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 → %%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 → %%water sink%% (holds water in tree trunks)
  • improves @@air quality@@ by exchanging CO2 → 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) → 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== → invasive species that couldn’t previously attack habitat
  • ==engress== → organisms w various diseases & viruses emerging as a result of habitat loss
  • carbon cycle → 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 ground→ soil erosions
  • decreased albedo → desertification
  • decreased photosynthesis & increased decomposition, combustion, burning of fossil fuels → more CO2 in the air → climate change
  • decreased transpiration → climate change
  • soil erosion → decreased infiltration to groundwater → less water in aquatic bodies/more runoff in aquatic bodies
  • increase in turbidity → decrease in primary productivity & albedo (heat up); increase nutrients → decreased O2 levels; algal booms
  • loss of biodiversity/habitat

5.3 The Green Revolution

• small laborious farms → large industrialized highly productive farms (1960s) to maximize crop yield
  • mechanization → 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 → 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 → 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 → 2NH3
  • irrigation → 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 → 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 → reducing artificial insecticide
  • cons: low nutrient soil from unfavorable lands, herbicide-resistant, bt crops can kill nontarget crops → 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 → soil erosion, increased evaporation of soil moisture → need for fertilizer
  • changes soil structure & composition
  • sequestration of CO2 released into the atmosphere
  • use of mechanization → fossil fuel use, emissions (contributing to climate change), and soil change
  • eutrophication → 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 → 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 → 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 → 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 → 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 → deprivation of cellular respiration → plant death
• salinization: salt buildup on soil caused by traces of freshwater entering soil and being evaporated over time
  • inhibits plant growth → 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 → 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 → more pesticide is needed to have the same effect on pests over time (or a stronger type of pesticide)
• pesticide runoff → 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 → 25% of the earth’s land is used for grazing
  • lots of animal waste that is displaced (ex. cow waste → methane → greenhouse gas in the atmosphere)
  • high in nitrates & phosphates → 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 → makes prone for bacteria resistant animals
  • soil compaction, erosion, damage, etc. → desertion & change to soil composition
  • reduces CO2, methane, and N2O emissions
  • water conservation → 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 → soil erosion & desertification → 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 → makes meat less expensive for consumers (little labor to raise)
• crowded → creates mass waste → 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 → endangerment of species → 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 → 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 → 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 → 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) → 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 → 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 → 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 → decreased oxygen levels
• acid mining drainage: acid water in old mines collected underground sulfuric metals over time → 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 → 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 → decreased chance of replenishing groundwater reserves & increased runoff (in the remaining runoff many impurities are present → health issues for humans)
  • carbon cycle: increased CO2 being spread to the atmosphere as a result of waste and fuel emissions → climate change (global warming)
  • increases air pollution from fuel emissions in factories and machinery
  • heat island effect: low albedo (absorb more sun) → higher temperatures
• remediation to urbanization: adding more vegetation → 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 → lower ecological footprints
• MDC → higher ecological footprints
• demographic transition → higher ecological footprints
• lower ecological footprint → more environmentally friendly

5.12 Introduction to Sustainability

• the ability to use and maintain a resource for the future
  • use = replenishment or input = output → sustainable
  • use < replenishment or input > output → wasteful
  • use > replenishment or input < output → unsustainable
• biological diveristy: healthier ecosystems strong to change/invasion → preserve nature
• food production: poor practices lead to soil degradation and water pollution → sustainable food practices
• global surface temperature/co2 concentrations: excess CO2 → increase in temperature & climate change → decrease energy use
• human population: population growth stresses planet capacity → demographic transition
• resource depletion: how fast does a resource get used up (how much do we have of that resource before it runs out) → 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 → 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 → collecting sediment and matter in runoff
• the inability to recharge groundwater reserves → 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 → 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 → 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 → 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 → reducing soil erosion
  • no till agriculture: no plowing at all
  • leaves soil; keeps it natural
  • perennial crops: harvesting crops year round
  • roots are intact → do not loosen up soil when harvested
• maintaing soil fertility → 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 → favorable for many types of crops
• overgrazing: overuse of pasture leading to plant damage
  • using it up faster than it can be replenished → 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 → water pollution with excess nitrogen → algal bloom/hypoxia
  • uneaten food pellets → water pollution
  • risk of escape → interbreed or compete with wild organisms
  • diseases/infections spread more easily → increased use of antibiotics → 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 → 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 → removes excess understory plants and dead matter
  • reduces forest fire severity by reducing dry matter
  • encourages new growth

\
\