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).

Revegetation Schedule

This section outlines priorities for revegetation of Herring island. These are as follows:

  1. Removal of P1 woody pest species (Tagasaste, Furze, Flax-leaf broom, Cape Wattle, Cotoneaster, Blackberry)

  2. Establish Riparian Scrub, Dry Sclerophyll Shrubland and Mixed Eucalypt Open Forest plantings in the vicinity of the access point on the south-east corner of the Island.

  3. Establish trial plantings in low-lying saline areas. A suitable strategy would be to plant lines of different salt-tolerant species to be used along a gradient from high to low salt areas. Health of plants in these plots must be monitored regularly. Periodic soil sampling should also be taken within these areas to monitor salt levels. Depending on salt levels, species composition in these areas may change to include species with lower salt tolerance more typical of remnant vegetation in the vicinity.

  4. Establish plantings in important habitat areas. These include plantings along the water margin protected by existing reed beds, the central hummocky area and the low-lying area within the conservation zone. These areas should be planted fairly densely to Provide cover. Potential pest species (eg. Acacia baileyana, Acacia longifolia, Acacia saligna) should be replaced at this stage.

  5. Establish plantings in remaining high-use areas (eg. the viewing mound). It will be important to get vegetation established early, as these areas will be particularly prone to user damage.

  6. Plant remaining areas within the levee to improve views and habitat value. Leave some areas comparatively open to allow for picnicking areas and views across the Island and out to surrounding areas. The inside bank of the northern levee will require dense tree and shrub planting as a visual screen against the South-eastern Freeway.

  7. Riparian areas are fairly densely-vegetated at the moment. These sites should be underplanted with indigenous riparian, species. Exotic species should be gradually removed. Retain important habitat trees (including dead specimens where safe to do so) until revegetation plantings are sufficiently mature, to fulfil the present habitat/aesthetic functions of these exotic species.
Planting Information

Planting stock should be propagated from species growing on Herring Island or from nearby areas on the lower-middle Yarra (eg. Studley and Yarra Bend Parks). Tubestock offers the best establishment rates. Ensure that stock is not root-bound. Direct sowing may be more suitable for some species (grasses, for example). This technique could be investigated in trial areas. Pre- sowing weed control is extremely important in areas to be established using this technique.

Adequate weed control is essential for the success of all plantings. The appropriate technique depends on existing vegetation in each area. In areas where indigenous grouncover or low shrub species remain, weeds may be controlled by a wick applicator with glyphosate, or hand removal. In areas where the understorey is substantially weedy, glyphosate should be sprayed at least two weeks prior to planting. Vegetable dye is useful to mark sprayed areas. Large areas of Kikuyu (Pennisetum clandestinum) may be left in place after spraying and used to mulch new plantings.

Following planting and watering-in, each plant should be mulched using weed mat (1 square metre per plant) or organic mulch free of weed propagules (i.e. weed seeds, stem fragments or corms). Given the logistic problems of the Island, weed mat is probably the most practical mulch to use, and is very effective. Remove and recycle (if possible) after two years.

As there are no rabbits on the Island, tree guards are not necessary. Stakes should only be necessary to mark areas planted to avoid mowing accidents and the like.

Aquatic species should only be planted in sheltered areas in the lee of existing reed beds. Particular care should be taken when planting these species to ensure that their habitat requirements are met (i.e. factors such as water depth/degree of inundation are crucial to their survival). Brief habitat notes are included in the species list.