Contemporary Environmental Issues Final (TCU)
Slattery's Final Exam
Terms in this set (117)
What percentage of rainfall infiltrates soil or lost in runoff?
In what ways do tropical forest act as system regulators?
Moderate air temperatures, maintain atmospheric humidity levels through evapotranspiration, and regulate stream flows by allowing rainfall to enter streams more slowly as a result of increased storage of water within the canopy
The Amazon Rainforest comprises what percentage of the world's rainforests?
In what ways do rainforests act as the "Earth's lung?"
By absorbing carbon dioxide and generating oxygen
If the current rate of deforestation continues, the world's rain forests will vanish within how many years?
__________ are the most diverse ecosystems on Earth
_____________ are home to more than half of the world's known living plant and animal species
A 4 square-mile (1,000 hectare) patch of rain forest contains over how many different kinds of species?
Approximately how many of hectares of forest does the world lose every year?
What continent has suffered the largest net loss of forests between 200 and 2005?
How many hectares of forest does South America lose per year?
What percent of world's deforestation takes place in Brazil alone?
What are the agents of deforestation?
Individuals, corporations, government agencies, or development projects that actually clear the forests
Most forest clearing is done for what purposes?
A type of deforestation that involves chopping down small areas and burning the tree trunks
Landless people make up what percentage of Brazil's population?
What percentage of deforested land is within 30 miles of a road?
What human activities play the most significant role in deforestation in Latin America?
Slash-and-burn farmers and cattle ranchers
What human activities play the most significant role in deforestation in Southeast Asia?
Commercial farming, logging, and oil palm plantations
What human activities play the most significant role in deforestation in Africa?
Overgrazing in dry forest zones, slash-and-burn farming, and high-grade logging
What motivations behind the agents of deforestation are often cited as the main cause of forest loss?
Poverty and overpopulation
How do international agencies, such as the FAO and intergovernmental bodies believe they can solve the problems that drive deforestation?
By encouraging development and trying to reduce population growth
What is the third major cause of deforestation?
__________ is the inevitable result of current social and economic policies being carried out in the name of development.
According to current estimates, about how much of Costa Rica's original forest cover is still standing?
What is the only major program in place right now to reverse the process of deforestation?
Payment for Environmental Services (PES) initiative
What does the PES initiative do?
Gives economic retribution to forest owners or land owners that want to establish forest plantations, due to environmental services they provide to society
What types of environmental services might forest or land owners that want to establish forest plantations provide to society in response to PES?
GHG reductions (via carbon sequestration), water protection, biodiversity protection for conservation and sustainable use, scenic beauty, and sustainable wood production
What are the aims of the PES program?
To protect primary forest, allow secondary forest to flourish, and promote forest plantations to meet industrial demands for lumber and paper products
Describes the variety of life on Eartha nd the natural distribution and patterns of organisms
What is the best estimate of how many species exist on earth?
about 10 million
About how many species have been catalogued and named?
Counting or estimating the amount of species that exist naturally within a habitat
What is the problem with species richness?
It only counts the number of species and does not address what species are common throughout the habitat and which ones are rare
A more quantitive measure of biodiversity (in comparison to species richness)
Simpson's Biodiversity Index
Simpson's Biodiversity Index measures...
the probability that two individuals randomly selected from an area will belong to the same species
As a general rule, diversity (increases or decreases) as you move from the equator toward the poles
What qualifies a region as a "hotspot?"
Must contain a large number of species of plants as endemics and must have lost at least 70% of its original habitat
How many hotspots do we currently have?
Where is the Mesoamerica Hotspot located?
What is the aim of the "Global 200 Ecoregions?"
To select priority Ecoregions for conservation within each of 14 terrestrial, 3 freshwater, and 4 marine habitat types
What are the Ecoregions chosen for?
Species richness, endemism, taxonomic uniqueness, unusual ecological or evolutionary phenomena, and global rarity
Human impacts have elevated the extinction rate by at least how many times the natural rate?
Why is the loss of biodiversity so important to our future?
It reduces the productivity of ecosystems and destabilizes ecosystems
What are the characteristics of many extinct and endangered species?
Species that: are restricted to a relatively small geographic area; depend on a certain type of habitat or food source and do not adapt well to changes (natural or human-caused); have low reproductive rates and low natural mortality; are slow moving and/or large; and are valued as food, pets, ceremonial objects, or marketable products to humans
Why do we value biodiversity?
Our survival depends on it; supports industries like agriculture, horticulture, pharmaceuticals, and cosmetics, loss threatens food supplies and sources of medicine and energy, and provides us with innumerable services that would be extremely costly or impossible to replace
Endangered Species Act (ESA)
Passed in 1873;prohibits any person from killing, or even harming, an endangered species or significantly altering the habitat that the species requires for survival, imposing civil/criminal penalties to enforce
What is an endangered species?
Any species that is in danger of extinction through all or a significant portion of its range
What is a threatened species?
Any species which is likely to become an endangered species within the foreseeable future
Why are wetlands important?
Disappearance of wetlands could make coastal regions vulnerable to frequent flooding and serve hurricane damage
What aspects of Hawaii influence biodiversity?
The difference in rainfall and climate, topographical diversity, and oceanic isolation
How many unique life forms found in Hawaii can not be found anywhere else on earth?
When did the unique ecosystems of Hawaii start to decline? Why?
With the arrival Polynesians in 4th Century AD; they brought with them other plant and animal species that have invaded and degraded the native ecosystems
What state is considered the extinction capital of the United States?
Debt-for Nature Swap
An organization pioneered by the WWF that comes in and tries to encourage governments that are in debt to establish their country on the ground of conservation--swapped nation's debt for their conservation efforts
What is the primary cause of soil degradation?
Erosion by wind and water
What are soils?
The product of an incredibly complex and symbiotic relationship between the mineral world and the living (organic) world
Why is organic matter in soil particularly critical?
Gives soils much of its fertility, erosion resistance, and water-holding capacity that supports plant growth
What are the 6 soil horizons?
Surface litter, topsoil, zone of leaching, subsoil, weathered parent material, and bedrock
Surface litter consists of...
fallen leaves and partially decomposed organic debris
Topsoil consists of...
Organic matter (humus), living organisms, and inorganic materials
What does the zone of leaching consist of?
Materials that are leached down from the topsoil, commonly small clay particles
What does subsoil consist of?
Accumulation of iron, aluminum, humic compounds, and clay from topsoil and zone of leaching
What does weathered parent material consists of?
Partially broken-down inorganic minerals; either slightly broken-up bedrock or material transported in from elsewhere
Which soil horizon is an impenetrable layer of rock?
What process occurs in the Weathered Parent Material horizon?
What factors influence soil formation?
Climate, organic matter, relief, parent material, and time
What causes removal of material from soil?
Uptake from plants (removes ions), erosion (removes ions, particulates, and organic matter), and leaching
What factors influence the organic matter within soil?
Climate, local geology, and native biological communities
What is translocation?
Ions, humus, compounds, and clays get moved down the profile from surface litter to topsoil through the zone of leaching and subsoil; ions move up the soil profile through capillary action
What is transformation (in the context for soil formation)?
Leaf litter and other organic matter is transformed by soil macro and microinvertebrates into humus; minerals are transformed via chemical weathering (carbonation, oxidation)
Soil erosion is a two phase process that involves...
The detachment of particles from the surface, and the transport of particles by erosive agents (primarily wind or water)
The amount of erosion in an area depends on what two factors?
The intensity of the erosion process and the resistance of the rock or soil in that region
Why is vegetation critical to erosion control?
Because it anchors soil in place with its roots and protects the soil surface from the full erosive force of wind and rain
On a global basis, what are the major causes of soil loss?
Overgrazing livestock, deforestation, agricultural activities, overexploitation of land to produce fuel wood, and industrialization
What is the leading cause of soil degradation worldwide?
Overgrazing of livestock (35%--chart on page 189)
How do soil scientist define how much soil we can lose every year without substantially altering soil productivity?
The Tolerable Erosion Value, or the T-value
What does the Tolerable Erosion Value (t-value) define?
An upper or allowable rate of soil loss in a particular region
Thin soils have (high/low) t-values.
Approximately what is the erosion rate in the US and Europe?
less than 17 t/ha/yr
Approximately what is the erosion rate in the Middle East and Korea?
About 50 t/ha/yr
Why is the rate at which we are losing soil significant?
Because we are losing soil significantly faster than it can be replaced
Soil conservation generally focuses on one of what three approaches?
1) agronomic measures 2) soil management techniques 3) mechanical methods
What is the total land area of the earth?
About 15 billion hectares (37 billion acres)
What is the potentially arable land area?
3.3 billion hectares
The slowly increasing amount of land area under cultivation is exacerbated by...
The ecologically high cost of bringing additional land into production and the fact that we continue to lose cropland at a rate of about 10 million ha/yr
Approximately what percentage of the earth is covered by water?
What are the two kinds of aquifers?
Unconfined and confined
What is an unconfined aquifer?
An aquifer wehre the water table defines the upper surface; recharged directly by infiltrating rainfall
What is a confined aquifer?
An aquifer in which water is under pressure between two confining layers of very low permeability called aquitards.
What characteristics do aquifers generally have?
Large volume in relation to the amounts of water being removed annually, moderately high porosity, and a well connected network of pores, fractures, and fissures (very permeable--speeds up water movement)
What is the estimate for total freshwater and saline-water withdrawals?
410,000 million gallons per day (410 billion gallons per day)
Is the majority of these withdrawals freshwater or salt water?
49% of total water withdrawn was used for what?
31% of total water withdrawn was used for what?
What three states account for 25% of all water withdrawals?
California, Texas, and Florida
The water withdrawal rate of 410 Bgal/day equates to how many gallons of water withdrawn per person everyday?
1,345 gallons per person per day
It is estimated that the average person in the US uses how many gallons of water per day?
About 98 gallons
According to the World Health Organization, what is the minimum number of gallons of water needed per person per day?
At current rates, _/_ people in the world will experience significant water shortages by 2025.
Water quality is used to describe...
The chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose
Clean Water Act (CWA)
Passed in 1972; established the basic structure for protecting surface water quality, employing a variety of regulatory and non-regulatory tools to sharply reduce and manage pollutant discharges in waterways and runoff
In what ways has the CWA helped the condition of the nation's waters?
Safer waters for swimming and fishing, reduction in wetland losses, reduction in amount of topsoil lost due to agricultural runoff, and expansion of the service of sewage treatment plans
What is point source pollution?
Pollution being released from a single outlet, meaning it is generally easier to monitor and control
What is non-point source (NPS) pollution?
Pollution that cannot be linked directly to one specific source (such as when runoff picks up pollutants from agricultural fields and deposits them into bodies of water)
Which type of pollution (point source or non-point source) is the nation's largest source of water quality problems and the reason that so many of our water bodies are not clean enough for uses such as fishing or swimming?
Non-point source pollution
What is sediment pollution the product of?
Why is sediment a pollutant?
Too much sediment in a stream can lead to detrimental effects on native aquatic life (smother fish eggs, newly hatched fish, and other aquatic organisms that fish rely on for food), decrease light that is able to penetrate the water, which leads to less photosynthesis of algae and aquatic plants, and act as a storage unit for other pollutants
It is estimated that what percentage of the sediment underlying our nation's surface water is significantly contaminated?
The unconsolidated mineral or material on the immediate surface of the earth that serves as a natural medium for the growth of land plants
How many ppm of oxygen are needed in bodies of water to be considered healthy?
The oxygen sag is a result of what?
Pollution: increased pollution results in increased BOD (demand for oxygen to decompose organic waste)--microrganisms eat through organic waste and use of oxygen, causing oxygen sag (below 5 ppm)
About how long does it naturally take for a stream to recover from oxygen sag?
About what percentage of the atmosphere does nitrogen gas make up?
How does nitrogen become "fixed?"
Converted to usable form by bacteria in soil and on roots of plants to create NH3
What is utrophication?
the depletion of oxygen and blooming of algae because they live off of organic material (nitrogen especially)
Why does utrophication happen?
Chronic over-ferilization; run off brings nutrients into water