Recovery Action Plan for Grey Box community

1.2.Description of Grey Box Woodlands in the Adelaide and Mount Lofty Ranges Region

The EPBC listed Grey Box (Eucalyptus microcarpa) Grassy Woodlands and Derived Native Grasslands of South-eastern Australia are defined by the following characteristics (Threatened Species Scientific Committee 2010a):
The vegetation structure of the ecological community is typically a woodland to open forest. The tree canopy is dominated (≥ 50% canopy crown cover) by Eucalyptus microcarpa (Grey Box). Other tree species may be present in the canopy and, in certain circumstances, may be co-dominant with Grey Box but are never dominant on their own.
The mid layer comprises shrubs of variable composition and cover, from absent to moderately dense. The mid layer usually has a crown cover of less than 30% with local patches up to 40% crown cover. The ground layer is also highly variable in development and composition, ranging from almost absent to mostly grassy to forb-rich. Ground layer flora commonly present include one or more of the graminoid genera: Austrodanthonia, Austrostipa, Elymus, Dianella and Lomandra; and one or more of the chenopod genera: Atriplex, Chenopodium, Einadia, Enchylaena, Maireana, Salsola and Sclerolaena.
In the Adelaide and Mount Lofty Ranges region Grey Box woodland is found predominantly on the western foothills of the Mount Lofty Ranges, on usually well drained clay to sandy loam soils and loams with quartzite surface stones and rocky outcroppings. The Grassy Woodlands of the region, including the Grey Box community, provide vital habitat for a large variety of plant and animal species, however many grassy woodland species are now rare or threatened and several have become extinct (especially bird species) (see Appendix A for threatened plants recorded in Grey Box woodlands).
The following description of Grey Box woodlands in the Mount Lofty Ranges region is adapted from Prescott and Turner (2010):
In its original state the tree stratum would have been dominated, often exclusively, by E. microcarpa. In many places this merges into smooth gum woodlands, particularly Blue Gum E. leucoxylon and Red Gum E. camaldulensis in valleys. However, some poorer sites also support some Pink Gum E. fasciculosa and groves of Drooping Sheoak Allocasuarina verticillata. At its best, tall specimens of E. microcarpa will reach up to 25 m and have a single trunk. In poor soils, the trees are much shorter and can be almost mallee in form. In many areas, the original trees have been cut for timber and trees may have a coppice appearance with 3-5 trunks and a height of much less than 20 m. Heights will be less under poorer rainfall and soil conditions. Trees can provide up to about 30% cover.
An associated tall shrub – small tree layer may provide a very open secondary canopy of up to about 10%. Typically this would include the species Golden Wattle Acacia pycnantha, Kangaroo Thorn A. paradoxa, Sticky Hop-bush Dodonaea viscosa, Native Cherry Exocarpos cupressiformis, Christmas Bush Bursaria spinosa, Native Apricot Pittosporum angustifolium (Armstrong et al., 2003 and Robertson,1998). Smaller shrubs are often limited and might include Pultenaea largiflorens, Hibbertia exutiacies, Acacia acinacea Astroloma humifusum, and Olearia ramulosa, and occasionally Xanthorrhoea quadrangulata (Armstrong et al., 2003 and Robertson,1998).
Most of the floristic diversity occurs in the ground layer, which is dominated by perennial grass species and well as other ‘grass-like’ species such as Iron grass Lomandra spp. Dominant native grasses in Grex Box woodlands include numerous species of Spear-grass Austrostipa spp. (eg A. nodosa, A. scabra, A. curticoma, A. elegantissima, A. gibbossa and A. multispiculis), Wallaby-grass Austrodanthonia spp. (eg A. auriculata, A. caespitosa, A. setacea and A. racemosa), Tussock Grass Poa spp. (eg P. labillardieri and P. clelandii) and Kangaroo-grass Themeda triandra.
Other grass and grass-like species may also include some of the following: Three-awned Grass Aristida behriana, Red-leg Grass Bothriochloa macra, Windmill Grass Chloris truncata, Silky Blue Grass Dicanthium sericeum, Tall or Common Wheat-grass Elymus scabrus, Blackhead Grass Enneapogon nigricans, Amphribromus archerii ,Chorizondra enodis, Finger Rush Juncus subsecundus, Little Sword-sedge Lepidosperma curtisiae, Lomandra densiflora, Lomandra multiflora var dura, and Little Mat-rush Lomandra nana/sororia.
There is a very diverse range of geophytes1 (> 50 species) dominated by lilies, peas, daisies, and orchids in the understorey which will vary according to minor changes in soil, water availability and previous history such as grazing and fire. Typical geophytes include Vanilla-lily Arthropodium strictum, Nodding Vanilla-lily Arthropodium fimbriatum, Garland Lily Calostemma purpureum, Native Flax Linum marginale, Yellow Star Hypoxis vaginata, and Rock Fern Cheilanthes austrotenuifolia. There may also sometimes be Lemon-beauty-heads Calocephalus citreus, Coarse Bottle-daisy Lagenifera huegelii (Armstrong et al., 2003), Pale Flax-lily Dianella longifolia (Davies 1997), and numerous orchid species (e.g. Sun-orchids Thelymitra spp., Leek-orchids Prasophyllum spp., Cowslip/Donkey-orchids Diuris spp., Spider-orchids Caladenia spp, Onion-orchids Mictotis spp. and Greenhoods Pterostylis spp.).
Other small ground cover species may include some of the following:, Blue Devil Eryngium ovinum, White Goodenia Goodenia albiflora, Cut-leaf Goodenia Goodenia pinnatifida, Hairy Heads, Hairy Tails Ptilotus erubescens, Corrugated Sida Sida corrugata, Spur Velleia Velleia paradoxa, Black’s Vittadinia Vittadinia blackii, Woolly New Holland Daisy Vittadinia gracilis, Wahlenbergia stricta, Scaevola albida, Kennedia prostrata, Convolvulus remotus, Glycine tabacina, Gonocarpus elatus, G. tetragynus, and Ecaena echinata.

The community is also tolerant of low nutrient levels and intolerant in terms of increased nutrient level. Many species are not competitive with woody weeds and introduced grasses in increased nutrient regimes.

E. microcarpa communities are known to occur on clay loam and sandy loam. Differences in soil and to some extent climate are likely to influence community composition and also transitional pathways. As an example, resistance to weed invasion is known to be greater on skeletal soils than the deeper soils. Similarly, the more fertile deep soils are likely to transition faster as they are better suited to many exotic weeds. The different soil profiles also support different species, for example, Lepidosperma curtisiae does not occur on skeletal soil sites but does at deeper soil sites.

Bond (2011) noted that there may be two distinct types or forms of Grey Box Grassy Woodland within the region. Ridge tops and north and western facing slopes with red brown earths and shales (more shallow and rocky) support smaller trees and a more grassy understorey, while southern aspects with light grey loams and clays support larger trees, with more herbaceous plants in the understorey (K Brewer pers. comm. 2011; P Paton pers. comm. 2011). The latter of the two types, which occurs on the deeper soils, is likely to be relatively rarer and have a greater proportion of its area impacted by weed invasion and disturbance. Further research is needed to confirm this.