APES Unit 5 test

Ecological services of forests

support energy flow and chemical cycling, reduce soil erosion, absorb and release water, purify water and air, influence local and regional climate, store atmospheric carbon, provide numerous wildlife habitats

Economic services of forests

fuelwood, lumber, pulp to make paper, mining, livestock grazing, recreation, jobs

Harvesting trees

selective cutting, clear cutting, strip cutting

selective cutting

intermediate age or mature trees are cut singly or in small groups

clear cutting

all trees in an area are removed

strip cutting

clear cutting in strips

clear cutting forests advantages

higher timber yields, maximum profits in shortest time, can reforest with fast growing trees

disadvantages of clear cutting

reduces biodiversity, destroys and fragments wildlife habitats, can lead to water pollution, flooding, and erosion, especially on steep slopes

surface fires

* Usually burn leaf litter and undergrowth
* Provide many ecological benefits

crown fires

* Extremely hot – burns whole trees
* Kill wildlife
* Increase soil erosion

global warming

* Rising temperatures
* Trees more susceptible to diseases and pests
* Drier forests – more fires
* More greenhouse gases

Deforestation

* Temporary or permanent removal of large expanses of forest for agriculture, settlements, or other uses

Deforestation in tropical forests

* Especially in Latin America, Indonesia, and Africa

Boreal forests

* Especially in Alaska, Canada, Scandinavia, and Russia

Deforestation can cause

water pollution and soil degradation from erosion, acceleration of flooding, local extinction of specialist species, habitat loss for native and migrating species, release CO2 and loss of CO2 absorption

Sustaining forests

* Emphasizing the economic value of their ecosystem services
* Removing government subsidies that hasten their destruction
* Protecting old-growth forests
* Harvesting trees no faster than they are replenished
* Planting trees

sustaining tropical forests-→ prevention

protect the most diverse and endangered areas, educate settlers about sustainable agriculture and forestry, subsidize only sustainable forest use, protect forest through debt for nature swamps and conservation concessions, certify sustainably grown timber, reduce poverty and slow population growth

Restoration

encourage regrowth through secondary succession, rehabilitates degraded areas, concentrate farming and ranching in already cleared areas

We can sustain the productivity of grasslands by:

* Controlling the numbers and distribution of grazing livestock
* Restoring degraded grasslands

Rangelands

* Unfenced grasslands in temperate and tropical climates that provide forage for animals

Pastures

* Managed grasslands and fences meadows used for grazing livestock

Overgrazing of rangelands

* Reduces grass cover
* Leads to erosion of soil by water and wind
* Soil becomes compacted 
* Enhances invasion of plant species that cattle won’t eat

Manage Rangelands more sustainably

* Rotational grazing
* Cattle moved around
* Fence damaged areas
* Suppress growth of unwanted plants
* Herbicides
* Controlled burning

RCRA: Resource Conservation and Recovery Act

* This act is also called the “cradle to grave” act as it gives the Environmental Protection Agency the authority to control any hazardous waste at all stages.
* It requires shippers, generators, and disposers to keep detailed accounts of the type and amount of hazardous waste that is handled from the time of generation to final disposal

CERCLA: Comprehensive Environmental Response, Compensation, and Liability Act

* This is also known as the “Superfund,” a U.S. law passed in 1980. 
* Its main purpose is to clean up and/or contain abandoned toxic waste sites using the concept of a *superfund.*
* The superfund money comes from taxes on those that produce hazardous waste.
* The EPA was given the power to hold the parties responsible for any toxic waste release.
* It authorizes actions for short term and long term responses based on the nature of the threat to human health

Clean Air Act

* This act was a major milestone in terms of air quality legislation and is considered one of the most comprehensive laws regarding pollution in the world.
* Set limits for __criteria pollutants__: also called conventional pollutants - the seven major air pollutants that are considered to have the most serious threat to humans.
* Sulfur Oxides (SOx)
* Carbon Monoxide (CO)
* Particulate Material (PM)
* Volatile Organic Compounds (VOCs)
* Nitrogen oxides (NOx)
* Ozone (tropospheric)
* Lead
* Lead was regulated particularly in fuels, leading to a dramatic decrease in the amount of lead in the atmosphere (this is specifically mention in the College Board CED)
* Set primary standards (to protect human health) and secondary standards (to protect property, visibility, and crops.)

Clean Water Act

* This act makes it unlawful for anyone to discharge any point source pollution without permits.
* The act requires that “Best Practicable Technology” (BPT) be used to clean point sources and “Best Available Technology” (BAT) be used to clean up toxins.
* This act funds construction of several important facilities such as sewage treatment plants and includes provisions for protecting wetlands.
* The main goal of this act is to get to the point where all water is “fishable and swimmable.”

Safe Drinking Water Act (SDWA)

* The intention behind this act is to “protect public health” through regulation of public drinking water supply.
* The act protects the sources of drinking water - including reservoirs, lakes, and rivers.
* Above ground or underground sources are included
* The act allows for the EPA to set health standards in order to protect Americans from possible water contaminants.

CITES: Convention on Int’l Trade in Endangered Species of Wild Fauna & Flora

* An *international agreement* regulating trade in living specimen & products derived from listed endangered species
* Prevents species from reaching point of endangerment or extinction due to international trade
* Countries collaborate to make sure any type of trade of the specimen is biologically sustainable and does not impede their survival

Endangered Species Act

* This United States law identifies endangered, threatened, and vulnerable species. In addition, it places restrictions and regulations on any recreational or commercial activities involving these.
* __Endangered__: a species is in danger of extinction
* __Threatened__: a species is likely to become endangered in the near future without further action or intervention
* Under this law, the US Fish & Wildlife Service is required to create recovery plans for each listed species, detailing how they will be supported in order to prevent possible extinction.

Montreal Protocol

* An international treaty to eliminate production and consumption of ozone depleting substances (ODS).
* The main goal is to protect the stratospheric ozone layer by phasing out substances including chlorofluorocarbons (CFCs), halons, and carbon tetrafluoride.
* It was signed by all members of the United Nations. According to the EPA, it was the “first treaty in the history of the UN to achieve universal ratification” and therefore is considered one of the most successful global-environmental actions.

Kyoto Protocol

* This was an *international agreement* that was a part of the United Nations’ Framework Convention on Climate Change.
* The aim of the protocol is to bind the countries that sign the act to regulations that reduce greenhouse gas emissions.
* The act set tighter regulations on more developed/industrialized countries. Therefore, the United States was one of the only countries to object to the protocol, with representatives refusing to sign it.

Delaney Clause Of Food, Drug, and Cosmetic Act

* The Delaney Clause is a provision of a larger amendment to the Food, Drugs, and Cosmetic Act of 1938.
* It states that chemical additives “found to induce cancer in man” or in animals could NOT be approved for use in foods by the FDA.
* Any __carcinogens__ causing “reasonable harm” could not be added to food or drugs.

Food desert

* Urban area where people have little or no easy access to nutritious food

Growing Power, Inc. in Milwaukee, WI

* Uses solar power
* Produces 150 varieties of vegetables
* Runs education program

Food security

* All or most people in a country have daily access to enough nutritious food to lead active and healthy lives

Food insecurity

* Chronic hunger and poor nutrition
* Causes:
* Political upheaval, war, corruption, and bad weather

under nutrition

* Not enough food to meet basic energy needs

malnutrition

* Not enough protein or other key nutrients

famine

* Severe shortage of food 
* Result in mass starvation, many deaths, economic chaos, and social disruption

iron

anemia

iodine

thyroid

over nutrition

* Excess body fat from too many calories and not enough exercise

three systems produce most of our food

* Croplands – 77% on 11% world’s land area
* Rangelands, pastures, and feedlots – 16% on 29% of world’s land area
* Aquaculture – 7%

three main grain crops

wheat, rice, and corn

irrigation

supply of water to crops

industrialized agriculture

* Heavy equipment
* Large amounts of financial capital, fossil fuels, water, commercial fertilizers, and pesticides
* Single crop

Goal is to steadily increase crop yield

* Plantation agriculture – cash crops
* Primarily in less-developed countries
* Increased use of greenhouses to raise crops

Traditional subsistence agriculture

* Human labor and draft animals for family food

Traditional intensive agriculture

* Higher yields through use of manure and water

Polyculture

* Crop diversity
* Benefits over monoculture

Slash-and-burn agriculture

* Subsistence agriculture in tropical forests
* Clear and burn a small plot
* Grow many crops that mature at different times
* Reduced soil erosion 
* Less need for fertilizer and water

Organic agriculture is on the Rise

* Crops grown with ecologically sound and sustainable methods
* No synthetic pesticides or fertilizers
* Has a number of environmental advantages
* Usually produces less than conventional agriculture

Green Revolution

* increase crop yields
* Monocultures of high-yield key crops
* Rice, wheat, and corn
* Large amounts of fertilizers, pesticides, water
* Multiple cropping

Second Green Revolution

* Fast growing dwarf varieties


* World grain has tripled in production

First gene revolution

* Cross-breeding through artificial selection
* Slow process
* Amazing results

Genetic engineering

* second gene revolution
* Alter organism’s DNA
* Genetic modified organisms (GMOs) – transgenic organisms

Meat production increased more than sixfold between 1950 and 2010

* Increased demand for grain
* Demand is expected to go higher

Animals for meat raised in:

* Pastures and rangelands
* Feedlots

Aquaculture, blue revolution

* World’s fastest-growing type of food production
* Dominated by operations that raise herbivorous species

Agriculture has harmful affects on:

* Biodiversity
* Soil
* Water
* Air
* Human health

Soil erosion

* Movement of soil by wind and water
* Natural causes
* Human causes

Two major harmful effects of soil erosion

* Loss of soil fertility
* Water pollution

Desertification

* Productive potential of topsoil falls by 10% or more
* Prolonged drought, human activities

Soil salinization

* Gradual accumulation of salts in the soil from irrigation water
* Lowers crop yields and can even kill plants
* Affects 10% of world croplands

Waterlogging

* Irrigation water gradually raises water table
* Can prevent roots from getting oxygen
* Affects 10% of world croplands

Agriculture Contributes to Air Pollution and Climate Change

* Clearing and burning of forests for croplands
* One-fourth of all human-generated greenhouse gases
* Livestock contributes 18% of gases
* Methane in cow belches

Projected Advantages of GMOs

* may need less fertilizer, pesticides, and water
* can be resistant to insects, disease, frost, and drought
* can grow faster
* may tolerate higher levels of herbicides

Projected Disadvantages of GMOs

* have unpredictable genetic and ecological effects
* may put toxins in food
* can promote pesticide resistant insects, herbicide resistant weeds, and plant diseases
* could disrupt seed market and reduce biodiversity

There Are Limits to the Expansion of the Green Revolutions

* Usually require large inputs of fertilizer, pesticides, and water
* Often too expensive for many farmers

Animal feedlots advantages

* increased meat production
* higher profits
* less land use
* reduced overgrazing
* reduced soil erosion
* protection of biodiversity

Animal feedlots disadvatages

* large inputs of grain, fish meal, water, and fossil fuels
* greenhouse gas emissions
* concentration of animal wastes that can pollute water
* use of antibiotics can increase genetic resistance to microbes in humans

harmful environmental problems in aquacutlture

* Several environmental problems
* Fish are caught to feed to other fish
* Inefficient process
* Environmental toxins
* Spread invasive plant species
* Fish farms produce waste

advantages of aquaculture

* high efficiency
* high yield
* reduced overharvesting of fisheries
* jobs and profits

disadvantages of aquaculture

* large inputs of land, feed, and water
* large waste output
* loss of mangrove forests and estuaries
* desire populations vulnerable to disease

First-generation pesticides

* Borrowed from plants

Second-generation pesticides

* Lab produced
* DDT and others

chemical pesticides advantages

* expand food supplies
* raise profits
* work fast
* are safe if used properly

disadvantages of chemical pesticides

* promote genetic resistance
* can kill pests’ natural enemies and harm wildlife and people
* can pollute air, water, and land
* are expensive for farmers

There Are Alternatives to Synthetic Pesticides

* Fool the pest
* Crop rotation; changing planting times
* Provide homes for pest enemies
* Use polyculture
* Implant genetic resistance – genetic engineering
* Bring in natural enemies
* Predators, parasites, and diseases
* Use insect perfumes
* Pheromones
* Bring in hormones
* Interfere with pest life cycle
* Alternative methods of weed control
* Crop rotation, cover crops, and mulches

IPM

* Coordinate – cultivation, biological controls, and chemical tools to reduce crop damage to an economically tolerable level
* Reduces pollution and pesticide costs

Disadvantages of IPM

* Requires expert knowledge
* High initial costs
* Government opposition

Zone of saturation

* Spaces in soil are filled with water

Water table

* Top of zone of saturation

aquifers

* Natural recharge 
* Lateral recharge

natural recharge of aquifers

precipitation that percolates downward through exposed soil and rock

lateral recharge of aquifers

side from nearby lakes, rivers, and streams.

surface water

* Surface runoff
* Watershed (drainage) basin

Main factors that cause scarcity of water

* Dry climates
* Drought
* Too many people using a normal supply of water
* Wasteful use of water

Withdrawing Groundwater advantages

* useful for drinking and irrigation
* exists almost everywhere
* renewable if not overpumped or contaminated
* cheaper to extract than most surface waters

Withdrawing Groundwater disadvantages

* aquifer depletion from overpumping
* sinking of land from overpumping
* some deeper wells are nonrenewable
* pollution of aquifers lasts decades or centuries

Overpumping Aquifers Has Several Harmful Effects

* Limits future food production
* Bigger gap between the rich and the poor 
* Land subsidence
* Mexico City
* San Joaquin Valley in California
* Groundwater overdrafts near coastal regions
* Contamination of groundwater with saltwater

Deep Aquifers Might Be Tapped

* May contain enough water to provide for billions of people for centuries
* Major concerns
* Nonrenewable
* Little is known about the geological and ecological impacts of pumping deep aquifers
* Some flow beneath more than one country
* Costs of tapping are unknown and could be high

Goal of dams

* Capture and store runoff
* Release runoff as needed to control:
* Floods
* Generate electricity
* Supply irrigation water
* Recreation (reservoirs)

Advantages of dams

* Increase the reliable runoff available
* Reduce flooding
* Grow crops in arid regions

Disadvantages of dams

* Displacement of people
* Flooded regions
* Impaired ecological services of rivers
* Loss of plant and animal species
* Fill up with sediment
* Can cause other streams and lakes to dry up

How Dams Can Kill an Estuary

* Only small amount of Colorado River water reaches Gulf of California
* Threatens aquatic species in river and species that live in the estuary
* Current rate of river withdrawal is not sustainable
* Much water used for agriculture that is inefficient with water use
* Reservoirs
* Leak water into ground below
* Lose much water through evaporation
* Fill up with silt load of river, depriving delta
* Could eventually lose ability to store water and create electricity
* States must conserve water, control population, and slow urban development

Problems with removing salt from the sea

* High cost and energy footprint
* Keeps down algal growth and kills many marine organisms
* Large quantity of brine wastes

We can use freshwater more sustainably by:

We Can Improve Efficiency in Irrigation

* Flood irrigation
* Wasteful
* Center pivot, low pressure sprinkler
* Low-energy; precision application sprinklers
* Drip or trickle irrigation, microirrigation
* Costly
* Less water waste