“An index of the area of productive land and aquatic ecosystems required to produce the resources used and to assimilate the wasters produced by a defined population at a specified material standard of living, wherever on Earth that land may be located.”
Used to determine environmental impact (I)
P = Number of People
A = Affluence, which is a measure of the consumption or amount of resources used per person
T = Environmental effects of the technologies used to obtain and consume the resources
Focus on Sustainability (Ways to protect human welfare and natural resource assets) (8)
Stabilize human population
Prevent pollution where possible
Restore degraded environments
Protect natural ecosystems
Use resources efficiently
Educate all boys and girls
Prevent and reduce waste
Eradicate hunger and poverty
Using technology to reduce consumption. Ex. CFC lightbulbs
New technology may cause environmental damage. Ex: Computers, Fracking
Meeting resource needs of the current generation without compromising the resources to meet the needs of future generations.
Tragedy of the Commons
Occurs when common-pool resources are abused by the public that uses them. (Ex. National Park Service, Forest Service, U.S. Fish and Wildlife)
Sustainable Development (Three Factors)
Environmentally Sound Decisions
Economically Viable Decisions
Socially Equitable Decisions
Five-step process in addressing an environmental problem
Scientific assessment: Is there a problem? How can it be addressed?
Risk analysis: A cost/benefit analysis: What would solutions cost us? What would be the benefit of resolving the problem?
Public education and involvement: Involve all stakeholders
Political action: Changing policy goals
Long-term evaluation: Actions taken must be evaluated over the long term: Surprisingly few projects are evaluated over time. As a result, learning is compromised. The result of failing to evaluate: Reoccurrence of the same problem or origin of a new problem caused by the “solution”
Definition of Ecology
Study of the distribution and abundance of organisms.
Why are organisms found where they are?
Definition of a Species
Group of organisms that don't interbreed with other such groups.
Definition of Populations
Groups of organisms living together in the same place at the same time.
Definition of Community
A set of interacting species occurring at the same place at the same time.
Definition of an Ecosystem
A community and its physical environment.
Definition of Landscape Ecology
Study of the landscape within which species live.
Range is not homogenous: Species are found in suitable habitat throughout their range
Populations may be more or less connected by gene slow amongst them.
Metapopulations consist of multiple populations that vary in connectivity:
Gene flow varies amongst populations, depending on their connectivity to other such populations.
Source/sink populations: Sources produce a net surplus of individuals. Sinks receive a net influx of individuals.
Habitat Connectivity: Sources and sinks must be connected. Source populations provide emigrants to sink populations.
Sources are more important than sinks.
Why this is relevant: Source populations must be conserved.
Their influence on community integrity is greater than other species
Their influence may be out of proportion with their actual density
Loss of keystone species radically alters a community
Loss of keystone species usually means reduction in biodiversity
May also lead to ecosystem collapse
Examples: Prairie Dogs, Sea Otters
Flow of energy through an ecosystem. Changes in energy flow can be due to anthropogenic forcing.
Cycling of nutrients through an ecosystem. Changes in nutrient cycles can also be caused by anthropogenic forcing.
What is forcing?
Human caused change in an ecosystem.
First and Second Laws of Thermodynamics
First Law: Energy can neither be created or destroyed
Second law: “…the total amount of energy available to do work decreases over time” (p. 53) I.e., energy
conversion isn’t 100% efficient. (This is why
large predators are so rare, there isn't much energy left at the top of the food web.)
Productivity after respiration losses (keeping themselves alive) are subtracted.
What is left over for the rest of the food web.
Basic measurement to determine how productive an ecosystem is.
Gross Primary Productivity
The rate at which energy is captured during photosynthesis.
This includes all energy, even the energy used to keep organism alive.
Top four most productive ecosystems (high net primary production):
Algal beds and reefs
Tropical rain forest
Swamp and marsh
Number of species found within a community (raw count)
Used a lot to describe biodiversity because sometimes species evenness is unknown.
Relative abundance of species.
Richness + evenness
Species rich communities aren’t necessarily
i.e. 10 species, but 1 species makes up about 90% of population (non-biodiverse) vs. 10% species A, 10% species B (biodiverse), etc...
Basic patterns of biodiversity:
Terrestrial: The latitudinal gradient; Closer to the equator, higher the biodiversity.
Oceanic: Nutrient load: Coastlines (relatively high nutrients and biodiversity); Upwelling zones (Occur wherever ocean currents bump up against continental shelves or coastlines which causes deep water to rise to the surface.)
Temperature: Relatively stable in oceans; warmer the better for biodiversity.
Photic zones: Where light penetrates and plants are found
Deep-sea hydrothermal vents: Volcanic vents provide a lot of nutrients, the base of the food web are the Chemosynthetic autotrophs.
Patterns of Terrestrial Biodiversity (4)
Climatic stability (Temperature and rainfall)
Description of changes in a community following a disturbance
Succession from bedrock.
A state in which soil hasn’t yet formed.
Succession from any earlier stage, but post formation of soil. (Still soil!!)
The end stage of succession
Type is determined by temperature, precipitation, and climatic stability
Referred to by dominant vegetation (i.e. the biomes)
Areas where ecosystems overlap.
Can have higher disturbance.
Also known as edge habitats.
Species found in these areas are generalists – can adapt to many different types of habitats.
communities where the habitat keeps becoming disturbed before it can reach climax
Ecosystem Services are the processes by which the environment produces resources that we often take for granted such as clean water, timber, and habitat for fisheries, and pollination of native and agricultural plants.
Why is it important to learn about biomes?
Different biomes offer different kinds of ecosystem services.
Different biomes have been impacted in different ways by human activity.
Different biomes respond differently to anthropogenic forcings.
Name 5 ecosystems and the services provided by them.
Name the 3 types of winds and their latitudes on the globe.
Determinants of biome type
Temperature - In general, warmer temperatures lead to higher biodiversity
Rainfall - In general, more rainfall leads to higher biodiversity
Stability - In general, the more stable the climate, the higher the biodiversity
Triangular Diagram that summarizes that types of biomes that occur.
Occurs in Extreme northern latitudes.
Extremly fragile habitat because of the permafrost.
Long harsh winters, short summers.
Geologically young soils.
Low species richness and low productivity.
Artic and Alpine Tundras the same except that alpine is in higher elevation.
Under threat for development and oil drilling.
Very extensive forests.
Conifers and evergreen trees.
Covers 11% of the earth's land.
Winters extremely cold and severe.
Temperate Deciduous Forest
(Also Known at Temperate Broad-Leaf Forest)
Deciduous trees mixed in with conifers.
Hot summers and cold winters.
Productivity limited because of variation in temperature.
Can handle a fair amount of disturbance but has been heavily disturbed because of how many people live in it.
Exists in temperate zones where you have enough rainfall that trees can grow. Throughout the year rainfall is high enough they are not running a water deficit.
Only about 1-2% of the original (never-been-logged) forest remains. Hit really hard by logging.
Large list of species that are now absent from Temperate Deciduous Forests.
Temperate Rain Forest
Around 10ft of rain/year.
Above freezing temperatures all year.
One of the most diverse habitats on earth.
Found from about Oregon up to about British Columbia.
Major controversies revolve around logging.
Spotted owls are the poster animal of this biome.
Conifers tend to dominate, floor is covered in ferns.
Temperate Zone Grasslands
Temperate zone grasslands are found in areas where you don't get enough rainfall for forests.
The tall grass prairies have been wiped out more because the area gets more moisture. (About 99% gone in US.)
Pretty steady climate type, but can have severe droughts.
Lots of annual plants, no sort of evergreen really in general.
Not very biodiverse.
Most damaged of any temperate zone biome because of agricultural value.
Productivity: due to farming in North America about 35-40% of organic matter has been removed over last 3-4 decades.
In general the drier grasslands cannot handle intensive farming. Leading to desertification - which creates a nucleus that spreads.
When drier areas are irrigated, water evaporates and draws salts up from the soil which create baked white areas on which nothing can grow.
Moderate Temperatures Year-round.
Also known as Mediterranean climates
Areas are drier than grasslands.
Fire is common.
Can be reasonably biodiverse, but have low biomass.
Rising air from the mountains condenses and falls on one side of the mountain and the other side of the mountain remains dry.
A lot of deserts wind up being about 23-30deg latitude.
Low biodiversity usually.
Fragile climate – takes a long time for things to regrow.
Lots of off-road vehicle damage.
Savanna: Tropical Grassland
More biodiverse than temperate grassland, but lower biomass.
African Savanna is dotted with trees, but most savannas are not.
Have Megafauna, which are heard of large animals.
Huge herds of large animals leads to the evolution of large predators.
Tropical Dry Forest
Another seasonal habitat.
Found around the equator sometimes, and definitely in the tropical areas.
Made up of deciduous trees that drop leaves during the dry season.
Also subject to desertification.
Tropical Rain Forests
Very high biodiversity.
Extremely poor soil - a lot of the nutrients found in the first couple inches of soil.
Largest carbon sink on the planet.
As you go up in elevation you get different biomes.
Rivers and Streams
Orders of Streams
1st Order - Headwater (little streams).
The higher the number, the bigger the stream.
Meandering Rivers vs Straight Rivers
Meanders slow down the water, slows flooding, and doesn't allow water rise as high.
On srtaight rivers the water gets higher and faster when flooding. (Dikes are built to try and prevent the flooding.)
First order stream and all the higher order streams and all the areas drained into those streams.
Further down water shed, more eutrophic lakes and the more pollution.
Very nutrient high from draining areas like agricultural lands.
Too much nutrients create an algal bloom.
Too much algae in the water creates an algal bloom.
When algae dies, the bacteria that decomposes it uses up all the oxygen which depletes oxygen out of the water creating a Dead Zone.
Zones without oxygen and anything needing oxygen.
Ecosystem Services of swamps and marshes
High primary and secondary production.
Microbes cleanse water (remove methane and such).
Biome where rivers feed into the sea.
Lots of change in salinity levels.
Pretty high nutrient loads, which means they are very productive.
Not real diverse because organisms have problems handling the high salinity changes.
Can be subject to a lot of development.
Marshy areas along coastlines.
Tend to not be very biodiverse or have high biomass.
Generally tropical and subtropical.
Go about as north as Florida.
Very still waters.
Not really biodiverse, but very productive.
In danger of being removed for development.
Encounters a lot of impact from pollution.
Heavy impacted by development because people like to build houses and hotels.
Very stressful environment.
Tends not to be rich in species.
Can become silted in by development.
Important Bentic Zones
Damaged by boating.
Used as fish nursaries.
Common along coastlines.
Kind of algae that grows up to 40-50ft long.
Very productive area.
Very important because light can penetrate them.
High biomass and high biodiversity in coral reefs.
At risk because of over-fishing and damage from anchors.
Reefs are near-shore habitats so encounter a lot of human activity.
One of the major problems is siltation.
Most corals have mutualistic relationship with algae, when algae is killed by siltation, coral dies too.
Occurs when algae are expelled from the bodies of corals (killing the coral).
Not sure why this occurs.
Various Threats to Water
Nonpoint Source Pollution
Point Source Pollution
Nonpoint Source Pollution
Runoff from land.
Release of ship's ballast water, which contains foreign crabs, mussels, worms and fishes.
Our technology allows people to make more money by catching more fish.
By the time people figure out fisheries are collapsing, it's too late.
Unintentionally catching things like turtles, dolphins, etc.
Areas where currents sweep.
Junk in the ocean winds up in the center (slow moving water).
5 of them, the biggest being the North Pacific Gyre.
Little pebbles that plastic bottles break down into.
Can be found on every coastline in the world.
Ingested by anything that can get them in their mouths and cause many deaths.
Two natural reservoirs of CO2 and CH4
Organic (Animal Respiration and methanogenic bacteria)
Inorganic (Coal, natural gas, volcanoes)
Anthropogenic additions of carbon
Automobiles and Industry
Normal Carbon Cycle
Plants > Animals > Dead Animals Release Carbon
Living Carbon Sinks
Geological Carbon Sinks
Soil, Peat, Coal, Natural Gas
Laberation can lead to catastrophic global warming.
Issues in the Oceans
Warming expands the oceans - increases the level of sea rise.
Increased carbonic acid - increases acidy of oceans
Nitrogen is a limiting nutrient of plant growth.
Nitrogen makes up 78.1% of the Atmosphere.
Organisms that can use atmospheric Nitrogen
Nitrogen-fixing bacteria (on roots of plants - source of most our nitrogen)
Nitrogen Cycle Timeframe
How Humans have screwed up the nitrogen cycle (3):
Eutrophication (too much N and P which causes algal blooms)
Nitrogen oxides (smog)
Acidification (acid rain)
Major Reservoirs of Phosphorus: Geological
Slowly released through weathering
Major reservoirs of Phosphorus: Organic
Plants take up P from soils (Mycorhizzal fungae are a key organism)
P is passed on to animals (during grazing)
How humans have screwed up the phosphorus cycle
"remains in the ocean for millions of years" (as rocks)
Driven by autotrophic bacteria (Break down sulfate bonds to obtain energy)
Anthropogenic Changes to the Sulfur Cycle
Global level of sulfur increased by ~160%
Acid rains: Creation of sulfuric acid in the atmosphere