Transcript Water and Land Use

Land Use
Human Nutritional requirements
• Males- 2500 calories; Females- 2000 calories
• Balanced intake of fats, carbohydrates and
proteins.
• Protein produces 4 calories of energy per gram
and should make up 30% of all calories
• Carbohydrates also produce 4 calories of energy
per gram and should make up 60% of all calories
• Fats produce 9 calories of energy per gram and
should make up 10% of all calories
Human Nutritional requirements
• Only about 100 species of plants are commercially grown to meet
human needs
• Of these Wheat and rice supply over half of the human caloric
intake
• 8 species of animal protein supply over 90% of the worlds needs.
• It takes about 16 pounds of grain to produce 1 pounds of meat
• 20% of the worlds richest countries consume 80% of the worlds
mean production
• 90% of grain grown in the US is for animal feed
• By consuming grain directly instead of consuming the animals that
feed upon it there would be a 20-fold increase in the amount of
calories available and an 8-fold increase in the amount of protein
available.
Human Nutritional requirements
• In terms of famine and malnutrition, 11
million children die each year from starvation
and 850 million people are considered
malnourished.
• Chronic undernourishment and
vitamin/mineral deficiencies result in; stunted
growth, weakness and increased susceptibility
to illness.
Types of Agriculture
• Agroforestry: harvestable trees or shrubs are
drown among or around crops or on pastureland
as a means of preserving or enhancing the
productivity of the land
• Alley Cropping: planting crops in strips with rows
of trees or shrubs on each side. Increases
biodiversity, reduces surface runoff and erosion,
improves uptake of nutrients, modifies the
microclimate for improved crop production,
improves wildlife habitat.
Types of Agriculture
• Crop Rotation: Planting a field with different crops
from year to year to reduce soil nutrient depletion.
Example: rotation corn or cotton which removes large
amounts of nitrogen from the soil, with soybeans that
replenish the nitrogen
• High-Input Agriculture: use of mechanized equipment,
chemical fertilizers and pesticides
• Industrial Agriculture or Corporate Farming:
characterized by mechanization, monocultures and use
of synthetic inputs such as chemical fertilizers and
pesticides. Emphasis on productivity and profitability.
Types of Agriculture
• Intercropping: to grow more than one crop in
the same field, especially in alternating rows
or sections
• Interplanting: growing two different crops in
the same area at the same time. To interplant
successfully, plants should have similar
nutrient and moisture requirements
• Low-input: Depends on hand tools and
natural fertilizers; lacks large scale irrigation.
Types of Agriculture
• Low-till, No-till or Conservation-till: Soil is
disturbed little or not at all to reduce soil erosion.
Has lower labor costs, reduces the need for
fertilizer and saves energy.
• Monoculture: the cultivation of a single crop
• Polyculture: planting a ploy of land with several
varieties of the SAME crop
• Tillage: Conventional method in which the
surface is plowed which then breaks up and
exposes the soil. This is then followed by
smoothing the surface and planting. This method
exposes the land to water and wind erosion
Types of Agriculture
• Organic Farming: relies on crop rotation, green manure,
compost, biological pest control and mechanical cultivation
to maintain soil productivity an control pests. This practice
excludes or strictly limits the use of synthetic fertilizers or
pesticides. Doesn’t use plant growth regulators, livestock
feed additives and GMOs
• Plantation: a commercial tropical agriculture system that is
essentially export oriented. Involves the deliberate
introduction and cultivation of economically desirable
species of tropical plants at the expense of widespread
replacement of the original native flora. Practices include;
modifications or disturbance of the natural landscape
through permanent removal or natural vegetation, changes
in drainage channels, application of chemicals to the soil
etc.
Types Of Agriculture
• Polyculture: Planting DIFFERENT crops in the
same place, in imitation of the diversity of natural
ecosystems. Avoids large stands of a single crop
(monoculture). Includes; crop rotation,
multicropping, intercropping and alley cropping.
Often requires more labor but has several
advantages over monoculture. The diversity of
crops avoids the susceptibility of monocultures to
disease. The greater variety of crops provides
habitat for more species, increasing local
biodiversity.
Green Revolution
• Occurred between 1950-1970
• Involved planting monocultures, using high applications of
inorganic fertilizers an pesticides and the widespread use of
artificial irrigation systems.
• Crop acreage increased by 25% but crop yield increased by 200%it then reached a plateau since it was easer and more economical
to increase production through different farming techniques than
to buy more land
• The 2nd green revolution began in the 70s and continues today
• It involves GMOs that produce the most yield per acer.
• In its contrast with past agriculture practices in which famers
panted a variety of locally adapted plant strains.
• Example: of all the wheat grown in the US today, 50% comes from
9 different genotypes
Criticisms of the Green Revolution
• Unsustainable
• Increasing food production in not synonymous with
increasing food security (famines are not can use by
decreases in food supply buy by socioeconomic dynamic
and a failure of public action)
• Produces monoculture of cereal grains, while traditional
agriculture usually incorporates polyculture
• There has been a drop in productivity due to desertification
and other forms of land degradation
• Necessary purchase of inputs led to widespread
establishment of rural credit institutions that cause smaller
farmers to go into debt and in many cases resulted in the
loss of their land.
Criticisms of the Green Revolution
• Increased use of pesticides, necessary to limit the high
levels of pest damage that happen in monoculture
• Salinization, water logging, and lowering of water
levels in certain areas increase as consequences of
increased irrigation
• Reduced agricultural biodiversity, as it relied upon only
a few high-yield varieties of each crop. This led to the
susceptibility of the food supply to pathogens that can
be controlled by agrochemicals as well as the
permanent loss of many valuable genetic traits bread
into traditional varieties over thousands of years.
Genetic Engineering and Crop
Production
• Genetic engineering involves moving genes
from one species to another or designing gene
sequences with desirable characteristics
• These include; pest, drought, mold and saline
resistance, higher protein yields and higher
vitamin content
• About 75% of all crops grown, derive from
genetically engineered or transgenic crop
species.
Genetic Engineering and Crop
Production
• PROS: require less water and fertilizers, higher
crop yields, less spoilage, faster growth which
may mean greater productivity, resulting in
lower operating costs, more resistant to
disease, drought, frost and insects, may be
able to grow in saltier soils.
• CONS: unknown ecological effects, less
biodiversity, may harm beneficial insects, may
pose allergen risk, may result in mutations
with unknown consequences, may cause
pesticide resistant strains
Case Study: Golden Rice
• Golden Rice is produced by splicing three
foreign genes, two from the daffodil and one
from bacterium, into a variety of rice that
supplies vitamin A to populations that
frequently suffer from vitamin A deficiency.
Irrigation
• ¾ of all freshwater is used on crops
• Worldwide, about 40% of all crop yields come from 16% of all
cropland that is irrigated.
• Use of irrigation depends on the climate and the degree of
industrialization
• Ex: Canada irrigates 10% of its crops, India irrigates 90% of its
crops.
• With inefficiencies (leakage, evaporation) up to 70% of irrigation
water is lost
• A drip irrigation would solve these problems but would be
expensive to install and is only used on 1% of crops world wide.
• Increases in population are outpacing the rate of land that is being
irrigated.
• Sustainable irrigation is limited because of costs, depletion of
water sources, competition for water by urban areas, waterlogging
and salinization.
Sustainable Agriculture
• 3 goals: environmental health, economic
profitability and social and economic equity
• Specific strategies must take into account;
topography, soil characteristics, climate, pests,
local availability of inputs and grower’s goals.
• Costs of Agriculture; topsoil depletion,
groundwater contamination, decline of family
farms, continued neglect of the living and
working conditions for farm laborers, costs in
production and disintegration of economic and
social conditions in rural communities.
Sustainable Agriculture- Efficient Use
of Inputs
• Sustainable farmers maximize reliance on
natural, renewable farm inputs with the goal
to develop efficient, biological systems that
don’t need high levels of material inputs.
• Approaches are those that are least toxic and
most energy efficient and yet maintain
productivity and profitability.
• Preventive strategies and other alternatives
should be used before chemicals
Sustainable Agriculture- Selection of
Site, Species and Variety
• Preventive strategies, when adopted early, can
reduce inputs and help establish sustainable
production systems
• When possible, pest-resistant crops should be
selected that are tolerant of existing soil or site
condition
• When site selection is an option factors such as
soil type and depth, previous crop history and
location should be looked at before planting
Sustainable Agriculture- Soil
Management
• Systems that impair soil quality resulting in
greater inputs of water, nutrients, pesticides
and/or energy for tillage to maintain yields
• The soil is viewed as fragile and living medium
that must be protected and nurtured to ensure its
long-term productivity and stability
• Methods to protect and enhance soil; use cover
crops, compost, manures, reducing tillage,
maintaining soil cover with plants or mulches,
regular additions of organic matter.
Sustainable Agriculture- Species
Diversity
• By growing a variety of crops- farmers spread
out the economic risk and are less susceptible
to radical price fluctuations associated with
supply and demand.
• Cover crops can have stabilizing effects on the
agroecosystrem by holding soil and nutrients
in place, conserving soil moisture with dead
mulches and increasing the water infiltration
rate and water-holding capacity.
Sustainable Agriculture- Species
Diversity
• To increase diversity crops and livestock can be
integrated in the same farming operation
• Growing row crops on more level land and pasture on
steeper slopes will reduce soil erosion
• Planting pasture and forage crops in rotation enhances
soil quality and reduces erosion
• Livestock manure can contribute to soil fertility
• Livestock can buffer the negative impacts of low rainfall
periods by consuming crop residue that in plant-only
systems would be considered crop failures.
• Feeding and marketing are flexible in animal
production systems.
Types of Pesticides
• Biological: living organisms are used to control
pests. Examples include; bacteria, ladybugs,
milky spore disease, parasitic wasps and
certain viruses
Case Study
• Bacillus thuringiensis (Bt) is a soil-dwelling bacterium that also occurs
naturally in the gut of caterpillars of various types of moths and butterflies,
as well as on dark surfaces of plants
• Proteins produced by Bt are uses as specific insecticides
• It works by secreting one or more toxins after being ingested by an insect
• The toxins are often specific to a family of insects and because of their
specificity, these pesticides are regarded as environmentally friendly
• Disadvantages:
– Constant exposure to a toxin can create evolutionary pressures for pests
resistant to that toxin
• Advantages:
– The level of toxin can be very high, thus delivering sufficient dosage to the pest
– It is contained within the plant system therefore only those insects that feed on
the crop perish
– It replaces the use of synthetic pesticides in the environment
Types of Pesticides
• Carbamates: also known as urethanes, affect
the nervous system of pests. 100 grams of a
carbamate has the same effect as 2,000 grams
of a chlorinated hydrocarbon (DDT). They are
more water soluble which brings a greater risk
of them being dissolved in surface water and
getting into the groundwater.
Case Study
• Potato growers on eastern Long Island, NY used Aldicarb
(carbamate) from 1975-1979 to control the Colorado
potato beetle and the golden nematode.
• In 1979 the residues were detected in well water- they
found that more that 2,000 wells were in excess of NY
health standards
• Studies in 1983 and 1984 showed contamination had
increased in areas with a deep water table
• About 1,400 wells are still contaminated today
• Aldocarb is highly water soluble and is persistent in the
environment
• Since the contamination of NY wells were first reported, 26
other states reported contamination as well.
Types of Pesticides
• Chlorinated Hydrocarbons: synthetic organic
compounds that affect the nervous system of pests.
They are highly resistant to decomposition and can
remain in the ecosystem for up to 15 years. During
1950s, DDT was linked with the thinning of eggshells in
certain species of birds such as the Bald Eagle
• Fumigants: used to sterilize soil and prevent pest
infestation of stored grain
• Inorganic: Broad-based pesticides. Includes arsenic,
copper, lead, and mercury. Highly toxic and accumulate
in the environment.
Types of Pesticides
• Organic or Natural: Natural poisons derived
from plants such as tobacco or
chrysanthemum
• Organophosphates: Extremely toxic but
remain in the environment for only a brief
time. Examples include malathion to control
mosquitoes and West Nile Virus
Pros and Cons of Pesticide Use
• PROS: kills disease carrying pests, increases food
supply, more food means food is less expensive, newer
pesticides are safer and more specific, reduces labor
costs and makes agriculture more profitable
• CONS: Accumulate in food chains, pests develop
resistance and create a pesticide treadmill, $5-10 in
damages for ever $1 spent on pesticides, runoff and its
effect on aquatic environments through
biomagnification, inefficiency- only 5% of a pesticide
reaches the intended pest, threatens endangered
species and pollinators, and human health
Integrated Pest Management-IPM
• Is an ecological pest control strategy that uses a
variety of methods
• When these methods are used in combination
they can reduce or eliminate the use of
traditional pesticides
• The aim of IPM is not to eradicate pests but to
control their numbers to a manageable level
• Chemical pesticides are a last result
• Employs a biological, physical and chemical
aspect.
Integrated Pest Management
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Polyculture
Intercropping
Planting pest-repellent crops
Using mulch to control weeds
Using pyrethroids or naturally occurring microorganism instead of toxic
pesticides
Natural insect predators
Rotating crops often to disrupt insect cycles
Using pheromones or hormone interrupters
Releasing sterilized insects
Developing genetically modified crops that are more insect resistant
Regular monitoring through visual inspection and traps followed by record
keeping
Construction of mechanical controls such as traps, tillage, insect barriers or
agricultural vacuums equipped with lights
Relevant Laws
• Federal Insecticide, Fungicide and Rodenticide
Control Act (FIFRA) (1947): Regulates the
manufacture and use of pesticides. Pesticides
must be registered and approved. Labels require
directions for use and disposal
• Federal Environmental Pesticides Control Act
(1972): Requires registration of all pesticides in
US commerce.
• Food Quality Protection Act (FQPA) (1996):
Emphasizes the protection of infants and children
in reference to pesticide residue in food
Forestry
• Forestry involves management, planting of new
trees, and sometimes fires
• Ecological Services of Forests:
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Providing wildlife habitat
Carbon Sinks
Affecting local climate patterns
Purifying air and water
Reducing soil erosion as they serve as a watershed,
absorbing and releasing controlled amounts of water
– Providing energy and nutrient cycling
Tree Plantations
• Large, managed commercial or government owned farms
with uniformly aged trees of some species (monoculture)
• They may not be native to the area and may be hybrids
(genetically modified)
• The main use is for pump or lumber
• Pine, spruce and eucalyptus are widely used due to their fast
growth rates
• Trees are harvested by clear cutting
• Short rotation cycles (25-30 years or 6-10 years in tropics) are
economically important factors
• 5% of the worlds trees are grown in plantations but make up
20% of the timber used
Tree Plantation
• 63% are grown in the worlds secondary-growth forests and 22% are
old-growth forests
• Annually, tropical tree plantations yield much more wood (25
m/hectare) than traditional forests (1-3 m/hectare)
• Tree plantations don’t support food webs found in old-growth
forests and they contain little biodiversity. Decaying wood is absent
which provides a vital link in an old-growth forest
• Conversion to tree plantation may result in draining wetlands and
replacing traditional hardwoods
• Newer techniques allow leaving blocks of native species in the
plantation
• The Kyoto Protocol encourages use of tree plantations to reduce
CO2 levels although carbon dioxide may eventually re-enter the
atmosphere after harvesting.
Tree Plantations
• PROS: Practical methods for trees that require full or
moderate sunlight in order to grow, efficient and
economical methods. Genetically improved species of
trees that resist disease and grow faster. Increases
economic returns on investments. Produces high yield
of timber at low costs and provides jobs
• CONS: Reduces recreation value of land, if planted on
steeply sloped areas, will cause soil erosion, water
pollution and flooding, reduces biodiversity, Promotes
monoculture and tree plantations that are prone to
disease or infestation through lack of diversity.
Old-Growth Forests
• Not been seriously impacted by human
activities for hundreds of years. They are rich
in biodiversity. Depletion of old-growth forests
increase the risk of climate change. Many oldgrowth forests contain species of trees with
high economic value but require a long time
to mature
Old Growth Forests
• Characterized by:
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Older and mixed-aged trees
Minimal signs of human activity
Multilayered canopy openings due to tree fall
Healthy soil profiles
Pit-and-mount topography due to tree falling and creating
new microenvironments by recycling carbon-rich organic
material directly into the soil and providing substrate for
mosses, fungi and seedlings
Decaying wood and ground level layer that provides a rich
carbon sink
Indicator species
Dead trees (snags) that are necessary nesting sites for
woodpeckers and spotted owls
A fungal ecosystem
Forest Fires
• Current forest fire frequency in the US is 4X the average for
1970-1986. Totally area burned is 7X.
• The US forest service has lengthened the wildfire season by
78 days
• The change in wildfire frequency appears to be linked to
annual spring and summer temps. Longer, warmer
summers have increased forest fires.
• Earlier springs lead to earlier snow melt and increased dry
season
• As forests burn they release CO2 into the atmosphere,
compounding problems of global warming
• Another reason for the increase in forest fires is a change in
fire management philosophy
• Any naturally started fire on federal land that is not
threatening resources is allowed to burn
Types of Forest Fire
• Crown Fires: occur in forests that have not
had surface fires in a long time. Extremely hot.
Burn entire trees and leap from tree top to
tree top. Kills wildlife, increases soil erosion
and destroys structures
• Ground Fires: occur underground and burn
partially decayed leaves. Common in peat
bogs. Difficult to detect and extinguish
Types of Forest Fires
• Surface Fires: burns undergrowth and leaf litter.
Kills seedlings and small trees. Spares older trees
and allows many wild animals to escape.
Advantages: burns away flammable ground litter,
reducing larger fires later, releases minerals back
into soil profile. Stimulates germination for some
species with serotinous cones (require heat to
open and release seeds, such as giant sequoia
and jack pint), helps keep pathogens and insects
in check and allows vegetation to grow in
clearings that provides food for deer, moose, elk,
muscrat and quail
Methods to Control Fires
• Prevention: burning permits, closing parts of the
forest during times of the year when the number
of visitors in high and during period of drought,
and education
• Prescribed burning: purposely setting controlled
surface fires and setting small, prescribed fires to
thin out underbrush in high-risk areas. It requires
careful planning and monitoring.
• Other strategies include allowing fires to burn
themselves out and creating large clear areas
around structures
Management and harvesting
• Even-aged management- essentially the practice of planting trees
• Uneven-aged management- maintain a stand with trees of all ages
from seedling to mature
• Selective cutting- specific trees in an area are chosen and cut
• High grading- cutting and removing only the largest and best trees
• Shelterwood cutting- removes all mature trees within a limited
time
• Seed Tree cutting- Majority of trees are removed except for
scattered, seed-producing trees used to regenerate a new stand
• Clear-cutting: all of the trees in an area are cut at the same time.
This technique is sometimes used to cultivates shade-intolerant
trees
• Strip cutting- clear cutting a strip of trees that follows the land
contour. The corridor is allowed to regenerate
Deforestation
• Conversion of forested areas to nonforested areas (used for
livestock grazing, grain field, mining, urban sprawl etc)
• Natural deforestation can be from tsunamis, flooding,
forest fire, volcanoes etc
• Can result in degraded environments with reduced
biodiversity and reduced ecological services. Can threaten
species with specialized niches, reduces habitats,
decreased soil fertility and allows runoff into aquatic
ecosystems
• Can cause changed in local climate patterns and increase
the amount of CO2 released into the air from burning and
tree decay.
• Indirect effects caused by edge effects and fragmented
habitats can occur
Deforestation
• Alters the water cycle potentially increasing or
decreasing the amount of water in the soil or
groundwater.
• This then affects the recharge of aquifers and the
moisture in the atmosphere.
• Shrinking forest cover lessens the landscape’s
capacity to intercept, retain and transport
precipitation.
• Lack of trees can increase runoff leading to flash
flooding or more extreme floods.
Deforestation
• Contributes to decreased evapotranspiration.
This lessens atmospheric moisture and
precipitation levels- this affects areas
downwind from the forest as well
• Forest can extract CO2 and pollutants from
the air, thus contributing to biosphere stability
and reducing the greenhouse effect.
• Forests are also a valued tourist attraction
Deforestation- Schools for thought
• Impoverished school: believes the major
cause for deforestation is the growing number
of poor people
• Neoclassical school: believes the major cause
is “open-access property rights:
• Political-ecology: school thinks the major
cause is entrepreneurs.
Case Study
• The Hubbard Brook Experimental Forest centered on how
deforestation affects nutrient cycles
• The forest consisted of several watersheds each drained by a single
creek Impervious bedrock was close to the surface which
prevented seepage of water from one forested hillside, ally and
creek ecosystem to another
• Conclusions:
– In a mature forest, nutrients coming into the forest are balanced by
nutrients leaving the forest
– Inflow and outflow of nutrients was low compared with levels being
recycled
– After deforestation occurred, water runoff increased, consequently soil
erosion increased which caused a large increase in the outflow of
nutrients. Increases in outflow of nutrients caused water pollution
– Nutrient loss could be reduced by clearing trees and vegetation in
horizontal strips. Remaining vegetation reduced soil erosion
Forest Management
• Forests cover about 1/3 of all land surface- 80% of these are closed
canopies (tree crowns covering more than 20% of the ground) and 20% are
open canopy (tree crowns covering less than 20% of the ground)
• 70% are located in N. America, the Russian Federation and S. America
• The US is the largest area of timbering in the Pacific Northwest employing
150,000 people- a $7 billion per year industry
• Forest account for 1/3 of the land in the US, 2/3’s are nonfederal lands
• The Forest Service consists of 155 national forests, 22 grasslands and was
established in 1905
– manages public lands in natural forests and grasslands (193 million acres)
– protects and manages natural resources on National Forest System lands.
– Provides community assistance and cooperation with state and local
governments, forest industries and private landowners to protect and manage
nonfederal forests, rangelands and watersheds
– Provides international assistance in formulating policy and US support for the
protection and management of the worlds resources
Relevant Laws
• Forest Reserve Act (1891): Gave the president
authority to establish forest reservations from
public domain lands
• Wilderness Act (1964): Created the legal
definition of wilderness in the US. Currently 4
agencies in charge of more than 106 million
acers of federal wilderness (National Park
Service, US Forest Service, US Fish and Wildlife
Service and Bureau of Land Management)
Relevant Laws
• Wild and Scenic Rivers Act (1968): Preserves and
protects certain rivers with outstanding natural ,
cultural and recreational values in a free-flowing
condition for the enjoyment of present and
future generations. Classifies rivers as wild, scenic
or recreational
• Multiple Use and Sustained Yield Act (1960,
1968): Directs the US Secretary of Agriculture to
manage national forests for recreation, wildlife
habitats and timber production through
principles of multiple use and sustained yield.
Relevant Laws
• Federal Land Policy and Management Act (FLPMA) (1976):
Along with the Taylor Grazing Act, outlines policy
concerning the use and preservation of public lands in the
US. Grants federal government jurisdiction on
consequences of mining on public lands. Grants Bureau of
Land Management responsibility to manage all public lands
not within national forests or parks- a multiple use policy
• Forest and Rangeland Renewable Resources Planning Act
(FRRRPA) (1976): Also known as the Notional Forest
Management Act. Requires the secretary of agriculture to
develop a management program for national forest lands
based on multiple use and sustained yield principals Also
addresses timber-harvesting rates, methods and locations
Relevant Laws
• National Forests Management Act (1976): Authorized
the creation and use of a special fund in situations
involving salvage of insect-infested, dead, damaged or
drowned timber and to remove associated trees for
stand improvement
• Healthy Forest Initiative (2003): Allows timber
companies to cut down economically valuable trees in
most national forests for 10 years. Timber companies
in return must clear out small, more fire-prone trees
and underbrush. Law may have consequences of
increasing fires by accumulation of slash and increasing
fire-prone younger trees.
Rangelands
Rangelands
• Are being compromised by overgrazing and
desertification. The federal government is
trying to manage and sustain the rangelands
Overgrazing
• Occurs when plants are exposed to grazing for too long
without sufficient recovery periods
• When a plant is grazed severely it uses stored energy in its
roots to support regrowth
• As this energy is used, the roots die back
• The degree to which the roots die back depends on the
severity of the grazing.
• Rood dieback does add organic matter to the soil which
increases soil porosity, the infiltration rate of water and the
soil’s moisture holding capacity.
• If sufficient time has passed, enough leaves will regrow and
the roots will regrow as well.
• A plant is considered over grazed with it is regrazed before
the roots recover.
• Overgrazing can reduce root growth by up to 90%
• Consequences:
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Overgrazing
Pastures becoming less productive
Soils having less organic matter and becoming less fertile
Decrease in soil porosity
The infiltration rate and moisture holding capacity of the soil
drops
Susceptibility to soil compaction increased
Desirable plants become stressed while weedier species thrice in
these harsher conditions
Biodiversity decreases by reducing native vegetation- leads to
erosion
Riparian areas are affected by cattle destroying banks and
streambeds
Eutrophication increased due to cattle wastes
Increases disease in native plants
Land is affected to the point that sustainability is threatened
Desertification
• Conversion of marginal rangeland or cropland to a more
desert type of land
• Caused by: overgrazing, soil erosion, prolonged drought or
climate changes as well as the overuse of resources such as
nutrients and water
• 1. overgrazing results in animals eating all available plant
life 2. rain washes away trampled soil since there isn’t
anything to hold the soil down 3. wells, springs and other
sources of water dry up. 4. what vegetation is left dies from
drought or is taken for firewood 5. Weeds that are
unsuitable for grazing may begin to take over 6. the ground
becomes unsuitable for seed germination 7. wind and dry
heat blow away the topsil.
Federal Rangeland Management
• Comprise 40% of the landmass in the US and are the
dominate type of land in arid and semiarid regions
• 80% of lands in the western US are classified as
rangelands
• Serve purposes like:
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A habitat for a wide array of game and nongame animals
A habitat for a diverse and wide array of native plants
A source of high-quality water, clean air and open spaces
A setting for recreational hiking, camping, fishing hunting
and nature experiences
– The foundation for low-input fully renewable food
production systems for the cattle industry.
Federal Rangeland Management
• Jurisdiction of public grazing rangeland is coordinated
through the Forest Service and the Bureau of Land
Management (BLM)
• Before 1995, grazing policies were determined by rancher
advisory boards composed of permit holders
• After 1995, resource advisory councils were formed made
up of diverse groups representing different viewpoints and
interests
• 40% of all federal grazing permits are owned by 3% (about
2000) of all livestock operators.
• Federal grazing permits average about $0.05 a day per
animal. Though the true cost of doing business would be
about $10-20 per day per animal
Methods of Rangeland Management
• Controlling the number and distribution of livestock so that
carrying capacity is not exceeded
• Restoring degraded rangeland
• Moving livestock from one area to another to allow for
rangeland to recover
• Fencing off riparian (stream) areas to reduce damage
• Suppressing the growth of invasive plants
• Replanting barren rangeland with native grass seed to
reduce soil erosion
• Providing supplemental feed at selected sites
• Locating water holes, water tanks and salt blocks at
strategic points that do not degrade the environment.
Rangelands
• Land administered by the BLM is inhabited by
219 endangered species of wildlife
• Livestock grazing is the 5th rated threat to
endangered plant species, the 4th leading
threat for all endangered wildlife and the
number one threat to all endangered species
in arid regions of the US
Relevant Laws
• Taylor Grazing Act (1934): Requires grazing
permits on federal land
• Renewable Resources Planning Act (RPA) (1974):
Mandates periodic assessments of forests and
rangelands in the US. Directs that the assessment
be conducted by the US forest Service and
consider a broad range of renewable resources,
including outdoor recreation, fish, wildlife, water,
ranges, timber and minerals
• Public Rangelands Improvement Act (1978):
Established a reaffirming a commitment to
manage, maintain and improve rangelands so
that they become as productive as feasible.
Urban Land Development
Planned Development
• There are more than 76 million residential and
about 5 million commercial building in the US
• Together these buildings use 1/3 of all energy
and 2/3 of all electricity consumed in the US
• Energy needs of buildings account for almost
half of the sulfur dioxide emissions, ¼ of the
nitrous oxide emissions and 1/3 of all carbon
dioxide emissions
Planned Development
• Green building and city characteristic focus on wholesystem approaches:
– Energy conservation through government and private industry
rebates and tax incentives for solar and other less-polling forms
of energy
– Resource-efficient building techniques and materials
– Indoor air quality
– Water conservation through the use of xeriscaping
– Designs that minimize waste while utilizing recycled materials
– Placing buildings near public transportation hubs that use a
multitude of venue (subway, bus, etc)
– Creating environments that are pedestrian friendly by
incorporating parks, greenbelts and shopping areas in accessible
areas
– Preserving historical and cultural aspects while blending a
natural feeling and aesthetics of a community
Suburban Sprawl and Urbanization
• Urbanization refers to the movement of people fro rural
areas to cities and the changes that accompany it.
• Areas that are experiencing the greatest growth in
urbanization are countries in Asia and Africa
• Asia alone has close to ½ of the worlds urban inhabitants
even though 60% of its population live in rural areas
• Africa, which is generally considered overwhelming rural,
now has a larger urban population than N America
• Reasons include: access to jobs, higher standards of living,
easier access to healthcare, mechanization of agriculture,
access to education
• Nations with the most rapid increases in their urbanization
rates are generally those with the most rapid economic
growth
• From 1950-1990- the world’s economy increased fivefold
Urbanization Pros
• Uses less land- less impact on the environment
• Better educational delivery system
• Mass transit systems decrease reliance on fossil fuels–
commuting distances are shorter
• Better sanitation systems
• Recycling systems are more efficient
• Large numbers of people generate high tax revenues
• Urban areas attract industry due to availability of raw
materials, distribution networks, customers and labor
pool
• Much of the pollution come from point sources,
enabling focused remediation techniques.
Urbanization Cons
• Impact on land is more concentrated and more pronounced
(runoff and flooding)
• Overcrowded schools
• Commuting times are longer because infrastructure can’t keep up
with growth
• Sanitation systems have grater volumes of wastes to deal with
• Solid-waste buildup is more pronounced. Landfill space becomes
scarce and costly
• Large number of poor people place strains on social services
(wealthier people move to suburbs)
• Higher population densities increase crime rates. Population
increase may be high than job growth
• Since population densities are high, pollution levels are also high
(urban heat islands, ozone levels, water and soil pollution)
Transportation Infrastrcture
Federal Highway System
• About 160,000 miles important to nation’s
economy, defense and mobility
• Although they receive substantial federal funding
and comply with federal standards, they are
owned, built and maintained by the states
• The system serves all major US cities. Unlike
counterparts in most industrialized countries,
interstates go through downtown areas and
facilitate urban sprawl.
• The distribution of virtually all goods and services
involve interstate highways at some point
• Residents of American cities commonly use urban
interstates to travel to their jobs.
Federal Highway Systems
• An efficient and well-maintained federal highway system can have
the following impacts:
• Less Pollutants: vehicles in stop and go traffic emit far more
pollutants than they do without frequent braking and acceleration
• Reducing Greenhouse Gases: improving traffic flow and reducing
congestion will decrease atmospheric carbon dioxide
• Improve Fuel Economy and Reduce foreign oil dependence: When
vehicles are stuck in traffic, fuel economy goes down- modest
improvements to the nation’s worse traffic bottlenecks would save
1 billion gallons of fuel each year
• Improve the Economy: Interstates return $6 in economic
productivity for every $1 invested
• Improve Quality of Life: allows produces to be distributed through
out the country in a short period of time.
Relevant Law
• Federal Aid Highway Act (1956): Authorized
construction of the Interstate Highway
System. Under the new law, the federal
government agreed to fund 90% of the
construction costs for interstates. States, in
turn, would provide the remaining funds,
administer the construction projects and
operate the completed interstate highway.
Canals and Channels
• The term canal is another word for strait, which is
defined as a narrow body of water that connect
two larger bodies of water.
• Occur naturally or can be constructed
• Repeated dredging of canals and channels is
often necessary because of silting
• In the US, channels frequented by ships are
generally maintained by the US department of
Interior and monitored and policed by the US
Coast Guard.
Channels and Canals
• Panama Canal- 48-mile canal connects Pacific
Ocean with the Atlantic Ocean. It allows water
transport without having to circumnavigate
South America
• Suez Canal- 163-mile canal that connects the
Red Sea with the Mediterranean It allows
water transport between Europe and Asia
without traveling around Africa- 8% of the
world’s shipping runs through here.
Roadless Areas and Ecosystem Impacts
• No roads= no development
• Havens for fish and wildlife whose habitats in
many other forest areas have been fragmented or
entirely destroyed
• They provide habitats for more that 1600
threatened, endangered or sensitive species and
include watersheds that supply clean drinking
water
• Roadless rule protects 60 million acers or 31% of
National Forest Lands – 2% of the total land in the
US
Relevant Law
• Roadless Area Conservation Rule (2001): This rule
places about 1/3 of the national forest system’s total
acreage off-limits to virtually all road building and
logging.
• More than ½ of the national forest land is already open
to such activity
• The plan protects 59 million acres of unspoiled national
forest land in 39 states.
• It preserves all current opportunities for public access
and recreation, including hiking, fishing, hunting,
camping and mountain biking, as well as the revenue
and jobs that these activities generate in local areas.
Public and Federal LandsManagement
• The BLM is responsible for managing 262 million acres of
land, about 1/8 of the land in the US.
• BLM also manages about 300 million additional acres of
subsurface mineral resources.
• Also responsible for wildlife management and preservation
of 400 million acers
• Most of the lands BLM manages are in the W. US, including
Alaska
• Dominated by extensive grasslands, forests, high
mountains, arctic tundra and deserts
• The BLM manages a wide variety of resources and uses
energy and minerals, timber, forage, wild horse, and
burrow population, fish and wildlife habitats, wilderness
areas, and archaeological, paleontological and historical
sites
Relevant Law
• Federal Land Policy and Management Act
(1976): Outlined policy concerning the use
and preservation of public lands. Granted
federal jurisdiction on consequences of mining
on public lands
National Parks
• There are over 1100 national parks in the world. Many
of them don’t receive proper protection from
poachers, loggers, miners or farmers due to the costs
involved
• In the US National Park System encompasses about 84
million acres, 4 million remain in private ownership.
• The largest area is in Alaska and is more that 16% of
the entire system
• US national parks are threatened by high demand of
large numbers of visitors, leads to congestion, eroded
trails, noise and pollution
• Other threats include off-road vehicles, introduction of
exotic species, commercial activities such as mining,
logging grazing and land development.
National Parks
• Solutions for National Park Problems:
– Reducing the amount of private land within national parks
through incentives to current owners
– Providing education programs to the public
– Setting quotas on attendance through advanced reservation
systems
– Adopting a fee system that covers all external costs
– Banning off-road vehicles
– Vanning autos and instead provide shuttle buses to control
traffic
– Providing tax incentives for property owners near national parks
to use land grants
– Conducting periodic and detailed wildlife and plant inventories.
Relevant Laws
• Yellowstone National Park Act (1872): Preserves the watershed of
the Yellowstone River “for the benefit and enjoyment of the
people”. For the first time, public lands were preserved for public
enjoyment and were to be administered by the federal
government
• National Park Service Act (1916): Established that national parks
are to be maintained in a manner that leaves them unimpaired for
future generations and established the National Park Service to
manage the parks
• Outdoor Recreation Act (1963): Laid out the Interior Department’s
role as coordinator for all federal agencies for programs affecting
the conservation and development of recreation resources
• Wilderness Act (1964): Wilderness was defined by its lack of
noticeable human modification or presence. Federal officials are
required to manage wilderness areas in a manner conducive to
retention of their wilderness character.
Relevant Laws
• Land and Water Conservation Fund Act (1965):
Established a fund, administered by the National Park
Service, to assist the states and federal agencies in
meeting present and future outdoor recreation
demands and the needs of the American people
• National Trails System Act (1968): Established a
national system of recreational, scenic and historic
trails
• Wild and Scenic Rivers Act (1968): Established a
system of areas distinct from the traditional park
concept to ensure the protection of each river’s unique
environment. Is also preserves certain selected rivers
that possess outstanding scenic, recreational,
geological, cultural or historic values and maintains
their free-flowing condition.
Wildlife Refuges
• President Theodore Roosevelt designated 4 acre Pelican
Island off of Florida in 1903 as the first wildlife refuge,
designed to protect breeding birds
• He designated another 52 refuges before he left office in
1909
• The early refuges were established primarily to protect
wildlife such as the overhunted bison or birds killed by
market hunters such as egrets and waterfowl.
• During the drought years of the Great Depression, refuges
were created to protect waterfowl
• The system developed and the National Wildlife Refuge
System consists of 547 refuges and more than 93 million
acers and is managed by the US Fish and Wildlife Service.
Wetlands
• Areas covered by water and support plants that can grow in watersaturated soils
• High plant productivity supports a rich diversity of animals.
• Countries with the most wetlands are Canada, Russia and Brazil.
• Wetlands were once about 10% of the land area in the US but have been
reduced to 5%, most wetlands are in Louisiana and Florida
• Most wetland habitat loss- 90%- is due to conversion of the land to
agriculture and the rest is due to urbanization
• 1/3 of all endangered species in the US spend some of their life in wetlands
• Wetlands serve as natural water purification systems by removing
sediments, nutrients and toxins from flowing water
• Wetlands along lakes and oceans stabilize shorelines and reduce damages
caused by storm surges, reduce risk of flooding and reduce saltwater
intrusion
Wetlands
• Fens are wetlands characterized by continuous sources of
groundwater rich in magnesium and calcium which makes
the soil very alkaline. This groundwater comes from glaciers
that have melted, depositing their water in layers of gravel
and sans. Water sits upon layers of soil that are not
permeable, thus keeping the water from sinking beneath
the surface, the water is forced to flow along the surface
where it picks up minerals in its path
• A Bog is a type of wetland that accumulates acidic peat, a
deposit of dead plant material (pre-coal). Bogs are located
in cold, temperate climates in boreal biomes in Western
Siberia, parts of Russia, Ireland, Canada and Minnesota and
Michigan. They are generally low in nutrients and highly
acidic. Carnivorous plants have adapted to these conditions
and use insects as their nutrients
Land Conservation Options
1.
2.
3.
4.
5.
6.
Protect biodiversity, wildlife habitats and the ecological functioning of
public land ecosystems through careful monitoring and enforcement
Adopt a user pay approach for extracting resources from public lands.
Eliminate govt subsidies and tax brakes to corporations that extract
publically owned resources
Institute fair compensation for resources extracted from public land.
Instead of the govt subsidizing the extraction of resources, the
corporations should be paying the government fair market value for
natural resources
Require responsibility for those who damage or alter public land
Adopt uneven-aged management forestry practices that foster
maintaining a variety of tree species at various ages and sizes. This
management technique fosters biological diversity, long-term
sustainable production of high-quality timber, selective cutting and
the principle of multiple use of the forests for recreation, watershed
protection, wildlife and timber
Include ecological services of trees in estimating value
Land Conservation Options
8. Reduce road building into uncut forest acres. Require restoration plans for
those roads that are currently in place, and require such plans for future roads
9. Coordinate with the Forest Service on leaving fallen timber and standing dead
trees in place to promote nutrient cycling and providing wildlife habitats.
10. Grow timber on longer rotations
11. Reduce or climate clear-cutting, shelter wood cutting or seed tree cutting on
sloped land
12. Rely on more sustainable tree-cutting methods such as selective and strip
cutting
13. Reduce fragmentation of remaining large forests
14. Require certification of lumber that is cut according to sustainable forest
practices
15. Use sustainable techniques for tropical forests: educating settlers about
sustainable forest practices and their advantages, monitoring and enforcing
cutting based on sound ecological principles and reducing subsidies that
encourage tropical deforestations, institute debt-for-nature and conservation
easements, creating subsidies for sustainable practices and rehabilitation the area
16. Solutions to urban land use problems include Zoning.
Land Conservation Options
• Preservation or Sustainable: to keep or maintain intact
• Remediation: The act or process of correcting a fault or
deficiency
• Mitigation: to moderate or alleviate in force or intensity
• Restoration: to restore to former good condition.
Ecosystem restoration involves management actions
designed to facilitate the recovery or reestablishment of
native ecosystems. A central premise of ecological
restoration is that restoration of natural systems to
conditions consistent with their evolutionary environments
will prevent their further degradation wile simultaneously
conserving their native plants and animals
Mining
Pre-Extraction
• Before mining begins, economic decisions are
made to determine if a site will be profitable
The factors that enter into the decision
include current and projected price, amount
of ore at the site, concentration, type of
mining required, cost of transporting the ore ti
a processing facility and cost of reclamation
Site Development
• Samples are taken from an area to determine
the quality and quantity of minerals in a
location. Roads and equipment are brought in.
Extraction- Surface Mining
• Surface Mining: soil and rock overlying the
mineral deposit (overburden) is removed and
stored (spoilbank). Used where deposits are
found near the surface, and where the
overburden is relatively thin or where
tunneling isn't an option. Surface mines are
typically enlarged until the deposit is
exhausted or the cost of removing large
volumes of overburden makes it impractical.
Extraction- Surface Mining
• 5 main forms:
– Strip mining: most commonly used to mine coal
or tar sand. Is the practice of mining a seam of
mineral by first removing a long strip of
overburden. Area stripping is used on fairly flat
terrain to extract deposits over a large area.
Overburden from one strip goes into the mined
remain of the previous strip. Contour strip mining
is when the strips go with the curvature of the
land.
Extraction- Surface Mining
– Open-pit Mining: extracting rock or mineral from the
earth in an open pit
– Mountain top removal: coal seam are removed and
the soil is placed in adjacent lows such as hallows or
ravines. Replaces previously steep topography with a
relatively level surface
– Dredging: bringing up underwater mineral deposits.
Usually employed to clear or enlarge waterways for
boats AND to recover minerals relatively efficiently
and cheaply
– Highwall Mining: uses continuous mining machine
driven under remote control into the seam exposed
by previous open-cut air operations. A continuous
haulage system carries the coal from the mine to an
open-air installation for stockpile and transport
Extraction- Underground
• Large shafts are dug into the Earth. There is less surface
destruction and waste rock produced than in surface
mining, but its unsafe.
• Often occurs below the water table so water must be
constantly pumped out of the mine to prevent flooding
• When a mine is abandoned, the pumping ceases and
the water floods the mine.
• This introduction of water often results in acid rock
drainage which is caused by certain bacteria
accelerating the decomposition of metal sulfide ions
that have been exposed to air and water.
Extraction- In Situ
• With in situ leaching, small holes are drilled into a
site
• Water-based chemical solvents extract the
resource
• Advantage: less-expensive since rocks don’t have
to be broken up or removed, shorter time to
production, requires less surface ground
disturbance and less mediation
• Disadvantages: fluids injected into the Earth are
toxic and can get into groundwater
Processing
• Involves intensive chemical processing during smelting
• This is the method by which a metal is obtained from it’s ore, either
as an element or a simple compound
• Usually accomplished by heating beyond the melting point,
ordinarily in the presence of reducing agents such as coke or
oxidizing agents such as air
• A metal whose ore is an oxygen compound (iron zinc lead) is heated
in a blast furnace to a high temp. The oxide combined with the
carbon in the coke, escaping as CO or CO2.
• Other impurities are removed by adding flux, with which they
combine to form slag.
• If the ore is a sulfide mineral (copper nickel lead) air or oxygen is
introduced to oxidize the sulfide to sulfur dioxide and any iron to
slag, leaving the metal behind.
Processing
• In cyanide heap leaching, goal ore is heaped into
a large pile.
• Cyanide solution is then sprayed on top of the
pile
• As the Cyanide percolates down, the gold leaches
out and pools at the bottom
• The gold extracted bay be only 0.01% of the total
ore processed. Liquid wastes containing cyanide
and other toxins are kept in tailing ponds which
eventually leak and enter groundwater.
Processing
• Tailings are the materials left over after the
process of separating the valuable fraction
from the ore
• Tailings represent and external cost of mining
• In coal an oil sands mining, tailings refers
specifically to the fine wastes suspendered in
water
Global Reserves
• 2 billion tons of minerals are extracted and used
each year in the US.
• At the same time the US imports 50% of its most
needed minerals
• As a mineral reserve becomes depleted, lower
grades of ore are mined, which causes more
processing and more pollution
• The US, Germany, and Russia represent 8% of the
worlds population but they consume 75% of the
most widely used metals, with the US consuming
20%
Global Reserve-Oil
• A large portion of Earths global crude oil reserve—45-70%-has already been depleted.
• It is estimated that there is a 50-year supply left on earth
• ½ is thought to be in the middle east
• The US owns 3% of the worlds oil reserves but used 30% of
the oil extracted worldwide each year
• Increased competition for foreign oil by China and India
increase the worlds cost of oil
• 2/3 of the oil used in the US if for transportation
• ¼ is used for industry
• Oil imports in the US increased from 52% in 1996 to a
projected 70% by 2010
Global Reserve- Coal
• Coal is currently the worlds single largest
source of fuel used to produce electricity
• China is the worlds largest producer
• Global coal reserves are expected to last
about 300 years at current extraction levels
Global Resources- Natural Gas
• Most of the worlds natural gas reserves are located in
the Middle East (34%).
• Europe, Russia and former USSR own 42% of the world
reserves
• The US possesses 3% of the total natural gas reserve
• Given US production levels, there is enough natural gat
to last about 75 years of domestic production
• This estimate doesn’t take into account expected
increasing levels of domestic production or the
potential opening of the currently restricted Arctic
National Wildlife Reserve.
Relevant Laws
• General Mining Law (1872): Grants free access to
individuals and corporations to prospect for minerals in
public domain lands and allows them, upon making
discovery, to stake claim to that deposit
• Mineral Leasing Act (1920): Authorizes and governs
leasing of public lands for developing deposits of coal,
petroleum, natural gas and other hydrocarbons,
phosphates and sodium in the US. Previous to the act,
these minerals were subjected to mining claims
• Surface Mining Control and Reclamation Act (1977):
Established a program for regulating surface coal
mining and reclamation activities
Fishing
Types of Commercial Fishing
• Bottom Trawling: uses a funnel-shaped net to drag the
ocean bottom. Shrimp, cod, flounder and scallops.
Analogous to clear-cutting forests. Species not wanted are
called bycatch
• Drift Net: Long expanses of nets that hand down in the
water. Traps turtles, seabirds and marine mammals. During
the 1980’s, 10,000 dolphins, whales and millions of sharks
were killed each year. 1992 UN voluntary ban on drift nets
longer than 1.5 miles are helping
• Longline: placing very long lines with thousands of baited
hooks. Swordfish, tuna, sharks, halibut and cod. Endangers
sea turtles, pilot whales and dolphins.
• Purse Sein: surrounds large schools of fish spotted by
aircraft with a large net. Net is then drawn tight. Tuna,
mackerel, anchovies and herring.
Overfishing
• Oceans supply 1% of human food and represent 10% of
worlds protein source
• China is responsible for about 1/3 of all fish harvesting
• 1/3 of total catch is used for other consumption (fish
oil, fish meal, animal feed)
• Another 1/3 is considered bycatch
• Maximum sustainable yield is the largest amount of
marine organisms that can be harvested without
causing the population to crash
• This yield is generally when a population is maintained
at ½ the carrying capacity
Methods to manage fishing in a
sustainable manner
• Regulate locations and number of fish farms and
monitor their pollution output
• Encourage the production of herbivores fish
species
• Require and enforce labeling of fish products that
were raided or caught with sustainable methods
• Set catch limits far below maximum sustainable
yield
• Eliminate govt subsidies for commercial fishing
Methods to manage fishing in a
sustainable manner
• Prevent importation of fish from foreign countries that
don’t adhere to sustainable harvesting methods
• Place trading sanctions on foreign countries that don’t
respect the marine habitat, including countries with
whale hunts
• Assess fees for harvesting fish and shellfish from public
waters
• Increase penalties for fishing techniques that don’t
allow for the escape of bycatch
• Ban the throwing back of bycatch
• Monitor and destroy invasive species on ship ballast
Methods to restore habitats for
freshwater fish
•
•
•
•
•
Planting native vegetation on stream banks
Rehabilitate instream habitats
Controlling erosion
Controlling invasive species
Restoring fish passages around human-made
impediments
• Monitoring, regulating and enforcing recreational
and commercial fishing
• Protecting coastal estuaries and wetlands
Aquaculture
• Known as mariculture or fish farming
• Involves stocking, feeding, protecting from predators,
and harvesting
• Growing about 6% annually and provides 5% of total
food production worldwide (mostly in less developed
countries)
• Kelp makes up about 17% of all aquaculture output
• Used to raise 80% of the mollusks, 40% of all shrimp
and 75% of all kelp we use
• Other common products include: seaweed, mussels,
oysters, shrimp, salmon, trout and catfish
Aquaculture
• Advantages: cold-blooded organisms convert
more feed to usable protein Example: for
every 1 million calories of feed requires, a
trout raised on a farm produces about 35 g of
protein whereas a chicken produces 15g and
cattle produces 2 g.
• For every hectare of hectares, intense ocean
farming can produce 58,000 kg of protein
where normal harvesting only produces 10 kg.
Aquaculture
• For it to be economical, the species must be marketable,
inexpensive to raise, trophically efficient, at a marketable
size within 1-2 years, and disease resistant.
• Aquaculture creates dense monocultures that reduce
biodiversity within habitats and requires large levels of
nutrients in the water
• Offers possibilities for sustainable protein-rich food
production and economic development in communities.
• However, on an industrial scale it poses sever threats;
threats to biodiversity, accidental release of alien or
modified organisms, transmission of diseases to wild stock,
displacement of local and indigenous human communities,
degradation of habitat.
Case Study: PCB
• Polychlorinated biphenyls (PCBs) were banned in the US in the late
1970s are slated for global phase-out under the treaty on POPs.
• PCBs are highly persistent and have been linked to cancer and
impaired fetal brain development
• Salmon farming has made salmon the third most popular fish in
the US and comprises 22% of all retail seafood. However, analysis
of US govts data found that farmed salmon are likely the most
PCB-contaminated protein source
• About 800,000 US adults have an increased cancer risk by eating
PCB-contaminated salmon
• Farmed salmon are fattened with ground fishmeal and fish oils
that are high in PCBs
• As a result, salmon farming operations that produce inexpensive
fish unnaturally concentrate PBCs
• AND salmon contains 52% more fat than wild salmon.
Relevant Laws
• Fish and Wildlife Act (1956): established a comprehensive national fish and
shellfish resource policy directed primarily to industry.
• Anadromous Fish Conservation Act (1965): Authorizes the Secretory of
Interior to enter into agreements with states and other non-federal
interests to conserve, develop and enhance the anadromous fish (fish that
migrate from the sea to fresh water to spawn) resources of the US.
• Marine Mammal Protection Act (1972): Prohibits, with certain exceptions,
taking of marine mammals in US waters and by US citizens on the high seas
and the importation of marine mammals and marine mammal products to
the US
• Magnuson Fishery Conservation and Management Act (1976): Governs
marine fisheries management in the US federal waters. Aids in the
development of the domestic fishing industry by phasing out foreign
fishing. To manage the fisheries and promote conservation. The Act
created 8 regional fishery management councils. The 1996 amendment
focused on rebuilding of overfished fisheries, protecting essential fish
habitat and reducing bycatch
Relevant Laws
• Fish and Wildlife Coordination Act (1980):
Assistance in training of state fish and wildlife
enforcement personnel and assistance to states
in the development and revision of conservation
plans for nongame fish and wildlife
• United Nations Treaty on the Law of the Sea
(1982): Defines the rights and responsibilities of
nations in their use of the worlds oceans,
establishing guidelines for business, the
environment and the management of marine
natural resources.
Global Economics
Global Economics
• The economy and the environment are intrinsically
linked such that both are causes and effects and inputs
and outputs of each other
• The environment contains all the resources that can be
used in the economy.
• The use of resources for economic purposed
continuously creates new environmental situations
• For example: while some resources are depleted and
transformed from usable to unusable states, economic
resources are used to expand additional resources. This
occurs through increasing available supply of materials
, opening land to agricultural production, transporting
resources from locations where they are in surplus to
areas of shortage and so on.
Global Economics
• Increased levels of economic activity and
improvements in living standards have occurred since
the end of WWII.
• People in wealthiest countries constitutes 15% of the
global population and enjoy average incomes 20X
greater that 85% of the population
• If the income of the poorest 85% were raised to only
1/3 of that of the richest countries, the level of total
world production and consumption would have to
double, with a similar increase in the use of resources
• Continued increases in living standards in poorer
countries will increase carrying capacity of the planet.
Global Economics
• Until recently, developments in the local
economies and local environments were
dispersed and isolated
• The didn’t typically result in cumulative process
that had widespread or global impact
• However, with greater increase in population
there is a significant increase in global
environmental disruption
• The effects of these disruptions have become
increasingly interlinked
World Bank
• Source of financial and technical assistance to developing
countries around the world
• The world bank ,owned by 184 member countries, provides
low-interest loans, interest-free credit and grants to
developing countries for education, health, building,
communication and environmental issues
• In 2001, the Bank endorsed an environmental strategy to
guide the banks actions in environmental areas; improving
quality of life, quality of growth and “greening” of
agriculture, water sanitation and other projects
• In 2005, they gave 13.8 billion dollars to the areas of
biodiversity, conservation, climate change, international
waters. Funded 740 million in projects to phase out ozone
depleting substances and 1.6 billion into projects that
reduce greenhouse gases
World Bank
• Also is the greatest single source of funds for
dam projects, supplying 50 billion for
construction of more than 500 large dams in
92 countries.
Tragedy of the Commons
• Garrett Hardin wrote “Tragedy of the Commons”
in 1968
• It parallels what is happening world wide in
regard to resource depletion and pollution
• Seas, air, water, animals and minerals are all
commons are are for human use
• Those who exploit them become rich
• The price of depleting the resources of the
commons is an external costs paid by the people
of the earth.
Tragedy of the Commons
• Limits:
– Economic decisions are generally short term, bases on
reactions in the world markets. Environmental decisions
are long term
– Land that is privately owned is subject to market pressure
– Some commons are easier to control that others. Land,
lakes, rangeland. Deserts and forests are geographically
defined and easier to control than air or open oceans. This
is the problems with the US and the Kyoto Protocol
– Incorporating discount rates into calculation of resources
would be an incentive for investors to bear the short term
cost for a long term gain
– Breaking a commons into smaller, privately owned
fragments the policies of governing the entire commons.
Different standards and practices used on one area may or
may not affect all other areas.