Unit 5 - APES

Individuals will use __**shared/public resources**__***** in their own self interest, __**degrading**__****** them

Tragedy of the Commons

Tragedy of the Commons

* Must be a _____ resource (not privately owned)


* Must be ___________ in some way

public, degraded, overused, depleted, used-up

Overgrazing, Overfishing, Water & Air Pollution, Overuse of groundwater

Examples of Tragedy of the Commons

Why does Tragedy of the Commons happen?

When it’s public, nobody suffers the consequences / people assume others will overuse resource if they don’t / no penalty for degrading

What problems does tragedy of the commons cause?

Overfishing can lead to fishery collapse (population crash) loss of income & starvation, Air pollution from coal power plants can lead to bronchitis, asthma, increased healthcare costs, Pesticide runoff from farms contaminates drinking water

negative costs associated with a human actions, that aren’t accounted for in the price (unintended side-effects)

Externalities

What’s the solution for Tragedy of the Commons?

private land ownership (individual or gov.) / fees or taxes for use (permit system for grazing, logging) / taxes, fines, criminal charges for pollution or shared air/soil/water resources

To solve TOC: Examples of taxes/fines

clean air act, clean water act, safe drinking water act

Manages rangelands in western US by collecting grazing fees from ranchers, evaluating land, and repairing effects of overgrazing

BLM (Bureau of Land Management)

a method of logging in which one area is rapidly and thoroughly cleared of all its trees at once.

clearcutting

Soil Erosion, Increased soil and stream temperature, Flooding and landslides

direct effects of clearcutting

What are two environmental problems associated with clearcutting?

soil erosion and increased soil and stream temperatures.

●Caused by loss of stabilizing root structure

●Removes soil organic matter & nutrients from forest

●Deposits sediments in local streams

○Warms water & makes it more turbid (cloudy)

Soil Erosion

●Caused by loss of stabilizing root structure

●Removes soil organic matter & nutrients from forest

●Deposits sediments in local streams

○Warms water & makes it more turbid (cloudy)

Increased soil and stream temperature

●Logging machinery compacts soil

●Increased sunlight dries out soil

●Loss of root structure = erosion of topsoil & O horizon

○All of these factors decrease H2O holding capacity of soil causing flooding & landslides

Flooding and landslides

Areas where the same tree species are repeatedly planted, grown, and harvested

Tree Plantations

Tree Plantations:

●Biodiverse, mature forests are replaced with single species forests

●Less species diversity = lower resilience

●Less habitat diversity for other org.

Lowers Biodiversity

Tree Plantations:

●All trees planted at the same time = all the same age

●Lowers biodiversity further (no dead trees for woodpeckers, insects, decomposers)

All the same age

Filtering of air pollutants, removal and storage of CO2 from atm., habitat for organisms

Forest Benefits

\-Reduces air filtering and carbon storing services

\-Cutting trees down releases CO2 from decomposition of leftover organic material

\-__**Slash & burn**__ method of clearing land for agriculture by cutting trees & burning them releases CO2, N2O and water vapor into the atmosphere (all GHGs)

Deforestation Consequences

Shift in agriculture away from small, family operated farms to large, __**industrial-scale agribusiness**__

The Green Revolution

Increased use of mechanization, GMOs, irrigation, fertilizers, and pesticides

The Green Revolution

Greatly increases efficiency of lands, short-term profitability, and food supply

The Green Revolution

Decreased world hunger and increased earth’s carrying capacity for humans

The Green Revolution

What were the negative consequences of the green revolution?

soil erosion, biodiversity loss, ground & surface water contamination

Increased use of tractors for plowing and tilling fields, and combines for harvesting = increased yield + profits

Mechanization

\-Increases reliance on fossil fuels (gasoline/diesel fuel)

\+Emits GHGs to atmosphere → climate change

\-Heavy machinery also compacts soil, decreasing H2O holding capacity

\+Makes topsoil more prone to erosion

negative consequences of mechanization

Genetically modified crops have genes for drought tolerance, pest resistance, faster growth, and larger fruit/grain

GMOS

Positives of GMOs

Increases profitability with fewer plants lost to drought, disease, or pests + larger plant size + yield/acre

Negative consequences of GMOs

GMO crops are all genetically identical so gen. diversity is decreased and susceptibility to diseases or pest is increased

manufactured artificially and contain minerals or chemicals

inorganic fertilizer

contain only plant or animal-based materials that are naturally occurring processes

organic fertilizer

Is organic fertilizer or inorganic fertilizer most likely to runoff?

inorganic fertilizer

What are the pros and cons of inorganic fertilizer?

The pros are there is no increased H2O holding capacity and no soil decomposers. The cons are it contaminates groundwater for drinking and causes eutrophication of surface waters.

Shift from organic fertilizers (like manure and compost) to synthetic fertilizers (man made ammonium, nitrate, phosphate)

Synthetic Fertilizer

Increases yield and profits with more key nutrients needed for plant growth (N, P, K) added to the soil

positives of synthetic fertilizer

\-Excess nitrate, phosphate are washed off fields and into nearby waters where they cause eutrophication (algae blooms)

\-Require FFs for production, releasing CO2 (climate change)

negatives of synthetic fertilizer

Drawing water from the ground or nearby surface waters and distributing it on fields to increase plant growth

Irrigation

Make agriculture possible in many parts of the world that are naturally too dry (don’t receive enough rain)

positives of irrigation

\-Can deplete groundwater sources, especially aquifers

\-Over watering can drown roots (no O2 access) and cause soil salinization (increase salt level in soil)

negatives of irrigation

chemicals sprayed on crops that kill weeds, insects, rodents and other pests that eat or damage crops

Pesticides

Increases yield and profits with fewer plants lost to pests

positives of pesticides

\-Can wash off crops in runoff and kill or harm non-target species in local soil or waters (bees especially)

\-*Ex: DDT thinned shells of bird eggs, especially eagles*

*Atrazine turns amphibians and fish intersex*

negatives of pesticides

Growing one single species (corn, wheat, soy) of crop

Monocropping

Highly efficient for harvest, pesticide and fertilizer application

positives of monocropping

\-Greatly decreases biodiversity (more prone to pests, fewer nat. predators)

\-Increases soil erosion (crops harvested all at once & soil left bare)

\-Decreases habitat diversity for species living in the area

negatives of monocropping

Arrange the following foods in order of highest to lowest in terms of global production: corn (maize), rice, wheat

corn, wheat, rice

Mixing and breaking up soil to make planting easier

Tilling

\-Increases erosion by loosening topsoil, breaking up leftover root structure from harvest

\-Loss of organic matter & topsoil nutrients over time

\-Increased PM in air (rerp. irr) and sediments in nearby water (turbidity)

negatives of tilling

Cutting down vegetation and burning it to clear land for ag. & return nutrients in plants to soil

slash and burn

\-Deforestation

\-Loss of: habitat, biodiv, CO2 sequestration (storage), loss of air pollution filtration

\-Releases CO2, CO, N2O - all GHGs that lead to global warming

\-Increases PM in air (asthma)

\-Lowers albedo, making area warmer

negatives of slash and burn

water carries excess nutrients (nitrates & phosphates) into groundwater or into surface waters (as **runoff**)

Leaching

\-Contaminates groundwater for drinking

\-Causes eutrophication of surface waters

negatives of leaching

●Trench dug along crops & filled with water

●Easy & inexpensive; water seeps into soil slowly

●\~66% efficient, 33% lost to runoff & evap.

Furrow Irrigation

●Flood entire field; easier but more disruptive to plants

●Can waterlog the soil & drown plants

●80% efficient - 20% runoff/evap.

Flood Irrigation

●Most efficient, but also most costly

●Over 95% efficient

●Holes in hose allow water to slowly drip out

●Avoids waterlogging & conserves waters

Drip Irrigation

●Ground or surface water pumped into spray nozzles

●More efficient (less water loss) than flood or furrow

●More expensive (requires energy for pumps & movement of sprinklers

Spray Irrigation

Which irrigation system is most efficient?

drip irrigation because it avoids waterlogging and conserves water. However, it is the most expensive.

Which irrigation system is least efficient?

furrow irrigation because most of the water is lost to runoff or evaporation. It is the easiest and most inexpensive though. 

Overwatering can saturate the soil, filling all soil pore space with water

Waterlogging

●Doesn’t allow air into pores, so roots can’t take in O2 they need

●Can stunt growth or kill crops

consequences of waterlogging

What is the solution to waterlogging?

drip irrigation, or soil aeration - poking holes or cores in soil to allow air in & water to drain through soil

poking holes or cores in soil to allow air in & water to drain through soil

soil aeration

the process of salt building up in a soil over time

salinization

How does salinization occur?

when water evaporates and salt is left behind in soil.

__________ used for irrigation naturally has small amounts of salt

Groundwater

Water evaporates, and salt is left behind in soil. Over time, it can reach toxic levels, dehydrating plant roots & preventing growth

negatives of soil salinization

What is the solution to soil salinization?

drip irrigation, soil aeration, flushing with fresh water, switch to freshwater source

power plants, metal/plastic manufacturing

Industrial

households (toilet, shower, drinking water)

Municipal

water for livestock, irrigation water for crops

Agriculture

H2O stored in pore space of permeable rock & sediment layers

Groundwater

an underground water system made of porous rock and sand.

Aquifer

Where is the Ogallala aquifer located? What is this aquifer primarily used for?

located in Texas. It’s used for irrigated agriculture.

How do impervious surfaces impact aquifers?

Impervious surfaces increase stormwater runoff and reduce groundwater recharge.

________ useable groundwater deposits for humans

Aquifers

rain water percolating down through soil into aquifer

groundwater recharge

________ aquifers recharge quickly

Unconfined

________ aquifers recharge are longer-term water deposits that recharge more slowly

Confined

excessive pumping near coast lowers water table pressure, allowing saltwater to seep into groundwater

Saltwater Intrusion

forms when water table is lowered by excessive pumping, depleting water & drying nearby wells

Cone of depression

kill rodents

Rodenticides

kill fungi

Fungicides

kill insects

Insecticides

kill plants

Herbicides

cycle of pesticide development, followed by pest resistance, followed by new pesticide development.

pesticide treadmill

Why did Rachel Carson write Silent Spring?

to raise people’s awareness of the harmful effects of the pesticide DDT.

Pesticides can cause pests to become **_______** to pesticide with overuse

resistant

improves productivity, protection of crop losses/yield reduction

advantages of chemical pesticide usage

contaminates soil, toxic to many organisms

disadvantages of chemical pesticide usage

What gives some pests resistant traits to pesticide?

genetic biodiversity

Gene for pest resistant trait is added to the plant through genetic modification

GMOs (Genetic Modification)

faster growth and fewer pesticides

advantages of gmo use

Roundup Ready crops have ________ herbicide (glyphosate) use since crops can’t be harmed by it

increased

Bt corn has __**_______**__ insecticide use, since corn makes its own insecticide (Bt crystals)

decreased

Is there genetic diversity in GM crops?

no, they’re all genetically identical

Also called feedlots - densely crowded method where animals are fed grain (corn) to raise them to as quickly as possible

CAFOs

\+Maximizes land use and profit (most meat production per/unit of area)

\+Minimizes cost of meat for consumers

positives of CAFOs

\-Given antibiotics & growth hormones to prevent disease outbreak & speed meat production

\-Animals produce large volume of waste which can contaminate nearby surface or groundwater

\-Produces large amounts of CO2, CH4 (methane), and N2O (greenhouse gasses → climate change)

negatives of CAFOs

Large, open storage pits for animal waste (manure)

Manure Lagoons