Rangelands glossary

The Department of Primary Industries and Regional Development uses the following definitions for terms used in our rangeland management publications.

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 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

  • 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

  • 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.

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.

  • 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.

  • Carrying capacity: the number of grazing units a paddock or management area can carry over the long term while maintaining or improving land condition.1 This is usually expressed as area per cattle or sheep unit in the rangelands: hectares per dry sheep equivalent or hectares per cattle unit.

    See Potential Carrying Capacity; Present Carrying Capacity; and Seasonal Carrying Capacity.

  • Cattle unit (CU): a standard unit used (1) to compare the feed requirements of different classes of livestock; (2) to assess the carrying capacity and potential productivity of a given area of grazing land; a CU is generally accepted as a full grown steer or dry cow of about 450 kilogram liveweight. One CU equals 7 dry sheep equivalents (DSE).

  • 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: the grazing of a specific area (station, paddock) by livestock throughout the year.

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.

  • 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): the feed energy required to maintain a 45 kilogram liveweight merino wether.

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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.

  • 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).

F

  • 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.

  • 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 due to 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

  • 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: an animal to forage relationship; the number of livestock units grazing an area in relation to the forage supply (or available forage).1

  • Grazing system: a specialised form of grazing management which defines the periods of grazing and non-grazing (rest).

  • Greenness index: also known as the Normalised Difference Vegetation Index (NDVI); 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 this difference, providing a measure of vegetation density and condition; see Normalised Difference Vegetation Index (Bureau of Meteorology).

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H

  • Halophytes: salt-tolerant plants, such as saltbushes, bluebushes and samphires.1,5

  • 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: a plant which does not produce a woody stem.1,5

  • 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).

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

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

  • 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

  • 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): see Greenness index.

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

  • 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. Also referred to as 'rangeland vegetation 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 pastoralism, 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; it is rated as ‘good’, ‘fair’ or ‘poor’ depending on how close the current condition is to the optimal condition.1,2

  • 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

  • Potential Carrying Capacity (Potential CC): the estimated long-term carrying capacity for an area (paddock, station or region) while maintaining or improving land condition, and 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 estimate is an average over a run of seasons: seasonal carrying capacity may be higher than the Potential CC in good seasons and well below Potential CC in poor seasons.

  • 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.

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R

  • Rangeland: the internationally recognised term for land supporting vegetation suitable for grazing; where livestock are grazed extensively on 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; is usually expressed as good, fair or poor.
  • Rangeland vegetation condition: the current status of the vegetation compared to the optimal status which could be expected given the potential of the area; rangeland vegetation condition is assessed as:

    • good: perennials present include all or most of the palatable plant species expected; some less-palatable species may be present; total perennial groundcover is close to the optimal for the site
    • fair: moderate loss of palatable perennials and/or increases in unpalatable species, but most palatable species are still present; foliar cover is below optimal for the site unless palatable species have increased, in which case foliar cover is similar to good condition rangeland
    • poor: conspicuous loss of palatable perennials; foliar cover has either decreased through loss of perennials (common in grasslands), or is stable or increased because of an invasion of unpalatable species.
  • 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; is usually expressed as improving, stable or declining.

  • 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.

  • Rotational grazing: a grazing scheme where livestock are cycled through a number of grazing areas over time.

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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 fluctuate markedly between seasons.

  • 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.

  • 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 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.

  • 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

  • Stocking rate: the number of specific kinds and classes of animals grazing a unit of area for a specific time period; normally expressed as animal type per unit area. 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 calculation. In a pastoral environment, stocking rate is often expressed as area per stock unit (e.g. 20 hectares per DSE).

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T

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

  • 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: the percentage of pasture that is consumed or destroyed by livestock; may refer to a single plant species or a whole vegetation community.

V

  • 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.

  • 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.
  2. Payne, AL & Mitchell, AA 2002, 'Pasture condition guides for the Pilbara', Miscellaneous publication 19/2002, Department of Agriculture, Perth.
  3. Payne, A & Schoknecht, N 2011, 'Land Systems of the Kimberley Region, Western Australia', Technical bulletin 98, Department of Agriculture and Food, Perth.
  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.
  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, viewed 23 June 2017 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. Western Australian Department of Agriculture, Technical Bulletin No 73. 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. Department of Agriculture and Food, Western Australia, Perth. Technical Bulletin 96. http://researchlibrary.agric.wa.gov.au/tech_bull/9/

Contact information

Matthew Fletcher
+61 (0)8 9166 4019
Wayne Fletcher
+61 (0)8 9690 2135
Page last updated: Wednesday, 11 April 2018 - 8:45am