SS

Unit 5 - Land & Water Use

5.1 Tragedy of the Commons

  • individuals will use shared resources in their own self-interest rather than maintaining the public good β†’ %%resource depletion%%
    • used by everyone, regulated by no one
    • no presence of sustainability
    • can be caused by ==overuse or degradation== of the resource
    • ex. ocean, seafood, air pollution, etc.
    • resolved by r%%egulations & replenish%% resources after use
    • ex. fishing licenses, land use permits, careful cutting of trees, country quotas, rebuilding trees, etc.
    • ensure %%compliance%% with laws through oversight (done by government agencies, fines, incentives, debt forgiveness, etc.)
    • can also be resolved by %%privatization%% (ie. owning land and regulating use on its own)

5.2 Clearcutting

  • forests provide many ecological services
    • forests β†’ %%water sink%% (holds water in tree trunks)
    • improves @@air quality@@ by exchanging CO2 β†’ O2 during photosynthesis
    • improves @@water quality@@
    • reduces water runoff by going into the topsoil and into groundwater reservoirs
    • carbon sink (bring in Co2 and store it in tree structures; organic matter enters topsoil)
    • %%economic significance%%: timber (trees before being cut down) β†’ lumber (trees after being cut down), livestock, tourism, high property values, potential minerals for medicine and other uses
  • ^^clearcutting^^: cutting all trees in a forest
    • causes loss in biodiversity, aesthetics, food sources, materials, etc.
    • ==ingress== β†’ invasive species that couldn’t previously attack habitat
    • ==engress== β†’ organisms w various diseases & viruses emerging as a result of habitat loss
    • carbon cycle β†’ decreased soil carbon on topsoil due to less organic matter falling from trees
    • topsoil blowing away & mudslides due to greater amounts of water entering the groundβ†’ soil erosions
    • decreased albedo β†’ desertification
    • decreased photosynthesis & increased decomposition, combustion, burning of fossil fuels β†’ more CO2 in the air β†’ climate change
    • decreased transpiration β†’ climate change
    • soil erosion β†’ decreased infiltration to groundwater β†’ less water in aquatic bodies/more runoff in aquatic bodies
    • increase in turbidity β†’ decrease in primary productivity & albedo (heat up); increase nutrients β†’ decreased O2 levels; algal booms
    • loss of biodiversity/habitat

5.3 The Green Revolution

  • small laborious farms β†’ large industrialized highly productive farms (1960s) to maximize crop yield
    • mechanization β†’ always ready, specialized/updated, easy to use, high efficiency/profits; causes combustion and reliance upon fossil fuels (CO2 buildup in the atmosphere, soil erosion, interruption of biogeochemical cycles)
    • monocultures β†’ easy to plant harvest and maintain, specialized pests (easy to eradicate); loss of habitat/biodiversity/ancestral varieties, increased risk of catastrophe (vulnerable to fungal and insect attacks)
    • artificial fertilizers/pesticides β†’ max yield, mass production, can fit any plant, easy use, no smell; easily dissolve in the runoff, disruption in nitrogen cycle (atmosphere to pesticide), negative health effects, contamination of groundwater, antiresistant pests
    • Haber-Bosch process: N2 + 3H2 β†’ 2NH3
    • irrigation β†’ scaleable, maximizing yield to potential; freshwater depletion, waterlogging & salinization
  • GMOs: genetically modified organisms
    • artificial selection: evolution controlled by humans to yield beneficial and preferable traits based on genetic material β†’ creation of GMOs (taking advantage of the genetic material of normally incompatible species, creating new traits)
    • ex. self-producing pesticide
    • creates crops on deserted land (drought, heat, salt tolerant conditions)
    • crops can be herbicide resistant
    • can be modified to fit habitat conditions
    • self-producing insecticide β†’ reducing artificial insecticide
    • cons: low nutrient soil from unfavorable lands, herbicide-resistant, bt crops can kill nontarget crops β†’ insecticide-resistant pests, economic/ethical/moral issues
    • loss of genetic diversity due to monoculture
    • loss of biodiversity as a result of killing nontarget species

5.4 Impacts of Agricultural Practices

  • arable: usable for crop growth
  • tilling: preparing soil for crops
    • bare soil β†’ soil erosion, increased evaporation of soil moisture β†’ need for fertilizer
    • changes soil structure & composition
    • sequestration of CO2 released into the atmosphere
    • use of mechanization β†’ fossil fuel use, emissions (contributing to climate change), and soil change
    • eutrophication β†’ runoff of nutrients and pollution in the soil to aquatic bodies
  • slash-and-burn agriculture: used in many developing countries for low-nutrient soil
    • consists of cutting trees and burning them, using the ashes to grow better trees
    • unsustainable β†’ quick use of nutrients, CO2 in the air from combustion
  • intensive agriculture: overuse of natural resources, pollution, loss of ancestral crop varieties
  • synthetic fertilizer: a form of nitrogen ammonia (phosphorus + potassium)
    • can cause runoff
    • overused
    • doesn’t improve soil structure
  • organic fertilizer: horse manure, anything natural that can stimulate crop growth
    • easy to transport, timed release, can be adjusted for further use, can be worked into the soil, digested vegetation = better soil structure
    • must be gathered
    • nutrient levels unknown
    • harder to use
  • pesticide overuse: max crop yield, hurts human health and causes resistance from weeds, kills nontarget species

5.5 Irrigation Methods

  • 70% freshwater β†’ irrigation use
  • %%flood irrigation%%: diverting water from a lake or river to the field
    • no mechanization, inexpensive, easily used in developing countries
    • needs nearby water, not for all plant types, tilled land, @@20% water lost to evaporation@@
  • %%furrow irrigation%%: building trenches near crops to divert water into
    • low mechanization, high sediment water usable, some control over precision
    • not efficient in sandy soil, difficult to apply in small amounts, @@33% water lost to evaporation (least efficient)@@, prone to soil erosion
  • more mechanized methods β†’ more prevalent in developed countries
  • spray irrigation: lines of pumps are used to spray out water onto crops
    • LEPA: low emission precision application
    • allows for nutrient supplements to be sprayed into the water, => 25% of water lost to evaporation (efficient), easy to program
    • costly compared to nonmechanized irrigation methods, uses fossil fuel/electricity for machinery, issues with nozzle (requires low to no sediment), can create ruts in soil β†’ prone to soil erosion
  • drip irrigation: water is directly given to roots through micropores in underground pumps
    • low evaporation rate at 5% (most efficient), reduces nutrient loss (goes directly to roots), no land modification needed
    • very expensive, require extensive mechanization, difficult to move, clogs easily
  • waterlogging: air pockets in soil are completely filled with water β†’ deprivation of cellular respiration β†’ plant death
  • salinization: salt buildup on soil caused by traces of freshwater entering soil and being evaporated over time
    • inhibits plant growth β†’ causing sandy deserted area
    • solutions: flushing out water from soil, making plants salt-tolerant
  • aquifers: infiltrated water is being used at a faster rate than replenishment β†’ overuse
    • ogallala aquifer: largest aquifer for crops in the united states
    • spans from nebraska to texas
    • pressure from freshwater pushes away saltwater from other bodies in coastal aquifers

5.6 Pest Control Methods

  • pesticide treadmill: pests become resistant to a pesticide caused by genetic mutations & overuse β†’ more pesticide is needed to have the same effect on pests over time (or a stronger type of pesticide)
  • pesticide runoff β†’ directly kills organisms/crops in its path unintentionally
    • contaminates groundwater supply, evaporation to other areas
    • becomes toxic in large amounts
  • biomagnification: storing pesticide in low trophic organisms in apex predators

5.7 Meat Production Methods

  • meat production: raising of livestock for human consumption
  • overconsumption of meat: prevalent in developed countries
    • extensive land use for grazing β†’ 25% of the earth’s land is used for grazing
    • lots of animal waste that is displaced (ex. cow waste β†’ methane β†’ greenhouse gas in the atmosphere)
    • high in nitrates & phosphates β†’ causing runoff
    • carries dangerous viruses and diseases for humans through fecal coliforms
    • more work to have the same amount of calories (10 percent trophic rule)
    • antibiotics/hormones β†’ makes prone for bacteria resistant animals
    • soil compaction, erosion, damage, etc. β†’ desertion & change to soil composition
    • reduces CO2, methane, and N2O emissions
    • water conservation β†’ improves topsoil
  • free-range grazing: allowing livestock to be raised in natural habitat (natural diet)
    • eating vegetation, insects, other organisms, etc.
    • no need for preventative antibiotics
    • requires more land per unit of livestock (inefficient)
    • must coexist with other organisms within an environment
    • fewer heads of cow to control for production
    • longer growth times
    • prone to overgrazing β†’ soil erosion & desertification β†’ loss of biodiversity

concentrated animal feeding operation (CAFO): feedlots; raising any type of livestock for human consumption

  • mass grazing of animals to meet economic standards
  • easy to clean, maintain, efficient, and large
  • usually fed grain to meet high caloric standards β†’ makes meat less expensive for consumers (little labor to raise)
  • crowded β†’ creates mass waste β†’ decrease of O2 levels in water that waste infiltrates
  • fecal coliforms can carry various diseases and health risks for humans in the water
  • extensive use of antibiotics and growth hormone use

5.8 Impacts of Overfishing

  • commercial: large-scale fishing (fishing in mass quantities)
    • left unregulated β†’ endangerment of species β†’ extinction of species
  • long-line: a long line of rope w hooks held by buoys to catch fish w bait
    • can be up to 28 miles long at any depth (pelagic: above the surface)
    • very efficient β†’ can catch much fish at once
    • prone to overfishing and capturing bycatch species
  • drift/gill net: a long net that catches fish gills
    • also prone to capturing bycatch species
    • have to untangle fish from the net to gain catch
    • very long, can be placed at any depth
  • purse seine: net with drawstrings (6.5k ft long & 650 ft deep)
    • catches lots of fish at once (many schools of fish)
    • can be tailored to species of any size
  • trawling: cone-shaped net dragged across the bottom
    • destructive to underwater benthic ecosystems
  • sonar: strategic use of technology to see the seafloor to locate fish
    • reduces fuel and carbon emissions; very profitable
    • interferes with natural navigation systems (ie. dolphins)
    • prone to overfishing
  • tragedy of commons within the fishing industry β†’ extinction of fish species and companies going out of business due to competition
  • bycatch: nontarget species caught in fishing nets
    • usually do not survive being caught, or tossed back into the water despite not being alive β†’ prone to extinction due to unregulated fishing practices
  • sustainable fishing: saving fish for future generations and allowing for replenishment of fish every cycle
    • uses catch limits of max sustainable yield
    • limit age/size of fish caught to minimize the amount of fish able to reproduce
    • law/treaties that protect overfished species (gov regulations)
    • ex. the convention on international trade in endangered species of wild flora and fauna (CITES) β†’ places halts on fishing species that are endangered
    • giving fines or denying trade with countries that breaks the regulation (consequences) OR subsidizing fishing operations for maintaining within MSY (incentivize)
    • modify fishing techniques to minimize bycatch
    • ex. turtle exclusion device (TED) (inserted in trawling nets with a net that allows turtles to exit from the lower large end of the net)

5.9 Impacts of Mining

  • mining: obtaining materials from the ground
  • ex. gold, diamonds, phosphorous rock, gravel, coal
  • ore: materials that are just mined
    • contains many impurities
  • refining: removing impurities from a substance
  • surface mining: mining materials starting from the ground down
  • strip mining: harvesting material in strips
    • requires a lot of equipment β†’ increase in pollution and fossil fuels
  • mountaintop removal: dig away from the top of the mountain to obtain materials (mainly coal)
  • target material: material after impurities are removed
  • tailings: impurities removed from the ore
  • overburden: soil on top of the ore
    • becomes spoil after soil is removed from on top of ore
  • cyanide heap leaching: adding cyanide to a pile of ore to remove impurities
  • prone to soil erosion β†’ desertification in areas where surface/subsurface mining takes place
  • invasive species to penetrate the Earth
  • more use of fossil fuels to operate mining equipment
  • soil runoff into bodies of water β†’ decreased oxygen levels
  • acid mining drainage: acid water in old mines collected underground sulfuric metals over time β†’ lower pH, more acid in water
  • remediation: to fix things back to what they were before
    • allow land to serve a new purpose

5.10 Impacts of Urbanization

  • urbanization: shifting from an agricultural lifestyle to a lifestyle with a large population density
    • gone through the demographic transition (stages 2-3)
  • mass transit: large populations of people traveling
    • lowers the amount of fossil fuels per person, very efficient, lowers emissions
  • more access to a variety of resources, minimizes land impact, and walkable
  • cities can be small though (ie. NYC)
    • negatively impacts the water cycle β†’ disrupts the path of water flow through dams (increasing water for humans)
    • upstream: flooding, runoff
    • downstream: lowering the amount of water for organisms living in that area
    • saltwater intrusion for coastal aquifers near the ocean as a result of depleting water from the reserve
    • impermeable surfaces: water is unable to penetrate through them β†’ decreased chance of replenishing groundwater reserves & increased runoff (in the remaining runoff many impurities are present β†’ health issues for humans)
    • carbon cycle: increased CO2 being spread to the atmosphere as a result of waste and fuel emissions β†’ climate change (global warming)
    • increases air pollution from fuel emissions in factories and machinery
    • heat island effect: low albedo (absorb more sun) β†’ higher temperatures
  • remediation to urbanization: adding more vegetation β†’ helps with runoff, replenishing groundwater, increasing albedo, increased CO2 intake into plants away from the atmosphere
    • extending mass transit systems in suburban areas
    • inventing permeable pavement
    • repurposing brownfields (abandoned areas)

5.11 Ecological Footprints

  • a measure of how much land is used to meet one’s needs (hectares/land required)
    • carbon footprint: the amount of energy used (transportation, electricity, etc)
    • built-up land: type of shelter living in (how big?)
    • forests: how much of the forest do you use? (paper, shelter, etc.)
    • cropland & pasture: food & nutrients
    • fisheries: also for food (seafood)
  • LDC β†’ lower ecological footprints
  • MDC β†’ higher ecological footprints
  • demographic transition β†’ higher ecological footprints
  • lower ecological footprint β†’ more environmentally friendly

5.12 Introduction to Sustainability

  • the ability to use and maintain a resource for the future
    • use = replenishment or input = output β†’ sustainable
    • use < replenishment or input > output β†’ wasteful
    • use > replenishment or input < output β†’ unsustainable
  • biological diveristy: healthier ecosystems strong to change/invasion β†’ preserve nature
  • food production: poor practices lead to soil degradation and water pollution β†’ sustainable food practices
  • global surface temperature/co2 concentrations: excess CO2 β†’ increase in temperature & climate change β†’ decrease energy use
  • human population: population growth stresses planet capacity β†’ demographic transition
  • resource depletion: how fast does a resource get used up (how much do we have of that resource before it runs out) β†’ three Rs (reduce, reuse, recycle)
  • sustainable yield: the max amount of resource that can be taken w/o reducing the availiable supply (50% of carrying capacity)
    • must be below the rate of replenishment of that resource
    • underuse: using <MSY of resource (<50%)
    • overuse: using >MSY of resource (>50%)
    • population grows fastest with it at 50% carrying capacity
    • research/planning β†’ reproductive abilities of a resource
    • setting quotas/limits
    • requiring permits
    • focus on long-term benefits
    • reforest (replace harvested trees)

5.13 Methods to Reduce Urban Runoff

  • water pollution β†’ collecting sediment and matter in runoff
  • the inability to recharge groundwater reserves β†’ water not percolating into the ground
    • solution for water infiltration: permeable pavement, planting trees, decreasing paved areas by using land efficiently, making land more permeable through small city design, public transportation

5.14 Integrated Pest Management

  • combination of pest control methods that are meant to minimize environmental disruption and reduce pest species
    • biological: natural pest predators
    • ex. ladybugs, farm cat/dog, parasitic wasps, praying mantis, bacteria/fungi
    • physical: crop barriers
    • ex. traps, tilling, screens, weed blockers, fences
    • chemical: pesticides (poisons)
    • causes harm to the environment
    • affects nontarget species
    • increases water pollution
    • brings risks to human health
    • ex. DDT, atrazine, glyphosate
  • crop rotation: changing the crop being planted in a field each time
    • ex. corn one year, soy next year
  • intercropping: planting two different crops on the same field
    • ex. allows all pests to be naturally against competitive β†’ minimizes damage from pests
  • benefits: decreases chemical pesticide use, economic savings, sustainable, targeted, minimize health risk and loss
  • drawbacks: complex, slow, expensive

5.15 Sustainable Agriculture

  • preventing soil erosion β†’ sustainable food practices
    • contour plowing: maintain the shape of a mountain or hill by plowing on the slope (contour)
    • allows water to slide down the hill/mountain to crops β†’ preserving soil
    • windbreaks: adding trees/breaks near crops
    • slows down wind speed to allow soil to be blown away
    • strip cropping: planting multiple types of crops, harvesting each type at differnet times
    • roots that hold soil together reduce erosion from wind/water
    • terracing: plowing steps in mountain
    • decreases velocity of water β†’ reducing soil erosion
    • no till agriculture: no plowing at all
    • leaves soil; keeps it natural
    • perennial crops: harvesting crops year round
    • roots are intact β†’ do not loosen up soil when harvested
  • maintaing soil fertility β†’ sustainable food production
    • crop rotation: changing the type of crops being planted on a field at a fixed interval
    • replenishes soil of natural nutrients
    • green manure: covers soil and decomposes in soil, providing nutrients for soil
    • limestone: increases pH (alkaline) & calcium β†’ favorable for many types of crops
  • overgrazing: overuse of pasture leading to plant damage
    • using it up faster than it can be replenished β†’ soil erosion and plant damage
    • rotational grazing: cycling livestock around different parts of pasture to not overgraze the whole area
    • dividing up pasture land to preserve other parts and give time for grazed land to replenish itself

5.16 Aquaculture

  • farming of seafood and aquatic plants by individual/corporation for business
    • can occur in marine/freshwater environments
    • china worldwide leader in aquaculture production
  • pros: highly efficient, less costs economically
    • allows meeting increasing protein source demands
    • compensates for decreasing wildfish harvests
    • opens more jobs and stable income for fisherfolk
    • less time-consuming and resource-consuming, less dangerous (more efficient, fewer cons)
    • less fossil fuel inputs
  • cons: arise from a large population in small space
    • organism waste β†’ water pollution with excess nitrogen β†’ algal bloom/hypoxia
    • uneaten food pellets β†’ water pollution
    • risk of escape β†’ interbreed or compete with wild organisms
    • diseases/infections spread more easily β†’ increased use of antibiotics β†’ water pollution & spread to wild organisms

5.17 Sustainable Forestry

  • forests are essential for many ecosystem services
    • ex. food, fuel, co2, air, water, recreation, aesthetics, etc.
  • collection of methods that attempt to mitigate the human impact of harvesting trees using forest resources
    • mitigating deforestation: reforestation, consumption from providers that use sustainable forestry practices, and the 3Rs of wood products
    • preserves biodiversity and ecosystem services
    • supporting companies that use sustainable practices
    • reduces the need to cut new timber
  • mitigating pathogens: affects ecosystem health
    • IPM β†’ minimizing infestations sustainably
    • ex. routine checks, underbrush thinning, common pest awareness, pest threshold, removing pests, using natural predators, chemical control (last resort), selective removal of diseased trees
    • reduce the impact of pesticide
    • reduced chance of disrupting the trophic structure
  • prescribed burns β†’ removes excess understory plants and dead matter
    • reduces forest fire severity by reducing dry matter
    • encourages new growth