A weed is simply a plant whose virtues have not yet been discovered.
(Ralph Waldo Emerson)
What do we mean by a weed?
Weeds have been defined simply as ‘plants in the wrong place’. What is ‘the wrong place’ is determined by our desires, values, and perceived economic needs. Many ‘weeds’ are plants which have thrived in the disturbed habitats from the last 12,000 years of agricultural and pastoral usage and have been transferred globally with cultural invasions of distant lands.
In urban areas, ‘weed’ identifications may stem from our desire for biotically poor lawns and managed gardens. Plants considered ‘weeds’ are especially successful at colonizing and maintaining their abundance under conditions of repeated disturbance.
To some people, ‘weeds’ are any non-native plant. To others, they tend to be undesired plants that are noticeably common within a particular landscape. But because our concepts of ‘weed control’, ‘invasive weeds’, etc., have largely been transferred from an ideology which is a consequence of agricultural and pastoral land use and its degradation, the term has also been used for native species which are thought to perhaps interfere with agricultural productivity. Thus species like the Native Leek (Bulbine bulbosa) has been described as a minor pasture and roadside weed, Common Rush (Juncus usitatus) as a weed in damp pastures, Flax Lilies (Dianella spp.) weeds of roadsides suspected of poisoning introduced livestock, Emu Bush (Eremophila spp) as highly invasive in semi-arid rangelands and many more native species. (1)
‘Environmental weeds’ have come to mean plants from other areas, which establish self-reproducing populations in natural or recovering ecosystems. In classic ecology, they are typically ‘pioneer species’. In practice, any plant that is neither native nor planted is often called a ‘weed’, whether or not it is causing a problem. But its presence may not always be harmful and does not automatically warrant its immediate eradication. It may even be beneficial. A number of scientists are now seeing that introduced species may be beneficial either by increasing the diversity and resiliency of native ecosystems, by functioning in ecosystem rehabilitation or, as indicators for underlying environmental conditions.
The term ‘weed’ is, in the main, a human value judgement and one strategy for dealing with weeds is to redefine what is considered a weed. The idea of a weed is culturally and geographically specific. Many ‘environmental weeds’ were brought into Australia for pastoral, horticultural, or agricultural pursuits and are often of economic importance. Some just followed in the footsteps of human European colonists. Also, what is now considered a weed has often in the past been a favoured food or an important medicine.
The ‘War on Weeds’
We need to change our language
Simplistic and emotional language relating to weeds has become commonplace in agriculture and Landcare. The trend over the last few decades has been to refer to the growth of non-native plants in disturbed habitats as an ‘invasion’ of natural environments. The resultant ‘war on invasives’ is underpinned with ‘scientific’ theories, scaremongering and far-reaching policies, based on highly subjective opinions of ‘good’ plants verses ‘bad’ plants.
Emotive language makes it difficult to see scientific, unbiased views on the ecological roles and impacts of exotic species. Many academics are calling for a different view of weeds and have commented on the language used to pave the way to an ‘attack on weeds’. Amongst them Dr. John Dwyer’s address at the 18th Australian Weeds Conference is an excellent outline of the issue.
For years I was troubled by the fact that so many of the terms used in the vocabulary of weed science (words such as alien, feral, invader, infestation) were emotive and judgemental. The term invasion carries associations of attack on our homeland by enemy forces, and suggests that we should automatically take action against the invader. Why do we speak of aliens, with overtones of enemy aliens or space invaders, instead of exotics, which carry a hint of excitement and romance? (2)
Other researchers have also critiqued the language of ‘invasion’. Tassin suggests some more positive alternatives:
Why not speak of, for instance, beautiful conquerors, intimate strangers, new companions, repairing flora, healing species, new altruistic plants, visiting species, new arrivals, wealth plants, animal explorers, witness plants, post-disturbance plants, sky-fall species, melting pot plants, voyager species, adventuring species, plants of change, species not staying put, globetrotter species, nomad species, vagabond plants, excursion plants, international plants, variegated mixes (better as ‘mélanges panaches’), species cocktails, crossbred (metisse) assemblages, informal plant networks, enriched ecosystems, syncretic assemblage, nouveau riche environments, winner species, etc.?
Too often, ‘invasives’ get confused with ‘aliens’ and ‘weeds’. While a plant can be all three of these, we should not confuse origin (aliens), behaviour (invasive), and judgement (weed). Many definitions of invasives muddle all three of these things. (4)
The effect of this language has been that governments, various corporations, organizations and the public spend billions of dollars trying to control the ‘fugitive’ plants! This war was created by the belief that a new, ‘exotic’ plant species entering a ‘native’ ecosystem is always harmful to the surrounding inhabitants. The NSW Coastcare strategy is a case in point with ‘Attack of the Killer Weeds’, ‘Weed Warriors’ etc. taken into schools to teach the next generation the language of war.
From this perspective the most invasive species and the one which makes the most devastating ecological changes, are modern Europeans with their introduced activities, plants and animals and their concepts of ‘modern’ and ‘racial superiority’. Little attempt has ever been made to adapt to the Australian environment.
The underlying language has helped develop a profitable ‘war on weeds’ for the chemical industry that has plastered over the lack of science behind the concepts of invasive weeds.
David Theodoropoulos believes that ìLike other pseudo-environmental front groups, they push destructive corporate interests in the guise of ecological concern.” (5)
He also analyses the role of the agrochemical corporations in influencing the ‘war on weeds’ approach at the highest political levels. “For example, Monsanto, a major herbicide manufacturer was a sponsor of the 1994 California Exotic Pest Plant Council meeting, has an employee on the Council’s board of directors, and was hawking their herbicides at a prominent booth. During breaks there was open discussion of ways to circumvent environmental laws restricting herbicide use in sensitive natural areas.” (6).
In the United States, Monsanto Company is on the Invasive Species Advisory Committee set up in 1999. There’s a well-known revolving door between chemical corporation executives and government positions. The extent to which this occurs in Australia has not been investigated though it is worthy of note that, like the US regulatory agency, our pesticide registration body, the Australian Pesticides and Veterinary Medicines Authority (APVMA) does not require research independent of that provided by product proponents to register products and it is glacially slow to update registration status as further independent research comes to hand.
Invasive Species Councils: Weeds of National Significance (WONS)
Government agencies have declared war on weeds, and powerful forces have joined together in waging war. Killing weeds is a multi-million dollar business for herbicide manufacturers and those recruited to the war effort. (2)
We’ve all heard a lot of bad stuff about introduced species, including driving native species to extinction and costing billions to control each year. The website for Weeds of National Significance makes it clear there is a conflation of environmental sustainability and agricultural economic interests. (6)
For the first time in Australia and the world, Weeds of National Significance have been released to move one step closer to a WIN against weeds that cause detrimental impacts worth billions of dollars to the sustainability of Australia’s productive capacity and natural ecosystems.
The problems listed that Weeds of National Significance apparently pose to Australians include:
- Threat to human health and safety
- Threat to plant communities
- Threat to pastoral industries
- Threat to cultural values
- Threat to cropping industries
- Threat to tourism
- Threat to forestry management
- Threat to the community
- Threat to water quality and supplies
- Threat to recreation and amenities
- Threat to infrastructure damage
It is estimated that weeds cost Australian farmers around $1.5 billion a year in weed control activities and a further $2.5 billion a year in lost agricultural production. The real cost of weeds to the environment is difficult to calculate, however it is expected that the cost would be similar to, if not greater than, that estimated for agricultural industries. (7)
Much of the costs for weed control are for weeds of agriculture or for the effect on agricultural products. A considerable expenditure now goes for cosmetic control in public spaces and for control under Landcare programs. And a considerable portion of Landcare spending goes to workshops, conferences and media, which promotes the ‘War on Weeds’.
These estimated costs do not include the human health or environmental costs of using herbicides. In addition, the environmental benefits of introduced species are not included.
We need to rethink this expenditure since, as David Holmgren points out, ‘economic contraction will see less money for weed control, while the high embodied energy cost of herbicides will reduce options for weed control…. Economic and geopolitical shocks could see a collapse in the capacity to manage land using machines and herbicides, such as occurred in Cuba during the 1990s.’ (8)
- Auld, B.A. And Medd, R.W., 1987. Weeds: an illustrated botanical guide to the weeds of Australia, Inkata Press).
- John Dwyer, 2012. Messages and metaphors: is it time to end the ‘war on weeds’? 18th Australian Weeds Conference. (PDF)
- Kull, Christian l 2014.Reflections on Invasion Biology.
- Tassin, Jacques & Christian A. Kull, 2014.Facing the broader dimensions of biological invasions. Land Use Policy, 42, 165ñ169
- Theodoropoulos, David.
- Weeds Australia
- Australian Government, Weeds in Australia.
- Holmgren, D., 2013. Weeds or Wild Nature: a Permaculture Perspective