Natural resource conservation : management for a sustainable future

Pearson New International Edition

Natural Resource Conservation;

...""^r a Sustainable Future

as John p. Resanold

Tenth Edition

KNV.14002191

ALWAYS LE A R N IN G " PEARSON*

13. Rangeland Management

Daniel D. Chiras/John R Reganold J75

14. Forest Management

Daniel D. Chiras/John R Reganold Ỉ9 9

15. Plant and Animal Extinction

Daniel D. Chiras/John R Reganold (>3S

16. Wildlife Management

Daniel D. Chiras/John R Reganold (|59

17. Sustainable Waste Management

Daniel D. Chiras/John R Reganold 489

18. Air Pollution

Daniel D. Chiras/John p. Reganold SIS

19. Global Warming and Climate Change

Daniel D. Chiras/John p. Reganold 545

20. Acid Deposition and Stratospheric Ozone Depletion

Daniel D. Chiras/john R Reganold 563

21. Nonrenewable Energy Resources: Issues and Options

Daniel D. Chiras/John R Reganold 581

22. Creating a Sustainable System of Energy: Efficiency and Renewable Energy

Daniel D. Chiras/John R Reganold 615

Appendix: The Nations of the World

Daniel D. Chiras/John p. Reganold 641

Appendix: Common Conversions

Daniel D. Chiras/John R Reganold 645

Index 649

Abortkn. The premature expulsion of the fetus from the uterus.

AbsUivnce. Refraining from sexual intercourse either during

key times of a woman’s menstrual cycle (around ovulation)

or urtil after marriage.

Abyssal Zone. The bottom zone of the ocean, characterized

by dirkness, close to freezing temperatures, and high water

presHJres.

Accelerated Erosion. Wearing away of the land surface pri￾marly as a result of human activities or, in some cases, ani￾mal ictlvities. Accelerated erosion operates at a much faster

rate tian geological erosion.

Accelerated Eutrophication. Accelerated increase in the

concỉnưatíon of plant nutrients in water bodies caused by

humtn actions (for example, excess fertilizer application on

farm fields).

Acid Mine Drainage. Sulfuric acid produced by underground

coal mines in areas with high levels of iron pyrite in the soil.

Acid Precipitation. Deposition of acids in rain, snow, mist,

and log.

A dd Precursors. A chemical such as sulfur dioxide that

give‘ rise to acids (In this case, sulfuric acid) after reacting

withother chemicals in the atmosphere.

Acid Rain. Rain that has a lower pH than "normal" rain—in

othei words, lower than pH 5.7. It is caused by the release of

oxides of sulfur and nitrogen into the atmosphere.

Activ^ed Sludge. The solid organic waste that has been in￾tensi/ely aerated and “seeded” with bacteria (in a secondary

or tcTtiary sewage treatment process) to promote rapid bacte￾rial cecomposition.

Active Fishing Gear. Devices and methods for fishing that

have mobility and are able to seek out and capture the fish or

sheltish. Examples include trawl nets, purse seine nets, and

large drift nets.

Active Solar System. System that gathers energy from the

sun md stores it for healing water or rooms.

Adaptive M anagem ent. Scientific management of natural

resoirces in which management strategies may be modified

as a result of scientific findings on the effectiveness of exist￾ing nanagement strategies.

Additive M ortality. The concept that one kind of death of an

animal population simply adds to the deaths caused by other

faclCTS.

Adsorption. The attraction of ions or compounds to the

surfa:e of a solid; for example, the atưaclion of ions to clay

partiries in soil.

Agent Orange. Defoliant used by American forces during

the Vietnam War.

Age S tructure D iagram (or Population H istogram ).

Graphical representation of a population according to age

and sex. This type of diagram aids in forecasting popula￾tion trends.

Aggregates. Soil particles grouped into a single mass or cluster.

Agroforestry. The practice of growing trees among crops or

on pastureland.

Algal Bloom. Dramatic increase in algal growth in a lake or

stream, resulting from high levels of nutrient pollution.

Alpha Particle. A positively charged particle (proton) that is

emitted from the nucleus of a radioactive atom.

Alternative A griculture. Nonconventional approaches to

agriculture that include, but are not limited to, organic,

ecological, biodynamic, integrated, low-input, and no-tlll

farming.

Altitudinal Migration. Seasonal movement of birds (e.g., gros￾beaks and finches) and mammals (e.g., elk and bighorn sheep)

up and down mountain slopes.

Ammonification. The process by which the bacteria of

decay convert complex nitrogenous compounds occuưing in

animal carcasses and the excretions of animals, as well as the

dead bodies of plants, into relatively simple ammonia (NH3)

compounds.

Anadromous Fish. Fish that begin life in freshwater, travel

to and mature in the sea. and return to their native stream to

reproduce and die. An example is the Pacific salmon.

Animal Unit Month. The amount of forage needed to keep

one head of cattle healthy for 1 month.

Annular Ring. A concentric ring, visible in the cross section

of a ưee trunk, that is useful in determining the age of the tree.

Anthropogenic Pollutants. Pollution from human sources;

for example, the combustion of fossil fuels. Compare with

natural pollution.

Antlmycin. A toxic substance that has been extensively used

by fisheries biologists to eradicate carp.

Aquaculture. Cultivation of fish and other aquatic organisms

in freshwater or saltwater for food, sport, and other goods

and services.

Aquifer. A subterranean layer of porous water-bearing rock,

gravel, or sand.

Aquifer Recharge Zone. A region in which surface water

seeps into groundwater, replenishing it.

From the Glossary of Natural Resource Conservatory, Tenth Edition, Daniel D. Chiras, John p. Reganold.

Copyright © 2010 by Pearson Education, Inc. Published by Pearson Benjamin Cummings, All rights reserved.

Glossary

Artificial Insemination. The technique employed by cattle

breeders in which sperm from a bull of one breed, such as a

Hereford, might be refrigerated and used, over a period of

lime, to fertilize the eggs of the same breed or other breeds of

cattle, possibly from widely separated localities.

Artificial Propagation. The captive breeding of fish, such as

in hatcheries.

Artificial Reef. A reef constructed of housing debris, rubble,

Junked automobile bodies, tires, sunken ships, and so on,

frequently placed in relatively shallow water near the coast.

Artificial reefs increase the number of breeding sites and

provide habitat for marine fish.

Asbestos. A naturally occurring fibrous mineral once used in

numerous applications, for example, for sound insulation and

heat insulation in buildings. When inhaled, asbestos fibers

can cause lung cancer and other diseases, which are most

prevalent in smokers.

Aseptic Container. A sterile chamber.

Backyard Wildlife H abitat. Habitat for wild species in

rural and urban environments designed to provide food,

shelter, and nesting sites for wild species such as songbirds

and butterflies.

B arrier Islands. Accumulations of coastal sediments parallel

to and near the shore created by coastal wave, wind, and cur￾rent action. These low-elevation islands are found worldwide.

Bathyal Zone. An ocean region of semidarkness in which

photosynthesis cannot occur and green plants cannot survive.

It is located between the euphotic and abyssal zones.

Beach N ourishm ent An expensive human management

practice of transporting sand from other sources and deposit￾ing it on a beach, temporarily replenishing eroded beach sand.

Bioaccumulation. Concentration of a chemical substance in

an organism.

Biochemical Oxygen Demand (BOD). See Biological Oxygen

IDemand.

Biogeochemical Cycle. See Elemental Cycle. Also known as

a nutrient cycle.

Biological Control. Means of conưolling pests using natural

enemies or other potentially less environmentally harmful

measures than chemical pesticides.

Biological Magnification (or Biomagnification). The in￾crease in concentration of a chemical substance in a food

web as it passes from lower levels to highest levels.

Biological Oxygen Demand (BOD). Measure of organic

matter in water samples. Assesses oxygen used by decom￾posing bacteria.

Biome. Region of the Earth with characteristic climate and

characteristic community of living organisms.

Biotic Potential (BP). The theoretical reproductive capacity

of a species.

Birth Rate. Number of births per 1 .CKX) people in a population.

Black Lung Disease. An occupational disease frequently

conưacted by coal miners.

Blackwater. Wastewater from houses that contains feces and

urine. Kitchen sink water, which carries large amounts of

food debris, also is considered to be blackwater.

Blister Rust. A fungus-caused disease of the white pine that

is characterized by the appearance of orange “blisters" on

the bark.

Bog. A shallow depression filled with organic matter; for

example, a glacial lake or pond basin filled with peat.

Botulism. A waterfowl disease caused by a bacterium and

characterized by eventual respiratory paralysis and death.

Breeder Reactor. A nuclear reactor that uses a relatively

small amount of uranium-235 as a "primer” to release energy

from the much more abundant uranium-238. This type of re￾actor produces plutonium-239 that can be used as a fuel in

other nuclear reactors.

Brownfield. A site that has been previously contaminated by

hazardous materials.

Brown Lung Disease. An occupational disease frequently

contracted by textile workers.

Browse Line. A line delimiting the browsed from unbrowsed

portions of shrubs and trees in an area where the deer popula￾tion exceeds the carrying capacity of the range.

Buffer. A chemical substance that protects soils and water

from increases in pH.

Bycatch. Captured marine organisms, including fish, shell￾fish. oceanic birds, and marine mammals that are not the

target species of a fishery.

Carbon Absorption. A process employed by a tertiary sewage

treatment plant in which dissolved organic compounds are

removed from the effluent as they pass through a lower packed

with small particles of carbon.

Carbon Dioxide. A chemical produced by the combustion of

organic materials, including oil, coal, natural gas, and wood.

C arbon Dioxide Fixation. The incorporation o f carbon

dioxide into glucose molecules during the process of

photosynthesis.

Carbon Monoxide. A clear, colorless, odorless gas produced

by the incomplete combustion of organic substances such a.s

coal or oil. In high concentrations, carbon monoxide expo￾sure can be lethal.

Carcinogen. A cancer-causing chemical.

Carrying Capacity. The capacity of a given habitat to sus￾tain a population of animals for an indefinite period of time.

Catadromous Fish. A type of fish that grows to sexual matu￾rity in freshwater but migrates to the ocean for spawning, An

example is the American eel.

Catalytic Converter. A device in the exhaust system of auto￾mobiles that oxidizes hydrocarbons to carbon dioxide and

water and converts carbon monoxide to carbon dioxide.

Catch-and-Release-Only Restrictions. Fisheries management

strategy for reducing angler pressure on a particular fish popula￾tion by requiring the fish to be released (essentially unharmed]

back into the water body from which it was caught.

Glossary

Cellular Respiration. The complete breakdown of glucose

in the cells of the body to produce energy needed by various

cellular processes.

Central Arizona Project. A multimillion-dollar project to

alleviate water shortage problems in Arizona by transporting

water from the Colorado River.

Certifled Forest A forest that has been certified by one of

several nonprofit organizations as having met criteria that

promote more sustainable timber production and harvest.

The Forest Stewardship Council is believed to promote the

most rigorous and potentially sustainable set of criteria for

certifying forests.

Chain Reaction. The sequence of events in a nuclear reactor

and nuclear bomb that occurs when neutrons emitted from a

radioactive atom bombard another atom and cause it to emit

neuưons, which in turn bombard yet other atoms, and so on.

In nuclear reactors, the chain reaction is conưolled to prevent

it from resulting in an explosion.

Channelization. The process by which a natural sưeam is

converted into a ditch for the ostensible purpose of flood con￾trol. Attendant environmental abuse is severe.

Chlorinated Hydrocarbon. A family of nondegradable pes￾ticides such as DDT. dieldrin, and toxaphene. Hydrocarbons

may have a harmful effect on nontargei organisms such as

fish and birds. They persist for a long time in the environ￾ment and undergo biological magnification as they move

through food chains.

Chlororganics. Potentially toxic organic compounds that

form in water ưealed with chlorine. Good examples are chlo￾roform and carbon tetrachloride.

Clear-Cutting. A method of harvesting timber in which

all trees are removed from a given patch or block of forest.

This is the method of choice when harvesting a stand

composed of a single species in which all trees are of the

same age.

Climax Community. The stable terminal stage of an ecolog￾ical succession.

Closed-Cycle Cooling System. A method of cooling power

plants in which the cooling water is continuously recirculated

instead of being discharged into a stream and causing ther￾mal pollution.

Closed Seasons. Fisheries management strategy that limits the

take of a particular fish species at critical times (e.g., spawning,

mating season) by prohibiting fishing during that particular

season.

Coal. An organic mineral produced from plant matter 250

million to 300 million years ago. When burned, it produces

energy that is harnessed to produce electricity.

Coal Gaslffcation. Production of combustible gas from coal.

Coal Liquefaction. Production of oil from coal.

Cocoroposting. Mixing of compost with sewage sludge.

Conform Bacteria. Bacteria that occur in the human gut. The

conform count is used as an index of the degree to which stream

or lake water has been contaminated with human sewage.

Command Economy. An economy in which the production

of goods is subject to cenưal control, as in Cuba or the for￾mer Soviet Union.

Commons. A public area over which no single nation has

sovereignty, such as the open ocean.

Community. All species living in a given area. Examples are

the community of an oak woods, an abandoned field, or a cat￾tail marsh.

Compensation Depth. The depth in a lake at which photo￾synthesis balances respiration. This level delimits the upper

limnetic zone from the lower profundal zone.

Compensatory Mortality. The concept that one kind of mortal￾ity replaces another kind of mortality in animal populations.

Compost. Partially decomposed organic matter that can be

used as a soil conditioner and fertilizer.

Condensation Nuclei. Particulates in the air that absorb

moisture and can facilitate cloud formation.

Conservation District. The admínisưative and operative unit

of the u.s. Department of Agriculture’s Natural Resource

Conservation Service. Conservation districts are organized

and run by farmers and ranchers.

Conservation Tillage. The practice of restricting plowing of

the soil to reduce erosion and leave enough of the previous

crop residues so that at least 30% of the soil surface is cov￾ered when the next crop is planted.

Consumer. Any animal link in a food chain.

Consumptive Use. The removal and alteration of natural

resources.

Contour Farming. Plowing, seeding, cultivating, and har￾vesting at right angles to the direction of the slope, rather

than down it.

Contour Mine. Mine used for coal and other minerals in

hilly terrain. Cuts are made along the contour of the land.

Control Group. In a scientific experiment, the conưol group

is the untreated group. It is identical to the experimental

group in every way except the lack of ưeatment.

Conventional Farming. An agricultural system that relies

heavily on agrochemicals, new varieties of crops, and labor￾saving, energy-intensive farm machinery.

Cooling Tower. Device used to reduce thermal pollution before

releasing cooling water from power plants and factories into

lakes and streams.

Coral Reefs. Elaborate ocean structures, found primarily in

tropical and subưopical waters, formed from the bodies of

animals having calcareous skeletons (made from calcium

materials) and certain species of algae that provide the sedi￾ment or “cement” that seals the coral framework.

Core Reserve. An area set aside for wildlife protection in which

no human activity is allowed. The core reserve is surrounded by

a buffer zone, a region permitting modest human activity.

Corridor, Terrestrial. A narrow suip of land that differs,

usually in terms of dominant vegetation (such as forest or

grassland), from the surrounding areas.

Glossary

Creel (or Catch) Limits. Fisheries management regulation that

controls Ashing pressure on a certain Ash species by restricting

the size or the number of Ash an angler may take home.

Critical Population size. Population size below which recov￾ery is impossible.

Critical Thinking. A process by which one analyzes facts,

assertions, and conclusions, attempting to discern their validity.

Crop Rotation. A planned sequence of various crops grow￾ing in a regularly recurring succession on one Aeld.

Cross-Media Contamination. The movement of a pollutant

from one medium, such as air, to another, such as water.

Crown Fire. A Are that spreads from treetop to treetop.

Cultivar. IVpe of plants culuvated to produce food or Aber.

Cyanosis. A disease that is characterized by a bluish discol￾oration of the skin and is caused by the impaired effective￾ness of hemoglobin to carry oxygen. An infant who drinks

water carrying loo high a level of nitrates may undergo

chemical changes of his or her hemoglobin that in turn will

result in cyanosis of the skin.

Cyclic Population. A population that peaks and troughs at

regular intervals. Good examples are the 4-year cycle of the

lemming and the 10-year cycle of the ruffed grouse.

Cyclone Filter. A type of air-pollution control device that

removes paniculate matter (dust) with the aid of gravity and

a downward-spiraling airstream.

Death Rate. Number of deaths per 1,000 people in a population.

Decreasers. A category of highly nuưiiious and extremely

palatable range plants that generally decrease even under

moderate grazing pressure.

Deepwater Swamp. Freshwater wetlands that suppon woody

vegetation, primarily various species of cypress, gum, and

tupelo trees, and remain Aooded all or most of the year.

Deferred-Rotation Grazing. A grazing management system

in which livestock are rotated between two or among more

range areas to increase the long-term efAciency of range con￾version into livestock production.

Demographic IVansition. A change in a population that is

characterized by decreasing birth and death rates. It usually

occurs when a nation becomes indusưialized.

Denitrification. The decomposition of ammonia compounds,

nitrites, and nitrates by bacteria, which can result in the

release of nitrogen into the atmosphere.

Density-Dependent Factor. A population-regulating factor,

such as predation or infectious disease, whose effect on a

population depends on the population density.

Density-Independent Factor. A population-regulating factor,

such as a storm, drought, flood, or volcanic eruption, whose

effect is independent of populaúon density.

Depletion Time. The time required until 80% of the avail￾able mineral supply is consumed.

Desalinization (or Desalination). The removal of salt from

seawater in order to make it usable by humans, crops, and

wildlife.

Desertification. The conversion of rangeland, rainfed crop

land, or irrigated cropland to desert-like conditions caused b

natural factors (climatic changes) and artiAcial factor

(human-induced activities).

Desert Pavement. The stony surface of some deserts, causei

by excessive erosion of the thin topsoil resulting from wate

and wind action.

Detritus. Organic matter derived from dead bodies of animals

insects, plants, and so on.

Detritus (or Decomposer) Food Chain. Sequence of organ

isms, each feeding on the one before it, starting with dea(

organic material (waste or animal and plant remains).

Deuterium. An isotope of hydrogen that contains one proto

and one neuữon. It can serve as fuel in nuclear fusion reactions

Dioxin. An extremely toxic chemical occurring in the herbi

cide 2,4,5-T. In some areas, it is suspected of causing birtl

defects and miscarriages.

Discards. The Ash and other aquatic bycatch species fisl

thrown back for various reasons, such as being nontarge

species, juveniles, endangered species, wrong size, inferio

quality, or surplus to quotas.

Discount Rate. A number used by economists and business

people to determine the present economic value of variou

business strategies.

Drainage Basin. See Watershed.

Drawdown. Lowering of the water level in a reservoir for th

purpose of flood conưol or hydropower.

Drawdown Phase. The occuưence of periodic low wate

levels common to many inland wetlands in regions that expe

rience very little precipitation during the summer months Q

alternate wet and dry years.

Dredge spoil. The sediment that has been scooped from hai

bor and river bottoms to deepen channels for navigation.

Dust Dome. A shroud of dust particles characteristicall

found over urban areas. It is caused by the unique atmosphei

ic circulation pattern that results from the marked temperatur

differences between the urban area and outlying farmlands.

Dynamic Equilibrium. Condition in a system in whic

change that occurs is corrected by natural mechanisms, so thỉ

the system remains more or less the same over long periods.

Ecological Island. Habitat cut OÍĨ from the surrounding are

by natural features such as water or by farms, cities, roadi

and so on. This habitat is highly vulnerable to species loss.

Ecological Justice. The concept that species other than human

have a right to exist.

Ecology. Study of the interrelationships that occur belwee

organisms and their environment.

Economic Externality. An economic cost that is not factore

into the determination of the cost of goods and services; fc

example, the economic cost of health effects of air pollutio

from factories.

Economic Incentives. Inducements to business and indi

viduals to encourage environmentally friendly actions, fc

Glossary

example, energy conservation or installation of renewable

energy systems.

Ecosphere. The total area in which living organisms occur.

Ecosystem. A conư-action for ecological system.

Ecosystem Simplification. The intentional or unintentional

elimination of species from an ecosystem. Such changes may

destabilize an ecosystem.

Ecotone (or Edge). A ưansition zone within a landscape

between two distinct ecosystems that usually has its own

unique soil, vegetation, and hydrologic characteristics.

Electrolysis. Breakdown of water using elecưiciiy. Electrol￾ysis results in the formation of hydrogen, a useful fuel.

Electromagnetic Spectrum. Range of energy given off by

the sun. At the lower end are low-energy radio waves; at the

higher end are high-energy gamma rays. Visible light falls in

the middle of the spectrum.

Electron. A negatively charged panicle occuning in the orbit

of an atom.

Electron Cloud. Region that surrounds the atomic nucleus

and contains electrons.

Electrostatic Precipitator. Device to remove paniculates

from smokestack gases.

Elemental Cycle. The cycle of movement of an element

(e.g,, niưogen, carbon) from the nonliving environment (air,

water, soil) into the bodies of living organisms and then back

into the nonliving environment.

Emphysema. A potentially lethal disease characterized by a

reduction in the number of alveoli in the lungs as well as a

reduction in total respiratory membrane area.

Endangered Species. A species that is in immediate danger

of extinction.

End-Point Separation. Process in which recyclables are

removed from municipal trash at central stations.

Energy. Defined by physicists as the ability to do work. Two

basic forms exist: potential energy and kinetic energy.

Energy Laws. Also known as the laws of thermodynamics.

Principles that describe the origin and behavior of energy.

See First Law of Energy: Second Law of Energy.

Energy Pyramid. Graphical representation of the energy in

the various trophic layers in a food chain.

Entropy. Disorder or randomness in any system.

Environmental Disniptors. Chemicals from human sources

that disrupt the endocrine system— for example, by mimick￾ing natural hormones or blocking hormone release by the

body, causing potentially serious problems with reproduction

and other bodily functions.

Environmental Justice. Attempts to ensure that disadvan￾taged groups of individuals do not share a disproportionate

amount of risk posed by human activities or technologies.

Environmental Limitations. Natural and human-induced

occurrences that can cause mortality in fish populations. Nat￾ural environmental limitations include storms, soil mass move￾ments, debris jams, winterkill, and predation by animals.

Human-induced limitations include dams, pollution, riparian

vegetation removal, and competition by exotic fish species.

Environmental Resistance (ER). Any factor in the environ￾ment of an organism that tends to limit its numbers.

Ephemeral Stream. A sưeam or creek that flows only dur￾ing the wet season.

Epillmnion. The upper stratum of a lake, characterized by a

temperature gradient of less than 1 °c per meter of depth.

Essential Element. A chemical element required for the nor￾mal growth of plants.

Estuary. Semi-enclosed inlet (bay) that forms a ưansitional

zone between a coastal river and the sea.

Euphotic Zone. The open-water zone of the ocean, character￾ized by sufficient sunlight penetration to support photosynthe￾sis. The euphoric zone is located just above the bathyal zone.

Euryphagous species. An organism having a highly varied

diet, such as a pheasant or opossum, in contrast to an animal

having a narrow (stenophagous) diet, such as an ivory-billed

woodpecker,

Eutrophication. The enrichment of an aquatic ecosystem with

nutrients (nitrates, phosphates) that promote biological

productivity (growth of algae and weeds).

Everglades. Large, unique, freshwater marsh wetlands locat￾ed near the southern tip of Florida and dominated by a sedge

called saw grass.

E-waste. A name for discarded electronic products such as

computer monitors and CPUs, televisions, VCRs, stereos,

copiers, fax machines, and cell phones. These products contain

toxic chemicals to which unprotected employees of recycling

facilities, often found in less developed countries, can be

exfX)sed.

Exclusive Economic Zone (EEZ). The 330-kilometer

(200-mile) belt of sea space extending from the coastline of

each nation over which each respective nation has economic

jurisdiction.

Exotic (Nonnative) Fish Species. Fish that have been inưo￾duced, either intentionally or accidentally, from a different

part of the country or from a foreign country into a water

body in which they are not native.

Experimental Group. In a scientific experiment, the group

that receives the treatment or exposure under study.

Exponential Growth. Growth of any entity (such as popula￾tion or resource demand) that occurs by a fixed annual per￾centage when the annual growth is added to the base amount.

Fabric Filter Bag House. An air-pollution control device

that operates somewhat like a giant vacuum cleaner in re￾moving solid particles from indusưial smokestacks.

Fall O verturn. The thorough mixing of lake waters during

autumn.

Faunal Collapse. Dramatic decrease in numbers and diversi￾ty of animal species.

Fibrous Root System. A complex root system, such as that

of grass plants, in which there are several major roots and a

Glossary

great number of primary, secondary, and tertiary branches.

This type of root system binds soil in place, preventing

erosion.

Field Capacity. The water remaining in a soil two to three

days after it has been saturated and after free drainage has

practically stopped.

First Law of Energy (or Thermodynamics). The principle

that energy can be neither created nor destroyed but can be

converted from one form to another.

Fishery. A place where fish or other aquatic species such as

shrimp and sponges are caught Also the species caught and

the occupation or industry—and technologies— involved In

catching fish and other aquatic species. The most common

usages have to do with place and species.

Fish Ladders. A series of step-like rungs designed and built

into hydroelectric dams for the purpose of providing safe

passage to fish as they migrate upstream to their spawning

grounds.

Floodplain. Flat areas of fine sediment deposition extending

outward from the bank tops of lowland streams that receive

floodwater and accompanying sediment when rivers and

streams periodically overflow their banks.

Fluidized Bed Combustion. Process in which coal is

crushed, mixed with bits of limestone, and air-blown into a

furnace, where it is burned.

Fluorocarbons. A group of chemical compounds containing

the elements carbon, chlorine, and fluorine. One type of

these compounds, manufactured by DuPont under the trade

name Freon, has been used in refrigerators, air conditioners,

and aerosol spray bombs.

Fluorosis. A dise'ase in animals caused by fluoride poisoning.

Symptoms in livestock include thickened bones and stiff joints.

Flyway. One of the major migration pathways used by water￾fowl. Examples include the Atlantic flyway and Pacific fly way.

Food Chain. The flow of nutrients and energy from one or￾ganism to another by means of a series of eating processes.

Food Web. An interconnected series of food chains,

Forage. Grasses, grasslike plants (sedges and rushes), forbs,

and shrubs that supply food and energy for domesticated an￾imals such as cattle, sheep, and horses, and for wild animals

such as deer, giraffes, and wildebeests.

Fossil Fuel. Organic fuels derived from ancient plant or ani￾mal matter, including coal, oil, shale oil. and natural gas.

Freon. A type of fluorocarbon compound manufactured by

DuPont for use in refrigerators, air conditioners, and aerosol

spray bombs. Freon compounds have contributed to the

breakdown of the shield of ozone in the upper stratosphere

that protects humans from ultraviolet radiation.

Freshwater Aquaculture. The controlled culturing, or

“farming,” of fish and other aquatic food that is practiced in

inland, freshwater ponds.

Freshwater Marsh. An inland wetland characterized by

nonwoody hydrophytes, shallow water depths, and shallow

accumulations of peat material. The term describes a diverse

group of inland wetlands, including prairie potholes, vema

pools, the Everglades, the Great Lakes marshes, and the Ne

braska sandhill wetlands.

Fuel Cell. A device that produces electricity from oxyger

and hydrogen.

Fuel Crops. Crops grown to generate ethanol or some Olhei

fuel that could replace traditional fossil fuels or Other energ)

resources.

Fuel Rods. Rods packed with enriched uranium used foi

fueling nuclear power plants.

Fusion. See Nuclear Fusion.

Game Animals. Species harvested for recreational purposes

Gamma Ray or Radiation. An intense type of radiation

similar to X-rays, that easily peneưates human tissues.

Gas-Liquid Chromatograph. Instrument used to determim

the source of an oil spill.

Gene. A segment of DNA that regulates some characteristit

of an organism, including behavior.

Generalist Species that can live anywhere and eat many dif

ferent types of food.

Genetic Diversity. A term used to indicate a great variety 01

organisms (many different species) occupying a given area.

Genetic Engineering. A complex process that involves the

isolation of genes, synthesis of genes, and their insertion intt

cells from the same or a different organism or species.

Genetic Erosion. A harmful effect on the gene pool of £

given species when a large number of artificially propagatec

fish are used to enhance a population. Research has showr

that the offspring of a hatchery fish bred with a native pareni

have a lesser chance of survival than pure native offspring.

Geographic Information Systems. A computer system con￾sisting of hardware and software designed to assemble anc

store geographical reference information about the Earth, in

eluding vegetation, land disturbance, and human settlemen

patterns. This information can be displayed, manipulated

and analyzed.

Geological (Natural) Erosion. Wearing away of the Earth'*

surface by water, ice, wind, or other geological agents undei

natural environmental conditions.

Geopressurized z^nes. Zones where heated groundwater iỉ

trapped by layers of impervious rock.

Geothermal Energy. Heat produced by the Earth from natu￾rally occurring radioactive decay and from magma. Thi*

heat energy can be tapped to heal buildings or to produce

electricity.

Glasphalt. A type of road-surfacing material that employ*

crushed glass in its manufacture rather than sand. It is more

durable than ordinary asphalt.

Glassification. A method of disposing of radioactive waste

by concenưating it and enclosing it in solid ceramic bricks.

Global Climate Change. Changes in the average weather con￾ditions or climate of the planet brought about by pollutants suef

as carbon dioxide and methane produced by human activities.

Glossary

Global Warmmg. The warming of the Eanh’s atmosphere and

oceans caused by a buildup of greenhouse gases such as carbon

dioxide and chlorofluorocarbons produced from human sources.

Grassland. Land in which grasses are the predominant form

of vegetation. Grassland is flat or rolling terrain with few or

widely distributed trees.

Graywater. Wastewater from showers, washing machines,

and sinks.

Grazer Food Chain. Sequence of organisms, each feeding

on the one before it, starting with plants or algae.

Great Barrier Reef. The largest chain of coral reefs in the

world, located off the coast of Queensland, Ausưalia, reach￾ing a length of over 2,000 kilometers (1,240 miles), and con￾taining over 2,500 individual reefs.

Greenhouse Effect. The warming influence caused by the

increased concentration of carbon dioxide and several other

pollutants in the Earth’s atmosphere.

Greenhouse Gas. Any one of several gases that ưap heat

escaping from the Earth’s surface, making the Earth’s atmos￾phere warmer.

Green Manure. The practice of plowing under or surface￾mulching plants (usually a grass or legume) while green, or

soon after maturity, for improving the soil.

Green Revolution. The increased food production capability

made possible in recent years because of selective breeding,

the increased use of fertilizer, the development of seed banks,

and the more intensive use of herbicides and insecticides.

Groins. Piers of stone spaced about 30 meters (100 feet)

apart that extend into the sea at right angles to the shoreline

for the purpose of retaining beach sediments.

Gross Domestic Product (GDP). The sum total of all goods

and services produced by an economy.

Gross National Product (GNP). The sum total of expendi￾tures by governments and individuals for goods, services,

and investments.

Gross Primary Production. The sum of all biomass produc￾tion in an ecosystem, not taking into account the losses due

to cellular respiration.

Groundwater. Water that has infilưated the ground, in con￾ưast to runoff water, which flows over the ground surface.

Groundwater Overdraft. Removal of groundwater at rales

that exceed its natural replenishment.

Gully Reclamation. The mending of a gully by either physical

methods (check dams of boulders or cement) or vegetational

means (planting of rapidly growing shrubs on the slopes).

Gyptol. The sex atưactant produced by the female gypsy

moth that serves to alUact the male moth from considerable

distances.

Habitat. The immediate environment in which an organism

lives. A habitat includes such components as cover, food,

shelter, water, and breeding sites.

Habitat Conservation Plans. Documents outlining steps to

protect habitat to protect endangered or threatened species.

Habitat Fragmentation. The breaking up of contiguous

areas of wildlife habitat, often by home building or farming.

Habitat Restoration. The combination of various strategies—

such as adding spawning gravels, revegetaling streambanks

and lake edges, establishing brush shelters, restoring the his￾toric meanders of rivers, creating pools and riffles, and placing

in-sưeam woody debris— for the purpose of improving habitat

for fish and other aquatic life.

Half-Life. The time required for one half of the radioactivity

of a given radioactive isotope (e.g., uranium, strontium) to be

dissipated.

Hardwood. A species of tree, such as oak, hickory, and

maple, that has relatively hard wood, in contrast to the soft

woods of the conifers such as spruce and pine.

Harvestable Surplus. The portion of a population that can

be taken by humans (hunters) without adversely affecting

subsequent populations of that animal.

Hazardous Wastes. Substances produced by homes and fac￾tories that pollute the air, water, and soils and can harm the

environment and human health.

Headwater Stream. The beginning segment of a river sys￾tem that is usually confined by a narrow valley, shallow

bedrock, and coarse sediments and thus tends to have a nar￾row, relatively straight channel pattern instead of one that is

wide and meandering.

Heartwood. The dark, central portion of a ưee trunk charac￾terized by the presence of dead xylem cells that have become

filled with gums and resins.

Heat Island. The tendency for the atmosphere of a city to be

warmer than the air in the surrounding farmlands. This is

partly the result of the greater number of heat-generating

sources (autos, factories, human bodies) in the city.

Home Range. The total area occupied by an animal during

its life cycle—that is, the area required for feeding, breed￾ing, loafing, and securing refuge from the weather and from

predators.

Horizon. A layer of soil with specific properties and charac￾teristics. The major horizons from the ground surface down￾ward to bedrock are designated as horizons o (organic layer),

A (topsoil), E (subsurface), B (subsoil), c (parent material),

and R (bedrock).

Host. An organism that contains parasites.

Humus. The semistable, dark-colored material that repre￾sents the decomposition products of organic residues and

materials synthesized by microorganisms.

Hybrid. The offspring that results from a cross of two differ￾ent species or strains of animals or plants. For example, the

Santa Gcnrudis cattle resulted from a series of crosses involv￾ing two parental types, the Brahmin cattle and the shorthorn.

Hydraulic Mining. A mining technique used to exưact gold

and silver in which a powerful stream of water is directed

against the face of the rock containing the minerals.

Hydrological Cycle. The circular movement of water

from the ocean reservoir to the air (clouds), to the Earth in