Unit 5.1: The Tragedy of Commons

• Tragedy of the Commons

  • Suggests that individuals will use shared resources in their own self-interest rather than in keeping with the common good, thereby depleting the resources

  • A commons is an area used by all but regulated by none

    • Use of commons without regulation skews towards self-interest, which leads to the degradation of the commons

• Sustainable Use of Commons

  • Regulate use of:

    • Hunting/fishing licenses

    • Land use permits

    • Country quotas (pollution, fish harvest, etc)

    • Selective cutting of trees

  • Replenish After Use:

    • Replant trees

    • Throw back fish that are gravid 

    • Rotate which grasslands are used for grazing

  • Ensure Compliance (enforcement / consequence):

    • Treaties

    • Laws

    • Oversight of treaties/laws

      • Fines

      • Incentives - subsidies, debt forgiveness, etc

  • Privatize commons to incentivize care of the commons

    • Does not work in all situations, for example, you can’t fence off the ocean

Unit 5.2: Clearcutting

• Forest Ecosystem and Ecological Services

  • Serves as a habitat

  • Aids in soil formation and retention 

  • Moderates local climate 

  • Serves as a good source

  • Removes air/water pollutants

  • Increases albedo of Earth

  • Serves a role in biogeochemical cycles - water, carbon, nitrogen, phosphorus

Timber - what you cut down from trees

Lumber - anything shaped from the timber

• Economic Benefits Provided by Forests

  • Grazing for livestock

  • Agricultural land for shade-tolerant plants

  • Ecotourism and aesthetics-related use

  • Impact on nearby real estate values

  • Source of agricultural products

  • Source of potential medicine

  • Source of land for other uses - agriculture, mining, residences

• Clearcutting - cutting down all the trees in a forest 

  • Impact:

    • Habitats and food sources for organisms and humans

    • Soil

    • Biogeochemical cycles

    • Air/water quality

    • Earth’s albedo and climate

    • Economic choices related to intact forests

  • Loss of:

    • Habitat/biodiversity 

    • Economic opportunities

    • Food sources

    • Aesthetic value

  • Increase of:

    • Albedo

    • Soil erosion / desertification 

    • Water evaporation from soil

    • Air pollution / climate change

  • Decrease of: 

    • Infiltration 

    • Soil formation 

    • Transpiration 

  • Ingress - go in

    • More parasites and predators could enter a forest if trees are cut down

  • Egress - leave

    • More diseased animals could leave a forest and go towards civilized areas if trees are cut down

  • Impacts of Clearcutting on Terrestrial Environments

    • Less leaves to form the rich layer on the top of soil

    • Anything trying to grow is dealing with less topsoil, water and nutrients 

      • Water cannot be absorbed by the ground and will just run off

    • Erosion could happen on a slope, leading to mudslides and potential destruction of habitats

  • Impacts of Clearcutting on the Atmosphere  

    • Less trees = more carbon dioxide 

      • This can contribute to climate change

    • Less water vapor in the atmosphere 

    • Equipment used to cut down trees release fossil fuels, causing more carbon dioxide to be in the atmosphere

  • Impacts of Clearcutting on Aquatic Environments

    • Remnants of cutting down trees and soil erosion can go into rivers and waterways

    • Increase in turbidity

      • Turbidity - the amount of solids in water

      • Decrease in aquatic primary productivity 

      • Decrease in albedo

    • Increase in water temperature 

      • Decrease in dissolved oxygen (DO) levels

    • Increase in nutrient load

      • Eutrophication (Topic 8.5)

    • Loss of habitat / biodiversity 

  • There can also be impacts on human life

    • Example: If fish die from turbidity, fishermen no longer have a source of income

Unit 5.3: The Green Revolution 

• The Green Revolution 

  • The transition from small farms with hand labor to large industrialized corporations that are very large scaled and productive operations 

    • Mechanized

      • Transition away from hardworking a field

      • Machinery does not have the drawbacks of living labor

      • Can be specialized and updated

      • Easy to use 

      • Efficiency leads to higher profits 

      • Fossil fuel use

        • Extraction

        • Combustion

        • Reliance upon 

    • Monocultures

      • Easy to plant, maintain, harvest

      • Only certain types of pests associated with this one crop

      • Loss of habitat and biodiversity 

      • Loss of ancestral varieties 

      • Increased possibility of catastrophic event

    • Use artificial fertilizer  

      • Made through the Haber Bosch Process 

        • N2 + 3H2 = 2NH3

      • Release nutrients over time

      • Can be customized for the type of plant

      • Mass produced 

      • Easily shipped and stored

      • Easily and quickly dispersed

      • No objectionable smell

      • Ensure higher yield due to maximized growth potential

      • Easily dissolve in runoff

        • Eutrophication (Topic 8.5)

        • Nitrogen-bearing ions in drinking water

      • Disrupts nitrogen cycle

    • Artificial Pesticides 

      • Herbicide, insecticide, fungicide

      • Can be customized for the type of pest

      • Mass produced 

      • Easily shipped and stored

      • Easily and quickly dispersed

      • Ensure higher yield due to minimized loss due to pest damage

      • Possible extermination of non target species 

      • Persistence 

      • Possible human health effects

      • Contamination of groundwater 

      • Evolution of pesticide-resistant pests (pesticide treadmill)

    • Extensive irrigation used

      • Customizable application

      • Maximizes yield by maximizing growth potential

      • Depletion of freshwater resources 

      • Associated environmental effects

    • Genetically modified organisms (GMOs) sometimes used - video 2 of this series 

  • Overall, advantages include maximizing yield per unit area and disadvantages include significant impact on the natural world

• Genetically Modified Organism (GMO)

  • Use of genetic material from other species

  • Artificial Selection VS GMOS

    • Artificial Selection - human-directed evolution that selects for traits beneficial to humans based on the genetic material available 

    • Creation of GMOs - human-directed evolution that selects for traits beneficial to humans that takes advantage o the genetic material of normally-incompatible species, thus creating new traits in the host species

  • GMOs can create their own pesticides 

    • Scientists use GMOs and insert their DNA into plants to give plants their own pesticides they can create 

• Benefits of GMOs:

  • They create crops that can grow on land once usable for agriculture 

    • Drought and heat-resistant, salt tolerant 

  • Crops can be herbicide resistant 

    • Easy and early application of herbicide without crop damage

  • Crops can produce their own insecticide 

    • Reduces use of artificial insecticides 

  • Expand range and hardiness of crops plants

• Drawbacks of GMOs:

  • Semiarid and arid lands converted to agriculture have low-nutrient soil

  • Weeds can become herbicide resistant with excess use of herbicide

    • Example: roundup - ready crops

  • Bt crops may kill no target species 

  • Bt crops can lead to insecticide-resistant pests 

  • Moral/ethical/economic issues with patented genetic modification

  • Unintended environmental consequences, pesticide treadmill, impacts on human society

Unit 5.4: Impacts of Agricultural Practices

• Arable Land - land capable of producing crops

• Tilling 

  • Bare soil -> soil erosion, evaporation 

    • Eutrophication 

    • Need for fertilizer 

  • Turned soil -> impacts soil structure 

  • Turned soil -> sequestered carbon released as CO2

  • Mechanisms of Tilling 

    • Mechanized farming equipment -> impact soil

    • Mechanized farm equipment -> emissions

    • Mechanized farm equipment -> fossil fuel use 

• Slash-and-Burn Agriculture  

  • Developing Countries 

  • Typically tropical rainforest

    • Low nutrient soil

  • Subsistence farmers 

  • Ash used as fertilizer 

  • Unsustainable 

    • Nutrient provided by ash quickly used

    • Cut down new plot of land for crops 

  • Resulting Impacts 

    • Desertification

      • Forest cannot grow back

    • Soil erosion

    • Decreased albedo

    • Increased evaporation

    • Decreased water infiltration 

• Intensive Agriculture 

  • These plants have less genetic diversity

• Synthetic VS Organic Fertilizer 

  • Haber-Bosch Process

    • N2 + 3H2 = 2NH3

    • N - P - K

  • Advantages of Synthetic Fertilizer

    • Easy to transport and use

    • Timed release 

    • Customizable

  • Disadvantages of Organic Fertilizer 

    • Must be gathered 

    • Nutrient levels unknown

    • Harder to use 

  • Disadvantages of Synthetic Fertilizer 

    • Water-soluble (runoff)

    • Often overused

    • Does nothing to improve soil structure 

  • Advantages of Organic Fertilizer 

    • Can be worked into soil

    • Contains partially-digested vegetation - improves soil structure 

• Pesticide Use and Overuse

  • Pesticide Treadmill - means you have overused pesticide

Unit 5.5: Irrigation Methods

• The largest human use of freshwater is for irrigation (70%)

• Types of irrigation include flood irrigation, drip irrigation, and spray irrigation 

• Furrow irrigation involves cutting furrows between crop rows and filling them with water. This system is inexpensive, but about ⅓ of the water is lost to evaporation and runoff.

• Flood irrigation involves flooding an agricultural field with water. This system sees about 20% of the water lost to evaporation and runoff. This can also lead to waterlogging of the soil. 

Flood Irrigation - most common irrigation form, floods the whole field to give water to crops

• Pros:

  • Easy 

  • Inexpensive 

  • Mechanicalization not required 

• Cons: 

  • Requires water nearby 

  • Not for all plant types

  • Land must be graded 

  • Levees needed

  • 20% of water lost to evaporation

  • Waterlogging/salinization

• Flood irrigation is easy to set up, but is inefficient and not suitable for all crops

Furrow Irrigation - building trenches on either side of where your crop is located

• Pros:

  • Low investment 

  • High-sediment water can be used

  • Allows for some precision of application 

• Cons:

  • Not efficient on sandy soil

  • Difficult to apply small amounts of

  • 33% of water lost to evaporation - least efficient 

  • Soil erosion

• Furrow irrigation requires a modest investment and is more precise than flood irrigation, but is very inefficient

Spray Irrigation - using pumps to pump out water to spray it out of a nozzle directly onto the plants and soil

• Pros:

  • Precision application

  • Supplements can be introduced into the water

  • Efficient - 25% or less lost to evaporation 

  • Can be programmed to run at certain times of the day

• Cons:

  • Larger up-front cost than flood and furrow irrigation 

  • Can include machinery run with electricity/fossil fuel use

  • Nozzles can clog

  • Pivot systems can wear ruts in soil

• Spray irrigation is moderately efficient and moderately expensive

  • Versatile

  • Less than 25% lost to evaporation 

Drip Irrigation - pipes that have micro pores that are buried under the ground that sweat water directly onto the roots when turned on

• Pros:

  • Very low evaporation rate (5%)

    • Extremely efficient 

  • Reduces nutrient leaching

  • No land grading needed

• Cons:

  • Very expensive, clogs easily

  • Requires mechanization

  • Placement makes any other processes difficult

• Drip irrigation is very efficient, but very expensive 

  • Less than 5%, lost to evaporate 

  • Once the pipes are put down, they cannot be moved and are vulnerable to punctures and dogs

Waterlogging - continuously watering soil until their air pockets are filled up, which caused the plant to be unable to perform cellular respiration, killing the roots and the plant itself

• Ways to Fix this: let the fields dry out, work sand into soil for more drainage, use drip irrigation for more precision

Salinization -  an increase in the total dissolved solids (TDS) of the aquifer caused by natural or anthropogenic factors, for example, salt

• Ways to Fix this: keep flushing the field with fresh water to get rid of the salt, grow plants that are salt tolerant 

• Aquifer - a body of permeable rock which can contain or transmit groundwater 

  • Ogallala Aquifer

    • Stretches from Nebraska to Texas

    • Overused 

Unit 5.6: Pest Control Methods

• One consequence of using common pest control methods such as pesticides, herbicides, fungicides, rodenticides, and insecticides is that organisms can become resistant to them through artificial selection. Pest control decreases crop damage by pests and increases crop yields 

• Crops can be genetically engineered to increase their resistance to pests and diseases. However, using genetically engineered crops in planting or other ways can lead loss of genetic diversity of that particular crop.

Pesticide Use and Overuse

• Pesticide treadmills can be a result of pesticide overuse 

• Hitting plants with pesticides might not completely demolish a plant of there is a portion of the plant that is mutated and resistant to the pesticide 

  • Then, the plant will grow more via that mutation, which will call for more use of the pesticide

• Certain insects either a mutation can also be resistant to insecticides, so you may need to use more of that insecticide

• The overuse of pesticides can result in the killing of non-targeted species that could be essential to the environment, such as bees

Why Use Pesticides at All?

• Using pesticides maximizes the yields of crops, which maximizes the amount of calories you can obtain, and will lead to more profit because those crops will not be damaged by mold

Genetically Modified Organisms (GMOs)

• Certain types of bacteria can create their own pesticides using their DNA

• Crops can be herbicide resistant

  • Easy and early application of herbicide without crop damage

• Crops can produce their own insecticides 

  • Reduces use of articulation insecticides

• Bt crops may kill no target species 

• Bt crops can lead to insecticide-resistant pests

• Monoculture with limited genetic variety can be susceptible to unforeseen change in the environment 

• Pros:

  • Can be tailored to the agricultural environment 

  • Can reduce pesticide use

• Cons:

  • Can drive selection of pesticide-resistant insects

  • Loss of biodiversity 

  • Loss of ancestral strains of crops plants

Unit 5.7: Meat Production Methods

• Methods of meat production include concentrated animal feeding operation (CAFOs), also called feedlots, and free range grazing

• Meat production is less efficient than agriculture; it takes approximately 20 times more land to produce the same amount of calories from meat as from plants

• Less consumption of meat could reduce CO2, methane, and N2O emissions; conserve water; reduce the use of antibiotics and growth hormone, and improve topsoil

Meat Production - the raising of cattle, chickens, turkey, pigs, sheep, goats, or any other livestock for consumption by humans

• Overconsumption of meat is an issue for the developed world

• Land Use

  • It takes a lot of land to raise livestock

  • 25% of land on earth is used to raise livestock 

• Animal Waste and Emissions

  • Animal waste can often end up in not-so-great places

    • Often, it can end up in waterways

  • Cows often emit methane, which can contribute to climate change

• Animal Waste and Lowered DO Levels

  • Increase in turbidity 

    • Decrease in aquatic primary productivity 

    • Decrease in albedo

  • Increase in water temperature 

    • Decrease in dissolved oxygen (DO) levels

  • Increase in organic matter/nutrient load

    • Increase in decomposition by aerobic bacteria 

    • Decrease in DO levels

    • Eutrophication (Topic 8.5)

• Animal Waste and Fecal Coliforms

  • Animals contain fecal coliforms, and it can end up in waterways and can end up being consumed by humans (not good)

• Antibiotic and Growth Hormone Use

  • Adds more outside chemical to meat 

• Soil Compaction

  • Can cause issues in soil when all the animals are in the same general area

Crop Production VS Meat Production

Reducing meat consumption could:

• Reduce CO2, methane, and N2O emissions 

• Conserve water

• Reduce the use of antibiotics and growth hormone 

• Improve topsoil

Two Main Methods of of Meat Production

• Concentrated animal feeding operations (CAFOs)/feedlots

• Free-range grazing

CAFOs (Concentrated Animal Feeding Operation)

• Can raise cattle, chickens, turkeys, pigs, sheep, goats, or any other livestock for consumption by humans

• Large but efficient 

• Animals are typically fed grain because it is high calorie

• They are crowded and create a lot of waste

  • This waste can head into waterways and other areas used by humans and other animals

• Pros:

  • More efficient means of production

  • Uses less land per head of livestock than other methods

• Cons:

  • Large, concentrated areas of animal waste

    • Possible water contamination 

    • Possibility of infectious pathogen released into waterways 

  • Antibiotic/growth hormone use 

Free-Range Grazing - can be cattle, chickens, pigs, sheep, goats, or any other livestock 

• Have free access to land to feed on

• Overgrazing - classic example of tragedy of the commons; area used by everyone and regulated by no one 

  • Can result in the grass being unable to grow back, leading to soil erosion

• Pros:

  • Animals eat natural food source

  • No preventative antibiotic use

  • Waste spread over a larger area by fewer animals

• Cons:

  • Possible tragedy of the commons via overgrazing

    • Soil degradation 

    • Water pollution

    • Desertification 

  • Large land use per animal

  • Higher cost for consumers than other methods

Unit 5.8: Impacts of Overfishing 

• Overfishing - has led to the extreme scarcity of some fish species, which can lessen biodiversity in aquatic systems and harm people who depend on fishing for food and commerce

• Commercial Fishing

  • Long-line - very long line with hooks evenly spaced held up by flotation devices that catch fish 

  • Drift net/gill net - very long net that can be set at varying depths to catch fish

  • Purse seine - a net that has two drawstrings that is very long and deep that can catch entire schools of fish, you are essentially pulling out a purse full of fish

  • Trawling - a cone shaped net that can be dragged in the middle of bottom of the ocean, when dragged across the bottom it’s like an eraser

  • Sonar - can detect fish and help you locate them

  • While these different devices are all efficient in some way, they can all lead to overfishing 

    • Can be a tragedy of the commons

• Bycatch - non-target species that are often caught when fishing

  • They are often processed with other fish or just tossed back into the ocean, they are not treated with much care 

  • Numbers of the population can suffer if they are a bycatch

• How to make fishing more sustainable 

  • Catch limited based on MSY (maximum sustainable yield)

  • Consumer Pressure

  • Limit age/size of fish caught

  • Modify techniques to reduce bycatch

    • Can insert some in a net to make sure bycatch get forced out

  • Bycatch guards

  • Incentives and fees

  • Laws/treaties that protect critical species 

    • 10 pieces of legislation involved in this course

    • Example: Great white shark is protected by CITES (The Convention on International Trade in Endangered Species of Wild Flora and Fauna

Unit 5.9: Impacts of Mining

Mining and Refining

• Mining - obtaining minerals from the ground

  • Gold

  • Diamonds

  • Phosphorus-bearing rock

  • Gravel

  • Coal

  • These are ores when they first come out of the ground, because they are are not completely pure

• Refining- industrial process that removes impurity from a substance 

• Two categories of Mining:

  • Surface mining

    • Open pit mine - continues digging into the ground, creating a pit

    • Strip mining - harvesting material in strips

    • Mountaintop removal - clearing the top of a mountain to find materials

  • Subsurface mining

    • This is dangerous and can negatively affect the health of minors

• Overburden VS Spoils

  • When material is on top of an ore (example: dirt) that is overburden

  • Once that excess material is removed, it is then referred to as spoils

• Ore VS Tailings and Target Material

  • The target mineral is what the desired resource is from the ore 

  • The tailings are the remnants of whatever was in the ore that is not desired or needed

• Cyanide Heap Leaching - stacking ores on top of one another, putting cyanide on it, which then creates waste slurry, which helps decipher the target mineral needed

  • If there is an open river or a break, that cyanide could enter other areas of the environment and affect it

Environmental Consequences of Mining

• Abandoned mines, as well as non abandoned mines, can cause soil erosion can occur if there is no vegetation 

• If there is a stream nearby, remnants and impurities from mining could end up the stream, causing turbidity 

  • This could impact the biodiversity of the organisms living there

• Acid Mine Drainage

  • Mine tailing, pyrite, oxygen, and water could produce sulfuric acid, and acid and heavy metals

Mine Remediation

• Remediation - trying to fix something back to the way it was before it was changed

• Mining Damage can be Remediated

  • Re-establish Vegetation 

    • Grade land

    • Enrich soil

    • Plant vegetation in keeping with original habitat

    • Monitor

  • Remediate acid mine drainage

    • Add a base

    • Remove tailings

    • Use bioremediation 

Unit 5.10: Impacts of Urbanization 

• Urbanization - shifting from agricultural to non agricultural jobs, leading to less rural areas and a more densely populated area

  • Many urban areas do not have much vegetation 

  • One of the main benefits of urbanization is mass transit 

    • It is a benefit from an environmental perspective because it lowers the amount of fossil fuel use per person, lowering emissions

      • It is also an efficient use for land

  • Since everything is close together, many people ride bikes or walk, and this movement benefits human health and also limits carbon emissions 

  • Loss of vegetation 

• Urbanization impacts the water cycle 

  • Upstream flow can cause flooding issues

  • Downstream issues will lead to depletion of sediments that organisms rely on

  • Saltwater Intrusion - saltwater can intrude into an aquifer of fresh water 

    • Only particular to coast water areas

  • Impermeable Surfaces - water cannot get through a surface 

    • Can lead to runoff

• Urbanization impacts the carbon cycle 

  • More waste due to larger population in an area, leading to more greenhouse gasses

  • Cities contribute carbon emissions to the air since they are heavily polluted 

• Urban Sprawl - as more people go into the cities, the less places they have to live, leading them to suburbs. However, this can lead to more carbon emissions and impermeable surfaces, and less vegetation since it is densely populated like a city but doesn’t have mass transit

• Heat Islands - urban areas that experience higher temperatures than the outer area

• Remediation - fixing the issues of urbanization such as runoff, loss of vegetation and increase in impermeable surfaces

• Urban Planning - building up instead of out, using less land and keeping things closer together so there is less of a need for transportation 

Unit 5.11: Ecological Footprints 

Ecological Footprint - a measure of how many resources a person uses, expressed in an area of land

• How much land is needed to sustain your life

• 5 Variables Involved in Ecological Footprint:

  • Carbon footprint - energy

  • Built-up land - settlements

  • Forests - timber and paper

  • Cropland and Pasture - food and fibers

  • Fisheries - seafood

• Ecological footprints compare resource demand and waste production required for each country

• How can we shrink our ecological footprint?

  • Carbon footprint - Use less energy

  • Built-up land - Build up not out

  • Forests - Reduce demands on paper and timber

  • Cropland and Pasture - Buy local farm raised produce and eat less meat

  • Fisheries - Buy eco-friendly fish

Unit 5.12: Introduction to Sustainability 

Sustainability - the ability to use and maintain a resource indefinitely or for future generations

• Example: a lake having an input of water equal to the amount of water we take out of a lake for resource 

  • The lake is being replenished and will be sustainable 

  • If we were using more lake water than what was being inserted, it would be unsustainable and cause depletion of water

    • This is what is happening with fossil fuels right now, which is why the prices are going up

  • If more water is being inserted than what is being taken out, the water is not wasteful and cause flooding

• Environmental Indicators that can guide humans to sustainability:

  • Biological Diversity - healthier ecosystems are resistant to disturbances 

    • When we are harvesting resources, we want to make sure it will be replenished but not wasteful

  • Food Production - poor practices lead to soil degradation and water pollution 

  • Global Surface Temperatures and CO2 Concentrations- excessive CO2 increases global temperatures creating climate change

  • Human Population - exponential population growth stresses our planet

    • Increase demand for resources, so we must prevent overpopulation 

  • Resource Depletion- will this resource be available in the future? How fast can we use it?

    • Sometimes builders will start using different products as certain resources are depleted and become more expensive

• How can we live sustainably?

  • Biological Diversity - preserve nature

  • Food Production - sustainable food practices

  • Global Surface Temperatures and CO2 Concentrations - decrease energy use

  • Human Population - demographic transition 

    • If we can push countries to later stages of demographic transition, this will help keep population numbers under control

  • Resource Depletion - reduce, reuse, and recycle

Sustainable Yield - amount of renewable resource that can be taken without reducing the available supply

• MSY - maximum sustainable yield

  • MSY = 50% of carrying capacity

  • A population grows the fastest and most efficiently when at 50% carrying capacity 

    • Example: if there are 100 fish in a lake, we could harvest 50 fish to continue sustainability 

• How can we Harvest Sustainable Yields?

  • Research and Planning - reproductive abilities of a resource 

  • Setting Quotas - setting limits

  • Requiring Permits - manages harvesters

  • Focus on long term - sustainability 

  • Reforest - replace trees that were harvested 

  • Understanding to leave a resource better than when you found it

Unit 5.13: Methods to Reduce Urban Runoff

• Two major problems with urban runoff include water pollution and an inability to recharge our ground water

• Methods we can use to Increase Water Infiltration 

  • Permeable pavement 

    • Allows water to infiltrate

  • Planting trees

    • Trees increase the permeability of soils

  • Smart city Design Public Transportation and build UP, not OUT

    • Having multiple homes built in less space decreases paved area

  • All of these solutions will lead to more permeability of surfaces, leading to increased groundwater recharge as well as decreasing water pollution 

Unit 5.14: Integrated Pest Management 

• Integrated Pest Management (IPM) - a combination of methods used to reduce and eliminate pest species 

  • Includes biological, physical, and chemical controls

    • Goal is to reduce the amount of chemical pesticides used to reduce the pesticide treadmill and poisoning of non-target species and humans

  • Biological Controls - introduction of natural pest predators, naturally controls pests

    • Examples: the farm cat or dog, parasitic wasps, praying mantis, lady bugs, green lacewings, specific bacteria and fungi 

  • Physical Controls - example barriers that protect crops, protects crops

    • Examples: Traps, tilling, screens, weed blocker, fences

  • Chemical Controls - poisons that kill past species, last resort 

    • Examples: glyphosate, atrazine, DDT

    • These are typically broad spectrum and not only hurt target species but other non target species as well

• Other methods include crop rotation and intercropping

  • By switching crops, pest species may not accumulate in numbers that warrant pesticide use

  • This will decrease crops

• IPM does not want to exterminate all agricultural pests. These organisms are part of the trophic structure of that ecosystem, and extermination isn’t sustainable or ideal in terms of biodiversity

• The heavy use of chemical pesticides can harm the environment 

  • The whole point of IPM is to decrease the use of chemical pesticides 

  • They affect:

    • Non targeted wildlife - unsustainable in terms of biodiversity 

      • Example: praying mantis, birds amphibians, bats

    • Water supplies - unsustainable by poisoning our waters

      • Example: water pollution, fish, insects, non-target aquatic plants, frogs

    • Human Health - exposure to pesticides can negatively affect health

      • Example: rashes, nausea, diarrhea, blindness

  • The herbicide atrazine has been linked to be an endocrine disruptive in frogs

• Benefits of IPM

  • Decreases the amount of chemical pesticides sprayed on crops

  • Economic savings

  • Sustainable 

  • Targeted

  • Minimizes loss of pollinators

  • Minimizes health risk 

  • Decreases pesticide resistance 

• Drawbacks of IPM

  • Complex

  • Slow

  • Expensive

Unit 5.15: Sustainable Agriculture 

• The preservation of soil is essential to maintaining sustainable food production practices

  • Methods that can help prevent soul erosion include: 

    • Contour Plowing - preserves natural topography of the land and leaves soil intact

    • Windbreaks - reduces wind erosion that may blow soil away

    • Strip Cropping - harvesting one crop at a different time will leave one crop holding the soil in place

  • Additional soil conservation practices include:

    • Terracing - decrease the velocity of water going downhill, reducing soil erosion

    • No Till Agriculture - leaves soil in place and does not loosen it so it can resist erosion 

    • Perennial Crops - crop roots hold soil together year-round, does not have to be replanted

• Maintaining soil fertility is also important in practicing sustainable food production

  • Practices include:

    • Crop Rotation - may replenish soils of nutrients naturally, for example legumes adding nitrogen to soil

    • Green Manure - adds bulk and NPK to soil that slowly decomposes 

    • Limestone - addition of limestone adds valuable calcium to soil and increases pH making soups more alkaline 

• Overgrazing - extensive grazing that causes damage to plants

  • Unsustainable in food production 

  • Leads to soil erosion and eventually destruction of pasturable fields

• Rotational Grazing - the cycling of livestock around a particular part of their pasture as to not overgraze an area

  • Sustainable agricultural food practices can be maintained this way 

  • Allows the cover crop to replenish and hold soil in place

  • Maintaining pasturable land is an important aspect of sustainable agriculture

Unit 5.16: Aquaculture 

• Aquaculture - the farming of fish, shellfish, mollusks, crustaceans and aquatic plants by an individual or corporation with the intent to sell the farmed organisms to consumers for profit

  • It has expanded because it is highly efficient

  • Can occur both in marine and freshwater environments, depending on the organisms being farmed

  • China is the worldwide leader in aquaculture production, for both marine and freshwater environments 

• Aquaculture as an Environmental Solution

  • As the human population increases and middle class expands among developing nations, the demand for quality protein sources is increasing

  • Wild fish harvests have been largely flat, decreasing worldwide since the 1990s.

  • Aquaculture provides much-needed income to fisherfolk, additionally it is generally less time consuming and dangerous than open water fishing

  • In terms of acreage and water consumption, aquaculture is more efficient at producing animal protein than terrestrial agriculture, and requires far less fossil fuel inputs

• Aquaculture helps mitigate overfishing and provides affordable, high-quality protein to humans efficiently and with less fossil fuel inputs

• Disadvantages of Aquaculture 

  • Waste from Organisms can pollute waterways with excess nitrogen, causing algal blooms and hypoxia conditions 

  • Uneaten Food Pallets from pens can pollute waterways

  • Farmed organisms may escape from pens and interbreed or compete with wild organisms

  • The sheer density of organisms in lens means infectious diseases and parasites can spread more easily 

    • These must be controlled through the use of antibiotics/anti parasitical in stocks

    • Medication residue can contaminate waterways 

    • Diseases in farmed organisms may spread to wild populations 

• Aquaculture as an Environmental Solution

  • Nearly all potential solutions to environmental issues have advantages and disadvantages 

  • Unintended consequences are also common with environmental solutions, since the natural world is complex with many interconnected biotic and abiotic factors

  • Advantages:

    • Provides high quality protein for a growing population

    • Provides stable income to fisherfolk, with less risk than open water fishing

    • Less acreage and less water use in kilo-for-kilo comparison with terrestrial agriculture means aquaculture is a more efficient means of animal protein production 

    • Fewer fossil fuels inputs needed than terrestrial agriculture 

  • Disadvantages:

    • Nitrogenous waste, pollute, waterways, leading to eutrophication

    • Uneaten feed, can pollute, waterways, leading to water quality issues

    • Escaped farmed organisms can be interbreed or compete with wild organisms

    • Diseases and parasites from densely packed farm populations, can spread to wild populations

    • Medication to control disease and formed organisms can pollute waterways

Unit 5.17: Sustainable Forestry

Forests 

• Forests are an important natural resource that provide ecosystem services to humans, such as:

  • Food

  • Medicine 

  • Fuel, fiber, and timber

  • Carbon sequestration

  • Air purification 

  • Water purification 

  • Flood and erosion mitigation 

  • Maintenance of biodiversity 

  • Recreation

  • Aesthetic and cultural value

Sustainable Forestry

• Refers to a collection of methods that attempts to mitigate the human impact of harvesting trees and using forest resources

  • These methods can include

    • Selective tree cutting, rather than clear cutting

    • Reforestation

    • Buying and using timber that is sustainably sourced and certified 

    • Reusing wood

    • IPM and selective tree removal to reduce disease 

    • Prescribed burns for forest health 

Mitigating Deforestation 

• Deforestation is obviously unsustainable forest use!

• Reforestation - the intentional restocking of existing forests and woodlands that have been depleted - can help

• Buying and using wood from certified providers that use ecologically sustainable forestry techniques, such as:

  • Selective harvesting of trees

  • Prohitbing logging in ecologically sensitive or highly biodiverse areas of forested land

  • Transportation of felled trees via techniques that lessen ecological disruption and soil compaction 

  • Reusing, repurposing, recycling wood products

Mitigating Pathogens

• Diseased trees can threaten the health of the entire forest ecosystem 

• IPM techniques can help minimize that threat of infestations in an ecologically sustainable manner:

  • Continual monitoring of health of tree standards

  • Thinning of underbush

  • Knowledge of common pest species

  • Understanding economic pest threshold

  • Setting pest traps/manual weeding

  • Biological control with natural predators

  • Chemical control with repellents, pesticides, and herbicides (parentheses as a last resort)

• The selective removal of diseased trees can also help slow the spread of infestations in a stand

The Role of Fire 

• Although we had to think of forest fires as negative, prescribed burns, can actually improve forest health and importance sustainable forestry technique

• Fire removes excess under plants, as well as dead tree, limbs, needles, and branches

• The selective removal of understory and dead plant matter can help reduce the severity of natural forest fires by adding the amount of dry matter, available as fuel, and can also help reduce pest infestation

Sustainable Forestry as an Environmental Solution

• Human activities and forest are generally disruptive, and deforestation has undeniably negative impacts on ecosystems and biodiversity

• Knowing this, why is sustainable forestry considered a solution to traditional force management?

• Sustainable forestry methods:

  • Often increase the economic cost of using forest resources and reduce profit margins from timber companies

  • Require forestry workers to be trained on how to properly use these techniques

• Advantages:

  • Mitigation of Deforestation

    • Preserves biodiversity

    • Preserves critical ecosystem services that forest provide

    • Economically supports organizations and timber companies, that employees sustainable methods

    • Reusing wood reduces the need to cut new timber

  • Using IPM and selective tree removal for pest management 

    • Ensures forestry workers are closely monitoring tree stands

    • Reduces impact of pesticide/herbicide use on non-targeted species, soil, and water

    • Reduces likelihood of trophic structure, disruption from pest eradication 

    • More closely mimics, natural balance of ecosystem

  • Prescribed Burns

    • Lessen the severity of naturally occurring fires by moving underbrush and debris

    • Encourage new growth of native species

    • Help manage past species