As mentioned in the text, the objectives of revegetation on Herring Island are to 'recreate' the vegetation of the Lower Yarra and to enhance both wildlife habitat and landscape values. Revegetation plantings are to be based on vegetation communities found further upstream at Yarra Bend Park. Additional salt tolerant species more characteristic of saltmarsh vegetation downstream are to be included in trial planting in saline areas. Brief descriptions of representative vegetation communities/ sub-communities are given below. More detailed species lists and a map (Figure 7), delineating where each vegetation community is to be planted are also included in this section.
1. Riparian Scrub
Riparian scrub occurs as a continuous corridor along the banks of the Yarra River. This vegetation is subject to periodic inundation. The overstorey consists of River Red Gum (Eucalyptus camaldulensis) and Silver Wattle (Acacia dealbata), with a fairly sparse cover of Manna Gum (Eucalyptus viminalis). The middle stratum of this community is a diverse association of shrubs and small trees. Typical species include Swamp Paperbark (Melaleuca ericifolia), River Bottlebrush (Callistemon sieberi), River Teatree (Leptospermum obovatum) and Hempbush (Gynatrix pulchella). The dominant understorey species is Tussock Grass (Poa labillardieri). At the River's edge, a number of water plants occur. These include Common Reed (Phragmites australis) and River Club-rush (Schoenoplectus validus). Marginal species are found on areas of the bank exposed to fairly frequent inundation (Bolboschoenus), in shallow water or mud (Phragmites australis), or in the river itself WaterRibbons,(Triglochin procera).
2. Mixed Eucalypt Open Forest
The remnant lower stratum vegetation on the north-east corner of the Island has affinities with the Yellow Gum woodland sub-community at Yarra Bend Park (YBPT, 1990). Mixed eucalypt open forest is a suitable vegetation type for the areas within the levee, on better quality (non-saline) soils. Major overstorey species are Yellow Gum (E. leucoxylon ssp. leucoxylon), River Red Gum (E. camaldulensis), Yellow Box (E. melliodora) and Manna Gum (E. viminalis). Middle stratum species include smaller trees and shrubs such as Lightwood (Acacia implexa), Sweet Bursaria (Bursaria spinosa var. macrophylla) and Black Wattle (Acacia mearnsii). A number of smaller shrubs are also found in open forest associations in Yarra Bend Park. Among these are Hop Goodenia (Goodenia ovata), Myoporum viscosum, Twiggy Daisy-bush (Oleada ramulosa) and various chenopod species. In relatively undisturbed condition, this vegetation community contains a diverse understorey of native grasses (Stipa, Danthonia and Poa species) and herbs (Chocolate Lilies, Everlastings, Flax Lilies etc.).
3. Escarpment Vegetation
This vegetation community is the closest approximation to the conditions on the exposed, dry slopes of the levee bank around the Island. In Yarra Bend Park, escarpment vegetation is found on exposed, hostile sites on sedimentary-derived soils.
3.1 Chenopod rocky open scrub sub-community
Species in this sub-community are particularly resilient to drought and exposed conditions. This would be the most suitable vegetation association on the relatively exposed bare ridge, areas on the northern levee. Some of these species (eg, Einadia nutans, Acacia pycnantha) already exist on this section of the levee. The dominant overstorey species is Yellow Gum (E. leucoxylon ssp. leucoxylon). Major middle stratum species are Golden Wattle (Acacia pycnantha), Gold-dust Wattle (A. acinacea) and Shiny Cassinia (Cassinia longifolia). The lower stratum is dominated by hardy Chenopod species (Einadia hastata, E. nutans, Enchylaena tomentosa), Pig-face (Carpobrotus modestus), drought-tolerant native grasses and Small-leaf Clematis (Clematis microphylla), a sprawling climber.
3.2 Dry Sclerophyll Shrubland
This sub-community would be suitable for planting on the east-, west- and southern portions of the levee bank. Again, the dominant overstorey species is Yellow Gum (E. leucoxylon ssp. leucoxylon). A number of shrub and small tree species characterise this sub-community. These include shrub species associated with Chenopod scrub, plus Lightwood (Acacia implexa), Sweet Bursaria (Bursaria spinosa var. macrophylla), Drooping Sheoak (Allocasuarina verticillata) and Hop-bush (Dodonea viscosa var. cuneata).
4. Swampy Tracts
These areas on the Island are either low-lying areas or areas of impeded drainage due to excessive salinity. Typical local species of poorly drained or periodically inundated areas are rushes (Juncus spp.), Tall Sedge (Carex appressa), Tussock-grass (Poa labillardieri) and Brown-back Wallaby-grass (Danthonia duttoniana), all of which presently occur on the Island. A number of salt-tolerant species (Juncus kratisii, Distichlis distichophylla, Danthonia spp.) have colonised saline areas on the Island. A number of additional salt-tolerant species should be used in planting trials to rehabilitate saline areas. These include Knobby Club-rush (Isolepis nodosa), Berry Saltbush (Atriplex semibaccata) and Seaberry Saltbush (Rhagodia candolleana).
This section outlines priorities for revegetation of Herring island. These are as follows: