2. Value and Maintenance
• Benefits to humans, direct or indirect
• Intrinsic value
• What kind of a world do we want to
live in?
• Redundancy in ecosystems (how much
is enough?)
3. Benefits to humans
• Direct use value = marketable
commodities
– Food
– Medicine
– Raw materials
– Recreational harvesting
– Ecotourism
4. Benefits to humans: food
• About 3,000 species (ca. 1% of
300,000 total) of flowering plants
have been used for food
• About 200 species have been
domesticated
• Wild relatives source of genes for
crop improvement in both plants and
animals
5. Benefits to humans: medicine
• Organisms as chemists
• About 25% of all medical prescriptions
in the U.S. are based on plant or
microbial products or on derivatives or
on synthetic versions
• Some medicinal products from animals
(e.g., anticoagulant from leeches)
8. Benefits to humans: ecotourism
• By definition based on biodiversity
• Growing portion of the tourism
industry
9. Indirect Use Value
• Indirect use value = services provided
by biodiversity that are not normally
given a market value (often regarded
as free)
• Include primarily ecosystem services:
atmospheric, climatic and hydrological
regulation; photosynthesis; nutrient
cycling; pollination; pest control; soil
formation and maintenance, etc.
10. Indirect Use Value
• Biosphere 2 was an attempt to
artificially create an ecosystem that
would sustain human life
• Ca. US$200 million invested in design
and construction plus millions more in
operating costs
• Could not sustain 8 humans for two
years
11. Intrinsic value
• Simply because it exists
• Moral imperative to be good stewards,
the preservation of other life for its
own sake
• Supported in many different religious
or cultural traditions
• Recognized in the Convention on
Biodiversity
12. Intrinsic Value
• Biophilia = the connection that human
beings subconsciously seek with the
rest of life (nature) or the innate
connection of humans to biodiversity
13. Intrinsic Value
• Biophilia = the connection that human
beings subconsciously seek with the
rest of life (nature) or the innate
connection of humans to biodiversity
• Should we put a monetary value on
everything?
14. Intrinsic Value
• Biophilia = the connection that human
beings subconsciously seek with the
rest of life (nature) or the innate
connection of humans to biodiversity
• Should we put a monetary value on
everything?
• If something can be valued, it can be
devalued.
15. What kind of a world do we
want to live in?
• Human co-opt about 40% of the
net primary productivity on an
annual basis
• Human population at over 6 billion
and growing at about 80 million
per year
• Loss of some biodiversity is
inevitable
16. What kind of a world do we
want to live in?
• Current extinction rate much higher than
background; also commitment to extinction
• Extinction is forever; species may have
unforeseen uses or values (e.g., keystone
species, medicinal value, etc.)
• Biodiversity has recovered after previous
mass extinctions, but are we also
eliminating that possibility by severely
restricting conditions conducive to
evolution?
17. What kind of a world do we
want to live in?
If 6 billion people consume 40% of
the annual net primary productivity,
what is the theoretical limit (=
carrying capacity) for humans under
current conditions?
2.5 x 6 billion = 15 billion
18. What kind of a world do we
want to live in?
But this number does not factor in the
costs of dealing with wastes or non-
renewable resources.
Nor does it leave room for other
biodiversity, upon which we depend
for ecosystem services (such as waste
removal/recycling).
Human population is expected to reach
ca. 12 billion by 2050.
19. What kind of a world do we
want to live in?
• This is why many now argue that we
have to find a way to put biodiversity
into the economic equation
• Previously no monetary values were
associated with natural resources
except the actual ones generated by
extraction (the world is there for us
to use)
20. What kind of a world do we
want to live in?
• Extraction costs (e.g., labor, energy)
usually computed
• But cost of replacement not included,
nor costs of the loss of the services
provided by that resource or its
ecosystem (e.g., cutting forest for
timber)
• Because costs are undervalued,
benefits of extraction are overvalued
21. What kind of a world do we
want to live in?
• Green accounting proposed as part of
the solution
• But requires that environmental assets
have proper prices (p. 171,
Chichilnisky essay in text)
• Tie in to property rights for natural
resources
22. Redundancy in Ecosystems
• Or, how much biodiversity is
enough?
• How much redundancy is built into
ecological processes/communities?
• To what extent do patterns of
diversity determine the behavior
of ecological systems?
24. Redundancy in Ecosystems
• Rivet hypothesis: most if not all
species contribute to the integrity of
the biosphere in some way
• Analogy to rivets in an aircraft—there
is a limit to how many can be removed
before the structure collapses
• Progressive loss of species steadily
damages ecosystem function
25. Redundancy in Ecosystems
• Redundancy hypothesis: species
richness is irrelevant; only the
biomass of primary producers,
consumers and decomposers is
important
• Life support systems of the planet
and ecological processes will generally
work fine with relatively few species
26. Redundancy in Ecosystems
• In the past (from fossils), most
ecological systems have been
conspicuously less species rich
• But no evidence that they operated
any differently
27. Redundancy in Ecosystems
• Major patterns of energy flow and
distribution of biomass in existing ecological
systems may be broadly insensitive to
species numbers
• But systems with higher diversity and more
kinds of interactions may be more buffered
from fluctuations
• Lack of data regarding the link between
species-richness and ecosystem function
28. Redundancy in Ecosystems
• Middle ground: ecosystem processes
often but not always have
considerable redundancy built into
them
– Not all species are equal (e.g., functional
groups, keystone species)
– The loss of some species is more
important than the loss of others
– Species loss may be tolerated up to some
critical threshold
