Unit 5: Land and Water Use

tragedy of the commons

individuals will use shared resources in their own interest rather than the common good

externalities

cost or benefits of a good or service that is not included in the purchase price

U.S. public lands

Federal government biggest landowner - 2.5% of country

Rangelands, national parks, national wildlife refuges, national forests, wilderness areas

multiple-use lands

may be used for recreation, grazing, timber, harvesting, and mineral extraction

ecosystem services provided by forests

\-habitat for species and us

\-timber from products

\-aids in soil formation/erosion control

\-food source

\-moderates local and global climate

\-removes air/water pollutants

\-hydrologic cycle/carbon cycle

clear cutting

removing all or almost all the trees in an area

benefits of clear-cutting

easiest, usually most economical

often stands are replanted

commercial timber operations

73% privately owned

allowed to harvest in exchange for a royalty that is a percentage by revenues

government spends more money on management than it receives in royalties (so logging is subsidized)

tree plantations

clear cut and quickly replanted with single fast-growing species

will never mature into diverse ecosystems; nutrient depletion from soil

selective cutting

removal of single trees or small amounts of trees

young seedlings grow next to established old growth trees

less erosion, loss of diversity, ets

industrial agriculture

mechanization and standardization applied to food production

energy subsidy

fossil fuel energy and human energy input per calorie of food produced

green revolution

shift to mechanization, fertilization, irrigation, pesticide use, and GMOs over last 100 years

monocropping

large plantings of single species or variety

artificial selection

humans cross breeding plants with desirable traits

GMOs

genetically altering an organism with desirable genes

arable land

land that is capable of producing crops

plow and till agriculture

turns soil upside down, push down crop residues, kills weeds and insects

increases erosion ~~by~~ loosening soil

increased evaporation

exposes organic matter to oxygen, increases CO2 in atmosphere from oxidation

leads to soil degradation with irrigation and over production

slash and burn farming (shifting agriculture)

cut down trees and vegetation, burn resulting ash provides nutrients to soil

nutrient-poor soil and warm climate

not sustainable

releases CO and CO2

leads to erosion, loss of topsoil to hold roots, positive feedback cycle

irrigation may lead to salinization, eventually leading to desertification

desertification

land is rendered completely unproductive

eutrophication

buildup of algae (from fertilizers)

intensive agriculture

loss of genetic diversity (lack of backup plan)

loss of specific soil nutrients completely - same plants year after year use same nutrients

increased use of fertilizer -> eutrophication

fertilizers

large amounts required to replace lost organic matter and nutrients

organic: mostly decomposed manure

synthetic/inorganic fertilizers

combustion of natural gas fixes and captures atmosphere nitrogen

methods of irrigation

furrow, flood, spray, drip

GMO

genetically modified organism

CAFO

concentrated animal feeding operations

free-range grazing

rangelands - dry, open grasslands used for the grazing of cattle

most common use of land in the U.S. (41%)

fishery

commercially harvestable population of fish within a particular ecological region

TED

turtle excluder device

types of surface mining

strip mining, open-pit mining, mountaintop removal, placer mining

strip mining

removal of strips of soil and rock to expose ore

open-pit mining

uses a large visible pit/hole

mountaintop removal

with explosives

placer mining

looking for minerals and metals in river sediments

subsurface mining

resource more than 100m below surface

urbanization

shift away from a lifestyle that is rural and based in agricultural jobs to non-agricultural jobs that bring settlement and high population density

urban sprawl

urbanized areas spread into rural areas, removing clear boundaries between the two

exurb

similar to suburb, but unconnected to a central city or densely populated area

suburb

an area surrounding a metropolitan center, with a comparatively low population density

urban blight

degradation of built and social environments of the city that often accompanies and accelerates migration to the suburbs

gentrification

higher-income families and corporations "restore" urban areas, but often at the expense of family-owned businesses, low-income housing, and social welfare institutions

consequences of urban sprawl

increase fossil fuel use

2x more land use per person than in cities

replaces farmland, increases distance to farms