledge – dependence
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All ecosystem services are needed to develop
understanding of biodiversity.
Direct use – live trade
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Ornamental plants including
geophytes, orchids and
succulents.
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Pets
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Animals for laboratory use,
recreation and ecotourism.
Live trade – dependence
Crassula coccinea
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Farmed organisms for live trade require the same inputs as
for agriculture.
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Wild harvesting of both plants and animals is dependent on
all the ecosystem services to sustain the organisms for
harvesting.
Problems with monetary values and
societal control
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Market values do not reflect the impacts of use on society
and biodiversity.
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Short term vs. long term benefits.
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Money may increase faster than the
resource reproduces.
The rarity of a species increases the
monetary value of the product though the
costs of obtaining it also increase.
The development of products takes time.
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Ownership. If I do not use this, someone else will.
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Who benefits? Informal vs. formal markets – political
hierarchy.
Chapter 1 Biodiversity: what is it?
Chapter to
2 The
evolution
of biodiversity
Links
other
chapters
Chapter 3 Biodiversity: why is it important?
Chapter 4 Global biodiversity and its decline
I hope that you found chapter 3 informative and that you will
enjoy chapter 4.