APES unit 5
5.1
- Tragedy of the commons: Individuals will use shared/public resources in their own self interests, degrading them
- Must be a public resource (the atmosphere or waterways) and must be degraded, overused, or depleted in some way
- EX; Overgrazing, overfishing, water and air pollution, overuse of groundwater
- Why does it happen
- When no one owns the resource (water, air, land) no one directly suffers the negative consequences of depleting it
- People assume that if they don't overuse the resource someone else will
- There is no penalty for overusing, degrading, polluting public resources
- Why is it bad
- Overfishing can lead to fishery collapse (population crash) loss of income and starvation
- Air pollution from coal power plants can lead to bronchitis, asthma, increased healthcare costs
- Pesticide runoff from farms contaminates drinking water
- Externalities: negative costs associated with human action, that are not accounted for in the price (unintended side effects)
- How to solve LOC
- Private land ownership (individual or governmental)
- Fee or taxes for use
- Ie. permit system for grazing logging
- Taxes, fines, criminal charges for pollution in air soil or water
- Examples: Clean air act, Clean Water act, Safe Drinking water, Bureau of land management (manages rangelands in western US by collecting grazing fees from ranchers, evaluation land, and repairing effects of overgrazing)
- a) Explain the tragedy of the commons, using an example other than overfishing:
- The tragedy of the commons is a concept in economics that describes a situation where individuals, acting in their own self-interest, deplete or degrade a shared resource that is available to all, leading to the long-term depletion or even destruction of that resource. An example of the tragedy of the commons is the overuse of a common pasture by multiple farmers. If each farmer grazes too many animals on the pasture, the land may become overgrazed and lose its productivity. This can ultimately result in a decrease in the amount of available food for all the animals and a decline in the quality of the land itself.
- b) Propose a solution to the example you provided above
- A solution to the issue of overgrazing is by collecting fees from ranchers in order to use a public pasture. This forces people to consider the degradation of the land before using it, preventing tragedy of the commons by regulating the amount of the pasture grazed due to economical restrictions.
5.2 Clearcutting
Direct effects of clearcutting
- Soil Erosion
- Caused by loss of stabilizing root structure
- Removes all soil organic matter and nutrient
- Deposits sediments into local streams
- Warms water (lack of shadow direct sunlight) and make it more turbid ( problem for fish and plants)
- Increased soil and stream temp.
- Loss of tree shade increases soil temp bc soil has less albedo than leaves of trees
- Loss of trees warms streams as erosion of sediments into rivers also warms them
- Flooding and landslides
- Logging machinery compacts soil
- Increased sunlight dries out soil
- Loss of root structure= erosion of topsoil and O-horizon
- All of these factors decrease h2o holding capacity soil causing flooding and landslides
- Tree plantations: Areas where the same tree species are repeatedly planted grown and harvested
- Lowers biodiversity
- Biodiverse, mature forests are replaced with single species forests
- Less species diversity= lowers resilience
- Less habitat diversity for other org.
- Same Age
- All trees planted at the same time= all the same age
- Lowers biodiversity further (no dead tress for woodpeckers, insects, and decomposers)
- Forest benefits (consquences of losing)
- Filtering of air pollutants
- Stomata (leaf pores) remove VOCs, NO2, PM from air and store in trees
- Removal and storage of CO2 from atm.
- Trees take in CO2 (photosynthesis) and store them as sugar, wood, other tissues and release O2
- Habitat for org.
- Many orgs. Live in forest (biodiv. ecotourism)
- SLASH AND BURN: Method of clearing land for agriculture by cutting trees and burning them releases CO2, N2O, and water vapor into atm. (all GHG)
a) Identify TWO causes for clear cutting
- One cause is for agricultural benefits, trees are cut down in order to clear up space for growing agriculture- for example tree plantations. Another is to build infrastructure and housing, cutting down forests to create spaces for growing neighborhoods and apartment complexes.
b) Explain how clear cutting maximizes short-term economic benefits, but jeopardizes long-term economic benefits
- A short term economic benefit is that clearcutting is often used for economical purposes and forests are cleared in order to create space for growing agriculture, which works short-term for the first few rounds of agriculture and allows farms to gain money quickly. However the long term effects of this is the removal of trees increases the heat of soil as trees have less albedo than soil it would prevent the soil from heating up too much, without trees the soil would heat up and lose water vapor increasing the rate of desertification and in the long term prevent agriculture from growing at all.
c. Describe how clearcutting impacts nearby water temperature
- Clear Cutting removes the trees from forests and completely clearing the land. This increases the temperature of water due to it increasing erosion as the lack of stabilizing root structures from the soil deposits soil into nearby rivers and streams therefore increasing the turbidity of water. Due to soil having higher albedo than water, thus the higher turbidity of water increases the albedo, allowing it to heat up, increasing the temp. Of water.
d. Describe TWO ecosystem services that are devalued by clearcutting
- One ecosystem service that is devalued by clearcutting is air filtration. The stomata from leaves absorb and remove VOCs, NO2, PM from air and store in trees, this decreases the pollution from the air and clearcutting would lead to more air pollution and more expensive methods of removing the pollution from the air. Another ecosystem service that is devalued by clearcutting is Carbon Sequestration. Trees take in CO2 (photosynthesis) and store them as sugar, wood, other tissues and release O2, and clearcutting would devalue this service and increase global warming as Carbon is a greenhouse gas.
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5.3 Green Revolution
- Green Revolution: The shift away from small family operated farms to large industrial scale agribusiness
- Increased use of mechanization, GMOs, irrigation, fertilizers, and pesticides
- Increased efficiency of lands, short-term profitability, and food supply
- Decreased world hunger and inc. carrying capacity for humans
- Bring neg. Consequences (soil erosion, biodiversity loss, ground & surface water contamination)
- Mechanization
- Increased use of tractors for plowing and tilling fields and combines for havestion= increased yields + profits
- Increased reliance on fossil fuels (gasoline, diesel)
- Emits GHG into atm => climate change
- Heavy Machiney also compacts soil, decreasing H2o holding capacity
- Makes topsoil more prone to soil erosion
- High yield variety crops
- Hybrid, or genetically mod. Crops that produce a higher yield (amount of crops produced per unit of area
- hybrid= cross-pollination different species, or parent plants with ideal traits
- Increased food yield and food stability in regions previously prone to famine (india, pakistan, Mexico)
- GMO’s= crops with new genes spliced into their genome
- GMO’s
- Genes for drought tolerance, pest resistance, faster growth and larger fruit/grain
- Increases profitability with fewer plants lost to drought, disease, or pests + larger plant size + yield/acre
- Ex; Bt corn has been modified with a gene that kills many different corn pests
- GMO crops are all genetically identical so gen. Diversity is decreased and susceptibility to diseases or pests is increased
- Synthetic fertilizer
- Shift from organic fertilizers (manure compost) to man-made fertilizers (ammonium, nitrate, phosphate)
- Increases yield and profits with more key nutrients needed for plant growth (N,P,K) added to the soil
- Excess Nitrate, phosphate are washed off into fields and into nearby water=> eutrophaction
- Requires FFs for production, releasing CO2 (climate change)
- Irrigation: Drawing water from the ground or nearby surface waters and distributing it on fields to increase plant growth
- Make agri. Possible in many regions of the world that are naturally too dry
- Can deplete groundwater sources (aquifers
- Overwatering can drown roots (no O2 access and cause soil salinization
- Pesticides
- Increase in use of pesticides
- Increased profitability and yields with fewer plants lost to pests
- Can wash off crops in runoff and kill or harm non-target species in local soil or waters (bees esp.)
- Ex; DDT => thinned shells of eagle eggs
- a. Identify THREE agricultural practices that are considered a part of the Green Revolution
- Mechanization, irrigation, and use of pesticides
- b. Describe the impact of the Green Revolution on agricultural yields
- The Green revolution led to High yield variety crops. Hybrid, or genetically mod. Crops that produce a higher yield (amount of crops produced per unit of area, Hybrid is the cross-pollination different species, or parent plants with ideal traits This impacted and increased food yield and food stability in regions previously prone to famine, such as India and Pakistan as well as increased the earth's carrying capacity for humans
- Describe a benefit and drawback of increased mechanization in agriculture
- A benefit of mechanization is the increased use of tractors for plowing and tilling fields and combines for havestion leads to increased yields and profits for farmers, thus increasing food sources and reducing hunger in countries. A drawback would be that Heavy Machinery also compacts soil, decreasing H2o holding capacity which makes topsoil more prone to soil erosion.
- Describe a benefit and drawback of GMOs
- A benefit of GMO’s is GMO’s can genetically modify plants with genes for drought tolerance, pest resistance, faster growth and larger fruit/grain, thus increasing profitability with fewer plants lost to drought, disease, or pests as well as larger plant size and increased yield per acre. A drawback of GMO’s is that GMO crops are all genetically identical so genetic diversity is decreased and susceptibility to diseases or pests is increased, thus if one plant gets infected all plants are susceptible to that plant, allowing for entire fields to get wiped out.
- Describe a benefit and drawback of synthetic fertilizers
- A benefit of synthetic fertilizers is that it Increases yield and profits with more key nutrients needed for plant growth (N,P,K) added to the soil. A drawback is that the cost efficiency of it allows farmers to use it in excess, and excess Nitrate, phosphate are washed off into fields and into nearby water, leading to eutrophication affecting the fishes and plants in nearby bodies of water.
- Describe a benefit and drawback of irrigation
- A benefit of irrigation is that it can make agriculture possible in many regions of the world that are naturally too dry. A drawback is that it can deplete groundwater sources and uses of aquifers.
5.4 Env. Impacts of Agri.
- Monocropping: Growing a single species (corn, wheat, soy) of crop
- Highly efficient for harvest, pesticide, and fertilizer application
- Greatly decreases biodiversity (more prone to pests, fewer nat. predators)
- Increases soil erosion (crops harvested all at once and soil is left bare)
- Decreases habitat diversity for species living there
- Tilling: Mixing and breaking up soil to make playing easier
- Losses soil for roots
- Increases erosion by loosening topsoil, breaking up left over root structures from harvest
- Loss of org. matter and top soil nutrients over time (short-term benefits> Longterm)
- Increases PM in air (rerp irr.) and sediments in nearby water (Turbity)
- Slash and burn: Cutting vegetation and burning it to clear lad for agri. And return nutrients in plants to soil
- Deforestation
- Loss of habitat, biodiv., co2 sequestration, loss of air pollution filtration
- Releases GHG (CO2, CO, N2O) leading to global warming
- Increases PM in the air (asthma)
- Lowers albedo, warming area
- Synthetic Fertilizers
- Don't return org. matter to soil; no increase H2O holding cap & no soil decomposer
- Leaching: water carries excess nutrients (N and P) into groundwater or surface waters (runoff)
- Contaminates groundwater drinking water
- Eutrophication
tilling is a farming practice that involves mechanically manipulating the soil to prepare it for planting. The process typically involves using a machine, such as a plow or tiller, to turn over the top layer of soil, break up clumps, and loosen compacted soil. One benefit of tilling is that it can help to improve soil structure, texture, and fertility. By loosening compacted soil and breaking up clumps, tilling allows water and air to penetrate the soil more easily, promoting root growth and nutrient uptake. One major drawback is tilling can increase soil erosion and decrease soil moisture retention, which can make it more difficult to grow healthy plants in the long term.
Land availability: In areas with rapidly growing populations and limited access to arable land, slash and burn agriculture may be used as a way to expand agricultural production. This is often the case in tropical regions where the soil is poor and farming is difficult. By clearing new areas of forest or bushland, farmers can open up new fields for cultivation and provide food and income for their families. Soil Fertility: In many areas of the world, the soil is low in fertility, making it difficult to grow crops. Slash and burn agriculture can be a way to temporarily increase soil fertility. When the natural vegetation is burned, the ash left behind can provide nutrients that are essential for plant growth, such as nitrogen, phosphorus, and potassium. Additionally, by leaving the land fallow for a period of time after harvesting, the soil can regain some of its nutrients before it is burned again.
Soil Erosion: Forests play an important role in preventing soil erosion. Their roots help to hold soil in place, preventing it from being washed away by rain. When forests are cleared, the soil can become more vulnerable to erosion, leading to a loss of topsoil and reduced soil fertility.
Synthetic fertilizer does not return organic matter to soil, unlike organic fertilizer, meaning there is no increased H2O holding cap & no soil decomposer. Synthetic fertilizer also leads to leaching, meaning water carries excess nutrients (N and P) into groundwater or surface waters (runoff, Contaminating groundwater drinking water and causing eutrophication
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5.5 Irrigation
- Furrow Irrigation
- Trenches dug along the crops and filled with water
- Easy and inexpensive; water seeps into the soil slowly and not causing a ton of erosion
- 66% efficient 33% lost to run off and evaporation
- Flood irrigation
- Flood entire field; easier but more disruptive to plants
- Can waterlog the soil and overwater and drown the plants
- 80% efficient and 20% lost
- Drip Irrigation
- Most Efficient but most costly
- 95%+ efficient
- Holes in hose allow water to slowly drip out
- Avoids waterlogging and conserves water
- Spray irrigation
- Groundwater pumper into spray nozzles
- More efficient (less water loss) than flood or furrow\
- More expensive (requires energy for pumps and movement of sprinklers)
- Water logging
- Overwatering can saturated the soil , silling all soil pore space with water
- Does Not allow air into pores so roots cannot take O2 they need
- Can stunt growth or kill crops
- Solution: drip irrigation or soil aeration poking holes or cores into soil to allow air in and drain water out
- Soil Salinization
- Salinization of salt building up in the soil over time
- The groundwater used for irrigation naturally has small amounts of salt
- Water evaporates and salt is left behind in soil over time it can reach toxic levels dehydrating their plant roots and preventing growth
- Solution: drip irrigation, soil aeration, flushing with fresh water, switch to freshwater source
- Global Human Water Use
- Industrial: Power plants, metal plastic manufacturing- 20%
- Municipal; any household water use- 10%
- Agricultural: water for livestock and irrigation for plants- 70%
- Aquifer and groundwater
- Groundwater: H2O stored in pool space of permeable rock and sediment
- Aquifers useable groundwater deposits for humans
- Replenished by groundwater recharge (rainwater percolating down through soil into aquifer)
- Unconfined aquifers recharge quicker
- Confined aquifers recharge are longer term water deposits that recharge more slowly
- Depletion of aquifers
- Cone of depression: forms when water table is lowered by excessive pumping, depleting water and drying nearby wells
- Saltwater intrusion: excessive pumping near coast lowers water table pressure, allowing saltwater to seep into the groundwater
5.6 Pest control methods
- Pesticides: chemicals that are toxic to pests
- Rodenticides kill rodents
- Fungicides kill fungi
- Insecticides to kill insects
- Can cause pests to become resistant to pesticides with overuse
- Genetic biodiversity gives some pests resistant traits to pesticides
- Pesticides artificially selects for pests with resistance by killing all non resistant pests and allowing the ones with the traits to reproduce and survive
- GMOs
- Gene for pest resistant traits is added to to the plant through genetic modification
- Bt corn with bacteria gene that produces Bt proteins toxic to pests
- Roundup ready crops are GM to be resistant to broad herbicides (roundup) meaning roundup will kill weeds but not crops
- GMOs and pesticide use
- Bt corn has decreased insecticide ise, since corn make it’s own insecticide (Bt crystals)
- Roundup Ready crops have increased hericide use since crops arent harmed by it
- GMO and Genetic Diversity
- GM crops all genetically identical (clones) so there is no genetic diversity in the pop.
- If there is a disease or pest that does affect GM crop there’s no chance of a genetic mutation providing an adaptive trait
5.7 Meat production
- CAFOS
- AKA feedlots- densely crowded method where animals are fed grain (corn) to raise them asap
- Maximizes land use and profit (most meat production per/unit of area)
- Minimizes cost of meat for consumer
- Given antibiotics and growth hormones to prevent disease outbreak and speed meat production
- Animals produce large volumes of of waste which can contaminate nearby surface or groundwater
- Lots of greenhouse gasses
- Manure lagoons
- Open large pits for animal waste
- Waste contains Ammonia, hormones, antibiotics, fecal coliform bacteria (ecoli)
- Heavy rain can flood lagoons and contaminate nearby surface and ground water with runoff
- e.coli=> toxic to humans
- Ammonia in the water causes eutrophication
- Antibiotics and growth hormones=> alter endocrine (hormonal system) of humans
- Denitrification of ammonia in manure produces N2O (gfg)
- Can be emptied and buried in landfills or turned in fertilizer pellets
- Free range grazing
- Animals usually cows graze and grow at a natural rate without growth hormones
- Pros
- No need for antibiotics with dispersed pop.
- Does Not require production of corn to feed animals
- Waste is dispersed all over the land away from cows and fertilize the grass instead of building in the lagoons
- Cons
- Requires more total land use/pound of meat produced
- More expensive to consumer
- Overgrazing
- Too many animals grazing in one area can remove all crops leading to top soil erosion
- Compacting soil leads to lack h2o capacity- hard to grow plant so more erosion
- Desertification: can occur if plants are killed by overgrazing and soil is compacting so much that cant hold enough water anymore
- Solution: rotational grazing (moving animals periodically) can prevent overgrazing
- Can even increase growth of grass by distributing manure (natural fertilizer) and clipping grass back to size where growth is most rapid
- Inefficiency of Meat
- Producing meat for humans to eat is far less efficient than producing plants in terms of energy, land and water use
- Energy: all energy needed to plant, grow and harvest plants to feed to animals
- Energy needed to bring water to animals
- Energy needed to house animals
- Energy needed to slaughter and package
- Land: all the energy needed to grow plants to feed animals plus room the animals take up
- Water: all the water for crops that animals eat PLUS the water the animals drink
One environmental benefit of eating a plant based diet rather than a meat based diet is to prevent the depletion of water sources. Beef and other animals use much more water than plants, therefore we would face less issues concerning the depletion of freshwater sources.
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5.8 Overfishing
- Fisheries and fishery collapse
- Fisheries: Pop of fish used for commercial fishing
- Fishering collapse: when overfishing causes 90% pop decline in a fishery
- Pop may never recover from fishery collapse due to: decreased biodiversity, inability to find mates, inbreeding depression
- Decreases biodiversity of fish pop and species biodiversity of ocean ecosystems if species are lost from ecosystems
- Economic consequences: lost income for fishermen, lost tourism dollars for communities
- Economic Impact
- Overfishing in period 1975-1985 leads to sharp loss of profits from 1985-2018
- Tragedy of the commons: no incentive or penalty to prevent overfishing from 75’-85’
- Bottom trawling
- Especially harmful method that involves dragging a large net along the ocean floor
- Bycatch: unintended species like dolphins, whales, turtles caught in nets
- Stirs up ocean sediment (turbity) and destroys coral reef structures
- Decreases biodiv. By killing non-target species and removing coral reef habitat
- Trophic cascade
- As we delete large predatory fisheries, we move down to smaller fish species
- Depletion of smaller fish population limits fishery recovery and decreases food supply of marine mammals and seabirds
5.9 Mining
Mining basics
- Ore: commercially valuable deposits of concentrated minerals that can be harvester and used as raw materials
- Metals: elements that conduct heat, electricity and have structural properties for building (found within ores)
- Reserve: the known amount of a resource left that can be measured in years left of extraction
- Overburden: soil, vegetation, and rocks that are removed to get an ore deposit below
- Tailings and slag: leftover waste material separated from the valuable metal or mineral within ore (often stored in ponds and mine site)
Surface Mining
- Removal of overburden to access ore near surface
- Different types: open pit, strip, mountaintop removal, placer
- Mtn. top removal= esp. Harmful to landscape and habitats, streams nearby
- Removal of veg and soil
- Topsoil erosion
- Habitat Loss
- Increases stream turb.
- Increase PM in air
- As ore near surface becomes more scarce, mning moves deeper underground to subsurface mining (more dangerous and expensive)
Subsurface Mining
- More expensive due to higher due to higher insurance and health care costs for workers
- Risks: poor ventilation leading to toxic gas exposure, mine shaft collapse, injury from falling rock, lung cancer, asbestos, fires, explosions
- Vertical shaft drilled down into ground
- Elevator to carry down workers and transport out resource
- Often used for coal
Environmental impacts of mining
- Acid mine drainage: rainwater leaks into abandoned mine tunnels and mixes with pyrite forming sulfuric acids
- Rainwater carrier sulfuric acid into nearby streams or infiltrates ground water
- Lowers PH of water, making toxic metals like mercury and aluminum more soluble in water sources (killing aquatic life)
- Methane release: coal mining releases methane gas CH4 from rock around coal
- Vented out mine to prevent explosion and continues to seep out after mine closes
- GHG=> climate change
Mine reclamation
- Process of restoring land to original state after mining has finished
- Includes
- Filling of empty mine shafts
- Restoring original contours of land
- Returning topsoil with acids, metals, and tailing removed
- Replating of native plants to restore community to as close to og state as possible
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5.10 Urbanization
Urbanization: Removing of vegetation to convert natural landscape to city (urban)
Replace soil, vegetation, wetlands, with impervious surfaces (concrete, asphalt cement) which don't allow water absorption
CO2 emissions:
- Cement production
- Construction machinery
- Deforestation (loss of future carbon sequestration decomp of cut trees)
- Landfills needed disposing trash
Urbanization prevents groundwater recharge causing precip. to runoff into local bodies of water
Urbanization in coastal cities
- Population growth in coastal cities can lead to saltwater intrusion due to
- Excessive groundwater withdrawal: near coast lowering water table pressure allowing salt water to seep into the groundwater
- Sea level rise: Due to the warming of the atm. (thermal expansion) and melting of icecaps (increases ocean volume) can contaminate fresh groundwater with salt
Trends in population
- Overall trend in US and many other nations is away from less rural to more urban
- Rural=> urban for jobs, entertainment, cultural attractions
- Urb. areas are more densely populated, minimizing driving and land use per person (dc. Env. impact per person)
- Suburbs: less dense areas surrounding urban areas
Urban sprawl: Pop movement out of dense suburban areas surrounding the city (DC=> woodbridge)
- Causes:
- Cheaper property in suburbs than in cities (larger home for same price)
- Cars make it easier to live in suburbs and get the same op. As urban areas
- Domino effect- neighbors leave so do you
- Fewer residents in cities lead to tax decline for city => decrease in city services=> more residents leaving
- Abandoned homes + businesses= blight (unslightly rundown infrastructure) so more people leave
- White flight=> more POC move in white neighborhoods from cities= white people leaving to the suburbs
- Expanded highway system makes travel easier and increases driving=> increase in fuel tax revenue=> builds more highways=> easier to commute from suburbs to city
- Solutions
- Urban growth boundaries: zoning laws set by cities preventing development beyond a certain boundary- build up not out
- Public transport and walkable city design that attracts residents to stay
- Mixed land use: residential, business, and ent. Buildings all located in the same area of a city
- Enables walkability and sense of place
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5.11 Ecological footprint
Ecological footprint: the measure of how much consumption expressed in area of land (gha- global hectare) which is a biologically productive hectare (2.47 acres)
- Factors (Land required for):
- Food production
- Raw materials (wood, metal, plastic)
- Housing
- Electricity production
- coal , NG, solar, wind, etc
Carbon Footprint: measured in tonnes of CO2 per year
- All CO2 released from an ind, or grps consumption
- Material goods
- Food production
- Energy use (gas, heat, electricity)
Increase Footprint: Affluence (wealth) increases ecological and carbon footprint
- Larger houses
- More travel
- More resources needed fro material goods (cars, etc.)
Meat consumption: more land, more water, more energy
Fossil fuel usage (heating, electricity, travel plastic)
Decrease footprint
- Renewable energy: wind, solar, hydroelectric
- Public transport
- Plant based diet
- Less consumption, less travel, less energy
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5.12 Sustainability
- Sustainability: Consuming a resource or using a space in a way that does not deplete or degrade it for future gens
- Ex: using compost (renewable) instead of synthetic fertilizer (fossil fuel dependant)
- Maximum sustainable yield: The maximum amount of a renewable resource that can be harvested without reducing or depleting the resource for future use
- Roughly ½ carrying capacity maximizes yield (resource harvest) and regeneration rate of pop
- Environmental Indicators of sustainability
- Biodiversity
- Genetic, species, and ecosystem
- Higher biodiv.= healthier ecosystem
- Declining Biodiv. Can indicate pollution habitat destruction climate change
- Global extinction rate= strong env. Indicator since species extinction decreases species richness of the earth
- Food Production
- Indicates ability of earth's soil, water, climate, to support Agr.
- Major threats= climate change, soil degradation, (desertification, topsoil erosion) groundwater depletion=> huge portions of the world near the equator dropped in agr. Productivity due to global warming
- Increasing meat consumption= further strain on food prod. (takes away water and land from grain production)
- Global grain production per capita has leveled off and shown signs of decline recently
- Atmospheric Temp and co2
- Life on earth depends on a very narrow temp range
- CO2 is GHG
- Increased co2= increased temp
- Deforestation (loss of CO2 sequestration) and combustion of FF (emission of CO2) increase in atm CO2
- Increasing CO2= unsuitable (dries out arable land, destroys habitats, worsens storms)
- Human Pop. and resource depletion
- As human pop grows,, resource depletion grows
- Resources harvested at an unsustainable rate from nat. Ecosystems and degrade eco health
- More paper (lumber) = deforestation
- More food= soil erosion, deforestation, ground water depletion
- More travel= FF mining= air, water soil pollution, habitat destruction
5.13 Reducing urban runoff
- Env. Cons of urban runoff
- Decreased water infiltration (groundwater recharge) due to impervious surfaces
- Rain washes pollutants into storm drains and into local surface waters
- Pollutants and effects
- Salts (plant and insect death)
- Sediment (turbidity)
- Fertilizer (eutrophication)
- Pesticides (kill non-target species)
- Oil and gas (suffocate fish and kill aq. insects)
- Solution: permeable pavement
- Specially designed to allow stormwater to infiltrate and recharge ground water
- Decreases runoff and decreases polluants carried into storm drains and into local surface water
- Decrease likelihood of flooding during heavy rainfall
- Con- more costly than reg pavement
- Rain garden
- Gardens planted in urban areas esp. Surrounding a storm drain
- Decreases runoff by allowing it to soak into garden soil surrounding storm drain
- Decreases chance of flooding during heavy rain event
- Creates habitats for local pollinator species, sense of place, co2 sequestration
- Solution: Public transit
- Less cars on road= less pollutants on streets to run off into storm drains and local waters
- Motor oil, gasoline, tire pieces, antifreeze
- Less cars= less lanes and parking lots which are impervious surfaces meaning more urban runoff
- Public transit decreases urban runoff, pollutants on roads, CO2 emissions, even traffic
- Solution: Building up not out
- Building up reduces amount of impervious surfaces (decreasing urban runoff
- Can be combined with green roof or roof top gardens to further decrease runoff
- Green roofs also co2 sequesters and filters air pollutants out
- Plants absorb NO2, PM, and other pollutants into stomata and tore in tissue or soil
5.14 IPM
- IPM basics
- Using a variety of pest control methods that minimize env. Disruption and pesticide use
- Researching and monitoring pests and targeting methods to specific pest life cycles
- Biocontrol (brining a nat. Predator or parasite to control pest
- Crop rotation
- Intercropping
- Bio control: introducing a nat predator, parasite, or competitor to control pest pop
- Can include actually purchasing and spreading the control orgs in fields or building habitats for them to attract them naturally
- Ladybugs for aphids
- Spiders for many pests
- Parasitic wasps for caterpillars
- Crop rotation
- Many pests prefer one specific type of crop or crop family- they lay eggs in soil so when they hatch they'd have preferred food source
- Rotating crops can prevent from becoming established since it disrupts their preferred food choice
- Also disrupts weed growth since diff crops can be planted at diff times preventing bare soil from being overtaken by weeds
- Intercropping
- Push pull system can be used
- Push plant emit volatile chemicals that naturally repels pests away from crop
- Pull plants emit chemicals to attract pests to lay eggs in them instead of crops
- Can provide habitat or pull plants that emit chems that attract natural predators
- Benefits and draw backs of IPM
- Pros
- Reduces death and mutations of nontarget species from synthetic pesticides
- Ex; intersex frogs (atrazine)
- Reduces effects on human consumers of produce
- Ex: many pesticides cause cancer
- Reduces Contamination of surface and ground water by agri. Runoff with pesticides
- Cons
- Can be more time consuming and costly
- ex : researching specific pests and planting numerous species of crops
5.15 Sustainable agriculture
- Soil conservation: agricultural techniques that minimize erosion (us is losing topsoil to erosion 10x faster than it forms)
- Prevents loss of
- Nutrients in top soil
- Soil moisture
- Decomposers in soil
- Org. matter that traps soil moisture
- Contour plowing: Plowing parallel to natural slopes of the land instead of down slopes prevents water runoff and soil erosion
- Forms mini terraces that catch water running off- conserving soil and water
- Terracing: cutting flat platforms into a steep hillside
- Flatness of terraces catches water and prevents it from becoming run off and eroding soil
- Perennial crops: Crops that live year round and are harvested numerous time
- Longer, more established roots and prevention of bare soil between harvests
- Windbreaks: using trees or other plants to block the force of the wind from eroding topsoil
- Can be used as source of fire wood (income)
- Can provide habitat for pollinators and other species
- No till: Leaving leftover crop remains in soil instead of tilling uder
- Add org. Matter to soil (nutrients, soil cover, moisture)
- Prevents erosion from loosened soil
- Strip cropping: alternating rows of dense crops with rows of less dense crops to prevent runoff from less dense crops
- Improving soil fertility: methods of restoring nutrients back in the soil (N,P, Ca, Mg)
- Crop rotation
- Replanting same crops continuously depletes soil of the same nutrients
- Crop rotation can allow soil to recover from nitrogen demanding plants like corn
- Peas and legumes have nitrogen fixing bacteria in their root nodules that can return nitrogen in the soil
- Green manure
- Leftover plant matter from a cover crop (crop planted in the offseason between harvest and replanting of main crop)
- Cover crop roots stablize soil limiting topsoil erosion
- Remains of cover crops (green manure) left on field break down to release nutrients into the soil
- Crushed limestone
- Limestone releases calcium carbonate (base) which neutralizes acidic soil
- Acidic soil has high H+ ion concentration, which displaces + charge nutrients from soil (leeching them out)
- Acidic soil makes toxic metals more soluble
- Calcium is needed as a plant nutrient as well
- Rotational grazing
- Regular rotation of livestock to diff. Pastures prevent overgrazing
- Overgrazing can kill plants, compact soil, and lead to erosion of topsoil
- Promotes pasture growth at a faster rate than normal- clips grass back to length where growth is fastest and encourages deeper root growth
5.16 Aquaculture
- Aquaculture benefits
- Raising fish or other aquatic species in cages/enclosure under water
- Requires only small amount of water, space, fuel
- Reduces risk of fishery collapse (90% pop decline in fishery)
- Doesn't take up any land space (compared to livestock)
- Aquaculture drawbacks
- High density produces high concentration of waste (e coli & eutrophication risks)
- High density= high disease risk which can be transmitted to wild pops as well
- May introduce GMO or non-native species into local ecosystem if captive fish escape
- Fish are fed antibiotics which can contaminate water via waste
5.17 Sustainable forest
- Forestry (using trees for lumber) that minimizes damage to ecosystem (habitat destruction, soil erosion, ets)
- Selective cutting or strip cutting: only cutting some trees in an area (biggest and oldes) to preserve habitat (biodiv.) and topsoil
- Using only human and pack animal labor to minimize soil compaction from machinery
- Replants native species being logged
- Maximizes long term productivity of land and preserves forest for future generations
- Sustainable forestry practices
- Using recycled wood, or simply reusing without recycling (furniture, decoration)
- Wood can be chipped and used as mulch for garden or agr. Fields
- Reforestation: replanting of trees in areas that have been deforested
- Selectively removing diseased trees to prevent spread of infection through entire forest
- Removes host for disease
- Decreases density, making spread less likely
- Fire suppression
- Stopping natural fires: fire suppression is the practice of putting out natural fires as soon as they start
- Leads to more biomass build up: putting out fires immediately leads to more dry biomass build up- makes future fires worse
- Monitoring instead: close monitoring can prevent fire damage and worse fires in the future
- Prescribed burns
- Dead biomass builds up
- Fuel for large forest fire
- Stored nutrients trapped in dead biomass
- Dead trees= susceptible to disease and pest spread
- Small controlled fires burn lots of dead biomass
- Uses up dead biomass (fuel) preventing larger forest fires later
- Promotes nutrient recycling
- Nutrients in dead biomass => new growth
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