A site where toxic wastes have been dumped or released, which has been designated for cleanup. …
Any material that can cause illness, death, disease, or birth defects when organisms are exposed to it, even in very low quantities. …
US legislation that seeks to ensure that the impacts of chemical substances on human health and the environment are identified (by the Environmental Protection Agency) and properly controlled before those materials are made available in the market, in order to protect people and the environment. …
Any waste that is poisonous to humans, animals, or plants. Contrast hazardous waste. …
A complex, highly toxicorganic substance that is produced by certain animals, plants, or bacteria and is harmful to other organisms. See also toxicant. …
A very small amount of a material, such as a concentration of less than one to ten parts per million. …
A gas (such as water vapour, ozone, nitrogen oxides, sulphur dioxide, and carbon dioxide) that is present in the atmosphere in only small amounts, either because of its very reactive nature or because it is produced or emitted at a very low rate. Many are greenhouse gases. …
A metal (such as cadmium, copper, chromium, mercury, nickel, lead, and zinc) that is naturally found in extremely small quantities in animal and plant cells and tissue but is necessary for growth. …
Any substance (such as radioactive isotopes and certain dyes) that is used to find out how something else moves through an organism or an environmental system. …
A process of river bedload movement that involves the rolling or sliding of particles (coarse sand and gravel) along the bed of the river. …
A method of logging in which timber is dragged or carried by tractor from where it is cut to a collecting point. …
In greenhouse gas emissions trading, an authorization that allows an emitter to emit a specified number of tonnes of emission within a given period of time. This allow emitters to determine the most economic way of covering their emissions, including buying additional permits, selling excess permits, and/or taking actions to reduce emissions. Also known as tradable permit . …
The commercial exchange (buying and selling) of goods and services. …
A major wind belt that circles the Earth, beyond the equatorial low pressure zone up to about 30? latitude in each hemisphere, in which the prevailing winds blow towards the equator, from the northeast in the northern hemisphere and from the southeast in the southern hemisphere. See also intertropical convergence zone. …
Agriculture that is based on traditional farming practices such as crop rotation, use of animal manures instead of chemical fertilizers, and use of animal power rather than machines. …
The body of knowledge and beliefs that is handed down from generation to generation, within communities. Also known as indigenous knowledge . …
The bundle of rights associated with long‐term natural resource use within traditional communities, which includes intellectual property rights, human rights, land rights, and religious rights. …
The title of a paper published in 1968 in Science magazine ( 13 December , Vol. 162, pp. 1243?8) by American biologist Garrett Hardin , in which he discusses present‐day attitudes towards the environment as being similar to how medieval villagers viewed common grazing land: all of the herdsmen had a right of access to the common pasture that (in those pre‐enclosure times) had no field bound…
A North American term for a relatively narrow path that is designed for use by pedestrians, horse riders, and/or off‐road vehicles; a designated corridor that is not classified as a highway, road, or street. …
A genetically inherited feature of an organism. See also genetic analysis, phenotype. …
In genetic engineering, the use of an external chemical to switch a plant's genetic traits on or off. Also known as genetic use restriction technology . See also terminator technology. …
Physical damage to plants and/or soil that is caused by many people or animals walking over it. …
A literary and philosophical movement that was begun during the early 19th century in New England by Ralph Waldo Emerson and others. It was a reaction against the rationality of the Enlightenment movement, was strongly influenced by the Romantic movement, emphasized the essential unity of all creation and the inherent goodness of humans. Transcendentalists believed that insight would reveal mor…
A (usually straight) line on the ground along which observations are made at some (usually regular) interval. …
Progressive change that removes evidence of an earlier state, such as the conversion of land from one use to another (such as deforestation). …
A device that is used to raise or lower the voltage of an electric current in distribution or transmission lines. …
A special type of strike‐slip fault which forms the boundary between two moving crustal plates, usually along an offset segment of a mid‐oceanic ridge. …
A junction between adjacent crustal plates which are moving alongside and parallel to one another. …
Containing genes from another species, which have probably been introduced using recombinant DNA technology. See also gene splicing. …
A rise in sea level relative to the land. See also sea level change. …
A type of pastoralism in which people and animals move seasonally in search of pasture, with winters usually spent in snow‐free lowlands and summers spent in the cooler uplands. See also nomadism. …
The process of changing from one state to another. …
A country whose economy is changing to advanced industrial and agricultural practices. Contrast developed country, developing country. …
A zone in which populations from two or more adjacent plant communities meet and overlap. …
The outer area of a biosphere reserve where reserve management is broadened to make it compatible with local socio‐economic development. …
A native species that has been introduced into suitable habitats within its own country, having previously been excluded by natural barriers. See also introduced species. …
1 In genetics, the switching of a segment of a chromosome to another chromosome. 2 In biology, the movement of water, nutrients, or chemicals within a plant. 3 In ecology, the deliberate movement of whole habitats or populations of species, by people, from one place to another. …
A disease that is transmitted from one individual to another by infection, through physical contact. …
A pipeline that moves a liquid or gas, or wires or cables that move electric power from place to place. …
The rate at which groundwater can flow through an aquifer. …
The conversion of one element into another by a process that takes place in the nucleus, such as the change from one isotope of an element into another one by irradiating or bombarding it with radioactive particles. …
A company that is controlled from its home country but has large operations in many different countries. Contrast multinational corporation. …
The evaporation of water from plants into the air through tiny holes (stomata) in their leaves. …
To transfer a plant from one location to another, or transfer an organ from one individual to another. …
The activity of moving things from one location to another, for example using vehicle to transport people or goods. …
US legislation that replaced the Intermodal Surface Transportation Efficiency Act, and authorized and funded highway, highway safety, transit, and other surface transportation programmes from 1998 to 2003 . …
A North American term for all of the private and public vehicles that move people and commodities, including cars, trucks, buses, motorcycles, railways (including trains), aircraft, ships, barges, and natural gas pipelines. Contrast commercial sector, industrial sector, residential sector. …
Waste that arises mainly from weapons production, and consists of clothing, tools, rags, and similar items that are contaminated with small amounts of radioactive elements (mostly plutonium) with half‐lives greater than 20 years. …
A relatively straight, long dune that is oriented at right angles to the prevailing wind or current. …
An oil pipeline that runs 1200 kilometres from oil wells at Prudhoe Bay in the north to the port of Valdez in the south, crossing large areas of permafrost by being raised above the ground. …
A pollutant (such as acid rain) that is carried by natural processes (the movement of air or water) across national or state borders. Also known as international pollution or trans‐boundary pollution . Contrast interstate pollution. …
The strip of land beside a road or trail that is normally visible from it. …
In economic evaluation, a method for determining the value of things (such as recreational resources) that are generally not bought and sold, based on the assumption that the costs met by individuals who travel to a particular site can be used as surrogate prices. …
A type of fishing net that is towed in the water or on the sea‐bed behind a vessel. It has a wide mouth and tapers to a small, pointed end. …
Wastewater that has been processed (physically, chemically, or biologically) in order to reduce its potential to cause health problems. …
Any physical, chemical, or biological process that makes a hazardous substance less hazardous. …
A site in the USA that is regulated by the Environmental Protection Agency, where a hazardous substance is treated, stored, or disposed. …
A formal, binding, written agreement between two or more countries, arrived at by negotiation. …
A large, perennial, woody plant that usually has one main trunk, a number of branches, and a crown of foliage. …
A hollow in a tree that provides a resting or nesting place for wildlife. …
The large‐scale death of trees that is caused by, or associated with, air pollution. Also known as forest death or, in Germany, Waldsterben. …
A stand of planted trees that are of the same age and species. When mature they will usually be harvested by clearcutting, followed by replanting. …
Any agroforestry practice that includes management of trees within the farmland. Also known as farm forestry . …
The upper limit of normal tree growth in mountains or high latitudes, above which the climate is too cold or windy for trees to grow. Also known as timber line . …
A growth ring in the cross section of a tree trunk, which indicates growth during one year. The number of rings corresponds to the age of the tree, and variations in ring width reflect the pattern of weather during the life of the tree. See also dendrochronology, dendroclimatology. …
A drainage pattern in which tributaries join at high angles, often approaching right angles, which is common in areas with rocks of different strengths (thus resistance to erosion) and in areas with regular series of folds (anticlines and synclines). …
1 A long, narrow ditch, often dug either to improve drainage or to install a pipe. 2 See ocean trench. …
The first period of geological time in the Mesozoic era, between about 245 and 208 million years ago, when large predatory reptiles (dinosaurs) evolved. …
A stream or river than flows into another river or a lake. …
A syntheticorganic compound based on tin, which is sprayed on the hulls of ships to control the growth of barnacles and other organisms and is extremely toxic to marine life. Also known as organotin . …
A wastewater treatment system in which the water is trickled over a bed of stones that are covered with bacteria. The bacteria break down the organic waste and produce clean water. …
A class of marine arthropod with three segments to its body. Trilobites were abundant in the Palaeozoic era but became extinct during the Permian. …
An explosive consisting of a pale yellow crystalline compound (C7 H5 N3 O6) that is a flammable and toxic derivative of toluene. …
An animal that lives its entire life within a cave and is specifically adapted to life in total darkness. Also known as a troglobion . …
Relating to food or nutrition, or to levels in a food chain. …
A level in a food chain that is defined by the method of obtaining food and defines the number of steps (energy transfers) up from the original source of energy, from primary producer, to primary consumer, secondary consumer, and tertiary consumer. …
The degree of biological productivity of a waterbody, which largely reflects the availability of nutrients within it. It may be oligotrophic (nutrient poor), mesotrophic (moderately productive), or eutrophic (very productive and fertile). …
The organization of feeding relationships in an ecosystem into the different levels in a food chain, such as producers (plants), primary consumers (herbivores), and secondary consumers (carnivores). …
Relating to, situated in, or characteristic of the tropics, the region on either side of the equator, between the Tropic of Cancer and the Tropic of Capricorn, in which climate varies relatively little from season to season. …
A climate zone which covers much of the equatorial and tropical regions, in which temperatures remain high throughout the year and precipitation can be very high at least during part of the year. There are five different climate zones within the tropics?equatorial wet, tropical wet‐and‐dry, monsoon, tropical steppe and desert, and west coast desert. …
An air mass that develops over large land masses in subtropical latitudes, contains hot dry air, and brings clear skies and low relative humidity. …
A general term for all cyclonic circulations originating over the warm waters of the tropics, which includes tropical depressions, tropical storms, and hurricanes. …
A tropical cyclone with wind speeds of up to 60 kilometres per hour. …
A desertbiome that is hot throughout the year, such as the Sahara. …
A moving mass of thunderstorms in the tropics that persists for at least 24 hours and has relatively light winds. …
Forest that grows in tropical climates with high temperatures and generally high annual rainfall. The two main types are tropical rainforest and monsoon forest. …
An air mass that develops over tropical or subtropical oceans, contains hot moist air, and often brings convectional rain in summer and drizzle in winter. …
A rainforestbiome which is found in the hot, wet tropical climate zone, mostly between latitudes 5? and 10?. In this humid zone temperatures remain uniformly high throughout the year. There are high diurnal variations in temperature, each month receives at least 60 millimetres of rainfall (so there is no dry season), annual rainfall usually exceeds 1500 millimetres, and there are periodic torrenti…
Deforestation of tropical rainforests that is caused by many things, including over‐intensive shifting cultivation, the collection of fuelwood for cooking and heating and for making charcoal, encroachment and clearance by landless peasant farmers, clearance for pasture or crops, commercial logging, grazing, road construction, ranching, mining, and fire. Ecologists are concerned at the pace and p…
A tropical forestbiome comprising a mixture of forest, open woodland, and grassy savanna that grows in a hot climate that has distinct wet and dry seasons. …
A very hot, dry tropical climate zone beyond the tropical wet‐and‐dry climate zone, at higher latitudes, dominated by relatively stable subtropical high pressure cells throughout the year. Many of the world's great deserts (including the Sahara, the Sonoran, and the Great Australian) are found in this climate zone. …
A tropical cyclone with maximum winds of between 64.4 and 120.75 kilometres per hour. …
A long area of low pressure in the tropics, accompanied by a cluster of thunderstorms, that has the potential to develop into a tropical depression. …
A tropical climate with enough rainfall to allow a dense tropical rainforest to grow. …
A tropical climate zone that lies outside the tropical wet climate and has a summer wet season and a winter dry season. This promotes the growth of savanna landscapes, dominated by scattered trees within extensive grassland. …
The line of latitude that runs 23?2? north of the equator, which is the farthest north that the Sun can appear directly overhead, and marks the northern limit of the tropics. …
The line of latitude that runs 23?27? south of the equator, which is the farthest south that the Sun can appear directly overhead, and marks the southern limit of the tropics. …
The part of the Earth's surface that lies between the Tropic of Cancer and the Tropic of Capricorn, which has a hot climate and no cold season. In America this zone is known as the neotropics and in Africa and South East Asia as the palaeotropics. …
The boundary in the atmosphere between the troposphere and the stratosphere, which is located at an altitude of about 20 kilometres in the tropics and falls with latitude to 10 kilometres at the poles. Jet streams are found in the tropopause. …
The portion of the atmosphere closest to the Earth's surface, which stretches up to the lower boundary of the stratosphere (the tropopause), and through which both pressure and temperature usually decrease with increasing height. It extends up to about eight kilometres at the poles and 16 kilometres at the equator, although the height varies through the seasons. Most of the troposphere lies within…
Ozone that is located in the troposphere. It is created by air pollution through the interaction of nitrogen oxides, volatile organic compounds, and sunlight, is a significant greenhouse gas, and causes widespread human health problems via photochemical smog. Contrast stratospheric ozone. …
The lowest point in a wave of air or water; the opposite of ridge. …
The deepening of a centre of low pressure in the atmosphere. …
A US‐based non‐profit conservation organization that is committed to conserving, restoring, and managing the country's trout and salmon fisheries and their watersheds. …
The sum of the market and non‐market (social) costs associated with the production and use of goods and services. …
The direction of the Earth's actual North Pole, as opposed to magnetic north. …
The direction of the Earth's actual South Pole, as opposed to magnetic south. …
A former headland in a river valley which has been sliced off by an advancing valley glacier. …
A giant wave (a seismic wave not a tidal wave) that is triggered by a submarine earthquake or volcanic eruption and moves across the ocean at a speed of more than 700 kilometres per hour. The word tsunami is Japanese for ?harbour wave?, and tsunamis cause widespread damage when they reach the coast. In the open ocean these giant waves have long wavelengths (up to several hundred kilometres) and sm…
A light‐coloured limestone that is formed in caves and around hot springs where groundwater saturated in carbonate is exposed to the air. Also known as travertine . …
A general term for an extrusivevolcanic rock formed of compacted volcanic ash and dust. See also pumice. …
Any abnormal mass of cells that results from uncontrolled cell division and multiplication, and can be benign (not cancerous) or malignant (cancerous). …
A treeless biome found in at high latitudes in arctic and subarctic regions that have long freezing winters and brief summers and where grasses, mosses, lichen, low shrubs, and a few flowering plants survive. The land is usually a flat or gently rolling plain, with black soil and permanently frozen subsoil (permafrost), and is usually very wet. …
In mining, a lateral or horizontal underground passage that is dug to reach a vein or mineral deposit. …
A device that measures the density of suspended solids in a liquid, based on the cloudiness of the mixture. …
The degree of cloudiness in water (or air) that is caused by the presence of suspended solids. …
A dense, flowing mass of water and suspended sediment, that is heavier than clear water and thus flows downhill along the bottom of the sea or a lake, often at high speed. See also density current. …
A device in which blades on a wheel are turned by the force of moving water or steam. The blades are connected by a shaft to a generator in order to produce electricity. …
Unstable flow of a gas or liquid, or instability in the atmosphere that produces gusts and eddies. …
A flow type that involves mixing within moving air or water, caused by irregular eddies. Contrast laminar flow. …
The physical mixing of air or water by turbulent flow. …
The surface layer of soil that includes a matted layer of grass and grass roots. See also sward. …
The process by which the water in a large body of freshwater is completely mixed by circulation during spring and autumn. Also known as overturn . See also mixing cycle. …
A clump of grasses or sedges that are bound together by their roots. …
Total volatile organic compound. See also Volatile Organic Compound. …
A root climber plant that raises itself up by twisting itself around another upright plant. Contrast scrambler. …
The location of the first described specimen of a species or subspecies, or where a particular rock type, stratigraphic unit, fossil, or mineral, was first identified. …
An acute, highly infectious and often fatal disease caused by the typhoid bacillus (Salmonella typhosa) that is transmitted by contaminated food or water. …
The name for a severe storm or hurricane in the western Pacific. …
Widely present, being or seeming to be everywhere. …
The most prestigious scholarship awarded to undergraduate students in the USA, given to those ?who have demonstrated outstanding potential and a commitment to pursuing careers related to the environment?.? …
The medium‐range numerical weather prediction model that is used in the United Kingdom. …
The process of returning waste materials to the environment in a form which will have the minimal environmental impacts. …
Aspects of the environment (such as food) that are directly important to the well‐being and fitness of an organism. Contrast proximate factor. …
A controversial book by Julian Simon ( 1996 ) that attacks neo‐Malthusian thinking and supports continued population and economic growth, arguing that there are few physical limits to the availability of natural resources or the ability of environmental systems to assimilate wastes. …
A type (order) of soil that develops in the tropics and subtropics. It is created largely by chemical weathering, has more clay in the B‐horizon than the A‐horizon, and has an acid subsoil. …
An igneous rock that has a relatively high content of magnesium and iron, but very little silica. Also known as ultramafic . …
Coal that has been washed, ground into fine particles, then chemically treated to remove sulphur, ash, and other substances. …
Any plankton organism that is less than two micrometres in size. …
In terms of wave exposure, a fully enclosed coast with a fetch of up to a few hundred metres. …
Radiation from the Sun that is within the non‐visible portion of the electromagnetic spectrum with a wavelength (0.39 micrometres to 0.01 micrometres) shorter than violet light, which is so blue that humans cannot see it. It can be useful or potentially harmful, depending on its wavelength. Type A (UV‐A) (longer wavelength) is generally beneficial to plants but type B (UV‐B) (shorter wavelen…
A species of plant or animal that has a large home range and broad habitat requirements, both of which overlap with other species, so that if it is given a large enough area for its own protection the other species will also benefit. …
The level of risk above which specific action by a manager or government is regarded as necessary in order to protect life and property, and to achieve stated objectives. Contrast acceptable risk, avoidable risk. …
Water that is held so tightly in the pores of the soil that it cannot be taken up by plant roots. Contrast available water. …
Lacking a resistance to change in pH, having a low buffering capacity. …
See United Nations Framework Convention on Biological Diversity. …
See United Nations Framework Convention on Climate Change. …
See United Nations Convention to Combat Desertification. …
See United Nations Conference on Environment and Development. …
See United Nations Conference on the Human Environment. …
See United Nations Convention on the Law of the Sea. …
See United Nations Conference on Desertification. …
An aquifer that contains water which is not under pressure, so the water level in a well is the same as in the water table outside the well. …
A gap in the rock record (particularly within a stratigraphic sequence) at a particular place, caused by the erosion of existing rocks before younger rocks are subsequently deposited on top. …
Loose, separate, or unattached, for example the individual particles in a sediment such as alluvium. …
Any fire that threatens to destroy life, property, or natural resources. …
Natural resources such as shale oil and tar sands that can be liquefied and used like oil. …
See United Nations Commission on Sustainable Development. …
See United Nations Conference on Trade and Development. …
A fire that can consume ground vegetation but not trees or shrubs. …
A technique for extracting minerals that consists of subsurface excavation with minimal disturbance of the ground surface. …
A large tank buried underground, used for storing hazardous substances or petroleum products such as gasoline or heating oil. See also leaking underground storage tank. …
To plant young trees or sow seed under an existing stand of vegetation. …
The plants beneath the canopy in a stand of stratified vegetation. Also known as undergrowth layer . Contrast overstorey. …
Any species of plant that is not desirable for a particular reason, for example because it is unpalatable, poisonous, or can injure animals. …
A natural resource that is assumed to exist, or has yet to be thought about. Contrast unidentified resource. …
Land that has not been enclosed with a fence or wall. …
See United Nations Educational, Scientific and Cultural Organization. …
A forest stand composed of trees of different ages and sizes, all growing together. Contrast all‐aged stand, even‐aged stand. …
Land or plants that have not been grazed by animals. …
A grazing animal (such as a cow, deer, bison, or sheep) that has hooves. …
A mineral resource that is assumed to be present within known geological areas, but has not yet been specifically located or described in detail. Contrast undiscovered resource. …
See United Nations Industrial Development Organization. …
A pollution control standard that is designed to regulate the discharge of point sources of pollution by enforcing compliance with effluent quality standards. …
The belief that the geological processes that have shaped the Earth through geological time are the same as those operating and observable today, that is they are uniform through time. Contrast catastrophism. …
Grassland that has not been agriculturally improved by being treated with chemical fertilizers or herbicides, so it is usually rich in wildlife. …
Any non‐deliberate release into the environment of genetically modified organisms. …
A native species that is found in only one place. …
1 A single undivided whole (thing or person). 2 A fixed quantity (for example of length, time, or value) that is used as a standard of measurement. …
The nation state that consists of England, Scotland, Wales and Northern Ireland. …
A commission of the United Nations that was created in December 1992 , as a result of the United Nations Conference on Environment and Development, in order to monitor and report on implementation of the Unced agreements at the local, national, regional, and international levels. …
A major international conference which met in Nairobi in August 1977 , and agreed a Plan of Action to Combat Desertification which was designed to prevent and stop the advance of desertification and, where possible, to reclaim desertified land for productive use. …
A major international conference that was held in Rio de Janeiro, Brazil, in June 1992 and is popularly known as the Earth Summit. The conference was the culmination of more than a decade of preparatory work, and it established the tone, pace, and direction of the international environmental agenda for the foreseeable future. The seeds for the Earth Summit were sown in Stockholm in 1972 , where…
The first major international conference to address the relationships between human activities and the environment, held in Stockholm, Sweden, in June 1972 . It produced a set of principles in the Stockholm Declaration, led to the founding of the United Nations Environment Programme, and was a catalyst for development of the modern environmental movement. It was followed up in 1992 by the Unite…
An organization set up by the United Nations in 1964 , which ?promotes the development‐friendly integration of developing countries into the world economy ? with a particular focus on ensuring that domestic policies and international action are mutually supportive in bringing about sustainable development?. …
An international convention that was adopted in November 1972 and came into force in 1975 , under which each state that signed it ?recognizes [its] duty of ensuring the identification, protection, conservation, presentation and transmission to future generations of the cultural and natural heritage?. …
An international convention that came into force in 1994 and was designed ?to regulate all aspects of the resources of the sea and uses of the ocean?. Amongst other things, it introduced the concept of the 200 mile (322 kilometre) Exclusive Economic Zones. …
An international convention that is designed to promote a new, integrated approach to the problem of land degradation in arid, semi‐arid, and dry sub‐humid areas, emphasizing action to promote sustainable development at the community level. …
The global development network set up by the United Nations in 1965 , which operates by ?advocating for change and connecting countries to knowledge, experience and resources to help people build a better life?, and provides technical support for development. …
An agency of the United Nations that was created in 1946 to promote collaboration between countries through education, science, and culture. It has headquarters in Paris, France, and national commissions in many countries. …
A major programme that was established in 1972 at the United Nations Conference on the Human Environment, to stimulate and coordinate sustainable environmental practices worldwide. See also Earthwatch. …
The first specialized United Nations agency that was created in 1945 to combat hunger and poverty, with a mission to raise living standards, agricultural productivity, nutrition levels, and rural living conditions. …
A framework for international action in protecting biodiversity that was agreed at the United Nations Conference on Environment and Development in 1992 . It calls on countries to identify endangered species and conserve the places where they live, and under it each nation agreed to prepare a National Action Plan or Biodiversity Strategy. …
A framework for international action in tackling the prospect of global warming associated with emission of greenhouse gases which was agreed at the United Nations Conference on Environment and Development in 1992 . It called for the stabilization of greenhouse gas emissions by the year 2000 to prevent serious induced global warming, and led to the Kyoto Protocol. Oil‐producing countries (par…
A part of the United Nations whose mission is to improve people's living conditions and promote global prosperity through offering tailor‐made solutions for the sustainable industrial development of developing countries and countries with economies in transition. …
An international organization of countries that was established in 1945 with 51 members, which by July 2000 had expanded to 188 members. Its purpose is ?to preserve peace through international cooperation and collective security?. …
A formula that is used to estimate rates of soil erosion by considering climate, soils, and topographic conditions at a site, as well as the extent to which the use and management of the soil reduce erosion. It has the general form A = R ? K ? L ? S ? C ? P in which A is the amount of soil lost from that field each year, R is the erosivity of the rainfall (based on amount and type of rainfall), K …
A solvent (such as water) that can dissolve almost anything, including both bases and acids. …
Having one brood and generation in a year or season. See also voltinism. Contrast bivoltine, multivoltine. …
A category for species under threat that is defined by the IUCNRed Data Book as including status unknown and insufficiently known. …
Petrol that has not been treated with lead. Contrast leaded fuel. …
Species that are not readily eaten by animals because they taste unpleasant. …
A fire that has started at random by either natural or human causes, or on purpose by an arsonist. …
Tree harvest that is not part of the allowable annual harvest, which can include the removal of dead material or non‐commercial species. …
The movement of water in a soil that is not completely filled with water. Contrast saturated flow. …
That portion of a soil or an aquifer in which not all of the pore space is filled with water, although some water may be present. Also known as vadose zone . Contrast saturatedSee also aeration zone. …
