Photographer: David Carr

Managing and enhancing biodiversity on your land helps build a resilient landscape that balances production and conservation

NATURAL GRASSLANDS ON ALLUVIAL PLAINS

INTRODUCTIONAll part of a CommunityEcological communities are groups of plants, animals and other organisms that naturally occur together. The structure and composition are determined by environmental factors such as climate, landscape position, soil, aspect and altitude.

While a particular ecological community will vary in structure and composition across its range, there are common elements that clearly identify one ecological community as distinct from another.

Ecological communities also exist in different condition ‘states’, each with defining characteristics. States range from high quality to degraded with several in between.

Management affects the state of a community and depending on the type of management action, can cause a community to make a ‘transition’ to a better or worse state.

Natural Grasslands on Alluvial PlainsNatural Grasslands on Alluvial Plains is the name given to the threatened ecological community Natural Grasslands on basalt and fine-textured alluvial plains of northern NSW and southern Queensland. This grassland occurs on fertile alluvial soils across our catchments and is characterised by perennial tussock grasses such as Mitchell grasses, Plains grass and Queensland blue grass. It usually has a diversity of grass species, saltbushes and herbs with occasional shrubs.

Large areas of these grasslands have been cleared for cropping in the catchments and remaining fragments are listed as critically endangered. The grassland and its waterways provide an essential home to many threatened species.

Natural Grasslands on Alluvial Plains is listed as a threatened ecological community under both the Australian Government’s Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and the NSW Threatened Species Conservation Act 1995 (TSC Act).

Activities which affect the condition or extent of Natural Grasslands on Alluvial Plains may require consent or approval.

Where does the Community Occur?Natural Grasslands on Alluvial Plains are usually found on the Liverpool Plains, the Moree Plains and the Darling Downs (Qld). On the Liverpool Plains, the community is usually dominated by Plains grass, while on the Darling Downs, Queensland blue grass dominates. Mitchell grass is usually the dominant species in drier parts of the distribution.

The community occurs within the Brigalow Belt South bioregion but patches extend into the Nandewar, Sydney Basin and DarlingRiverine Plains bioregions also.

IdentificationNatural Grasslands on Alluvial Plains is a community that changes with seasonal conditions. It is a grassland community dominated by perennial tussock grasses. The dominant grass species are usually Mitchell grasses (Astrebla spp.), Plains grass (Austrostipa aristiglumis), Queensland blue grass (Dichanthium sericeum), Kangaroo grass (Themeda australis), Yadbila (Panicum queenslandicum) or one of 13 other indicator grass species. There may be many grass species present, with several co-dominating. The composition of the grassland will change according to seasonal rainfall, temperature, fire and management.

These grasslands are usually found on cracking clay soils. The soils where they occur are derived from basalt or are alluvial, quaternary soils. They occur on plains with a slope less than 5 degrees.

Natural grasslands have very few trees or shrubs, but will have a diversity of herb species including legumes, orchids, daisies and lilies.

What is not Natural Grasslands on Alluvial Plains?Many other ecological communities have a grassy understorey, with many species in common with Natural Grasslands on Alluvial Plains. These include Weeping Myall, Coolibah – Black Box Woodland and Box-Gum Grassy Woodland, which are also threatened ecological communities. These communities, and other grassy woodlands like Bimble Box Grassy Woodland, have a higher cover of trees and shrubs than Natural Grasslands on Alluvial Plains.

Photographer: Greg Steenbeeke Profile drawing of Natural Grasslands on Alluvial Plains community

Description

INDICATOR GRASS SPECIES

Aristida leptopoda White speargrass Astrebla elymoides Hoop Mitchell grass Astrebla lappacea Curly Mitchell grass Austrodanthonia bipartita Wallaby grassAustrostipa aristiglumis Plains grass Bothriochloa biloba* Lobed bluegrass Bothriochloa erianthoides Satin top grass Dichanthium sericeum Queensland blue grass Digitaria divaricatissima Umbrella grassElymus plurinervis Wheat grass Eriochloa crebra Cup grass Eulalia aurea Silky brown topPanicum decompositum Native millet Panicum queenslandicum Yadbila grass Thellungia advena Coolibah grassThemeda avenacea Native oat grass Themeda australis Kangaroo grass Walwhalleya proluta Rigid panic

OTHER GRASS SPECIES

Chloris truncata Windmill grassEnteropogon acicularis Twirly windmill grassEragrostis leptocarpa Drooping lovegrassEriochloa pseudoacrotricha Early spring grassIseilema membranaceum Small flinders grassLeptochloa divaricatissima Paspalidium jubiflorum Warrego grassSporobolus caroli Fairy grass

HERB SPECIES

Alternanthera denticulata JoyweedAtriplex leptocarpa Slender-fruit saltbushAtriplex muelleri Mueller’s saltbushAtriplex semibaccata Berry saltbushBoerhavia dominii TarvineCarex inversa Knob sedgeChamaesyce drummondii Caustic weedCullen tenax EmufootCyperus spp. NutgrassesDesmodium spp. TrefoilGoodenia glauca Pale goodenia

Glycine spp. Glycine spp.Marsilea spp. NardooNeptunia gracilis Native sensitive plantPolymeria longifolia Clumped bindweedPortulaca oleracea PigweedSalsola kali Soft rolypolySclerolaena muricata Black rolypolySida trichopoda SidaSolanum esuriale QuenaVittadinia cuneata FuzzweedWahlenbergia spp. Blue bells

ASSOCIATED WOODY SPECIES

usually absent but may be up to 10% cover

Acacia pendula Weeping MyallAcacia stenophylla River CoobaAlectryon oleifolius RosewoodAtalaya hemiglauca WhitewoodCasuarina cristata BelahEucalyptus coolabah CoolibahEucalyptus largiflorens Black BoxEucalyptus populnea subsp. bimbil Poplar BoxMyoporum montanum Western BoobiallaVachellia farnesiana Mimosa

*Listed as threatened under State and/or Commonwealth legislation

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Plants of Natural Grasslands on Alluvial Plains

PHOTO KEY:

1 Yadbila grass – Greg Steenbeeke

2 Kangaroo grass – Greg Steenbeeke

3 Queensland blue grass – David Carr

4 Mitchell grass – Greg Steenbeeke

5 Nut grass – Greg Steenbeeke

Animals of Natural Grasslands on Alluvial Plains

BIRDS

ParrotsRed-winged parrotBudgerigarBlue bonnetPale-headed rosellaEastern rosellaRed-rumped parrot

CockatoosMajor Mitchell’s cockatoo ● Sulphur-crested cockatooLittle corellaCockatielGalah

Ground feeding and low nesting birdsEmuBush stone-curlew ● Australian bustard ● King quailStubble quailBrown quailPainted button-quailRed-chested button-quail ▲ Little button-quail ▲ Banded lapwing ▲ Masked lapwing Crimson chat ▲ White-fronted chat ▲ Brown songlarkRufous songlarkGolden-headed cisticolaSinging bushlarkRichard’s pipitSouthern whiteface ▲ Tawny grassbird ▲ Little grassbird

Ground feeding birdsPeaceful doveCrested pigeon Double-barred finchPlum-headed finchZebra finchWhite-winged fairy-wren ▲ Variegated fairy-wrenSuperb fairy-wren

Aerial feeding birdsWhite-breasted woodswallow ▲ Black-faced woodswallowLittle woodswallow

White-backed swallowWelcome swallowFork-tailed swift ■ White-throated needletail ■ Restless flycatcherWillie wagtail

Medium to Large bush birdsPallid cuckooGround cuckoo-shrikeWhite-bellied cuckoo shrike ▲ Pied butcherbirdGrey butcherbird Australian ravenLittle ravenTorresian crow Little crow ▲ Australian magpieMagpie-larkApostlebirdJacky winterScarlet robin (winter) ● Flame robin (winter) ●

Small bush birdsInland thornbillYellow-rumped thornbillChestnut-rumped thornbill ▲

Birds of preyWedge-tailed eagleSwamp harrier ▲ Spotted harrier ● ▲ Black-shouldered kiteWhistling kiteLetter-winged kite ▲ Black kiteLittle eagle ● Brown falconNankeen kestrelAustralian hobbyBlack falcon ▲

Nocturnal birdsBarking owl ● Grass owl ● Barn owlSouthern boobook

IntroducedFeral pigeonCommon starling

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KEY:

● Species, population or community listed as vulnerable or endangered under the EPBC and/or TSC Act

■ Species listed as migratory under the EPBC Act

▲ Species identified as present or returning to vegetation communities in good condition

PHOTO KEY:

1 Pale headed rosella – M Coulton

2 Spotted harrier – Phil Spark

3 Bush stone curlew – Phil Spark

4 Red rumped parrot – Iestyn Taylor

5 Yellow-bellied sheath-tailed bat – Leah Mackinnon

6 Striped-faced dunnart – Phil Spark

7 Planigale – Phil Spark

ParrotsRed-winged parrotBudgerigarBlue bonnetPale-headed rosellaEastern rosellaRed-rumped parrot

CockatoosMajor Mitchell’s cockatoo ● Sulphur-crested cockatooLittle corellaCockatielGalah

Ground feeding and low nesting birdsEmuBush stone-curlew ● Australian bustard ● King quailStubble quailBrown quailPainted button-quailRed-chested button-quail ▲ Little button-quail ▲ Banded lapwing ▲ Masked lapwing Crimson chat ▲ White-fronted chat ▲ Brown songlarkRufous songlarkGolden-headed cisticolaSinging bushlarkRichard’s pipitSouthern whiteface ▲ Tawny grassbird ▲ Little grassbird

Ground feeding birdsPeaceful doveCrested pigeon Double-barred finchPlum-headed finchZebra finchWhite-winged fairy-wren ▲ Variegated fairy-wrenSuperb fairy-wren

Aerial feeding birdsWhite-breasted woodswallow ▲ Black-faced woodswallowLittle woodswallow

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MAMMALS

Terrestrial (land dwelling)Paucident planigale ▲ Narrow-nosed planigale ▲ Striped-faced dunnart ● Fat-tailed dunnart ▲ Common dunnart Red kangaroo ▲ Eastern grey kangarooShort-beaked echidna

MicrobatsGould’s wattled batInland broad-nosed batLittle broad-nosed batLittle forest batSouthern freetail batInland freetail batWhite-striped freetail-batYellow-bellied sheath-tailed bat ● Lesser longeared bat ●

IntroducedEuropean cattleGoatDingoDomestic dogFoxHorseCatBrown hareRabbitHouse mouseBlack ratPig

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KEY:

● Species, population or community listed as vulnerable or endangered under the EPBC and/or TSC Act

■ Species listed as migratory under the EPBC Act

▲ Species identified as present or returning to vegetation communities in good condition

PHOTO KEY:

8 Shingle back lizard

9 Five clawed work skink

10 Eastern brown snake

11 Desert tree frog

12 Sloane’s tree frog

REPTILES

DragonsBurn’s dragonEastern bearded dragonLong-tailed earless dragon ▲

TurtlesEastern snake-necked turtle

SnakesYellow-faced whip snakeDe Vis’s banded snakeRed-naped snakeGrey snake ▲ Mulga snakeSpotted black snakeRed-bellied black snakeEastern brown snakeVariable black-naped snakeCurl snake

Geckos Tessellated geckoBox-patterned gecko

Blind snakesProng-snouted blind snakeRobust Blind Snake Brown-snouted blind snake

Legless lizardsPatternless delmaExcitable delmaBurton’s snake-lizard

SkinksFive-clawed worm-skink ● Robust ctenotusCommon dwarf skinkSouth-eastern morethia skinkCommon bluetongueShingleback lizard

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AMPHIBIANS

Ephemeral dams, ponds, wetlands

Frogs & frogletsWater-holding frog

Rough frogStriped burrowing frog

Green tree frogBroad-palmed frog

Peron’s tree frogDesert tree frog

Eastern sign-bearing frogletCommon eastern froglet

Sloane’s froglet ● Bullfrog

Long-thumbed frogOrnate burrowing frog

Salmon striped frog Spotted marsh frog

Painted burrowing frog

Toads & toadletsHoly cross toad ▲ Wrinkled toadlet

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Photographer of all photos on this page: Phil Spark

Photographer: Greg Steenbeeke

Threats Clearing – conversion of native grasslands to cultivation for cropping is now illegal under the Native Vegetation Act 2003, but still occurs due to a lack of awareness of the conservation significance of grasslands. Before converting any pasture to cropping or sewn pasture, consult the CMA about your responsibilities.

Clearing for mining is also a significant threat.

Grazing – knocks out highly palatable or vulnerable species such as legumes. There can also be a change in the dominant species from Austrostipa and Dichanthium to Chloris species, then Sporobolus species and finally a mixture of unpalatable weeds. Undergrazing can also be a threat, as tussock grasslands will become simpler unless the biomass of the dominant tussock grass species are occasionally reduced by fire or grazing.

Weed invasion – weedy perennial grasses present the greatest threat to this community. The main threatening species are: Coolatai grass (Hyparrhenia hirta), African love grass (Eragrostis curvula), Buffel grass (Cenchrus ciliaris) and Green Panic (Panicum maximus). The establishment of some of these species as ‘improved’ pastures adjacent to grassland communities is a significant threat. Lippia (Phyla nodiflora) is a major threat in periodically-inundated areas. Mimosa (Vachellia farnesiana) and African boxthorn (Lycium ferocissima) are less of a threat but do displace grassland species.

Changed flooding regimes – alter the species composition of natural grasslands, often favouring weed species. These changes may come about through irrigation, road construction, building of floodplain structures or channel construction.

Changed fire regimes – affect grassland communities by changing species composition and relative abundance. Too frequent fire can encourage fire tolerant species like Coolatai grass over native species.

Feral animals – pigs can cause significant localised damage to grasslands by uprooting plants and creating opportunities for weed invasion. The house mouse competes with grassland fauna for food and habitat, particularly during high population outbreaks. Disturbance from rabbit burrowing and grazing can also alter species composition.

Climate change – can result in changes to water availability and fire regimes. It is also likely to change the distribution and impact of weed species.

Lack of awareness – of the importance or scarcity of this vegetation community is a major threat as some farmers carry out destructive acts without even knowing the significance of grassland communities.

Management The aim of management of Natural Grasslands is to maintain or increase the extent of the community and to maintain or improve its condition.

Grazing Management – should aim to increase the diversity of species in degraded stands, and to allow natural fluctuations in species composition in response to seasonal conditions to occur. A mix of occasional short, heavy grazing and regular light stocking is likely to favour optimal stand development and survival.

Avoid grazing when the soil is saturated to prevent pugging, particularly on grey clays. Where possible, avoid grazing when plants are flowering and setting seed.

Not converting to cropping – before ploughing new areas for cropping, assess whether or not the site supports Natural Grassland. Seek advice from the CMA if you are unsure. Don’t allow cultivation to creep into adjacent grassland areas.

Restoration – natural grasslands can be re-established over time through assisted regeneration and revegetation. Previously cropped areas can be left to regenerate, provided invasive grasses are controlled. Avoid planting trees or dense shrub cover into areas of Natural Grasslands. Seed of many grassland grasses is available from commercial seed suppliers.

Increasing awareness – become more aware of the occurrence and extent of Natural Grasslands on your property and in your district. Many of the few remaining stands are located on stock routes and roadsides and can be inadvertently destroyed by road maintenance, grading, dumping soil or inappropriate fire or grazing regimes. Natural grasslands are most likely to occur on parts of your property where cropping does not occur, such as adjacent to waterways, in rocky areas or around areas of other native vegetation.

Controlling and not spreading weeds – spot spray small outbreaks of invasive grasses in and around patches of Natural Grassland. Cut and paint the stumps of invasive shrubs such as African boxthorn with glyphosate. When maintaining roads avoid bringing machinery from weedy areas into stands of grassland and avoid cutting drains or dumping soil in grassland patches.

Threats and Management

ECOSYSTEM FUNCTION: HOW HEALTHY GRASSLANDS WORK FOR YOUHealthy Natural Grasslands on Alluvial Plains provide a wide range of benefits that are often called ‘ecosystem services’. These include traditional services like grazing for livestock, but also other services such as:

• financial benefits• soil formation and cycling• nutrient cycling• water capture, filtration and delivery to water bodies• pollination• pest management (e.g. reducing pest pressure on crops)• regional climate buffering• shade and shelter (e.g. for livestock)• breakdown and absorption of wastes• a sense of place• scenery

Photographer: Greg Steenbeeke

www.lls.nsw.gov.au1300 795 299

8:30 am to 5:30pm Monday to Friday

FURTHER INFORMATIONLook for “Natural Grasslands” on the EPBC Species Profiles and Threats database (SPRAT) at www.environment.gov.au/biodiversity/threatened/index.html

Commonwealth Listing Advice on Natural grasslands on basalt and fine-textured alluvial plains of northern New South Wales and southern Queensland. www.environment.gov.au/biodiversity/threatened/communities/pubs/88-listing-advice.pdf

Nadolny C., Hunter J. & Hawes W. (2010) Native grassy vegetation in the Border Rivers-Gwydir Catchment: diversity, distribution, use and management. In: Report to the Border Rivers-Gwydir CMA.

Photographer: Greg Steenbeeke