Unit 5: Land and Water Use

Notes

Agriculture

• Urbanization and industrialization: machines ready to work land and harvest crops → farms = factories

• Incr amount of fossil fuels, new pesticides/fertilizers, expanded irrigation, dev of new high-yield seed types

• Decr genetic variability of crop plants; huge problems in erosion

• As cost of fuel rises, cost of food rises

• Traditional subsistence ag: each family grew crops for themselves; families primarily relied on animal and human labor to plant and harvest crops (provides enough food for one family’s survival)

• Still practiced in dev countries

Slash and burn

• Area of vegetation is cut down and burned before being planted with crops

• Because soils in edv countries are generally poor, farmer has to leave area after a relatively short time and find another location to clear

• Severely decr amount of available forest → contributes to deforestation

Fertilizers and pesticides

• If chem fertilizers were suddenly no longer used, total output of food in the world would drop about 40%

• Bad

• reduction of organic matter and O2 in the soil

• Large amounts of energy to produce, transport, and supply

• Washed into watersheds as dangerous pollutants

• FIFRA

• [1947] Federal Insecticide, Fungicide, and Rodenticide Act

• Requires EPA to approve the use of all pesticides in the US

Irrigation

• Repeated irrigation leads to salinization: sig buildup of salts on soil’s surface → land unusable for crops

• Mitigate: flood fields w massive amounts of water tomvoet he salt deeper into the soil

• DA: waterlogs plants roots which kill crops, causes water table of region to rise

Integrated pest management

• introducing natural insect predators

• Intercropping

• Using mulch to control weeds

• Diversifying crops

• Crop rotation

• Releasing pheromone or hormone interrupters

• Traps, barriers

Genetically engineered plants

• Add genes from one species to another to encourage desirable characteristics (ex. golden rice)

• Discourage biodiversity → harm beneficial insects and organisms

• Pose new allergen risks, incr antibiotic resistance, could cause new pesticide resistant pests

• Cross pollination can contaminate other crops

Monoculture

• Least amount of plants monopolizing the foods we eat

• Plantation farming: monoculture cash crop exported to dev nations

Soil degradation

• Contour plowing: rows of crops plowed across hillside, preventsoersion that can occur when rows are cut up and down on a slope

• Terracing: flat platforms that are cut into the hillside to provide a level planting surface → decr soil runoff and erosion on slope

• No-till methods: plant seeds without using a plow to turn the soil

• Crop rotation: provides soils with nutrients

• Animals an be rotated from site to site to solve overgrazing

• Intercropping (strip cropping): planting bands of diff crops across a hillside; prevent erosion by creating an extensive network of roots (plant roots holds the soil in place and decr soil erosion)

Meat production

• CAFO: lots of meat or dairy animals confined in small areas

• benefits: minimizes land costs, improves feeding efficiency, incr energy that goes into meat

• disads: bacteria, disease, water disposal, decr nutrient content qual of animal feed, ethical concerns

Urban runoff

• water from rain and snow that collects on man made surfaces and is directed out of cities

• picks up pollutants like oil and trash and then are dumped into large bodies of water

• increase water infiltration, replace pavement and concrete with more permeable pavement materials (pavers with pore holes), plant trees and building structures taller

Forest resources

General notes

• Old growth forest: one that has never been cut; contain incredible bioD, highly evolved intricate niches for multitude of organisms; myriad habitats

• Second growth forests: cutting has occurred and a new younger forest has arisen naturally

• Plantation/tree farms: planted and managed tracts of trees that are harvested for commercial use

• Silviculture: management of forest plantations for the purpose of harvesting timber

• Clear-cutting: removal of all trees in an area (typically done in areas with fast growing trees)

• Selective cutting: removal of select trees in an area → leavers majority of habitat in place and has less of an MPX on the ecosys

• Difficult to remove these trees from the forest

• Uneven-aged management: trees that take longer to grow

• Shelter-wood cutting: mature trees cut over a period of time

• Agroforestry: trees and crops planted together

• Creates mutualistic symbiotic rela between trees and crops

• Trees create habitats for animals that prey upon the pests that harm crops → roots stabilize and enrich soil

• Good: maintains habitat/bioD; releases O2; stores carbon; slows gw; absorbs air pollutants; reg local temps and maintains micro/regional climates; reduces erosion- preserves soil quality; maintains nutrient cycles

Deforestation

• Removal of trees for ag or exportation purposes

• Industrialized countries: high demand for weed, less deforestation

• Developing countries: small demand for wood, more deforestation

• converting forests into ag/ranch land

• using trees/charcoal for fuel/source of income

• protecting forests through regs is less common

• harvesting timber for use as building materials

• using forested land for commercial purposes by corporations or industrialized countries

• clearing forested land to accommodate growing rural pops (ex. roads, homes, schools)

• Already poor soil is further degraded and can only support crops for a short time

• Loss in biodiversity, erosion, depletion of nutrients in the soil

• Decrease deforestation

• enforce laws or regs that restrict cutting of trees

• encourage sustainable ag/forestry programs

• intro more efficient cooking methods that reduce use of wood as fuel source

• est programs to promote alt building materials that decr demand for wood

• dev econ programs to incr individual incomes/decr reliance on forest conversion

• reduce pop growth resulting in less demand for wod for fuel and income

• promote ecotourism to protect natural areas and discourage tree harvesting

• Water quality and deforestation

Forest policy

• USFG owns 35% of all land in the US

• [1916] national park sys: manage and preserve forests and grasslands

• Wilderness preservation areas: open only for recreational activities with no logging permitted

• National forest system, natural resource lands, national wildlife refuges → federally controlled lands that allow logging with a permit

• Greenbelts: open or forested areas built at the outer edge of a city

• No one is permitted to build in them → incr QOL for ppl living nearby

• Borders cities, putting limits on city growth

• Add green spaces in urban areas when satellite towns are built outside the greenbelt and interconnected by highways and mass transpo methods

Natural events

• Tree diseases and existence of pests

• Mitigate by: removing infected trees; removing select trees/planting them sparsely to provide adequate spacing; use chemical and natural pest controls; carefully inspecting imported trees and tree products; developing pest/disease resistant species of trees thru genetic engineering

• Forest fires

• Surface fires: burn only forests’ underbrush; do little damage to mature trees; protects forest from more harmful fires by removing underbrush and dead materials that would burn quickly and at high temperature, escalating more severe fires

• Crown fires: start on ground or canopies of forests; spread quickly and are char by high temperatures bc they consume underbrush and dead material on the forest floor → huge threat to wildlife, human life, and property

• If there are fewer fires, the amount of fuel (dry leaves, needles, wood) builds up to high levels → when this large amount of fuel ignites, fires are much hotter and flames are larger

• SOLUTION: controlled burns (small fires)

Ocean resources

General notes

• Fishery: industry or occupation devoted to catching, processing, or selling of fish, shellfish, or other aquatic animals

• 1 bil ppl depend on fish as their main source of food // 1 mil ppl employed in the fishing industry

Overfishing

• Capture fisheries: caught in the wild and not raised in captivity for consumption

• By-catch: any other species of fish, mammals, or birds that are caught that are not the target fish

• Driftnets: float through the water and indiscriminately catch everything in their path

• Long lining: use of long lines that have baited hooks and will take in numerous aquatic organisms

• Bottom trawling: ocean floor scraped by heavy nets that smash everything in their path (incl whole marine mountains known as seamounts)

• SOLUTION: restrictions on the use of drignets; installation of ribbons on bait hooks that scare away birds and prevent them from being caught; bans on bottom trawling

• Aquaculture (fish farming)

• Raising of fish and other aquatic species in captivity for harvest

• Fish raised in captivity are those with the highest economic value

• Helps to meet worldwide demands for fish but its not able to solve for all fishery problems

• CONCERN: accidental release of farmed fish into the wild?

• Potential to introduce new diseases to ocean fish and contaminate the native gene pool

• Ex. carp release from fish farming causing issues in Mississippi River and Great lakes

• CONCERN: fish raised in captivity are fed captured wild fish → we want to kill fewer wild fish

• Killing of whales

• Norway consumes whales; Japan captures whales for scientific use

• However, JAP has been eating the whales it catches bc they think that whales eat too many fish that could instead be caught by humans

• Tourism

• Whale watching tours disrupt whale migration patterns and cause whales stress

Threatened aquatic ecosystems

• Coral reefs

• Structures found in warm, shallow tropical water (diverse and ecologically crucial ecosystems)

• Created by small marine animals called cnidarians → mutualistic relationship with photosynthetic algae called zooxanthellae

• Provide local pop with great variety of seafood; important rec areas for humans

• Coral bleaching: higher than usual water temperature cause the death of zooxanthellae = death of coral reef

• Some bleaching is normal, but high water temperatures can be caused by weather fluctuations such as El Niño

• Mangrove swamp

• Coastal wetlands found in tropical and subtropical regions (trees, shrubs, other plants that can grow in brackish tidal waters; often located in estuaries)

• Huge diversity of animals bc estuarine swamps are constantly replenished with nutrients transported by freshwater runoff from the land

• Support: bacteria, other decomposers, filter feeders → worms, protozoa, barnacles, oysters, invertebrates → shrimp and fish → wading birds, pelicans, crocodile

• Nurseries for shrimp and recreational fisheries; exporters of organic matter to adjacent coastal food chains; enormous sources of valuable nutrients

• Prevent shoreline erosion → shields inland areas from severe damage during hurricanes and tidal waves

• Threatened by shrimp aquaculture and degradation of Western coastlines

Legislation

Water importance

General notes

• Industries: fisheries, recreation, transp, ag, etc

• Biggest water users

• 73% agriculture

• 21% industry

• 6% domestic use

• Since the 1950s, global water use has tripled bc of population growth and improvements in the global standard of living

• Groundwater: water from below the ground (wells or aquifers)

• Aquifers: underground beds or layers of earth, gravel, porous stone that yields water

• Unconfined aquifers: water is free to flow both vertically and horizontally

• Confined aquifers: boundaries that don’t readily transport water

• Water-stressed countries: have a renewable annual water supply of about 1000-2000 m3 per person

• Water-scarce countries: have a renewable annual water supply of less than 1000 m3 per person

• Developing countries that have rapidly increasing populations = water scarcity problems will grow over time

• Ex. algeria, egypt, libya, kenya, rwanda, tunisia, israel, jordan, kuwait, SA, syria, belgium, hungary, netherlands, singapore, barbadoes, malta, lebanon, morocco, niger, somalia, S AFR, sudan

Env MPX

• Groundwater reliance

• Depressed water table

• Drying up of local groundwater sources

• Subsidence/sinking

• Ex. [late 1990s] drought in FL resulted in severe reduction in aquifers → roads collapsed bc of a lack of struc support

• Aquifers become compacted → mineral grains collapse on each other and the area is unable to hold as much water

• Urbanization: groundwater incapable of being replenished bc they build structures and roads impermeable to precipitation

• SOLUTION: Interbasin transfer

• Water is transported very long distances from its source (aqueducts or pipelines)

• Disadvantages

• Different geographic areas arguing over water rights

• Increase salinity of water

• Change climate of ecosystem

• SOLUTION: desalination

• Simple physical process, but not econ viable

• A lot of energy to remove salt through distillation or reverse osmosis

Water rights

• Riparian right: right of people who have legal rights to a riparian area (relating to the banks of a natural course of water)

• Prior appropriation: water rights given to those who have historically used water in a certain area (water squatters’ rights)

Mining

General notes

• Excavation of earth for the purpose of extracting ore or minerals

• Metallic minerals: mined for metals → extracted through smelting and used for various purposes

• Nonmetallic minerals: mined to be used in their natural state

• Mineral deposit: area in which a particular mineral is concentrated

• Ore: rock or mineral from which a valuable substance can be extracted at a profit

Env MPX

• Disrupts ecosys and scars land; leave pollutants

• Ex. Acid forms as water seeps through mines and carries off sulfur-containing compounds → chemical conversion of sulfur-bearing minerals occurs through a combo of biological and inorganic chemical reactions → buildup of extremely acidic compounds in the soil → acid mine drainage that can severely harm local stream ecosystems called GANGUE

• Tailings: piles of gangue

• Strip mining

• Strpiping the surface layer of soil and rock (overburden) in order to expose a seam of mineral ore

• Used when ore is relatively close to the surface → least expensive and least dangerous mining method

• Removes massive amount of topsoil - greater impact on surrounding environment than underground mining

• Ex. mountaintop removal trnadorsm summits of mountains and destroys ecosystems

• Refinement of mined minerals often requires extensive energy input

• Mined → transported to a power plant → burned in its original state

Regulations

• Air, land, and water harmed by mining can be reclaimed through mine restoration projects

• [1977] surface mining control and reclamation act (SMCRA): program to help coal mines manage pollutants