Weeding out a major environmental concern From 'The Source' Issue 12 February 2001, Melbourne Water http://thesource.melbournewater.com.au/content/archive/February2001/qand... Geoff Carr How serious is the problem of environmental weeds in and around Melbourne? Environmental weeds constitute the most important environmental issue in and around Melbourne, rural Victoria and in Australia. All vegetation types are prone to weed invasion and there are at least 850 to 900 seriously invasive weed species in Victoria. Some of these are widespread, some are localised, but we have seen the gross modification or elimination of a lot of vegetation around Melbourne because of weed invasion. With current trends, nothing is likely to change in terms of the weed species' presence and behaviour. They are not going to suddenly change their ecology and stop invading forests. If you go to the hills east of Melbourne, you will find ivy all over the place. The projection that you can make is that ivy will eventually invade the forests of East Gippsland. What impact would that have? A catastrophic impact on flora and fauna and the elimination of most animal and plant species, as well as ecosystem functions. For example, the water yield in the catchment of Cape Town, South Africa, will decrease by one-third because of the invasion of woody weeds which use much more water than native vegetation. Now that ecosystem service or function is going to be terribly compromised. What can be done about it? At least 70 per cent of all environmental weeds come from gardens and horticulture or farming. It is ironic that last year the Federal Government announced the 20 worst weeds in Australia. They included English broom, which costs hundreds of thousands to manage each year in Victoria and New South Wales, and yet it is available in every other nursery in southern Australia. What is the answer? It is absolutely mandatory to have legislation to stop people growing nasty plants. We don't have to throw out the entire garden flora. A very small suite of garden species needs to be taken out of the nursery trade. I would prohibit the cultivation and trade of a range of weed species, so that if you live in the Dandenong Ranges it would be illegal to grow ivy, but if you live in Mildura it would be fine. It is horses for courses. It is ridiculous that people are spending hundreds of thousands a year cleaning weeds out of national parks when most of the weed species are grown in private gardens and get carted into these parks. Almost every weed infestation that you can think of starts from a point source, like a disease. We have got to take an epidemiological model with weed invasion and go out and control it before it becomes an intractable problem. What happens now is that land management agencies wait until there is a landscape full of weeds and then they throw their hands up in the air and say it is intractable. Of course it is intractable at that stage. Do our land managers have sufficient technical expertise to tackle these problems? You need ecological and botanical expertise for all land management. We get a lot of land management driven by planners, soil scientists or water people. There is grossly insufficient expertise on the ground. How do you change that? I don't know. It is getting worse because people with expertise have been shunted on, or given the golden handshake, and training in universities or tertiary institutions is inadequate and theory driven. You need never see a plant in the wild to get a degree in land management. Do councils have good people in charge of land management? They have some very good people, but they are extremely hampered by a lack of funding and resources. So there might be office-bound people who are doing very good things on education and so forth, but very little is happening out there on the ground. What would you do if you could make sweeping changes? I would initiate a "hit squad" at a local or regional level to remove weeds. I am tired of the notion that we can't possibly afford to do that - the community is awash with money. If you had a proper evaluation, you would conclude that weeds have potentially horrendous impacts, including excess water use and increasing fire risks. Who is going to growl if they have got to pay $10 or $20 extra on their rates a year to fund a squad of properly trained people to eliminate weeds? Do people know enough about weeds? You certainly have to have community education. If people ask why should I get rid of my ivy or broom, you can't just say because they're weeds. You have to have accessible information. Can community and environmental groups bridge the gaps? Almost all environmental management is carried out by Landcare or "Friends of" groups. There has been a cynical tendency in recent years for governments to offload all management on to community groups, and that is contemptible because it is an abrogation of moral and practical responsibility. If there is no one there locally, nothing will happen. There are wonderful things going on with community groups, but it is historically fortuitous that anyone is on the ground anywhere to do those things. But isn't it appropriate that local community groups are involved in these issues? Most certainly, but there is inadequate support for them and an unreasonable expectation that they will produce the goods. Is revegetation sometimes seen as a cure-all? There is an act of faith at the moment that planting trees across the landscape is a good thing, that it is going to re-establish connectivity, ameliorate climate problems, reduce salting and so on. Do you disagree with that? I don't think there has ever been a proper evaluation of the outcomes and cost-effectiveness of revegetation and its potential to maintain ecosystems in the long term. We are talking tens or scores of years to know the real outcomes. With some replanting, you will end up with an understorey of phalaris, which is a weed that is not going to do anybody any good. So while revegetation might make somebody feel good for a while, poorly planned revegetation may have no conservation value. Is the money being put into the environment going to those groups that make the most noise? Funding is driven very much by politics and by careers. We need to sit down with the right sort of expertise and work out just how we are going to spend money on environmental management. Are we doing enough to protect our waterways? We have to consider what is achievable here and not mumble on with the usual rhetoric about tree planting. We need to eliminate certain weed species and a good example of that is willows. Melbourne Water is fantastic in the techniques it has developed to manage willows. Do you think the community has learned enough about using water wisely? Everywhere I go I see profligate water use, but 20 years or 25 years ago we were having the conversations that we are now having about wasting water, with campaigns such as Don't be a Wally with Water. Today I see municipal horticulture that is incredibly inept - practices such as watering median strips in the middle of the day. What does it matter if the grass goes brown in summer? I see median strips being irrigated even after a couple of centimetres of rain. Most of the water goes on to the pavement anyway and a lot of the watering is controlled by computers. It is environmentally unaccountable. Similarly, why do people feel that their lawn has to be green in the summer? We are being exhorted all the time to plant exotic species that come from wet climates. Most of our garden flora comes from Asia, Europe or North America. If you plant oak trees in the streets you have to water them in summer. What are the implications of this for nurseries and landscape architects? The onus is on government agencies to identify the costs and say this is an improper use of the resource. Nowadays it is routine to install irrigation systems in gardens. These systems are turned on whether the water is needed or not, to water plants that shouldn't be there in the first place. If we insist on growing these water-loving plants, maybe there are other ways of capturing water, such as that from roofs and roads.