Plant Protection Quarterly Vol.16(3) 2001 127 plants (Acacia sophorae and Leptospermum laevigatum) are invasive in the Peninsula’s Native plants as environmental weeds on the native bushland (Table 1). Native weeds on the Mornington Pe- Mornington Peninsula ninsula pose varying levels of risk and threat to vegetation integrity and diver- Scott Coutts, Parks Victoria, PO Box 400, Rosebud, Victoria 3936, Australia. sity, relative to, vegetation communities Email: [email protected] type, their environment, weed ecology and presence of vectors and other factors. The most threatening and invasive weeds have the behaviour to dominate and de- The Mornington Peninsula features a sur- issues associated with human occupation, velop into monoculture or major under- prising variety of vegetation types and disturbance, and modified landscapes en- storey structural species and reduce diver- landforms from coastal saltmarsh, wet- hance the spread and dominance of these sity, shading out as a canopy, exhibiting lands, coastal scrub and heathlands to weeds. allelopathic responses, altering and de- foothill forests, riparian forests and rural On the Peninsula many parks are linear stroying habit, etc. landscapes. Many sites and species of in- in nature, are segmented or a small rem- Local (indigenous) plants that are con- ternational, national, state and regional nant surrounded by varied land uses and sidered serious environmental weeds significance are present. The fact that it is often urban development. Many vectors along with their hybrids, are invading the close to Melbourne and attracts many visi- for weed spread exist as well including majority of our Parks and Reserves except tors to the natural and cultural features, park visitors, foxes, blackbirds, starlings, where occurrence is indigenous. Acacia and that it has many linear parks with ru- garden and roadside escapee’s, vehicles sophorae (Coast Wattle) extends inland in- ral and urban interfaces, creates major (including management vehicles) and vading many vegetation communities challenges in natural resource manage- many more including native fauna. Other particularly as it hybridizes with A. ment. This is particularly the case when means of invasion include dumped gar- longifolia (Sallow Wattle) making identifi- managing the many diverse Parks and den refuse, arboretums, planting’s – gar- cation of the cross very difficult. A. Reserves on the Mornington Peninsula dens, nurseries (point of sale and infesta- sophorae also behaves as a weed in its in- which include Mornington Peninsula Na- tion: i.e. Boronia, Grevillea and Blue digenous vegetation community taking tional Park, French Island National Park, Gums etc.), railway reserves, road re- over niches created by disturbance, veg- Arthurs Seat State Park and Langwarrin serves. etation senescence and modification. Flora and Fauna Reserve. These Parks and Some thirty species of native plants and Acacia longifolia is not indigenous and is Reserves comprise a great diversity of their hybrids including two local native a major invader of woodlands and many vegetation communities and over 15 eco- logical vegetation class’s (EVC’s). The major threat to the habitat of many Table 1. Native plants as environmental weeds on the Mornington threatened, rare or significant flora and Peninsula. fauna species and communities repre- Family Genus and species Common name Origin sented in the Parks and Reserve systems is Fabaceae Oxylobium lanceolatum Native Willow WA weed invasion. Many thousands of dol- Pittosporaceae Sollya heterophylla Bluebell Creeper WA lars, volunteer, contractor and staff time Pittosporum undulatum Sweet Pittosporum Vic are targeted to the control, monitoring and Mimosaceae Acacia baileyana Cootamundra Wattle NSW research of weeds. Parks Victoria has de- Acacia decurrens Early Black Wattle NSW veloped Environmental Management Sys- Acacia elata Cedar Wattle NSW tems, research partnerships and Environ- Acacia floribunda White Sallow Wattle NSW mental Information Systems to record and Acacia longifolia Sallow Wattle Vic monitor environmental management pro- Acacia paradoxa Kangaroo Thorn Wattle Vic grams such as pest plants, pest animals, Acacia prominens Gosford Wattle NSW threatened species, catchment and marine Acacia pycnantha Golden Wattle Vic management, fire and native animal man- Acacia saligna Golden wreath Wattle WA agement. Acacia longifolia × oxycedrus (hybrid) Vic A large proportion of the pest plant Acacia retinodes var. retinodes Wirilda Vic program, other than targeting legislated Acacia sophorae Coast Wattle Vic/NSW state and regionally prohibited weed spe- Acacia sophorae × longifolia (hybrid) Vic cies, is in controlling environmental Paraserianthes lopantha Cape Wattle WA weeds threatening our remnant ecosys- Myrtaceae Leptospernum laevigatum Coastal Tea tree Vic tems and rare and threatened flora and Leptospernum laevigatum fauna. × juniperinum (hybrid) Vic Many of these environmental weeds are Kunzea ericoides Burgan Vic native plants outside their pre-European Melaleuca armillaris Giant Honey Myrtle NSW natural distribution and spread into other Eucalyptus botryoides Southern Mahogany NSW natural vegetation communities primarily Eucalyptus lehmannii Bushy Yate WA due to human habitation and activities. Eucalyptus globulus Blue Gum Vic They are opportunistic, filling niches in Eucalyptus maculata Spotted Gum NSW the ecosystem, many having the potential Proteaceae Hakea suaveolens Sweet Hakea WA to monopolize and modify natural sys- Grevillea rosemarinifolia Rosemary Grevillea Vic tems on the peninsula. These weed species Grevillea spp. Grevillea hybrids Gardens are definitely not in balance, as when Other species Actinotis helianthi Flannel Flower Nurseries present in the vegetation communities Boronia spp. Boronia Nurseries of their natural distribution, and many 128 Plant Protection Quarterly Vol.16(3) 2001 vegetation communities. As indicated Acacia longifolia and A. longifolia × knowledge and development of treatment above, A. longifolia hybridizes with A. sophorae are controlled using cut and methods and biological control agents. sophorae and also with A. oxycedrus (Spike paint/drill and fill hand removal, chemi- More resources and funding need to be Wattle), the latter producing infertile seed. cal application and fire followed up with directed into the eradication of environ- Its natural distribution extends through hand removal, utilizing the Bradley tech- mental native weeds or any weed species Gippsland and used widely in the past as niques. Fire must be of an intensity to that threaten the integrity of our repre- an Aboriginal food in having a large pro- crown into canopy requiring a high inten- sentative parks and reserve systems and tein filled seed. Acacia longifolia is a prolific sity fire with good elevation of fuels. This other remnant indigenous habitat. Educa- obligate seeder with seed persisting in the species is sensitive to herbicide and killed tion and awareness of the general public, soil for many years, seed is readily germi- a simple cut paint technique. Many thou- staff, volunteers and contractors and the nated by fire creating a dense mono- sands of seeds germinate post fire and use of ‘environmentally aware’ contrac- culture requiring intense management. mature to seeding in four years. tors is imperative. Of key importance is Leptospermum laevigatum (Coastal tea Leptospermum laevigatum is controlled the development and implementation of a tree), a coastal indigenous species, in- using cut and paint hand removal and fire weed strategies, prioritizing control in sig- vades primarily from disturbance such as followed up with hand removal utilizing nificant habitat and vegetation communi- road construction, land clearing and de- Bradley technique principles. As mono- ties, risk to indigenous species and target- velopment, and has the potential to create culture this species is difficult to burn with ing of new infestations. a monoculture and severely impact on di- the lack of understorey and would gener- versity by shading and perhaps an ally burn only under wildfire conditions Further reading allelopathic response in its leaves. These creating a fire of high intensity and burn- Carr, G.W., Yugovic, J.V. and Robinson, monocultures are generally a desert in ing the canopy. The time of year when K.E. (1992). Environmental weed inva- terms of diversity with the odd orchid, burning this species is important given it sions in Victoria. (Department of Con- sedge or herb existing where once rich obligates its seed post summer and has servation and Environment, and Eco- heathland and coastal scrub stood. L. immature green seed capsules in Spring logical Horticulture, Victoria). laevigatum hybridizes with L. myrsinodes whilst the seedbank has been harvested by Costermans, L.F. (1994). Native trees and and possibly L. juniperinum. It is an obli- ants etc. ensuring minimal recruitment shrubs of south-eastern Australia. gate seeder colonizing tracks and any dis- post burn. Management techniques need (Lansdowne Publishing Pty Ltd., Syd- turbed site and niche. to balance the risk of control methods to ney). Pittosporum undulatum (Sweet Pitto- the ecosystem and species of rare and Environment and Natural Resources sporum) is another serious invader and threatened flora and fauna. Committee (1998). Report on weeds in threat to many of the Peninsula’s natural Pittosporum undulatum is a very aggres- Victoria. ecosystems with the ability to invade the sive invader and treatment relies