Rangelands glossary

Common terms

All terms are arranged alphabetically:

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

A

• Abundance: the total number of individuals of a species in an area, population or plant community.

• Alluvial plain: a plain formed by the repeated deposition of sediment from a river when it floods.¹

• Animal equivalent (AE): also referred to as animal unit equivalence or adult equivalent. AE is used in some other states of Australia, and is the same as the cattle unit (CU) used in northern Western Australia. See Livestock comparisons for estimating grazing pressure in the rangelands for more detail. The modern use of these terms is based on calculated energy requirements for standard animals (cattle and sheep) for maintenance and movement. AE is based on the feed energy to maintain a 450 kg Bos taurus steer 2.25 years of age, walking 7 kilometers each day. 1 AE has an energy requirement of approximately 73 MJ ME/day. based on feed enrgy requirements, 1 AE = 8.4 DSE.

• Animal selectivity: the degree to which animals preferentially consume some plants or plant parts from the total amount of forage available to them.

• Annual: a plant which grows from seed and completes its life cycle, including flowering and seeding, within 1 year or less; some annuals can live longer than 1 year when growing conditions are favourable; see also short-lived perennial.¹ Examples are: wheat, subterranean clover, lupins, canola.

• Arid: a region or climate where lack of sufficient moisture severely limits growth and production of vegetation; the actual limit of sufficient moisture varies according to temperature in the specific location. The arid zone is defined as areas which receive an average rainfall of 250 millimetres (mm) or less. The semi-arid zone is defined as areas which receive an average rainfall between 250–350mm.

• Available forage: the proportion of forage production that is accessible for use by a specified kind or class of grazing animal.

• Awn: a fine, hair-like structure that is attached to the flowering parts of many grasses. Threeawns (Aristida spp.) are so named because of the 3 awns that are attached to the seed.¹

B

• Basal area (ground cover by perennial grasses): in the rangelands, this term is used for the percent of ground covered by the base or butts of perennial tussock grasses. Basal area of tussocks is a consistent way of measuring the health of a tussock grassland from year to year. Tussock bases persist in both drought and good seasons and can be measured (basal cover %) despite being hidden by stems and leaves in good seasons. Foliar cover % varies with seasonal and grazing effects. See canopy cover and projected foliage cover for woody perennials.

• Biennial: plants that complete their life cycle over 2 years.¹

• Bioregion: a large, geographically distinct area of land with common characteristics, such as geology, landform patterns, climate, ecological features and plant and animal communities; see Department of the Environment and Energy.

• Bores: usually refers to drilled, lined holes into a confined or semi-confined aquifer (artesian systems). Bore linings are perforated only in the aquifer space at the bottom of the bore, below the confining layer, and the outside of the bore pipe is sealed down to the confiining layer, to prevent leakage upward from the aquifer. The water in this type of bore is higher in the bore than the top of the aquifer due to hydrostatic pressure.

C

• Calcareous: containing lime or limestone.¹

• Canopy: the aerial portion of vegetation that provides groundcover when viewed from above. Usually refers to shrubs or trees and not annuals. See basal area for perennial grasses.

• Canopy cover: the percentage of ground covered by a vertical projection of the outermost perimeter of the natural spread of plant foliage; small openings within the canopy are generally included. Also referred to as projected foliage cover.

• Carrying capacity: the number of livestock units a paddock or management area can carry over the long term while maintaining or improving land condition.¹ This is often expressed as hectares per livestock unit (e.g. 20 hectares per dry sheep equivalent (DSE)) or livestock units per square kilometre (e.g. 5 DSEs per km²).
  
  Carrying capacities provide long-term guides to the potential productivity of the rangeland but should not be considered absolute values. The actual grazing value and forage availability of a particular paddock or station at any time will vary with seasonal conditions, rangeland condition, watering points and the degree of recent utilisation.
  
  See Potential Carrying Capacity, Current Carrying Capacity, Present Carrying Capacity, Sustainable Carrying Capacity and Seasonal Carrying Capacity.

• Cattle unit (CU): this unit was used in Western Australia, and is based on observations of feed intake relative to a DSE. In general, 1 CU = 7 DSE, and was based on a 400 or a 450 kg steer. Western Australia is now adopting the well researched AE unit, which has an equivalent of 1 AE = 8.4 DSE.  See Livestock comparisons for estimating grazing pressure in the rangelands for more detail.

• Coastal: on or near the coast.¹

• Coastal heath vegetation type: occurs as a very narrow margin along coastal fringes. On the exposed coastal rim the vegetation is scattered. The mid-slopes of the seaward dunes are dominated by the close, mid-height shrub layer. Some very scattered low shrubs or isolated tall shrubs occur, but are rarely dominant.¹¹

• Co-dominant: a species equally dominant with 1 or more other species in a pasture.¹

• Continuous grazing and continuous set stocking: Continuous grazing is a management system where livestock run in a paddock continuously over time with no, or only infrequent, spells from grazing. Continuous set stocking (see set stocking) refers to the situation where livestock numbers in a paddock vary little from month to month, or from year to year.

  The main benefits of continuous grazing are that it is simple to apply, requires minimal labour and can deliver good production and land condition outcomes if managed well. Disadvantages of set stocked continuous grazing are that pasture utilisation may be above or below the optimal level at any one time. There is also the potential for overgrazing with livestock habitually revisiting preferred areas.

  For good production and land class outcomes, set stocked continuous grazing systems should be conservatively stocked, to minimise the decline of preferred pasture species and land types. Risks to land condition and production can be minimised in a continuous grazing system by:
  - preparing a forage budget and adjusting stocking rate accordingly
  - spelling the paddock during the growing season once every 3-4 years to allow full pasture recovery
  - rotational burning to minimise patch grazing. (MLA)

• Cryptogamic crusts: a fragile, biological soil surface crust – found in arid and semi-arid environments – comprised of plants that have no true flowers or seeds, including ferns, mosses, liverworts, lichens, algae (cyanobacteria), and fungi (cryptogams). Cryptogamic crusts protect the soil from erosion, provide nitrogen from cyanobacteria, and influence local water movement (hydrophobic when completely dry, then gradually absorbent).

• Current Carrying Capacity: the Potential CC discounted for an assessed decline in rangeland condition, based on defined ‘discount factors’ for each land system. All other factors are as for the Potential carrying capacity: the estimated long-term carrying capacity for an area (paddock, station or region) while maintaining or improving land condition, the area is fully developed for grazing (particularly water-point distribution); all feed is accessible to livestock; grazing by native and feral animals is controlled; and there is good practice grazing management.
  Present Carrying Capacity is an alternative name for this.

D

• Decreaser: plants that decrease in frequency as grazing pressure increases, because they are preferentially grazed. Decreasers in a given pasture type are usually productive and palatable. Plants that are decreaser perennials in rangeland pastures are also often called desirables.^1,2

• Density: the number of individuals of a certain species per unit area; it is not a measure of cover.¹

• Desirables or desirable species: those species in a given pasture type that are usually productive, palatable and perennial. Desirables generally decrease in frequency as grazing pressure increases because they are preferentially grazed. Plants that are desirable in rangeland pastures are also often called decreasers.^1,2

• Driver: An aspect of a system that causes or contributes to a change on another aspect of the system. For instance, climate change is a driver of water availability.

• Drought: a prolonged period without rain, compared to the norm, leading to a shortage of water for vegetation and animals. This term is now mainly used for programs that provide government assistance, and these have particular requirements to be eligible. A more useful term in the highly variable climate of Western Australia is 'dry season'.

• Dry sheep equivalent (DSE): 1 DSE is based on the feed energy of 8.7 MJ ME/day required to maintain a 45 kilogram liveweight Merino wether with zero weight change, no wool growth additional to that included in maintenance, and walking 7 km/day (Petty et al 2018, McLennan et al 2020). DSEs can be used for small livestock types and classes, and cattle units (CU) are preferrred for cattle. See Livestock comparisons for estimating grazing pressure in the rangelands for more detail.

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E

• Ecologically sustainable development (ESD): The State of Western Australia's Biodiversity Conservation Act 2016 (BCA) defines the principles of ESD as:
  (a) decision-making processes should effectively integrate long-term and short-term economic, environmental, social and equitable considerations
  (b) if there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation
  (c) the present generation should ensure that the health, diversity and productivity of the environment is maintained or enhanced for the benefit of future generations
  (d) the conservation of biodiversity and ecological integrity should be a fundamental consideration in decision-making
  (e) improved valuation, pricing and incentive mechanisms should be promoted.

• Ecology: the study of relationships and interactions of living organisms with other living organisms and their surrounding environment.

• Ecosystem: the biotic and abiotic environment and the ecology in a clearly defined system, such as a drop of water, a habitat, a land system or the whole earth itself. An ecosystem = environment + ecology.

• Effective rainfall: effective rainfall infiltrates the soil and is available to plant root zones (i.e. it is not lost to evaporation, run-off or deep drainage). In its simplest form, effective rainfall is precipitation above a threshold of a fixed event size (e.g. 5mm), below which no response in plant growth occurs. Effective rainfall is not the same everywhere or all the time because factors, such as rainfall sequence and timing, temperature, soil type and slope, also affect how much rain must be received before plants can take it up.⁶

• Environment: the surroundings in which an organism lives, including biotic (other living organisms) and abiotic (e.g. soil, water, atmosphere) factors.

• Ephemeral (plant): a plant that goes through its entire life cycle in a very short time. In the rangelands, this usually refers to a very short-lived annual.

• Erosion: the process by which soil particles are detached and moved from the land surface (usually called soil erosion) by the action of wind (usually called wind erosion) or water (usually called water erosion). Natural erosion occurs in undisturbed natural environments, and is usually a very slow process. Accelerated erosion occurs in disturbed environments, often resulting from human influence on soil, vegetation or landforms.¹⁴

• Erosion assessment: Using the Australian Soil and Land Survey: Field Handbook¹⁴. Each of these forms of erosion may be active, stabilised or partly stabilised, and may be minor, moderate or severe.

  • Sheeting: the relatively uniform removal of soil from an area without the formation of conspicuous channels.
  • Microterracing/Terracettes: small terraces on slopes resulting from soil creep or trampling by hoofed animals.
  • Scalding: the removal of surface soil to a heavier textured subsoil, which is devoid of vegetation and relatively impermeable to water.
  • Pedestalling: where rocks or plants appear raised on a pedestal, because the surrounding soil has been eroded away.
  • Rilling: small channels less than 30 centimetres (cm) deep, caused by surface water flow, which can be easily filled or stabilised
  • Guttering: channels formed intially from vehicle or livestock tracks on a slight grade, eroded by water movement. Gutters can be less or more than 30cm deep.
  • Gullying: channels that are more than 30cm deep caused by water erosion.
  • Accelerated accretion of soil material: the deposition of eroded material by wind (aeolian) or water (alluvial).
  • Tunnelling: the removal of subsoil by water while the surface remains relatively intact. Common in dispersive soils.

F

• Feed budgeting: the practice of estimating whether the feed available is sufficient to meet requirements of livestock. Feed budgeting can help prevent overgrazing  and undergrazing, and optimising the conversion of quality feed into product. Overgrazing reduces plant leaf area and carbohydrate stores in the roots, thereby reducing production. Undergrazing allows pasture quality to deteriorate, and misses production and profit opportunities (See MLA Supplementary feeding).

• Forage: (noun) browse and herbage which is available as food for grazing animals or for harvesting for feed (i.e. hay or silage).

• Forage supply: see Available forage.

• Forbs: any herbaceous plant that is not a grass or grass-like. Forbs can be annual or perennial.

• Frequency: "Plant frequency is defined as the number of times a plant species is present within a given number of sample quadrats of uniform size placed repeatedly across a stand of vegetation (Mueller-Dombois & Ellenberg 1974, Daubenmire 1968). Plant frequency is a function of quadrat size and reflects plant density and dispersion. The sensitivity of frequency data to density and dispersion make frequency a useful parameter in documenting changes in plant communities (Despain et al. 1997, Smith pers. comm. 1997).

  • Frequency has a number of advantages: it is objective, there is no estimation or subjective evaluation necessary because it depends on presence rather than amount, and it is quick and simple.

  • There are also a number of disadvantages: it is relatively insensitive to short-term fluctuations, but is more responsive to longer-term shifts in management; data collected does not necessarily relate to more concrete parameters, such as density, weight, height or biomass; and because frequency values depend on the size of the quadrat used in sampling, data collected from different sized quadrats are not comparable.

  • Frequency is not well-suited to larger shrubs due to quadrat size. Frequency can be used to indicate trends in range condition, but will be more accurate when used in conjunction with additional monitoring techniques."⁷

• Frontage: pastures associated with major rivers and watercourses, usually associated with relatively high pastoral potential, and often with reduced productive capacity as a result of heavy grazing pressure.^3,4

• Functional group: an aggregation of like land systems, based on the published description of landform, dominant land unit or pasture type, and underlying vegetation; a primary functional group can be split according to the overstorey; the 110 land systems in the Kimberley are classified into 10 functional groups; south of the Kimberley, the 444 land systems are classified into 50 functional groups.

G

• Gilgai microrelief (soils): mounds and depressions on the soil surface associated with clays that shrink and swell. These formations are also called crabholes or melonholes, and can be circular, subcircular, linear or contoured.

• Good practice grazing management:

• Grassland: a vegetation community dominated by grasses, grass-like plants and/or forbs; characterised by perennial tussock and hummock grasses, occurring primarily in the Kimberley and Pilbara; in the Pilbara, there is a gradual change from tussock or hummock grass understoreys in northern pastures to predominantly shrub understoreys in southern pastures.

• Grazing intensity: the cumulative effect of grazing on rangeland vegetation during a particular period.⁹ It has several factors: grazing pressure; grazing frequency; the period; and the stage of growth of the vegetation.

• Grazing pressure: for a given area, it is the amount of forage removed by livestock in relation to the amount of forage available.¹ See utilisation for recommended grazing pressures (usually about 30% at the paddock level).

• Grazing radius (from pastoral water points): for cattle is generally within 5km of the water point. The estimate of sustainable carrying capacity is based on 100% pasture carrying capacity within 3.5km, 50% in the 3.5–5km area, and 0% beyond 5km. The grazing impact around a water point is called the piosphere.

• Grazing systems: specialised forms of grazing management which defines the stocking rates and livestock movements, the periods of grazing and non-grazing (rest). Take care in using or applying these terms, as casual use often combines systems under one name. See continuous grazing and continuous set stocking;  set stocking; rotational grazing, cell grazing and time control grazing; tactical grazing.

• Greenness index: also known as the Normalised Difference Vegetation Index (NDVI), is derived from satellite data. 'Live green vegetation absorbs visible light (solar radiation) as part of photosynthesis. At the same time plants scatter (reflect) solar energy in the near infrared. This difference in absorption is quite unique to live vegetation and provides a measure of the greenness of the vegetation. NDVI is an index which measures the difference between near-infrared (which vegetation strongly reflects) and red light (which vegetation absorbs), providing a measure of vegetation density and condition. See Normalised Difference Vegetation Index (Bureau of Meteorology).

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H

• Halophyte: a plant adapted to living in highly saline habitats; a plant that accumulates high concentrations of salt in its tissues. Adjective: halophytic¹²

• Heath vegetation group: consists of 4 separate vegetation types: low heath, scrub heath, tree heath and coastal heath. This vegetation group was first described in Payne et al. (1987)¹⁰ who noted "complex plant assemblages that are generally unsuited to pastoral development and production".¹¹

• Herb: any seed-bearing plant which does not have a woody stem and dies down to the ground after flowering. Adjective: herbaceous¹²

• Hummock grass: spinifexes that grow together as large rounded mounds or ‘hummocks’ that can be up to several metres across, often forming rings around a central dead or decaying patch.¹

• Hummocking: the process of accumulation of wind blown soil around the base of plants. This is commonly around the base of perennial grass clumps, including hummock grass.

I

• Identifier grasses: Some grasses (called ‘identifier’ grasses) are typically associated with – although not limited to – particular pasture types. Identifier grasses are useful to determine pasture type because they tend to be present regardless of pasture condition. They will be easiest to find in pasture in good condition, and are usually still common in fair pasture condition. As the pasture approaches poor condition, identifier grasses are sometimes present only as a few scattered plants or butts, and they may be hard to find.

• Increaser: plants that increase in frequency as grazing pressure increases, because they are not grazed by preference. Increasers in a rangeland pasture type are generally unpalatable and are often called undesirables. Undesirables include woody weeds and other weedy, prickly or toxic species which invade overgrazed pasture. Largely ignored by livestock, undesirables tend to increase under prolonged heavy grazing, and in large numbers are an indication of poor pasture condition.^1,2

• Indicator species (indicator): plants that either increase or decrease in population density and distribution in response to grazing pressure and indicate the condition or condition trend of the pasture for the purpose of pastoral (grazing) use. See 'increaser' and 'decreaser'.

• Intermediates or intermediate species: those species in a given pasture type that include moderately or slightly palatable perennial grasses, shrubs and trees and palatable annuals; may increase under heavy grazing at first because livestock concentrate on the more-desirable perennial species, but if the desirable perennial species are grazed out, intermediate species will also start to decline.¹

L

• Land conservation district (LCD): community groups constituted under section 22(1) of the Soil and Land Conservation Act 1945; comprise pastoral leasehold land, defined conservation areas (which may have formed part of the pastoral estate prior to declaration as conservation areas) and unallocated Crown land (UCL).

• Land degradation: includes soil erosion, salinity, eutrophication, flooding and the removal or deterioration of natural or introduced vegetation, that may be detrimental to the present or future use of land (adapted from the Soil and Land Conservation Act 1945). There is no definition of the term in the Environmental Protection Act 1986 or the Land Administration Act 1997.
  Most other definitions are based on human-induced or human-influenced change in the capacity for present or future use of that land:
  • changes that are additional to those occurring naturally and carries with it the notion of change that is undesirable and brought about by humans (The Australian Collaboration)
  • deterioration in the quality of land, its topsoil, vegetation, and/or water resources, caused usually by excessive or inappropriate exploitation (Business Dictionary)
  • the temporary or permanent decline in the productive capacity of the land, and the diminution of the productive potential, including its major land uses (e.g., rain-fed arable, irrigation, forests), its farming systems (e.g., smallholder subsistence), and its value as an economic resource (International Encyclopedia of the Social & Behavioral Sciences in Science Direct)
  • the loss of the economic and biological productivity of land, primarily through human activities (Enviropaedia)
  • the decline in quality of natural land resources, commonly caused through improper use of the land by humans (Soil Conservation Service NSW)
  • the many processes that drive the decline or loss in biodiversity, ecosystem functions or their benefits to people and includes the degradation of all terrestrial ecosystems (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES))
  • a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land. It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable (Wikipedia).

• Landscape function: the way in which landscapes acquire, use, cycle and lose physical and biological resources.

• Landscape function analysis (LFA): a monitoring procedure that uses rapidly acquired field-assessed indicators to assess the biogeochemical functioning of landscapes at the hillslope scale.

  The procedure has been applied in natural landscapes and those rehabilitated after mining, in climatic regimes ranging from the arid zone (150mm annual rainfall) in Australia to tropical rainforest near the equator in Indonesia (4000mm annual rainfall) and in land-uses ranging from traditional rangelands through mining to conservation of biodiversity.

  It uses visually assessed indicators of soil surface processes that gauge how effectively a hillslope is operating as a biophysical system. It is the synthesis of much published material from a variety of sources and is based mainly on processes involved in surface hydrology: rainfall, infiltration, runoff, erosion, plant growth and nutrient cycling. It is comprised of 4 components:
  A    a conceptual framework
  B    a field data acquisition
  C    a data reduction and tabulation
  D    an interpretational framework
  (Reference 13).

• Land system: a recurring pattern of vegetation, topography and soils in the landscape.

• Livestock units: used to standardise the carrying capacity and stocking rate of a given area of grazing land. The accepted and defined livestock units in Australia are cattle units, dry sheep equivalents, and animal equivalents.

• Low heath vegetation type: vegetation type dominated by a moderately close to fully closed low shrub layer. Some very scattered mid-height shrubs or isolated tall shrubs may occur but are never dominant.¹¹

M

• MODIS (Moderate Resolution Imaging Spectroradiometer): 'is a key instrument aboard the Terra (originally known as EOS AM-1) and Aqua (originally known as EOS PM-1) satellites. Terra's orbit around the Earth is timed so that it passes from north to south across the equator in the morning, while Aqua passes south to north over the equator in the afternoon. Terra MODIS and Aqua MODIS are viewing the entire Earth's surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths' (NASA MODIS)

• Monitoring: the process of making repeated observations, assessments or measurements in the same area, and analysing and interpreting data to judge progress towards meeting management objectives; observations can be direct, such as by measuring attributes at fixed sites in the field, or indirect, such as by acquiring data from remotely sensed images.

N

• NDVI (normalised difference vegetation index): also known as a greeness index, is derived from satellite data. 'Live green vegetation absorbs visible light (solar radiation) as part of photosynthesis. At the same time plants scatter (reflect) solar energy in the near infrared. This difference in absorption is quite unique to live vegetation and provides a measure of the greenness of the vegetation. NDVI is an index which measures the difference between near-infrared (which vegetation strongly reflects) and red light (which vegetation absorbs), providing a measure of vegetation density and condition.

O

• Overstorey: the uppermost canopy of the tallest trees or shrubs.

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P

• Palatability: the degree to which a grazing animal finds a plant attractive to eat; this can vary with the age of the plant or the type of soil it is growing on.¹ Note that palatability is not a good indicator of nutritional value.

• Pastoral condition: an assessment of the condition of vegetation cover for grazing (pastoralism). For example, a highly degraded area with few palatable species would be classed as 'poor' condition.

• Pastoralism: the husbandry of domesticated grazing animals on native or exotic pasture.

• Pastoral value: the value of a pasture or an individual species for carrying livestock, based on the quality and quantity of livestock feed it provides.¹

• Pasture condition: describes the current condition of the vegetation compared with the optimal condition which could be expected considering the potential of the area. Note: earlier surveys used the term 'vegetation condition' in the rangeland condition matrix. The ratings used in rangeland surveys for rangeland pasture condition are:

  1. Excellent or very good: for the land unit/vegetation type, the compositions and cover of shrubs, perennial herbs and grasses is near optimal; free of obvious reductions in palatable species or increases in unpalatable species, or the habitat type supports vegetation which is predominately unattractive to herbivores and is thus largely unaltered by grazing.

  2. Good: perennials present include all or most of the palatable species expected; some less palatable or unpalatable species may be present in low numbers, but the total perennial cover is not very different from optimal.

  3. Fair: moderate losses of palatable perennials and/or increases in unpalatable shrubs or grasses, but most palatable species and stability desirables still present; foliar cover is less than on comparable sites rated 1 or 2 unless unpalatable species have increased.

  4. Poor: conspicuous losses of palatable perennials; foliar cover is either decreased through general loss of perennials or is increased by the invasion of unpalatable species.

  5. Very poor: few palatable perennials remain; cover is either greatly reduced, with much bare ground arising from loss of stability desirables, or has become dominated by a proliferation of unpalatable species.

• Pasture type: a distinctive mix of plant species, soil type and landscape position.^1,2 For instance, the Ribbon grass alluvial plain pastures in the Kimberley; this pasture type has ribbon grass (Chrysopogon fallax) as the identifier species, grows on the 'black soils', and occurs on level alluvial plains throughout the Kimberley.

• Perennial: a plant which lives for 3 or more years; plants that complete their life cycle over 2 years are biennial.¹

• Piosphere: the localised impact of grazing around a point. For instance, the radiating grazing pressure around a watering point that leads to bare soils and erosion.

• Potential Carrying Capacity (Potential CC): the estimated long-term carrying capacity for an area (paddock, station or region) that maintains or improves land condition. PCC assumes that all pasture types are in good condition; the area is fully developed for grazing (particularly water-point distribution); all feed is accessible to livestock; grazing by native and feral animals is controlled; and there is good practice grazing management.
  
  The Potential CC for a particular land system is calculated using the capacities of the component pasture types and the proportional contribution (by area) to the land system. Potential CCs are assessed at the time of the rangeland survey, in discussion with pastoral lessees.
  
  Note that the present (or current) carrying capacity is less than PCC, because not all pastures remain in good condition with pastoralism. The seasonal carrying capacity (the number of livestock units that can be carried in a given year) may be higher than the Potential CC in good seasons and well below Potential CC in poor seasons.

  The Valuer General provides the following terms of reference for calculating the Potential Carrying Capacity:

  1. the PCC is the estimated number of livestock equivalents (CU) that can be annually carried over the long-term on a lease while maintaining or improving rangeland condition
  2. all pasture types are in good rangeland condition (that is the potential forproducing palatable pasture hasn’t been reduced)
  3. the area is fully developed (particularly with respect to water point distribution and placement) and available to livestock
  4. all feral herbivores are under control and good grazing management is practiced
  5. the estimate is the average carrying capacity across the full range of seasonal conditions
  6. an understanding of each land unit’s ability to support sustained livestock grazing
  7. good rangeland condition is assessed as; the perennials being present include all or most of the palatable plant species expected, though some less-palatable species may be present and total perennial groundcover is close to the optimal for the site
  8. areas that are physically inaccessible are removed from assessment
  9. good grazing management has been practiced
  10. introduced pastures (eg Buffel) are included in assessment
  11. no supplementation is provided
  12. reserves, UCL stock routes excluded

• Preferential grazing: where livestock selectively graze more-palatable species before less-palatable species; this can lead to the more-palatable species being grazed out of a pasture.¹

• Preferred species: plant species that are preferred by all (or a group of) animals and are grazed by first choice; preference can vary between cattle and sheep.

• Present Carrying Capacity (Present CC): the Potential CC discounted for an assessed decline in rangeland condition, based on defined ‘discount factors’ for each land system. All other factors are as for the Potential carrying capacity: the estimated long-term carrying capacity for an area (paddock, station or region) while maintaining or improving land condition, the area is fully developed for grazing (particularly water-point distribution); all feed is accessible to livestock; grazing by native and feral animals is controlled; and there is good practice grazing management.
  
  The extent to which the carrying capacity of a land system is discounted as rangeland condition changes from good to fair to poor, is a function of the composition and amount of vegetation in communities common on that land system. The discount factors vary between land units.
  
  'Current Carrying Capacity' is a preferred term, as it avoids confusion when the acronym PCC is used.

• Projected foliage cover: the percentage of ground area occupied by the vertical projection of the foliage of woody vegetation (works best on fairly dense shrubs and trees). See basal area for perennial tussock grasses.
  Other terms used for this are: projected crown cover, canopy cover, foliar cover, and cover.

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R

• Rangeland: the internationally recognised term for land supporting vegetation suitable for grazing; where livestock graze extensive native vegetation; where rainfall is considered to be too low or erratic for agricultural cropping or for improved pastures.

• Rangeland (or range) condition: the state of a rangeland ecological community in relation to its ability to conserve water, soil and nutrients compared to an optimal state unaltered by grazing or physical disturbance; usually expressed as good, fair or poor. DPIRD's rangelands officers use the matrix of soil erosion extent and pasture condition ratings to arrive at the range condition score (good, fair or poor) for each monitoring site or lease inspection point during assessments. See rangeland condition rating system for more information.

• Rangeland condition trend: the change in health or condition (ecological status) of the base resource and the direction of change, described by changes in the density or frequency of indicator plant species and/or soil surface condition; is not an absolute measure of rangeland condition and data from at least 2 points in time are required for assessment; indicates how land management strategies are physically affecting the rangeland; usually expressed as improving, stable or declining.

• Rangeland monitoring: the periodical recording of natural resource condition in the rangelands – usually vegetation, soils and water, and may include biology and other features of a monitored site.

• Rangeland vegetation condition: the current status of the vegetation compared to the optimal status which could be expected given the potential of the area.

• Resilience: the ability of a plant, pasture or ecosystem to withstand disturbance.¹

• Resource capability: the capability of a resource, such as land or vegetation, to sustain a particular use without degradation.

• Resource capture: the capacity of the area to capture resources (water, soils, litter, seeds, nutrients) and provide habitat for populations of plants, animals, and micro-organisms; capacity depends on physical attributes of the soil surface and associated plant, litter, fallen timber and rocks.

• Riparian: 'The riparian zone can generally be described as the land that directly influences or is influenced by a watercourse. That is, the corridor of land in which a stream functions. The riparian zone includes the immediate vicinity of the stream, which consists of the bed, banks and adjacent land, as well as the floodplain, which carries large floods. The width of the riparian zone can vary greatly depending on the type of river or stream and the catchment. Therefore the area of the riparian zone that requires special management will also vary.' (Water Notes, Western Australia)

• Rotational grazing, cell grazing and time control grazing: 'the practice of rotating livestock through a series of paddocks. By the time the last paddock in the series has been grazed, the first has been rested allowing sufficient pasture growth for the paddock grazing sequence to commence again.

  Rotational grazing involves higher paddock-by-paddock stocking rates than set stocking. It focuses on grazing plants intensively at the most nutritious stage in their growth cycle while allowing palatable species to continue to thrive by providing adequate rest time between grazing events.

  Rotational grazing usually allows for higher overall stocking rates; supports the persistence of palatable perennial pasture species; may require more infrastructure and possibly a greater labour input that set stocking.'
  
  'Cell grazing and time control grazing are similar to rotational grazing, but are more intensive and involve more paddocks or 'cells'. In time control grazing, paddock moves are determined by plant growth - the faster the growth, the more moves and vice versa.'

• (MLA)

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S

• Savanna: area of grassland (generally tropical or subtropical) with scattered trees; a dry climate, punctuated by a distinct summer wet season, encourages the growth of grasses and discourages the growth of trees.

• Scrub heath vegetation type: vegetation type dominated by moderately to fully closed, medium to low shrublands, with patches of taller shrubs and small trees.¹¹

• Seasonal Carrying Capacity (Seasonal CC): the number of livestock units a paddock or management area can carry in the current season while maintaining or improving land condition; this carrying capacity can markedly fluctuate between seasons. Stocking rate in that season should be at or less than the seasonal CC.

• Seasonal quality: an indication of the relative value of rainfall on a given site for a defined period – usually 12 months – for vegetation growth; vegetation is the basic resource for livestock and fauna (forage and shelter) and for soil protection. The scoring system is based on rainfall in the defined period relative to long-term rainfall, and its seasonal distribution (summer and winter). Seasonal quality in the grasslands (mostly northern WA) is most influenced by summer rainfall; seasonal quality in the shrublands (mostly southern rangelands) is most influenced by winter rainfall. Seasonal quality is expressed as above average, average or below average.

• Seral community: an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community.

• Set stocking: 'the practice of grazing livestock in a particular paddock for an extended period of time. Under such a regime the paddock is rarely rested; the stocking rate is usually calculated so that the number of livestock can be grazed throughout the year; supplementary feeding may be used to correct seasonal imbalances in feed supply to demand' (MLA).

• Severely degraded and eroded (SDE): drastically altered areas of rangeland where few, if any, perennial plant species remain, and the area has much bare ground with major soil redistribution or soil deflation. Where rangeland has been mapped at 1:250 000, the smallest mapped areas of SDE are 40ha.

• Short-lived perennial: perennial species that have a short life span, typically 3 to 5 years.

• Shrubland: a vegetation community characterised by shrubs with a variable acacia or eucalypt overstorey; occur primarily in the southern rangelands (Gascoyne, Murchison, Goldfields and Nullarbor); in the Pilbara, there is a gradual change from tussock or hummock grass understoreys in northern pastures to predominantly shrub understoreys in southern pastures.

• Soil erodibility: the susceptibility of a soil to detachment and transportation by wind or water (related to soil properties taken in isolation).

• Soil erosion: the process by which soil particles are detached and moved from the land surface (usually called soil erosion) by the action of wind (usually called wind erosion) or water (usually called water erosion).

• Soil erosion rating (rangelands)

• Soil surface condition: an assessment based on soil surface characteristics with the following ratings:

  • very good: stable soil surfaces, abundant accumulated decomposing litter in places, many physical barriers (including live plants) to retard water flows and promote infiltration
  • good: soil surface mostly stable, some accumulated litter and live plants, minor evidence of loss of water or litter from site, but ability of the site to intercept resources is suboptimal
  • fair: some litter but with little evidence of decomposition, some signs of topsoil loss, reduced objects (including few live plants) to intercept water flows
  • poor: significant topsoil loss, few objects to intercept water flows, minimal litter present
  • very poor: almost total loss of topsoil, exposed surfaces shedding resources, very few objects to intercept water flows.

• Soil organic carbon (SOC): the carbon component of soil organic matter (SOM). SOC is easier to measure than SOM, and is therefore often used to estimate SOM because the proportion of carbon to other elements in SOM is fairly stable.

• Spell grazing: 'locking up pastures (removing livestock) at critical times in their growth cycle to allow plants to replenish root reserves and set seed. This reduces the risk of over grazing and encourages pasture plant recruitment through seed set.
  
  An example of spell grazing is wet season spell grazing in northern cattle production systems which involves destocking paddocks during the wet season to allow plant recovery and new native pasture plant recruitment through seed set.
  
  Spell grazing can cause possible overgrazing on other paddocks if livestock are bought together at higher than optimal stocking rates while other paddocks are being spelled.' (MLA)

• Spelling (of pastures): removal of all grazing animals for a period, to allow recovery of leaf area and root energy reserves of mature desirable plants, germination of other plants in addition to desirable plants, and to allow seed production and release. Spelling is an integral part of good pasture improvement.

• spp.: abbreviation of species (plural), referring to more than 1 species of the same genus; for example, Triodia spp. includes all kinds of spinifex grass.¹

• Stability desirables (rangeland plants with no indicator value): species which are largely unaffected by grazing and which usually only decrease in number after natural disturbance such as hail damage or fire (e.g. mulga - Acacia aneura, hard spinifex - Triodia spp., eucalypt trees).  These species are not palatable, or only slightly palatable (or out of reach of browsing animals). They confer stability on the landscape and contribute to important landscape processes such as water retention and nutrient cycling.

• Stocking rate: the number of specific kinds and classes of animals grazing a unit of area for a specific period. In the rangelands, stocking rate for pastures or landforms is often expressed as hectares per stock unit (e.g. 20 hectares per DSE) or livestock units per square kilometre (e.g. 5 DSEs per km²). To allow comparisons, the classes of stock are usually expressed in standard livestock units, either dry sheep equivalent (DSE) or cattle unit (CU). Using standard units allows other grazers, such as kangaroos, rabbits and other feral grazers, to be included in the estimation. See Livestock comparisons for estimating grazing pressure in the rangelands for more detail.
  The actual stocking rate should always be determined by the available feed and condition of pastures (see feed budgeting).

• Sustainable carrying capacity (rangeland pastures): the estimated number of livestock units that can be carried, averaged over a 10 year or longer period, based on the present carrying capacity of pastures within the grazing radius of water points, to maintain livestock productivity and pasture condition. Adding or retiring water points will have a major effect on the sustainable carrying capacity. Note that this term assumes good practice grazing management. Note that the estimated carrying capacity of an area decreases in the order: potential carrying capacity; present carrying capacity; sustainable carrying capacity.

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T

• Tactical grazing: 'uses a range of grazing methods, including set stocking and rotational grazing (and spell grazing), throughout a single year or series of years, to meet different animal and pasture objectives at various times. This allows a balance to be struck between the demands of various classes of livestock for growth rate, reproduction and maintenance and feed supply.' (MLA) Tactical grazing usually requires more infrastructure (fences and watering points) than for set stocking.

• Total grazing pressure (TGP): the demand for forage by all grazing animals, both domestic and non-domestic, relative to forage supply.

• Total stocking rate: the sum of all grazers and browsers that eat the pasture, expressed in a single standard unit: usually dry sheep equivalents (DSE) or cattle units (CU).

• Tree heath vegetation type: vegetation type similar to scrub heath but with a more dominant tree stratum of eucalypts or, less commonly, wattles.

• Trend: see rangeland condition trend.

• Tussock grass: bunch grass, where the stems of the grass are bunched together forming a grass clump or ‘tussock’.¹

U

• Undesirables (or undesirable species): those species in a pasture type that are generally unpalatable. Undesirables include woody weeds and other weedy, prickly or toxic species which invade overgrazed pasture. Largely ignored by livestock, undesirables tend to increase under prolonged heavy grazing, and in large numbers are an indication of poor pasture condition. Undesirables are often increasers.^1,2 However, this is not consistent for a given species: Triodia intermedia is undesirable and an increaser in soft spinifex pastures, but may have no indicator value or be desirable in another pasture type (eg in hard spinifex hill pastures). T. intermedia is desirable in hard spinifex hill pastures, but would not necessarily be expected to decrease under grazing.

• Upland: an area of land elevated above the plain.¹

• Utilisation (of available pasture): the most common use is the percentage of pasture production by weight that is consumed or destroyed by livestock. Rangeland pasture utilisation to maintain the perennials and optimise livestock production is usually 15 to 40%, and commonly less than 30%. For individual perennial grasses, this level of utilisation means leaving at least 100 mm of vegetation above ground (Field Guide to Common Grasses of the Southern Rangelands).

V

• Vegetation condition: In a general sense, the quantity and health of all vegetation in a given area. See pasture condition for assessing rangeland condition.

• Vegetation cover: the proportion or percentage cover of the ground by vegetation when viewed from directly above; vegetation cover has a good negative correlation with erodibility of the soil surface, i.e. as vegetation cover increases, the erodibility of the soil surface decreases.

W

• WARMS: Western Australian Rangeland Monitoring System; a set of permanent rangeland monitoring sites in pastoral Western Australia; established by the then Department of Agriculture Western Australia in the early 1990s.

• Water erosion: the process by which soil particles are detached and moved from the land surface (usually called soil erosion) by the action of water.

• Water points (pastoral leases): can be natural (rivers, streams, water holes, and springs) or artificial (bores, dams, troughs). Livestock base their grazing from water points, and spend most of their time within a grazing radius of 5km.

• Wells: usually refers to drilled or dug holes, with perforated or ‘leaky’ lining above and into the unconfined aquifer. The water in a well is at the same level as the top of the aquifer.

• Wind erosion: the process by which soil particles are detached and moved from the land surface (usually called soil erosion) by the action of wind.

• Woodlands: a vegetation ecosystem that contains widely spaced trees with their crowns not touching; in the WA rangelands, woodlands support an understorey of shrubs and herbaceous plants including grasses.

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References

1. Ryan, K, Tierney, E, Novelly, P & McCartney, R 2013, 'Pasture condition guides for the Kimberley', Bulletin 4846, Department of Agriculture and Food, Western Australia, Perth, https://www.agric.wa.gov.au/rangelands/kimberley-pasture-condition-guide-bulletin-4846.
2. Payne, AL & Mitchell, AA 2002, 'Pasture condition guides for the Pilbara', Miscellaneous publication 19/2002, Department of Agriculture, Perth, http://researchlibrary.agric.wa.gov.au/misc_pbns/7/.
3. Payne, A & Schoknecht, N 2011, 'Land Systems of the Kimberley Region, Western Australia', Technical bulletin 98, Department of Agriculture and Food, Western Australia, Perth, https://www.agric.wa.gov.au/rangelands/land-systems-kimberley-region-western-australia.
4. Wilcox, DG & McKinnon, EA  (1974) A report on the condition of the Gascoyne catchment, Department of Agriculture and Department of Lands and Surveys, Perth, https://www.agric.wa.gov.au/rangelands/report-gascoyne-river-catchment-following-2010%E2%80%932011-flood-events.
5. Wheeler, JR (ed.), Rye, BL, Koch, BL & Wilson, AGJ 1992, Flora of the Kimberley region, Department of Conservation and Land Management, Perth.
6. Fernandez, RJ (2007) 'On the frequent lack of response of plants to rainfall in arid areas', Journal of Arid Environments, vol. 68, pp. 688–691.
7. Ritchie, M & Anderson, E 1996, 'How to monitor vegetation and soils', in J Tothill and l Partridge (eds), Monitoring grazing lands in northern Australia: proceedings of a workshop held in Gatton, Queensland, Australia, l5–17 October 1996, Tropical Grassland Society of Australia Occasional Publication No. 9, https://www.tropicalgrasslands.asn.au/Monitoring%20book/06monitoring%202%203%20pp44-56%20LR.pdf.
8. Ludwig, JA & Bastin, GN 2008, Rangeland condition: its meaning and use, Discussion paper prepared for the Australian Collaborative Rangelands Information System (ACRIS) Management Committee, ACRIS Management Unit, CSIRO Sustainable Ecosystems, Northern Territory.
9. Holechek, JL, de Souza Gomes, H, Molinar, F & Gait, D 1998, 'Grazing intensity: critique and approach', Rangelands, vol. 20, no. 5, pp. 15–18.
10. Payne, AL, Curry, PJ & Spencer, GF 1987 'An inventory and condition survey of rangelands in the Carnarvon Basin, Western Australia', Technical bulletin 73, Western Australian Department of Agriculture, http://researchlibrary.agric.wa.gov.au/tech_bull/2/.
11. Hennig, P 2009, 'An inventory and condition survey of the lower Murchison River area, Western Australia', Technical bulletin 96, Department of Agriculture and Food, Western Australia, Perth, http://researchlibrary.agric.wa.gov.au/tech_bull/9/.
12. Glossary of botanical terms – FloraBase, Department of Biodiversity, Conservation and Attractions [online database], Perth, https://florabase.dpaw.wa.gov.au/help/glossary.
13. Tongway, DJ & Hindley, NL 2005, Landscape functional analysis: procedures for monitoring and assessing landscapes, CSIRO, Canberra, viewed 14 May 2019, https://www.researchgate.net/profile/David_Tongway/publication/238748160_Landscape_Function_Analysis_Procedures_for_Monitoring_and_Assessing_Landscapes_-_with_Special_Reference_to_Minesites_and_Rangelands/links/0deec52c915ae0139e000000/Landscape-Function-Analysis-Procedures-for-Monitoring-and-Assessing-Landscapes-with-Special-Reference-to-Minesites-and-Rangelands.pdf.
14. National Committee on Soil and Terrain, 2009, Australian Soil and Land Survey Field Handbook, Third edition. CSIRO Publishing: Collingwood, Australia.
15. Petty S, Blood D, Addison J & Petty E (2018) Potential carrying capacity review, Spektrum Consulting report for Landgate, Western Australia, accessed 26 July 2021.
16. McLennan SR, McLean I and Paton C (2020) Re-defining the animal unit equivalence (AE) for grazing ruminants and its application for determining forage intake, with particular relevance to the northern Australian grazing industries, Meat and Livestock Australia, North Sydney, Australia, accessed 26 July 2021.