Werriwa Tablelands Cool Temperate Grassy Woodland ranges in structure from woodland to low open woodland. It is characterised by a sparse to very sparse (woodland to open woodland) tree layer dominated by Eucalyptus pauciflora (snowgum) either in single species stands or with E. rubida (candlebark) as a co-dominant. Other tree species have been recorded within the community, although very infrequently and always as canopy sub-dominants.
Tree height and cover vary as a function of moisture availability, drainage and past land management. The tree layer becomes shorter and sparser with declining moisture availability or increasing levels of soil waterlogging. Trees may be reduced or absent due to historic management.
A continuous ground layer is usually present,although this may vary in composition and cover due to natural variation and historic management. The ground layer is typically dominated by Themeda triandra (syn. T. australis; kangaroo grass), Gonocarpus tetragynus, Microlaena stipoides (weeping grass), Austrostipa bigeniculata (tall speargrass), Hypericum gramineum (small St. John’s wort), Poa sieberiana (snowgrass), Asperula conferta (common woodruff), Lomandra filiformis (wattle mat-rush), Anthosachne scabra (syn. Elymus scaber; tall wheatgrass), Hydrocotyle laxiflora (stinking pennywort), Leptorhynchos squamatus (scaly buttons), Haloragis heterophylla (rough raspwort), Oxalis perennans, Schoenus apogon (common bog-rush), Tricoryne elatior (yellow Autumn-lily), Plantago varia (variable plantain), Acaena ovina, Carex inversa, Panicum effusum (hairy panic), Calocephalus citreus (lemon beauty-heads) and Chrysocephalum apiculatum (common everlasting).
Species of sub-shrubs such as Pimelea curviflora, Astroloma humifusum (native cranberry) and Hibbertia obtusifolia (hoary guinea flower) may be interspersed with grasses and forbs at some sites. Sites regenerating following tree removal, or the cessation of stock grazing may support a second, shorter layer of Eucalyptus species of variable density.
The community can also occur as secondary grassland where trees have been removed but the understorey composition remains largely intact. The composition can be difficult to separate from natural temperate grassland, with landscape cues such as the presence of snow gum in a similar landscape position used as a guide.
This CEEC replaces the northern distribution of the formerly listed 'Tableland Snow Gum, Black Sallee, Candlebark and Ribbon Gum Grassy Woodland in the South Eastern Highlands, Sydney Basin, South East Corner and NSW South Western Slopes Bioregion' Endangered Ecological Community, noting changes in the species assemblage.
Distribution
Werriwa Grassy Woodlands (WGW) occur in the Southern Tablelands of NSW, occupying broad valley floors and gentle slopes and low rises of the moderately undulating Southern Tablelands of NSW. It has been commonly recorded on a wide variety of substrates including basalt, fine-grained sedimentary rocks, granite, acid volcanics and alluvium but rarely on steep ridge lines on the tablelands. Geographically, it occurs on the eastern fall of the Great Dividing Range between Golspie in the north and Majors Creek in the south. The community has been recorded as far to the east as Marulan and as far west as Carwoola.
Habitat and ecology
- The trees may occur as pure stands dominated by snow Gum, or with candlebark as co-dominant to sub-dominant. Non-characteristic trees may occur as subdominant.
- The understorey in intact sites is characterised by native grasses and a high diversity of herbs; the most commonly encountered include kangaroo grass (Themeda australis) and common snow-grass (Poa sieberiana) with others including weeping grass (Microlaena stipoides), purple wiregrass (Aristida ramosa), tall speargrass (Austrostipa bigeniculata), tall wheatgrass (Anthosachne scabra) and a variety of forbs.
- Shrubs are generally sparse or absent, though they may be locally common. Sub-shrubs (woody species <0.5 m tall) may be common. The most common shrubs and sub-shrubs include Pimelia curviflora, native cranberry (Astroloma humifusum) and hoary guinea-flower (Hibbertia obtusifolia).
- Remnants may occur on the lower, more fertile parts of the landscape where resources such as water and nutrients are abundant; sites on midslope situations where resources are scarcer are more common.
- Sites with particular characteristics such as a variety of age classes in the trees, patches of regrowth, old trees with hollows and fallen timber on the ground are very important as wildlife habitat. Sites with a full range of such attributes are rare.
- Sites in the lowest parts of the landscape often support large trees which have leafy crowns and reliable nectar flows. These sites are important for insectivorous and nectar feeding birds and generally have the largest hollows.
- Sites that retain only a grassy groundlayer and with few or no trees remaining are important for rehabilitation, and to rebuild connections between sites of better quality.
- Remnants support many species of threatened fauna and flora.
- Retention of remnants is important as they contribute to productive farming systems (stock shelter, seed sources, sustainable grazing and water-table and salinity control).
- The fauna of remnants (insectivorous birds, bats, etc) can contribute to insect control on grazing properties.
- Some of the component species (e.g. wattles, native legumes) fix nitrogen that is made available to other species in the community, while fallen timber and leaves recycle their nutrients.
- Disturbed remnants are considered to form part of the community, including where the vegetation would respond to assisted natural regeneration.
Regional distribution and habitat
Click on a region below to view detailed distribution, habitat and vegetation information.