Dry coastal vegetation occurs on well-drained soils along the coast. It can occur on sand dunes, cliffs and rocky shores. It is dominated by plants that are confined to the coastal zone. The most common dominant species in Tasmania are sea rockets (
Cakile species), marram grass (
Ammophila arenaria), coast fescue (
Austrofestuca littoralis), coast spinifex (
Spinifex sericeus), blue daisy-bush (
Leucophyta brownii), boobyalla (
Myoporum insulare), coast wattle (
Acacia sophorae), coast beard-heath (
Leucopogon parviflorus), and coastal tea-tree (
Leptospermum laevigatum). Sea rockets are weeds that occupy the high tide line, while the introduced marram grass occupies foredunes where it competes with native vegetation.
Where to see dry coastal vegetation
Dry coastal vegetation exists around much of Tasmania's coastline with varying degrees of invasion by weeds. In many areas clearing, grazing and shack building have led to a loss of coastal vegetation. The cliff and rocky shore vegetation in most national parks is still in good condition. However, sand dunes free from invasion by marram grass are relatively rare. The best accessible example of sand dune vegetation free of marram grass is at Friendly Beaches in Freycinet National Park.
Biodiversity values of dry coastal vegetation
Dry coastal vegetation is well reserved in Tasmania. Several rare or threatened plants are found in dry coastal vegetation, which is also important for providing nesting sites for threatened birds. Birds such as the hooded plover (
Thinornis rubricollis) and red-capped plover (
Charadrius ruficapillus) nest just beyond the high tide mark among natural debris and sometimes in pigface (
Carpobrotus rossii). However, they do not nest in taller vegetation, including area infested with marram grass. The dune stabilising effect of marram grass changes the natural landscape of the beach, creating ledges of vegetation that are unsuitable nesting habitat for beach birds and sometimes making it impossible for little penguins (
Eudyptula minor) to reach their burrows. Little penguins nest in coastal scrub and many colonies are threatened through habitat loss. Mutton bird or short-tailed shearwater (
Puffinus tenuirostris) rookeries are also found in coastal scrub and the burrows are vulnerable to damage by stock.
All fauna listed under the Japan Australia Migratory Bird Agreement (JAMBA) and the China Australia Migratory Bird Agreement (CAMBA) are significant and include most international migratory birds and nationally listed threatened fauna.
A number of rare migratory species roost and forage in coastal areas during the northern winter, including the bar-tailed godwit (
Limosa lapponica), the red knot (
Calidris canutus), the lesser golden plover (
Pluvialis dominica), and the grey-tailed tattler (
Tringa brevipes).
Refer to Threatened Species for more information.Management Issues for dry coastal vegetation
The major management issue for dry coastal vegetation is weed invasion. It is particularly susceptible to weed invasion because of the high degree of natural disturbance, its relatively high fertility, and the large number of potentially invasive weeds that occur in adjacent gardens and farmlands.
One of the most threatening invasive weeds, marram grass, is still planted to stabilise dunes. Like many other invasive weeds in the coastal zone it can disperse in sea currents and is currently spreading down the west coast of Tasmania.
Another weed, the sea spurge (
Euphorbia paralias), is spreading by currents southward in Tasmania and is one of the most serious threats to coastal biodiversity. It spreads rapidly and vigorously colonises a variety of habitats such as herbfields, dry slopes and rocky shores.
Invasive woody plants found in dry coastal vegetation include South African boneseed (
Chrysanthemoides monilifera), New Zealand mirror bush (
Coprosma repens), and South African boxthorn (
Lycium ferocissimum). Trampling by stock and humans can destabilise coastal soils leading to increased rates of weed invasion. Stock can also introduce weeds in their faeces and on their coats.
Fire is not necessary to maintain dry coastal vegetation. Certain fire regimes can eliminate some coastal species. For example, on King Island coastal tea-tree has disappeared because the area has been burnt twice in quick succession. Fires can also lead to cliff destabilisation and the development of unnatural sand dunes. Dunes are active landforms that are regularly mobilised by natural processes. Any increase in access by people, stock or vehicles is likely to cause greater sand mobility than would occur naturally.
If your dry coastal vegetation is in excellent condition maintain your current management regime. However, be aware of the first signs of invasion by the most threatening weeds such as sea spurge, marram grass and South African boneseed. If these weeds appear eliminate them using the advice given in Weeds in Your Bush .
The condition of your dry coastal vegetation can be improved by:
- reducing or excluding stock
- excluding fire or reducing its frequency
- hardening and restricting access roads and pathways
- reducing the abundance of threatening weeds
- strategic planting of local native shrubs and grasses in degraded areas
See also:Weeds on this site for more information.