AP Environmental Science Unit 5 Cheatsheet: Land and Water Use

Tragedy of the Commons: Individuals use shared resources in self-interest rather than for common good, leading to depletion.

Key concept: Personal gain vs. collective sustainability—the core tension in resource management.

Examples on test: Overfishing, aquifer depletion (Ogallala), overgrazing, deforestation.

Question strategy: When asked why a shared resource is depleted, identify the incentive for individual users to extract more than sustainable yield allows.

Effects of urbanization:

• Resource depletion (freshwater, minerals)
• Saltwater intrusion in hydrologic cycle
• Increased CO₂ (fossil fuel burning, landfills)
• Impervious surfaces (roads, buildings, parking lots) prevent water infiltration → flooding
• Urban sprawl: shift from high-density to low-density suburbs → habitat loss, resource strain

Mitigation methods:

• Permeable pavement (replaces traditional pavement)
• Tree planting (increases infiltration)
• Public transportation (reduces emissions)
• Build up, not out (reduces sprawl)

Sustainability: Human use of resources without depletion for future generations.

Sustainable yield: Amount of renewable resource that can be taken without reducing supply.

Environmental indicators: Biological diversity, food production, global surface temperature, CO₂ concentration, human population, resource depletion.

Ecological footprint: Compares resource demands and waste production per individual or society.

Soil conservation methods: Contour plowing, windbreaks, perennial crops, terracing, no-till agriculture, strip cropping.

Soil fertility improvement: Crop rotation, green manure, limestone addition.

Sustainable forestry: Reforestation, ecologically sustainable harvesting, wood reuse, IPM for pathogens/insects, prescribed burns (controlled fire to reduce natural fire risk).

Aquaculture: Efficient, small water area, low fuel. Drawbacks: wastewater contamination, escaped fish compete/breed with wild populations, disease transmission to wild fish.