Land Theme Report

Australia State of the Environment Report 2001 (Theme Report)
Prepared by: Ann Hamblin, Bureau of Rural Sciences, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06748 5

Glossary

agrichemicals: manufactured chemicals produced to perform specific plant and animal protection actions in agricultural activities. They include insecticides, herbicides (to kill weeds), fungicides (to kill fungal pathogens), anthelmintics (to kill internal animal parasites), and hormone preparations for both plants and animals. The term is not normally used to cover fertilisers.
agricultural land: any land on which crops or pastures are cultivated or domestic stock are grazed
algal blooms: a sudden proliferation of microscopic algae in water bodies, stimulated by the input of nutrients such as phosphates
anthropogenic: of human origin or human induced; can be used in the context of emissions that are produced as a result of human activities
arable land: land that is, or has the potential to be, cultivated for crop production
arid zone: often arbitrarily defined in Australia as those areas receiving less than 250 mm of annual rainfall in the south and 350 mm (or sometimes higher) in the north
baseline information: information relating to a specific time or defined area of land or water, from which trends or changes can be assessed
benchmark: the value for an indicator that has some defined environmental significance (or threshold) in the functioning of the natural system. An example is the concentration of pollutants that can be tolerated without damaging health. Whereas targets have a basis in policy and reflect human values, benchmarks are scientifically determined (see targets)
best practice: an agreed standard of practice that conforms with an internationally agreed set of standards. Professional bodies, the International Organization for Standardization (ISO) and other agreed standards institutions have sets of standards covering a wide range of practices. ISO 9000 series cover practices in manufacturing industries, and ISO 14000 series cover environmental management of processed goods.
biodiversity: the variety of all life-forms: the different plants, animals and micro-organisms, the genes they contain and the ecosystems they form. Often considered at three levels: genetic diversity, species diversity and ecosystem diversity.
biogeographic region: an extensive region distinguished from adjacent regions by its broad physical and biological characteristics
biological control: controlling a pest by the use of its natural enemies
biomass: the quantity of organic materials within an ecosystem (usually expressed as dry weight for unit area or volume)
BIOS model: BIOSequil, a steady state biosphere model developed by CSIRO Land and Water for quantifying the coupled balances (stores and fluxes) of carbon, nitrogen, phosphorus and water in Australian landscapes. Estimates of biomass production and nutrient stores have been determined. BIOSequil has been applied at a spatial resolution of 5 km across the Australian continent.
broadacre farms: commercial farms producing relatively low value crops such as wool, sheep meat, beef, cereals, on large areas
bushfire: almost any form of fire burning out of control (see prescribed fire)
calcareous: composed of, or containing lime or limestone
carrying capacity: the maximum population size that can be supported indefinitely by a given environment, and can apply to any trophic level of organism (carnivore, herbivore, microbial, autotrophic, etc)
catchment: the area determined by topographic features within which rainfall will contribute to runoff at a particular point under consideration
CFCs (chlorofluorocarbons): synthetic products, which do not occur naturally and contain chlorine and fluorine; commonly used in various industrial processes and as refrigerants and, prior to 1990, as a propellant gas for sprays; deplete ozone in the stratosphere and are powerful greenhouse gases
chenopod shrubland: areas dominated by shrubs of the Chenopodiaceae family (commonly known as saltbushes and bluebushes)
chlorophyll: the green pigment in plants that functions in photosynthesis by absorbing light from the sun
clearfelling: the removal of all trees on a specified cutting area (see coupe); in many cases some trees are retained for environmental protection or conservation reasons
clearing: removing vegetation, particularly trees and shrubs, from a landscape, often with the intention of replacing it with plants regarded to be more directly useful to humans
climate: the synthesis of the day-to-day weather conditions in a given area; the actual climate is characterised by long-term statistics of the state of the atmosphere in an area
climate variability: the natural year-to-year and season-to-season variation of the climate system
codes of practice: sets of guidelines adopted by management agencies concerned with minimising impacts of operations on the environment and with worker safety
conservation farming (tillage): farming systems designed to reduce runoff so that water storage in the soil is maximised and soil erosion is reduced
coupe: an area of forest harvested in a single operation; usually 10 to 300 hectares harvested over a single season
desertification: the degradation of land in arid, semi-arid, and other areas with a dry season; caused primarily by over-exploitation and inappropriate land use interacting with climatic variations
diffuse-source pollution: pollution from sources such as an eroding paddock, urban or suburban lands and forests; spread out, and often not easily identified or managed
domestic animals: selection of animals with desired traits for use by humans: for food (meat, milk and milk products), other animal products (hair, hides for leather, horn, wool), transport (bullocks, camels, horses), or recreation and pets (cats, dogs, racing horses, dogs, falcons, pigeons) (see also feral)
drainage: the interception and/or removal of surface and/or groundwater from a given area by natural or artificial means
dry sclerophyll: a type of eucalypt forest found in moderate rainfall (less than 1000 mm per year) areas sometimes called 'open forests' (see wet sclerophyll)
dryland cropping: cropping without irrigation, usually in areas of relatively low rainfall
dryland salinity: land salinity that occurs as a result of clearing deep-rooted perennial vegetation, or other activities that interfere with the water and salinity balance and lead to shallow water tables; hydrological response to the replacement of deep-rooted perennial native vegetation with shallow rooted annuals which use less water; as a consequence of which more rainfall enters the groundwater, causing water tables to rise close to the soil surface
Ecologically Sustainable Development (ESD): development that improves the total quality of life, both now and in the future, in a way that maintains the ecological processes on which life depends (for the ESD core objectives and guiding principles, see Council of Australian Governments 1992b)
ecology: the scientific study of living organisms and their relationships to one another and their environment
economic efficiency: the extent to which managers are able to make optimum use of resources in production by accounting for the relative prices of resources and products; prices are used to select from a number of technically efficient combinations of resources; where market prices do not coincide with community values the result is the selection of products and practices that are socially inefficient
ecosystem: a dynamic complex of plant, animal and micro-organism communities and their non-living environment interacting as a functional unit
ecosystem services: the role played by organisms and environmental processes in creating a healthy environment for human beings, from production of oxygen to soil formation and maintenance of water quality
effluent: (a) a discharge or emission of liquid, gas or other waste product; (b) description of a stream network which draws water out of or away from a river or water body
El Nio: a warm water current which periodically flows southwards along the coast of Ecuador and Peru in South America, replacing the usually cold northwards flowing current; occurs once every five to seven years usually during the Christmas season (the name refers to the Christ child). Occasionally (e.g. 1925, 1972-73, 1982-83 and 1990-94) the occurrence is major and prolonged; the opposite phase of an El Nio event is called a La Nia (see enso)
endemic: native to a particular area and found nowhere else; having originated in the region where it is now found
ENSO (El Nio -Southern Oscillation): a suite of events that occur at the time of an El Nio; at one extreme of the cycle, when the central Pacific Ocean is warm and the atmospheric pressure over Australia is relatively high, the ENSO causes drought conditions over eastern Australia (see El Nio, SOI)
environmental indicators: measures of physical, chemical, biological, social, cultural or economic factors which best represent the key elements of complex ecosystems or environmental issues
environmental stress: the damaging influence of human activities on the environment (for example, through pollution or consumption of natural resources) or that generated by natural events such as storms or droughts
erodible: susceptible to erosion: erosivity is the capacity (e.g. of rainfall) to erode, erodibility is the susceptibility (e.g. of soil or rock) to erode
eutrophication: process by which waters become enriched with nutrients, primarily nitrogen and phosphorus, which stimulate the growth of aquatic flora and/or fauna
evapotranspiration: water withdrawn from soil by evaporation and/or plant transpiration
exotic species: a species occurring in an area outside its historically known natural range as a result of intentional or accidental dispersal by human activities (including exotic organisms, GMOs and translocated species see also native species, novel biota)
Extensive Landuse Zone: the non-improved land tenures of Australia that are used for grazing. These occupy over 60% of the continental area.
fallow: a phase when land is not being actively cropped
fauna: the entire animal life of a region (see also flora)
feral: animals that have reverted to a wild state from domestication (for example, feral cats, pigs, dogs, camels, horses, donkeys etc), sometimes accompanied by reversion of those traits selected for in domestication (morphology, size, behaviour).
fertiliser: natural and synthetically produced inorganic and organic plant nutrient compounds. Nitrogen, phosphorus and potassium salts are the most heavily and extensively used, but micro-nutrients and trace elements are manufactured to correct deficiencies in essential nutrients for plants for the elements calcium, magnesium, sulphur, zinc, iron, copper, manganese, molybdenum, - and also for cobalt in animals. Organic fertilisers are derived from plant and animal residues but plants acquire them as simple salts after decomposition and breakdown in the soil.
fire regime: the pattern of fires at a location; includes the frequency, intensity and seasonality of the fires
flora: the entire plant life of a region (see also fauna)
flux: the rate at which heat (energy, radiation, carbon dioxide, water vapour etc) flows across unit area (e.g. heat flux is the flow of heat in a heat exchange process)
forest: The Australian definition (National Forest Inventory) is 'an area dominated by trees having usually a single stem and a mature stand height exceeding two metres with an existing or potential crown cover equal to or greater than 20%'. This definition is somewhat different to that of the United Nations Food and Agriculture Organization, which is 'land with tree crown cover of more than 10% and area of more than 0.5 ha. Trees should be able to reach a minimum height of 5 metres at maturity'.
freehold tenure: land owned privately (see also leasehold land)
fresh water: water containing no significant amounts of salts, potable water suitable for all normal uses; also known as potable water
gene: the basic unit of heredity
geographic information system (GIS): a package of computer programs specifically designed to deal with data that are spatially related; a set of tools for collecting, storing, retrieving, manipulating, analysing and displaying mapped data from the real world
GL (gigalitre): one thousand million litres
grassland: areas dominated by grasses and with few or no trees
greenhouse effect: a popular term used to describe the role of atmospheric trace gases- water vapour, carbon dioxide, methane, nitrous oxide, ozone-in keeping the Earth's surface warmer than it would be otherwise; also known as enhanced greenhouse effect
groundwater: water occurring below the ground surface
gully erosion: a form of erosion involving the formation of deep, steep-sided channels or gullies which cannot be removed by cultivation (see rill erosion, sheet erosion)
habitat: the place where an animal or a plant normally lives and reproduces
hardwood: timber from sources other than pines and cypresses; includes timbers from eucalypts, wattles and most rainforest species ( see softwood)
headwaters: the upper parts of a river drainage system
heath: a vegetation dominated by small shrubs with small hard leaves
heavy metal: metallic element with relatively high atomic mass (over 5.0 specific gravity), such as lead, cadmium, arsenic and mercury; generally toxic in relatively low concentrations to plant and animal life
hectare (ha): 10 000 square metres. There are 100 hectares in 1 km²
herbivore: an animal that consumes plants
improved pasture: pasture that is sown with a mixture of introduced grasses and legumes inoculated with rhizobia to fix nitrogen, and fertilised on a regular basis. Such pastures, if well managed, are very much more productive than native pastures and rough grazing, which may consist of native shrubs, grasses, weeds, with or without a tree canopy. The most highly managed pastures may produce more than 20 times the dry matter and protein per hectare than rough grazing.
infiltration: the passage of water through the soil surface and into the soil matrix
Intensive Landuse Zone: Agricultural area of Australia where the predominant landuses are cropping (both irrigated and rainfed) and improved grazing, with introduced grasses and legumes
invertebrate: an animal without a backbone composed of vertebrae; examples include insects, worms, snails, mussels, prawns and cuttlefish (see vertebrate)
KL (kilolitre): one thousand litres, or one cubic metre
L (litre): a unit of volume equal to 1/1000 of one cubic metre
land cover: the physical state of the land surface, including vegetation, soil, rock and human made structures, but specifically used in relation to vegetational changes, to describe the proportion of land covered by vegetation
Landcare: a voluntary and cooperative movement that brings together rural people, government agencies and others with an interest in the long-term health of the land; the term was first used in Victoria in 1986 but spread nationally after 1988 when the Australian Conservation Foundation and the National Farmers' Federation persuaded the Commonwealth Government to provide significant financial support
leakiness: horizontal and vertical leaching of cations from the soil profile into the water table and where it intercepts the ground surface
leasehold land: land owned by governments on behalf of the people they represent but leased to specified people or organisations for a specific purpose; about 50% of Australia, mostly in the drier regions, comes under some form of leasehold; governments retain a variety of controls over how leasehold land is used
medic: species of the genus Medicag o, including lucerne, that have symbiotic rhizobia which fix nitrogen
microgram (g): 1 x 10^-6 grams
ML (megalitre): one million litres, or 1000 cubic metres, (1 acre foot = 1234 cubic metres)
multiple use: managing an area to achieve multiple goals or multiple outputs; (e.g. timber production, water and recreational opportunities)
native species (indigenous species): species that are native to (i.e. occur naturally) in a region (see exotic species)
naturalised: an exotic species that, once introduced into an area, has the capacity to adapt to the new environment, survive in competition with the endemic floral and faunal populations, reproduce itself and establish itself as a persistent part of the plant community in one or more habitat (see also exotic species)
Net primary productivity (NPP): the ratio of all biomass accumulation and biomass losses in units of carbon, weight or energy, per land surface unit, over a set time interval (usually a year)
nitrogen fixation: the conversion of gaseous nitrogen into more complex molecules that can be used by plants and other organisms; often carried out by micro-organisms in the soil or closely associated with some plant species (e.g. the legumes or pea relatives)
novel biota: a species occurring in an area outside its historically known natural range as a result of intentional or accidental dispersal by human activities (including exotic organisms, GMOs and translocated species) (see also exotic species)
off-site impacts: consequences of an action or decision that occur beyond the area (e.g. the farm or catchment) under consideration; also known as externalities
old-growth forests: forests dominated by mature trees and with little or no evidence of any disturbance such as logging, road building or clearing
open woodlands: an area with scattered trees in which the tree crowns cover less than about 30% of land surface (see woodland)
organochlorine: a hydrocarbon compound containing chlorine. Includes many pesticides and industrial chemicals.
particulate matter: in this report, the term particulate matter has been used interchangeably with particles
pastoral areas: those areas used predominantly for grazing livestock with little or no cultivation or improved pastures
pathogen: agent causing disease
perennial plants: plants that live for more than one year
peri-urban: low density housing and road development on the periphery of urban areas, still retaining small areas of rural land within networks of suburban building
pest: an animal, or sometimes a plant, occurring where it is not wanted by humans (see weed)
photosynthesis: the biochemical process in plants and certain other organisms by which energy from the sun, captured by chlorophyll, powers the production of organic matter from carbon dioxide and water, releasing oxygen (see chlorophyll)
point-source pollution: pollution from an easily discernible, single source such as a factory (see )
pollution: the direct or indirect alteration of the physical, thermal, biological or radioactive properties of any part of the environment in such a way as to create a hazard or potential hazard to the health, safety or welfare of any living species
population: a group of individuals of the same species, forming a breeding unit and sharing a habitat
precipitation: any form or all forms of liquid or solid water particles that fall from the atmosphere and reach the Earth's surface; includes drizzle, rain, snow, snow pellets, ice crystals, ice pellets and hail
prescribed fire: a fire deliberately lit and controlled by humans, usually as part of a land management program (e.g. to reduce the chance of uncontrollable bushfires, or to control weeds)
primary productivity: the rate at which plants produce organic matter through photosynthesis, generally expressed as net (all increase minus all decay)
primary salinity: salinity mobilised in the landscape from a change in the hydrologic cycle either from climate change or clearing
productivity (biological): the rate of accumulation of organic material in an ecosystem or the rate of change in the physical agricultural production of a unit of land, as described by yield (tonnes/ha) per year
productivity (economic): the sum of technological change and change in economic efficiency. 'Total factor productivity' is the ratio of the index of all product outputs of production to the index of all inputs used to produce the same level of output.
rangelands: areas of native grasslands, shrublands and woodlands that cover a large proportion of the arid and semi-arid regions, including tropical savanna woodlands: regular cropping is not practised and the predominant agricultural use, if any, is grazing of sheep and cattle on native vegetation
recharge: the action by which water is added to a rock layer either naturally or artificially
reduced (or minimum) tillage: a soil management system in which tillage is avoided as much as possible
residence time: the period during which a substance remains in its active form in the environment
rill erosion: a form of erosion involving formation of shallow gutters which may be removed by cultivation (see gully erosion, sheet erosion)
risk analysis: classical risk analysis, as used in engineering applications for example, is a matrix analysis of type of impact by frequency of occurrence. Risk is predictive, hazard is qualitatively estimated
runoff: that portion of precipitation not immediately absorbed into or detained upon the soil and which thus becomes a surface flow
salinisation: the process by which soluble salt levels in the soil increase to the point where plant growth is affected (see secondary salinity)
saltbush: see chenopod shrubland
savanna: a vegetation type with scattered trees over a grassland, usually found in subtropical areas
secondary salinity: human induced, largely believed to be related to irrigation, results from rise in naturally saline watertable to less than one metre from the root zone, causing salinisation (see salinisation)
semi-arid zone: lands where rainfall is so low and unreliable that crops cannot be grown with any reliability (see arid zone)
sheet erosion: the removal of a fairly uniform layer of soil from the land surface by raindrop splash and/or runoff (see rill erosion, gully erosion)
shrubland: an area dominated by short, multi-stemmed plants; a typical example is the chenopod shrublands but sometimes the 'mallee' is classified as a shrubland (see chenopod shrubland)
siltation: deposition of sediments from water in channels, harbours, etc
sinks: processes or places that remove or store gases, solutes or solids in accumulating parts of the environment
SLA (Statistical Local Area): Population and related socio-economic statistics are gathered by collection districts, aggregated to SLAs and in turn these are aggregated to statistical divisions, and then to States and Territories. SLAs are roughly equivalent to administrative shires, and often follow the same boundaries. There has been substantial re-alignment of SLA boundaries in recent years, particularly in Victoria which has made analysis of spatially dispersed data (such as agricultural statistics) difficult to compare across years.
sodic soils: soils with a high proportion of sodium relative to calcium, potassium and magnesium in the composition of the exchangeable cations on the clay fraction. This causes poor physical conditions through dispersion (spreading out of the clay in water); Sodicity affects about 30% of Australian soils.
softwood: timbers from trees such as pines and cypresses; in Australia most softwood comes from pine plantations (see hardwood)
SOI (Southern Oscillation Index): an indicator based on the pressure gradient between the quasi-stationary low pressure region over Indonesia and the centre of the subtropical high pressure cell over the eastern Pacific Ocean. Traditionally, Darwin and Tahiti are used as the sites for determining the magnitude of the Southern Oscillation. A negative SOI is associated with higher than normal pressures over Darwin and drought conditions over much of eastern Australia (see ENSO)
soil acidification: a gradual increase in the acidity of a soil as a consequence of a variety of natural processes and management actions
soil conditioner: a chemical that improves the physical or chemical behaviour of soil by stabilising soil aggregates (or crumbs), changing the pH, or both. Common conditioners include lime (and dolomite) to correct acidity, and gypsum (calcium sulfate) to correct sodicity
species: a group of plants, animals or micro-organisms that have a high degree of similarity and generally can interbreed only amongst themselves to produce fertile offspring, so that they maintain their 'separateness' from other such groups
stocking rate: the number of animals carried per unit area of land on a year-long basis. If animals are 'set stocked' they occupy the same land all year, whereas animals that are rotationally or cell stocked occupy different areas as the pasture grows and decays in regions of variable seasonal growth.
stocking density: the statistical number of animals on a farm or in a region, divided by the total area of grazing land available
surfactant: a material that facilitates and accentuates the emulsifying, wetting and other surface-modifying properties of substances
suspended solids: any solid substance present in water in an undissolved state, usually contributing directly to turbidity
symbiotic: a close association between the individuals of pairs of species often leading to mutual gains
targets: are specified levels or ranges of measurable parameters that decision-makers have agreed they will try to achieve. Targets are policy tools, but they may have a scientific base. Australia's commitment at Kyoto to restrict greenhouse gas emissions to 108% of 1990 levels by 2008-2012 is an example of a target.
tillage: mechanical disturbance of the soil by using various implements to alter the soil structure; usually done to create a seedbed, kill weeds or increase water entry (see reduced (or minimum) tillage)
total factor productivity: see productivity (economic)
trend: a general direction or tendency; an indication of change (or its absence) in a property or condition
turbidity: (a) a measure of the extent to which passage of light through water is reduced by suspended matter (b) the cloudy conditions caused by suspended solids in liquids
urbanisation: the shift of population from rural to urban areas
vector: a disease carrier
vertebrate: an animal with a backbone composed of vertebrae, examples include mammals, fishes, frogs, amphibians, reptiles and birds (see invertebrate)
water table: a surface defined by the level to which water rises in an open well or piezometer
weed: a plant species growing where it is not wanted by humans, generally in relation to agricultural production or conservation of endemic biodiversity
wet sclerophyll: a type of eucalypt forest found in high rainfall (more than 1000 mm per year) areas; sometimes called 'tall-open forests' (see dry sclerophyll)
wetland: the land area alongside fresh and salt waters, that is flooded all or part of the time; marine and estuarine wetlands include tidal basins, saltmarshes and mangroves
wilderness: 'a large tract of land remote at its core from mechanised access or settlement, substantially unmodified by modern technological society or capable of being restored to that state, and of a sufficient size to make practicable its long-term protection of its natural systems'. (The Macquarie Dictionary 1997)
woodland: an area with scattered trees where the portion of the land surface covered by the crowns is more than 30% (open woodland) but less than 60% (forest)
zero tillage: a production system in which there is no tillage at all. Many Australians use the term incorrectly to describe what should be referred to as reduced tillage (see reduced (or minimum) tillage).