Australasian Plant Conservation
Originally published in Australasian Plant Conservation 20(2) September - November 2011, p 15-16
The Bega Valley Shire's Coastal Weeds Project
Stuart B. Cameron
Bermagui, NSW. Email: email@example.com
Signs have been provided at three key sites infested with garden escapees. These picture escapees visible at the site, show where they originated and provide information on responsible gardening and disposal of garden waste.
Photo: Stuart Cameron.
Bitou (Chrysanthemoides monilifera subsp. rotundata) can smother native vegetation along coastal dunes.
Photo: M. Fagg.
The Bega Valley Shire’s Coastal Weeds Project commenced in July 2007 and is still continuing. It is an effort to integrate, support and intensify a range of activities to control and raise community awareness of the impact of environmental weeds along the Shire’s coastline that extends about 125 km from Wallaga Lake to Cape Howe, at the state border. It is the coolest, driest, most southerly and most sparsely populated section of the NSW coastline.
There is great geological and geomorphological diversity, with lengthy dune-backed beaches, stretches of rugged cliffs and rocky headlands, and numerous intermittently open lagoons and tidal estuaries. A comparable diversity in natural vegetation types is present, ranging from subtropical and warm temperate rainforests to heath, salt marsh and the predominant dry eucalypt forests. The greater proportion of the coastal native vegetation has never been cleared for agriculture or otherwise much modified by European settlers. About 70% of this coast is conserved in national parks.
Coastal settlement is largely confined to Bermagui, Tathra, Merimbula/Pambula and Eden, each embedded in the national parks. The Shire has a small resident population of about 30 000 with a low average income. As a result the Council has limited resources to invest in weed control and the number of potential volunteers is low. The local Koori population is disadvantaged by poverty and high levels of unemployment. Tourism is the most significant local industry by turnover and employment and the coast is the key attraction for visitors.
Viewed from an economic perspective the project is about caring for the region’s key economic asset. From an environmental perspective it is about conserving one of the finest stretches of coastline in south-eastern Australia.
The Southern Rivers Catchment Management Authority (CMA) has played a key role in obtaining and providing funding and in overseeing the project. Council, the National Parks and Wildlife Service (NPWS) and local volunteers have also made major contributions. The steering committee comprises all major local natural resource managers—the Southern Rivers CMA, Bega Valley Shire, NPWS, Lands Department, Far South Coast Landcare, as well as representatives from Victoria and the neighbouring shires to the north. Its ‘whole-of-landscape’ perspective is key to the project’s success.
Assessing the problem
The first stage was to determine what environmental weeds we have, where they are, which are the most threatening, the most effective techniques to tackle them, and what work was already under way. Local botanist Stuart Cameron, appointed project officer, undertook the survey and prepared a report. The findings were conveyed to agencies and the community in a series of meetings which endorsed its recommendations.
About 90 invasive species are having a significant impact locally, falling into three groups. Species dispersed by ocean currents, particularly Sea Spurge (Euphorbia paralias) and Beach Daisy (Arctotheca populifolia) threaten local beaches and are present, usually in low numbers, on almost all of them.
Two significant local weed problems Bitou (Chrysanthemoides monilifera subsp. rotundata) and Marram Grass (Ammophila arenaria) result from ill-conceived policies of government agencies who advocated planting them in the past. Both are capable of wholly displacing local native vegetation.
Fully 80% of local environmental weeds are garden escapes. Spread mainly by dumping and garden overflow, these species are moving out into native vegetation from the periphery of all coastal settled areas. Overall, thus far, the impact of these garden escapes is negligible along the greater part of our coast. However the entire coastline is threatened over the longer term since they have well established bridgeheads around all coastal settlements and at abandoned farm sites embedded in national parks. We already have weeds capable of thriving in all the major coastal habitats—beaches, dunes, salt marshes, cliffs, dry ridges, and rainforests.
Climate change will expose us to new threats, such as lantana which is currently a very limited local problem due to its frost sensitivity but with a major infestation established just over the northern border of the Shire.
The key finding of the benchmark survey is that we have a great, but fleeting, opportunity to prevent an environmental weed take-over on the Far South Coast.
Tackling the problem
The project provides for work by professional contractors and for regular six-monthly ‘sweeps’ along the coast by teams of workers from the three local Aboriginal Lands Councils. These work crews search and weed all beaches as well as working on peri-urban sites nominated by the various local volunteer groups. The main species controlled are Sea Spurge, Beach Daisy, Bitou, Asparagus ferns (Asparagus spp), arums (Zantedeschia aethiopica) and milkworts (Polygala myrtifolia, P. virgata).
We have achieved a significant reduction in weed prevalence since the project commenced and the Koori workers are deservedly proud of their achievements. Boosted by this support, local volunteer groups have been able to move part of their efforts from weed control to planting and rehabilitation.
Raising awareness of the environmental weed problem and its causes is a major challenge and an important part of the project. The problem is primarily located in human values, attitudes, beliefs and behaviours, and we need to deepen and widen community engagement about all aspects of it, from garden plant promotion and selection through to disposal of garden waste and control of those species which have already escaped.
We tackle awareness raising on many fronts, including placing articles in local papers and talking to community groups and local agencies to equip gardeners with the skills to assess a garden plant for potential invasiveness, assess the riskiness of their garden, how it sits in the landscape, and how likely its plants are to escape.
We run ‘weed walks’ to show what is happening in local landscapes, introduce participants to potentially invasive plants and how garden plants escape into the landscape, and show how weeds vary in their impact and may be prioritised in control programs. The walks help give participants a sense of the totality of the landscape beyond their own properties and allow concerned locals to meet and form connections which can lead to the formation of new volunteer groups.
Our ‘Unintended Gardens’ signage is an innovative approach where we have installed signs at garden escape infested sites at each of our coastal settlements. They picture escapees visible at the site, show where they originated on a world map, and exhort the reader to responsible gardening and disposal of garden waste.
We feel our project provides a model for effective use of the sparse resources available to control the spread of environmental weeds into native vegetation along the Far South Coast. It delivers both environmental and social benefits, including Koori employment, and has achieved some impressive results on the ground in only four years. Even so its future is far from secure. A few years inattention due to funding cuts would very easily see the weeds reclaim all that we have gained. But we have proven that a take-over by environmental weeds is NOT inevitable, it can be averted quite cheaply and easily. If it does happen it will be because our community has decided, in effect, that it is content for that dismal process to take place.