Lecture 19 Flashcards
Natural resources and sustainability
Life depends on the
materials available on
Earth, and the solar
energy fixed in
photosynthesis
* Resources to support
life are limited
* These resources have
to be used in a
sustainable manner, or
life ceases
Conservation
Meaning of “conservation”:
1. Stewardship of the natural world
“Biological conservation”
* Focus of Chapter 14
- Sustainable use of renewable natural
resources
“Resource conservation”
* Focus of Chapter 15
*conservation means the sustainable use of the resources on earth
*conservation of stuff we harvest sell and consume
Resource ecology
Resource ecology deals with links between
ecological knowledge and natural resource
management
- Sustainable development:
- human economy that could run indefinitely
- People are healthy and can afford the things they need to live indefinitely.
- Simultaneously wants economy and ecosystems to run indefinitely
- Ecologically sustainable economy: sustainable development while
maintaining biodiversity
Ecosystem services
Ecosystems have profound effects on our
environment – e.g. on atmospheric
composition and the hydrological cycle
* Ecosystem services are vital for all
organisms, including humans
* Conventionally, our economy has not valued
these services
- The problem with conventional economics is that we have failed to place value on theses ecological servises
The value of the world’s ecosystem capital
- group of ecologist coming together with a group of economists to put a price on environmental resources
- the current value of the entire biosphere is estimated to be worth on average 33 trillion dollars per year
water worth 100 us $ per hectare per year= carbon capture
Fresh water = 10 000 us $ per hectare per year
Ecological damage
Failure 1: Conventional economics don’t account for these values, or the costs of ecological damage:
Failure 2: We also don’t put a direct value on the costs of pollution
ex.
* Air pollution
* Water pollution
* Reduced soil fertility
* Declining stocks
* Declining biodiversity
Ecological economics
Ecological economics places value on the relationships between economies and ecosystems
* Must find ways to put value on the surrounding systems: Energy, materials, services provided
* Costs: Repairing environmental damage,
including habitat restoration
Population and economic growth
*Ecological economics becomes harder as the Population and resource use have
grown dramatically
* Consumption growth is mainly in
the developed world (global north)
* Population growth is mainly in the
developing word (global south)
Non-sustainable development
Our economy and our approach to natural
resources are not sustainable
Why?
- there are a lot of non-renewable resources
(fossil fuels, metals) that we are depleting too quickly - We are using sustainable resources
in non-sustainable ways (forests, fisheries, fresh water)
Sustainable development
Sustainability depends on:
* Decreased use of non-renewable energy
- Increased use of renewable energy and
materials - Increased production efficiency (we have to make sure these things are available and priced fairly)
*Improvement of social equity in social equity (must be available for all)
Sustainable development requires renewable energy sources, e.g. photovoltaics
Renewable resources
The most prominent examples of renewable resources are diverse manifestations of sunlight:
* Direct solar energy (passive solar)
* Wind energy
* Ocean current energy (turbines at the bottom of the ocean catching ocean currents)
* Hydroelectricity
* Photovoltaic solar energy (solar panels)
* Biomass energy (turn it into fuel for cars)
Easter Island
Sits by itself in the middle of the Pacific Ocean
- tiny volcanic island
- Moai, giant stone heads
- colonized in 300 CE
- Extraordinary navigators
- use small open boats to explore open ocean
- Completely covered by an endemic palm tree
- Used trees to build houses and boats
- Flourishing economy with rich culture in the 1500
Chopped down the last of the endemic palm trees in the year 1600
- ecological colaps
- Descended into tribal warfare cannibalistic
- no one could remember who created the sculptures
- 1882 colonists came
- Only thing left is the statues
- self-contained ecosystem
- Easter Island is a metaphor for the earth
all the resources that we will ever have are here
- Life on earth depends on the material available here
- resources must be maintained to support life on earth
Maximum sustainable yield
- The theoretical upper limit of harvest of a resource that will result in the largest
sustainable long-term yield - Logistic population growth curve vs carrying capacity in graph
In the middle of both = maximum sustainable yield - The theoretical upper limit of harvest of a resource that will result in the largest sustainable long-term yield
- But there are problems with
calculating this limit: - Environmental conditions change (must recalibrate system every time)
- Population models require estimation ( not exact)
Regeneration
Over time, renewable resources regenerate
Natural regeneration: spontaneous recovery after harvest
* Sometimes natural recovery is fast
* Typically management is
necessary:
E.g. after clear-cut, prescribed burning,
planting seedlings
you can have multiple plots harvested at different times
Working down the resource
Selective harvest of large individuals or species in a community can lead to overexploitation, known as “working down” the resource
Working down the resource: selective harvest of a particular kind of organism in an ecosystem
- After large individuals are harvested, remaining ones are fast-growing
and productivity may be maintained - But the resulting community is quite
different
Secondary growth may be more productive than the old growth, but does not contain large individuals
Example of working down the resources: Historical changes in Lake Erie
Total harvest of all fish from Lake Erie has been fairly consistent over time:
Initially, the most valuable species were exploited:
lake herring (extirpated), lake sturgeon (now being reintroduced)
After collapse, smaller species were harvested:
yellow perch and rainbow smelt
Total harvest has remained constant during this “working down” of the fishery resource
We hunted biggest stuff first, then their # decline then second biggest….
WE have the same number of tones of fish, but this isn’t proper resource management
Forestry
Forestry is an important renewable resource
- In Canada, forestry sustains about 6% of our
economy, employing about 500,000 people - Different harvest methods have different
environmental impacts
Forest plantations
Forest plantations are more productive than
naturally regenerating stands, but require more investment
* Plantations can have a high bird density,
although many bird species are often
missing from these young forests
- don’t see woodpeckers in planter forests-not enough deadwood
- Different nutrient levels
- same amount of harvest but very different community (worked down resource)
Marine resources
- Fisheries are a second resource of importance
- In Canada, harvesting mostly involves capture of wild animals
- Potentially renewable resource
- Harvest limits, no other management drives the way this works
- Anadromous (move from freshwater to salt water environment) salmon is being stocked in rivers
- Aquaculture rapidly growing industry
Atlantic cod
Historically important food fish
* Grand Banks were immensely productive
* Near-shore stocks depleted by 1900
* Modern technologies facilitated large captures even with declining stocks
* Moratorium (no more) in 1992
* Infanit resource highly declined
Salmon
Salmon aquaculture is a
thriving industry in Canada
* Salmon is farmed on both
Atlantic and Pacific coasts
* Aquaculture challenges:
eutrophication, and
deoxygenation
* Toxic chemicals
* Parasite and disease
transmission to wild fish
* Genetic effects of escapes
Why do we continue to over-harvest resources?
- Humans use potentially renewable resources in non-sustainable ways
*We view ourselves as legitimately empowered - We are self-interested (adjust ecological systems that do us well, don’t consider others)
- We are socio-technologically
empowerment - We hold a cornucopian world-view (assume infinite growth is possible)
- We follow a false economy ignoring ecological value (we try and shoot for more money over ecological success
A human economy that runs indefently
d
How does an ecological economy differ from conventional economy
d
