Ecological Footprint and Population Dynamics Overview

Carrying capacity

The maximum, equilibrium number of organisms of a particular species that can be supported indefinitely in a given environment without being adversely impacted.

Ecological footprint

Concept developed as a way to measure the individual impact humans were having on the environment.

Ecologically productive land area

Areas of Earth currently capable of biological production.

Biocapacity

The capacity of an ecologically (biologically) productive area to generate an ongoing supply of renewable resources and to absorb its spillover wastes (expressed in global hectares or global acres).

Ecological overshoot

The biological phenomenon used by ecologists to describe a species whose numbers exceed the ecological carrying capacity of the place where it lives.

Virtual water

The sum of water used in the various steps of the production chain.

External water footprint

Water that is used in other countries to create the products and services you import.

Internal water footprint

Water you use that is sourced in your own country.

Water footprint

The total volume of freshwater that is used to produce the goods and services consumed by the individual, community or business.

Malthusian Trap

As population increases, we will also need more food which requires more land and other resources. Once population exceeds food production, war, famine, poverty, and depopulation may predominate.

Tragedy of the Commons

Individuals act according to self-interest but contrary to the best interest of the whole by depleting resources in the commons.

J-curve

Maximum reproductive capacity of a population under optimum environmental conditions. All resources are available, all the time.

S-curve

Limitations on resources. Population hits a point of maximum growth (carrying capacity), then levels out.

Environmental resistance

Pressure exerted on a population by an ecosystem. Populations are influenced by the environment and require resources to support them.

Density-independent resistance

Limitations to a population regardless of population size.

Density-dependent resistance

Affects population based on the population size and how close it is to carrying capacity.

Bottom-up control

Pressure from the bottom of the food chain.

Top-down control

Pressure from the top of the food chain.

General growth rate

Initial number of individuals in a population. Expressed as percent.

Rate of natural increase (RNI)

Isolated populations.

Population growth rate (PGR)

Used for populations that are NOT geographically isolated. Includes immigration and emigration.

Doubling time

The amount of time it would take for a population to INCREASE by a factor of 2 (double). Positive growth rate.

Halving time

The amount of time it would take for a population to DECREASE by a factor of 2 (half). Negative growth rate.

Fertility rate

The number of individuals born to a reproducing female in their lifetime.

Replacement fertility rate

Rate needed to replace each individual from one generation to the next without increasing or decreasing the population (RNI = 0%).

Monoculture

Repeated production of a single crop within an agricultural area.

Permaculture

Production of a variety of crops within an agricultural area.

Eutrophication

The over-enrichment of water with nutrients.

Agricultural runoff

Transports excess fertilizer into surface water.

Genetically modified organisms (GMOs)

An organism or microorganism whose genetic material has been altered by means of genetic engineering.

Bioaccumulation

The accumulation of substances, such as pesticides or other chemicals, in an organism. Occurs when the organism absorbs a substance faster than which the substance is lost.

Biomagnification

The increasing concentration of toxins in an organism as a result of ingesting other plants or animals in which the toxins are more widely dispersed.

Land use for livestock

77% of land is used for livestock and 23% for crops.

Advantages of GMOs

Higher nutrient content, better quality, larger yields, pest and herbicide resistance.

Disadvantages of GMOs

May trigger food allergies, may cross-breed with other plants, cost, misinformation, unknown consequences.

Top demand sectors for energy

Electricity generation, transportation, and heating/cooling.

Renewable Energy

Resources that can be replenished in our lifetime (solar, wind, hydropower).

Non-Renewable Energy

Resources that will run out or never replenish in our lifetime (Oil, coal, and natural gas).

Hydraulic fracturing (fracking)

Process of extracting oil and gas from bedrock.

Advantages of fracking

Increased energy production, lower energy cost, and reduced coal dependency.

Disadvantages of fracking

Environmental impacts (like earthquakes), water usage, and public health risk.

Point-source pollution

A type of pollution where the source can be identified.

Nonpoint-source pollution

A type of pollution where the source cannot be easily identified.

Atmospheric deposition

Pollutants can transfer from the air to land or water.

Dry Deposition

Air pollutants settle directly from air to the surface.

Wet Deposition

Air pollutants mix with moisture in the air and reach the surface through rain.

Major sources of outdoor air pollution

Transportation, factories, and power plants.

Major sources of indoor air pollution

Chemicals from cleaning products, animal hair, chemicals from paint, and cigarette smoke.

Six principal air quality constituents

Carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone, and sulfur dioxide.

Factors determining ozone levels

Temperature, population, and emissions.

Stratospheric Ozone

Forms naturally in the upper atmosphere and absorbs UV radiation from the sun.

Ground-Level Ozone

Forms from reactions of anthropogenic emissions in the lower atmosphere and can trigger respiratory problems.

Mercury emissions

Coal combustion is the primary cause of mercury emissions into the environment.

Bioaccumulation vs. Biomagnification

Bioaccumulation is building up over time in a single organism; biomagnification is an increase in concentration as the trophic levels of the food chain get higher.

Infrared radiation

A type of electromagnetic radiation with wavelengths longer than visible light but shorter than microwaves.

Greenhouse gas

Chemical compounds that absorb infrared radiation.

The greenhouse effect

The trapping of the sun's warmth in a planet's lower atmosphere, necessary to keep the Earth warm enough to support life.

Carbon assimilation

Plants remove carbon dioxide from the atmosphere and convert it to carbohydrates through photosynthesis.

Net primary productivity (NPP)

Used to calculate an area's capability to assimilate or emit carbon. NPP = (carbon assimilation) - (carbon emission).

Greenhouse Effect

Process where greenhouse gases trap heat in atmosphere.

Average Earth Temperature Without Greenhouse Gases

Approximately -18ºC (-0.4ºF) without greenhouse effect.

Common Greenhouse Gases

Includes carbon dioxide, methane, nitrous oxide, CFCs.

Sources of Greenhouse Gas Emissions

Methane from permafrost, melting polar ice caps.

Reflection

Radiation bounces off Earth's surface without energy change.

Absorption

Radiation converted to thermal energy in materials.

Positive Feedback Cycle

Reaction product increases reaction rate, destabilizing system.

Carbon Assimilation

Process where plants absorb carbon from atmosphere.

Carbon Emissions

Release of carbon dioxide by animals and processes.

Net Primary Productivity (NPP)

NPP = carbon assimilation - carbon emissions.

Negative NPP

More carbon emitted than assimilated, indicating loss.

Positive NPP

More carbon assimilated than emitted, indicating gain.

Biodiversity

Variety of life at each organizational level.

Species Diversity

Variety and abundance of species in an ecosystem.

Genetic Diversity

Variability of genes within a single species.

Habitat Diversity

Variety of different habitats in an ecosystem.

Species Richness

Total number of species in a community.

Species Evenness

Relative abundance of different species in ecosystem.

Heterogeneity

Measure of richness and evenness in biodiversity.

Minimum Viable Population

Minimum individuals required for species survival.

Island Biogeography Theory

Explains species richness based on immigration and extinction.

Habitat Fragmentation

Human development divides habitats into smaller patches.

Biological Corridor

Passages allowing species movement between habitats.

Buffer Zone

Transitional area between natural and human environments.

Ecosystem Goods and Services

Benefits derived from ecosystem functions by humans.

Importance of Biodiversity

Supports healthy ecosystems and natural resource abundance.

Simpson's Biodiversity Index (D)

Measures probability two individuals belong to same species.

Simpson's Index of Diversity (1-D)

Measures probability two individuals belong to different species.

Reciprocal Index (1/D)

Measures diversity based on probability of different species.

Human Impact on Natural Habitats

Fragmentation leads to smaller, isolated habitats.

Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

International agreement for the careful monitoring of international trade of wildlife fauna and flora

Charismatic megafauna

Large animals with widespread popular appeal that many environmental activists focus on for achieving environmental action

Poaching

The illegal hunting or capturing of wild animals

U.S. Endangered Species Act of 1973

Provides a framework to conserve and protect endangered and threatened species and their habitats both domestically and abroad. Prohibits: Importing, Exporting, Taking (harming, harassing, killing), Possessing, Selling, Transporting of endangered and threatened species. Includes: Species, Subspecies, Populations, and Habitats

Demand for rhino horns

Traditional Chinese medicine, symbol of status and wealth

Government of the Republic of South Africa's plan

Flood market with Rhino horns and price of product will plummet. Allow the government to sell their billion-dollar rhino horn stockpile, which they have acquired from confiscating contraband.

Disadvantage of South Africa's plan

May encourage poaching because poaching would be perceived as condoned by the government. Difficult to estimate current and potential demand.

Advantage of South Africa's plan

Reduces and eliminates need for an illegal market (potentially)

Safari Clubs and Private Game Reserves

Highly restricted permitting system for the trophy hunting of black rhino to raise money for conservation and possibly solve within breeding the rhino population.

Disadvantage of Safari Clubs plan

May increase poaching

Advantage of Safari Clubs plan

Ensures population breeding of rhinos will not be impacted by hand picking the older males in the rhino population to be hunted