AP Environmental Science - Unit 9 Global Change Notes

9.1 & 9.2 - Stratospheric Ozone Depletion and Reducing Ozone Depletion

• Learning Objective STB-4.A: Explain the importance of stratospheric ozone to life on Earth.
  • Essential Knowledge STB-4.A.1: The stratospheric ozone layer is critical for the evolution, health, and survival of life on Earth.
  • Essential Knowledge STB-4.A.2: Stratospheric ozone depletion is caused by anthropogenic factors like chlorofluorocarbons (CFCs) and natural factors like the melting of ice crystals in the Antarctic spring.
  • Essential Knowledge STB-4.A.3: Decreased stratospheric ozone increases UV rays reaching Earth, leading to skin cancer and cataracts in humans.
• Stratospheric Ozone & Life on Earth
  • Ozone in the stratosphere absorbs UV-C and much of UV-B radiation.
  • Without the ozone layer, life on land would be impossible due to significant tissue damage and DNA mutation caused by UV-B & UV-C radiation.
  • Human health benefits: Prevention of skin cancer and cataracts.
  • UV-B & UV-C mutate DNA (skin cancer) and cause oxidative stress in eyes (cataracts).
  • Tropospheric ozone is a respiratory irritant, damaging to plant tissue, and a precursor to photochemical smog.
• How Ozone Absorbs UV-B & UV-C
  • UV-C breaks O_2 into two free oxygen atoms (2 O).
  • A free oxygen atom combines with an O2 molecule to form ozone (O3).
  • UV-C reverses the reaction by breaking ozone (O3) into O2 and O.
  • Continued formation and breakdown of O_3 in the stratosphere absorbs all UV-C and much UV-B radiation.
• Anthropogenic Ozone Depletion
  • CFCs (chlorofluorocarbons) are a primary human cause of O_3 breakdown.
  • Used as refrigerant chemicals and propellants in aerosol containers.
  • UV radiation causes a free chlorine atom to separate from CFCs.
  • Chlorine atoms bond to one oxygen atom of ozone (O3), converting it into oxygen (O2).
  • A free O atom then bonds to O from chlorine monoxide to form O_2 and a free Cl atom.
  • One single Cl atom can persist in the atmosphere for 50-100 years and destroy up to 100,000 ozone molecules.
• Natural Ozone Depletion
  • Antarctica spring melt forms polar stratospheric clouds (PSC).
  • Clouds are made of water & nitric acid (HNO_3) and form in consistent -1000 F temp range above Antarctica.
  • In presence of PSCs, chlorine nitrate (ClONO2) and hydrochloric acid (HCl) react and give off Cl2.
  • Cl_2 is photolyzed broken by sun into 2 free Cl atoms.
  • Cl atoms break O3 down into O2 over and over.
• Learning Objective STB-4.B: Describe chemicals used to substitute for chlorofluorocarbons (CFCs).
  • Essential Knowledge STB-4.B.1: Ozone depletion can be mitigated by replacing ozone-depleting chemicals with substitutes that do not deplete the ozone layer. Hydrofluorocarbons (HFCs) are one such replacement, but some are strong greenhouse gases.
• Reducing Ozone Depletion
  • The main way to reduce anthropogenic O_3 depletion is phasing out & replacing CFCs.
  • The Montreal Protocol (1987) was a global agreement to phase out CFCs from production in refrigerators, aerosols, and other uses.
  • Replaced with HCFCs (CFCs with hydrogen added).
  • Replacement for HCFCs is HFCs (still GHGs, but not O_3 depleting since they don’t contain Cl).
  • HCFCs still deplete O_3 and act as GHGs, but to a lesser degree than CFCs.
  • Not a permanent solution, but a temporary transition option (phase out in developed nations after 2020, developing nations have until 2030).
  • Replacements for HFCs are HFOs (just HFCs with C-C double bonds that shorten atm. Lifetime & GWP).

The Greenhouse Effect

• Learning Objective STB-4.C: Identify the greenhouse gases.
  • Essential Knowledge STB-4.C.1: The principal greenhouse gases are carbon dioxide, methane, water vapor, nitrous oxide, and chlorofluorocarbons (CFCs).
  • Essential Knowledge STB-4.C.2: While water vapor is a greenhouse gas, it doesn't contribute significantly to global climate change because it has a short residence time in the atmosphere.
  • Essential Knowledge STB-4.C.3: The greenhouse effect results in the surface temperature necessary for life on Earth to exist.
• Learning Objective STB-4.D: Identify the sources and potency of the greenhouse gases.
  • Essential Knowledge STB-4.D.1: Carbon dioxide, which has a global warming potential (GWP) of 1, is used as a reference point for the comparison of different greenhouse gases and their impacts on global climate change. Chlorofluorocarbons (CFCs) have the highest GWP, followed by nitrous oxide, then methane.
• Solar Radiation
  • Not all incoming solar radiation reaches earth’s surface.
  • 26% is reflected back into space by clouds & the atmosphere.
  • 19% is absorbed by the atmosphere & clouds & radiated out into space & down to earth.
  • The rest reaches earth’s surface where it can be absorbed or reflected (depending on the albedo of the surface it strikes).
  • Lighter, higher albedo surfaces reflect sunlight, directly back out into space, or into clouds/GHGs that absorb it.
  • Darker, lower albedo surfaces absorb sunlight & release infrared radiation (which we feel as warmth).
• The Greenhouse Effect
  • Gases in Earth’s atmosphere trap heat from the sun & radiate it back down to earth.
  • Without the greenhouse effect, Earth would be too cold to support life.
  • Solar radiation (light waves like UV & visible light) strike earth’s surface, heating it.
  • Earth’s surface releases infrared radiation.
  • Greenhouse gases absorb infrared radiation & radiate it both out into space and back toward earth.
  • The portion coming back to earth is the “greenhouse effect”.
• Greenhouse Gases & Sources
  • Important Greenhouse Gases (GHGs):
    • CO_2 - FF comb, decomposition, deforestation
    • Methane (CH_4) - natural gas extraction & combustion, animal agriculture, anaerobic decomp. (especially permafrost thaw)
    • Nitrous oxide (N_2O) - agricultural soils (denitrification of nitrate, especially in overwatered, over-fertilized soils)
    • CFCs/HCFCs/HFCs - refrigerants, blowing agents in aerosol products
    • Water vapor (H_2O) - evaporation & transpiration from plants - Technically a GHG by definition, but doesn’t drive atm. temp change.
• Global Warming Potential (GWP)
  • Measure of how much a given molecule of gas can contribute to the warming of the atmosphere over a 100-year period, relative to CO_2
  • Based on 2 factors: Residence time & Infrared absorption.
  • CO_2 has a GWP of 1.
  • Methane (CH4) remains in atm. around 12 yrs, absorbs more IR than CO2.
  • N2O remains in atm. around 115 yrs, absorbs much more IR than 300 CO2.
  • CFCs remain in atm 50-500 yrs, absorb much, much, much more IR than CO_2.

9.4 Increase in Greenhouse Gases

• Learning Objective STB-4.E: Identify the threats to human health and the environment posed by an increase in greenhouse gases.
  • Essential Knowledge STB-4.E.1: Global climate change, caused by excess greenhouse gases in the atmosphere, can lead to a variety of environmental problems including rising sea levels resulting from melting ice sheets and ocean water expansion, and disease vectors spreading from the tropics toward the poles. These problems can lead to changes in population dynamics and population movements in response.
• Thermal Expansion
  • Water molecules move slightly further apart when they’re heated.
  • All the water molecules of the ocean moving slightly apart leads to sea level rising.
• Melting Ice Sheets & Glacial Ice
  • Increased greenhouse gases lead to a warmer climate & more melting of continental ice sheets (Antarctica) and glaciers.
  • This water flows into the ocean and leads to sea level rise.
  • Sea ice (such as N polar ice) melt does NOT cause sea level rise, only land-based ice sheets and glaciers.
• Env. Impacts of Sea Level Rise
  • Flooding of coastal ecosystems like estuaries (mangroves, salt marshes).
  • Loss of species that depend on arctic and tundra ecosystems (polar bears, penguins, reindeer).
  • Loss of thaw-freeze cycle that glaciers go through, depriving surrounding ecosystems and human communities of water source
• Human Impacts of Sea Level Rise
  • Relocation of coastal human populations.
  • Saltwater intrusion contaminating wells.
  • Increase in flood frequency = higher insurance and repair costs, lost property.
  • Refugees forced to move inland
• Disease Vectors
  • Living organisms (usually mosquitoes, ticks, fleas) that can transmit diseases from human to human or animal to human.
  • Ex: malaria, Zika, West Nile, dengue fever, cholera.
• Expanded Range of Disease Vectors
  • Warmer temperatures allow insect-transmitted diseases to spread to parts of the world previously too cold.
  • As the insect vectors expand their range further from equators, toward poles, new human populations are at risk.

9.5 Global Climate Change (Part 1)

• Learning Objective STB-4.F: Explain how changes in climate, both short- and long-term, impact ecosystems.
  • Essential Knowledge STB-4.F.1: The Earth has undergone climate change throughout geologic time, with major shifts in global temperatures causing periods of warming and cooling as recorded with CO_2 data and ice cores.
  • Essential Knowledge STB-4.F.2: Effects of climate change include rising temperatures, melting permafrost and sea ice, rising sea levels, and displacement of coastal populations.
  • Essential Knowledge STB-4.F.3: Marine ecosystems are affected by changes in sea level, some positively, such as in newly created habitats on now-flooded continental shelves, and some negatively, such as deeper communities that may no longer be in the photic zone of seawater.
  • Essential Knowledge STB-4.F.4: Winds generated by atmospheric circulation help transport heat throughout the Earth. Climate change may change circulation patterns, as temperature changes may impact Hadley cells and the jet stream.
• Historic Climate Change
  • Earth’s climate has varied over geologic time, largely due to variations in earth’s orbit around the sun.
  • Varies in eccentricity bringing it closer to and further from the sun at different times.
  • Varies in obliquity exposing northern latitudes to higher insolation at different times.
  • Leads to predictable variation in Earth’s climate called Milankovitch Cycles.
• Earth’s Historical Climate
  • Scientists have measured and estimated earth’s historical temperature and CO_2 levels using 3 main pieces of evidence.
    • Foraminifera shells in ocean sediments - different species have diff. temp. tolerance.
    • Air bubbles in ice cores that contain ancient atmospheric gas (CO_2 levels).
    • ^{16}O vs. ^{18}O isotope concentrations in ancient ice (^{18}O = temp.).
  • Global ice ages, followed by warmer periods occur roughly every 100,000 years.
  • CO_2 levels are strongly correlated with temperature, but causality isn’t fully understood.
• Effects of Climate Change
  • Rising Temperature - habitat/species loss, drought, soil desiccation, heat waves, increased precipitation in some regions.
  • Rising Sea Level - due to glacial, continental ice sheet melt + thermal expansion.
  • Melting of Permafrost - permanently frozen tundra soils that begin to thaw & release methane & CO2 from anaerobic decomposition (CH4).
• Impact on Coastal Communities
  • Property loss, damage, potential relocation: Coastal communities, especially poorer ones that can’t build up may need to relocate inland.
  • Seawalls or other barriers can be built higher, but this just delays eventual flooding.
  • Loss of barrier islands: islands that buffer coastal communities/ecosystems from wind & waves may be lost as sea level rises
• Impact on Atmospheric Currents
  • Widening & weakening of hadley cell: as temp. diff. between equator and poles decreases, air ascending and expanding from equator travels further before sinking.
  • This shifts subtropical zones (dry, desert biomes) toward the poles and expands the tropics.
  • Regions between 300 and 60o may experience drier climate as cool, dry, descending air from hadley cell shifts north & south
  • Weakened, destabilized Jet Stream: as arctic warms faster than other areas of earth, temp. difference between equator & poles weakens.
  • Leads to extreme cold spells in eastern US & dry spells in western US.

9.5 Global Climate Change (Part 2)

• Learning Objective STB-4.F: Explain how changes in climate, both short- and long-term, impact ecosystems.
  • Essential Knowledge STB-4.F.5: Oceanic currents, or the ocean conveyor belt, carry heat throughout the world. When these currents change, it can have a big impact on global climate, especially in coastal regions.
  • Essential Knowledge STB-4.F.6: Climate change can affect soil through changes in temperature and rainfall, which can impact soil's viability and potentially increase erosion.
  • Essential Knowledge STB-4.F.7: Earth's polar regions are showing faster response times to global climate change because ice and snow in these regions reflect the most energy back out to space, leading to a positive feedback loop.
  • Essential Knowledge STB-4.F.8: As the Earth warms, this ice and snow melts, meaning less solar energy is radiated back into space and instead is absorbed by the Earth's surface. This in turn causes more warming of the polar regions.
  • Essential Knowledge STB-4.F.9: Global climate change response time in the Arctic is due to positive feedback loops involving melting sea ice and thawing tundra, and the subsequent release of greenhouse gases like methane.
  • Essential Knowledge STB-4.F.10: One consequence of the loss of ice and snow in polar regions is the effect on species that depend on the ice for habitat and food.
• Impact on Marine Ecosystems
  • Altered range of marine ecosystems: some new marine habitats will be formed by rising sea level flooding coastline.
  • Some areas of ocean will become too deep to receive sunlight & photic zone will shift up, further from ocean floor
  • Altered ranges for organisms: warm water holds less O_2, so many fish populations have declined, or migrated to cooler waters
• Impact on Ocean Circulation
  • Suppression of thermohaline circulation: global ocean current that redistributes heat from the equator, salt, and nutrients by mixing ocean waters could slow or stop altogether.
  • Ice melt from Greenland especially cold, fresh water buildup in the north Atlantic.
  • Freshwater is less dense than salt, preventing it from sinking.
  • This cold north atlantic slows warmer Gulf Stream waters, cooling Europe & slowing global thermohaline circulation
• Unequal Global Warming
  • Polar regions of earth are warming faster than other regions (polar amplification).
  • Especially the arctic (N pole) because there is more land & less water to absorb heat.
  • Melting sea ice = more exposed ocean water, which absorbs more sunlight than ice & snow, leading to more ice melting (positive feedback loop)
  • Distribution of tropical heat to poles by thermohaline circulation also warms poles
• Unequal Global Warming (cont.)
  • Melting of Permafrost - permanently frozen tundra soils that begin to thaw & release methane & CO2 from anaerobic decomposition (CH4).
  • Air pollution adds soot & other PM to atmosphere, distributed to poles by atmospheric circulation.
  • Darker, soot/PM covered ice absorbs even more heat due to lower albedo
• Impact on Polar Ecosystems
  • Arctic sea ice loss = habitat loss
  • Seals use it for resting and find holes for breathing
  • Algae grow on ice, forming the base of the arctic food web
  • Polar bears use ice for hunting seals at breathing holes

9.6 Ocean Warming

• Learning Objective STB-4.G: Explain the causes and effects of ocean warming.
  • Essential Knowledge STB-4.G.1: Ocean warming is caused by the increase in greenhouse gases in the atmosphere.
  • Essential Knowledge STB-4.G.2: Ocean warming can affect marine species in a variety of ways, including loss of habitat, and metabolic and reproductive changes.
  • Essential Knowledge STB-4.G.3: Ocean warming is causing coral bleaching, which occurs when the loss of algae within corals cause the corals to bleach white. Some corals recover and some die.
• Atmospheric Warming and Ocean Warming
  • As the atmosphere warms, heat is transferred to the ocean.
  • Oceans absorb much of the earth’s heat due to the high specific heat of water (est. 90% of earth’s warming from the past 50 yrs. occurred in oceans).
  • Heat absorbed by the ocean can transfer back to the atmosphere for decades
  • Thermohaline circ. distributes heat absorbed at the surface to depths & other areas of earth
• Effects of Ocean Warming on Marine Species
  • Warmer water holds less O_2; causing resp. stress or suffocation.
  • Migratory routes and mating seasons can be altered, especially for whales
  • Reproductive timing, often tied to temp. change, can be disrupted (fish esp.).
  • Habitat loss: coral bleaching with heating ocean; shallow, sunny waters ideal for algae & coral become deeper from ice melt
  • Toxic algae blooms: toxic blue-green algae prefer warmer waters & warm temperature prevents mixing of water, enabling algae blooms
  • Blue-green algae release toxins into the water that can kill marine species & block sunlight & lead to hypoxia
• Coral Bleaching
  • Coral reef = mutualistic relationship between coral & photosynthetic algae called zooxanthellae; algae supply sugar & coral supply CO_2 + detritus (nutrient-containing org. matter.)
  • Algae have a narrow temp. tolerance and leave the reef when temp. rises
  • Coral lose color & become stressed and vulnerable to disease without algae (main food source)
  • Pollutants from runoff (sediment, pesticides, sunscreen) can also force algae from the reef

9.7 Ocean Acidification

• Learning Objective STB-4.H: Explain the causes and effects of ocean acidification.
  • Essential Knowledge STB-4.H.1: Ocean acidification is the decrease in pH of the oceans, primarily due to increased CO_2 concentrations in the atmosphere, and can be expressed as chemical equations.
  • Essential Knowledge STB-4.H.2: As more CO2 is released into the atmosphere, the oceans, which absorb a large part of that CO2, become more acidic.
  • Essential Knowledge STB-4.H.3: Anthropogenic activities that contribute to ocean acidification are those that lead to increased CO_2 concentrations in the atmosphere: burning of fossil fuels, vehicle emissions, and deforestation.
  • Essential Knowledge STB-4.H.4: Ocean acidification damages coral because acidification makes it difficult for them to form shells, due to the loss of calcium carbonate.
• Ocean Acidification
  • Increased CO2 in the atmosphere increases ocean CO2 (direct exchange).
    • CO2 combines with ocean water to form carbonic acid (H2CO_3)
    • Carbonic acid dissociates into Bicarbonate ion (HCO_3^-) and H^+ ion
• Calcium Carbonate & Marine Organisms
  • Marine organisms that make shells use calcium (Ca^+) and carbonate (CO_3^{2-}) ions to build their calcium carbonate shells (calcification).
  • CO_2 increase & ocean acidification makes carbonate ions less available.
  • Carbonic acid increased H^+ ions which bond w/carbonate to form Bicarbonate (HCO_3^-).
  • Marine shells breakdown as pH decreases and carbonate ions are less soluble in ocean water.
  • Fewer carbonate ions = less calcification; weaker shells of coral, mollusks, and urchins
• Climate Change & Ocean Acidification
  • Anthropogenic causes for ocean acidification: fossil fuel combustion (CO2), deforestation (CO2), and coal/gas combustion (NOx/SOx → acid precip.).
  • CO_2 increase is directly correlated with ocean acidification
  • Inverse relationship b/w atm. CO_2 & ocean pH (low pH = more acidic).
  • Ocean pH has decreased from 8.2 to 8.1 in the past 150 years; could decrease to 7.8 by 2100
  • pH = log scale so 8.2 to 8.1 = 30% decrease

9.8 Invasive Species

• Learning Objective EIN-4.A: Explain the environmental problems associated with invasive species and strategies to control them.
  • Essential Knowledge EIN-4.A.1: Invasive species are species that can live, and sometimes thrive, outside of their normal habitat. Invasive species can sometimes be beneficial, but they are considered invasive when they threaten native species.
  • Essential Knowledge EIN-4.A.2: Invasive species are often generalist, r-selected species and therefore may outcompete native species for resources.
  • Essential Knowledge EIN-4.A.3: Invasive species can be controlled through a variety of human interventions.
• Invasive Species Basics
  • Species not native to an area, introduced often by human transport.
  • r-selected, generalists.
  • No natural predators to control population, high biotic potential & low parental care, diverse habitat & food needs, highly adaptable, highly competitive for resources, can thrive in their non-native habitats
• Invasive Species To Know
  • Zebra Mussel
    • Aggressive filter feeders take algae many other species rely on
    • Clog intake pipes
    • 1 mil. eggs/yr, transported by ship ballast water
  • Kudzu Vine
    • Planted to limit soil erosion in the southern US, grows very rapidly
    • Outcompetes natives for sunlight (growing over them), no herbivore control in US
  • Asian Carp
    • Brought in to control algae growth in aquatic farms, escaped to Mississippi river; outcompete native fish for food and space, decreases fishery production & value
  • Emerald Ash Borer
    • Larvae laid in bark, eat their way into phloem
    • Spread by wood packing materials of ships/planes & fire wood, disrupts tree nutrient transport, killing them
  • Cane Toad
    • Introduced to eat cane beetles causing sugarcane crop loss in Australia, became invasive due to huge appetite, drove declines in other amphibians and small reptiles
  • Pythons (FL)
    • Brought to Florida as pets, released into wild by owners, decimated mammal populations in Everglades ~90-95%, aggressive hunters with no natural predators, expanding range due to global warming
• Controlling Invasives
  • Invasives are estimated to cost the US $120 billion/year (2005 est.)
  • Control/removal methods: Laws preventing transport of invasives, removing of hosts to reduce spread, introduction of natural predator, careful boat cleaning & inspection, physical removal

9.9 Endangered Species

• Learning Objective EIN-4.B: Explain how species become endangered and strategies to combat the problem.
  • Essential Knowledge EIN-4.B.1: A variety of factors can lead to a species becoming threatened with extinction, such as being extensively hunted, having limited diet, being outcompeted by invasive species, or having specific and limited habitat requirements.
  • Essential Knowledge EIN-4.B.2: Not all species will be in danger of extinction when exposed to the same changes in their ecosystem. Species that are able to adapt to changes in their environment or that are able to move to a new environment are less likely to face extinction.
  • Essential Knowledge EIN-4.B.3: Selective pressures are any factors that change the behaviors and fitness of organisms within an environment.
  • Essential Knowledge EIN-4.B.4: Species in a given ecosystem compete for resources like territory, food, mates, and habitat, and this competition may lead to endangerment or extinction.
  • Essential Knowledge EIN-4.B.5: Strategies to protect animal populations include criminalizing poaching, protecting animal habitats, and legislation.
• How Species Become Endangered
  • Poaching: Poachers hunt exotic species for fur, tusks, horns; may also be over harvested or hunted for food, removed from wild & sold as pets
  • Special food/habitat needs: Niche specialists are more prone to endangerment due to specific food/habitat needs; less tolerant of changing climate, habitat loss, wildfires, deforestation, urbanization, etc.
  • Invasives: Invasives can outcompete natives for resources (food, water, sun, space); Zebra mussels have endangered 30 native mussel species in US rivers
  • Climate Change: Shifts habitats of many species - Migration to new habitat is harder with fragmentation/loss changes in temperature/precip. can occur too rapidly for some species to migrate or adapt.
• Protecting Endangered Species
  • Poaching Prevention: Hiring of armed guards to monitor populations and prevent poaching
  • Protect Wildlife Habitats: Designating areas with important habitats; Prevention of hunting, development, fragmentation, and deforestation allows species to breed and reestablish population size
  • Legislation: Laws that punish poaching severely, with stiff fines or jail time; CITES: International agreement, Endangered Species Act: US law giving USFWS the power to designate species as endangered or threatened
• Endangerment by Taxon
  * 41% Amphibians
  * 25% Mammals
  * 13% Birds
  * 33% Warm Water Coral
  * 34% Conifers
• Specialists vs. Generalists
  * Specialists
  Less likely to move to a new habitat, or adapt to new conditions. Endangered by rapidly changing conditions
  * Generalists
  More likely to move to a new habitat, adapt to new conditions. Less likely to be endangered
• Competition & Endangerment
  • Interspecific competition: competition for resources (food, nest sites, water) amongst members of different species. Can cause species to become threatened, especially when combined with general habitat fragmentation or loss due to human land use, or climate change

9.10 Human Threats to Biodiversity

• Learning Objective EIN-4.C: Explain how human activities affect biodiversity and strategies to combat the problem.
  • Essential Knowledge EIN-4.C.1: HIPPCO (habitat destruction, invasive species, population growth, pollution, climate change, and overexploitation) describes the main factors leading to a decrease in biodiversity.
  • Essential Knowledge EIN-4.C.2: Habitat fragmentation occurs when large habitats are broken into smaller, isolated areas. Causes of habitat fragmentation include the construction of roads and pipelines, clearing for agriculture or development, and logging.
  • Essential Knowledge EIN-4.C.3: The scale of habitat fragmentation that has an adverse effect on the inhabitants of a given ecosystem will vary from species to species within that ecosystem.
  • Essential Knowledge EIN-4.C.4: Global climate change can cause habitat loss via changes in temperature, precipitation, and sea level rise.
  • Essential Knowledge EIN-4.C.5: Some organisms have been somewhat or completely domesticated and are now managed for economic returns, such as honeybee colonies and domestic livestock. This domestication can have a negative impact on the biodiversity of that organism.
• HIPPCO
  • Habitat Fragmentation/Loss: Deforestation, Wetland draining, River water level decrease from dams
  • Invasive Species: Species such as the Zebra Mussel and Kudzu Vines outcompete natives.
  • Population Growth: Drives habitat loss due to urbanization.
  • Pollution: Oil spills/Pesticides reduce or remove non-target species..
  • Climate Change: Shifts biomes & species habitats, changes precipitation
  • Over Exploitation: Over hunting to extinction
• Habitat Fragmentation
  • Roads & Pipelines: Fragments habitats + collisions with vehicles
  • Agricultural & Urban Land Use: Clearing of ecosystems
  • Logging: Breaking of larger Ecosystems into smaller patches that disrupt living patterns.
• Metapopulations
  • Habitat Fragmentation creates isolated and smaller subpopulations
  • Smaller subpopulations have less diverse genes that make them less resilient to disturbances and mutations.
  • Larger Metapopulatons are connected by habitate corridors; these allow crossbreeding and increase genetic diversity.
• Edge Effect
  • Edge Habitat’s are where the characteristics of 2 or more ecosystems meet.
  • Biodiversity is at highs here due to the variety of food and shelters
  • Habitat corridors allow invasive and potentially disruptive species to use both bordering ecosystem
• Climate Change
  • Temperature: Warming Temp will decreases precipitation, that causes desiccation
  • Precipitation: Climate change can increase precipitation expansion in ecosystems
  • Sea Level: Ecosystems become sumberged and more saline levels rise
• Crops
  * GM use and selective breeding lead to less genetic diversity, making crops more vulnerable to disease.
• Livestock
  * Domestication of species for crop use decreases generic and species biodiversity.
• Mitigating Biodiversity Loss
  • Protecting important habitats by creating national parks
  • Connecting fragmented habitats to breed others
  • Sustainable land use and decreasing land waste
  • Restoring Lost Habitats