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Contentious Perspectives on Weeds - A Report on the Seminar Presentations

by Adam Grubb (Director and Manager of Design & Education, Very Edible Gardens Pty Ltd)

The series of seminars to accompany the 45th annual meeting of the Weed Society of Victoria certainly lived up to the promise in the title, Contentious Perspectives on Weeds.

Around 50 people made their way to the city fringe location of the Department of Primary Industries (DPI) offices at Attwood where a broad ranging and passionate collection of presenters gave their perspective on weeds, from the realms of psychology, culture, permaculture, beekeeping, biofuels, edibility, art, ecology, and even military strategy.

 John Dwyer, who recently completed his PhD thesis Weeds in Victorian Landscapes, presented a paper on ‘Weed psychology and the War on Weeds’.  He suggested that weeds are themselves more of a psychological rather than a botanical category, and questioned why “fear and loathing” have become widespread in our approach to weeds.   One thread of investigation was tracing the heritage of the weed concept to our desire for control and cleanliness, and notions of dirty pollutants in contrast to virtuous crop or native plant cleanliness.  These are deep human concepts that exist in all studied cultures.  Dwyer suggested that emotive language reflects and compounds fear and anxiety towards weeds.  While he acknowledged many actual cases where this is justified, especially in agriculture, he said the language used makes it difficult to clarify scientific, unbiased views on the ecological roles and impacts of exotic species.  Terms like 'noxious', 'feral', 'alien', and 'invader' are examples of emotive language.  Facilitator Brendan Roughead, in part-jest, asked how our perspective might change if we referred to exotic weeds as “new Australians.”

Dr Paul Downey from the University of Canberra presented next on ‘The plant invasion processes, and understanding the impacts of plant invasions’.  It was an impressive distillation of what seemed an uncountable number of his own published papers and field work.  He questioned: If this is a war on weeds, where are the achievable goals, where are the strategies, and where is the information gathering and feedback needed to proceed successfully?  He said, “We need to achieve something as a result of the killing; not just killing per se.”  He presented on some of his own work with Bitou Bush, and offered ways to judge the impact on biodiversity a weed has, decide strategically on areas to focus on, choose achievable goals, and report on the outcomes in a standardised, statistical way.  He also mentioned what was for me one of the most memorable part of the conference, the Von Manstein Matrix, but you'll need to Google that!

Co-originator of the Permaculture concept, David Holmgren, presented on the topic ‘Weeds or wild nature? A permaculture perspective’.  It was the broadest and most difficult to summarise presentation, which took in limits to growth and the topic of global peak oil, indigenous perspectives on nature, 19th century economic botany, ecological systems thinking, and his own work studying native ecosystems of Central Victoria.  He said that weeds are adapted to disturbance, and “almost all 'weed invasions' occur in a context of human disturbance, to a greater or lesser degree.”  He referred to weeds performing the role of ecological pioneers, stabilising soil and water resources, and providing habitat while other longer lived species become established.  He said “many exotic species have greater potential to better stabilise soil and water resources than locally indigenous species.” Holmgren showed the results of some of his own work with the local community in managing Spring Creek at Hepburn Springs, using sown and volunteer natives and exotics, including willows, to stabilise and push forward succession in highly eroded gullies.  He believes that “novel ecosystems” of mixed indigenous and exotic species are of interest and inherent value, and can serve as models for sustainable perennial agriculture.

David Severino, Chairperson, Victorian Apiarists’ Association, Melbourne, presented next on ‘The place of weeds in the honey industry’.  Bees are required for pollinating a large percentage of the global food production. Without weeds providing a varied diet and emergency food supply when mainstream crops fail to flower, David believes that the industry could not effectively provide this important pollination service.  By way of one example, the industry would have lost thousands of bee colonies in the almond crops this year, were it not for weeds.  David listed capeweed, clover and many other weedy species as essential to his personal beekeeping business and to the industry in general. Blackberry, Patterson's Curse and Blanket Weed honeys are also highly sort after by consumers for their flavour.

Graeme Allinson of DPI presented Bruce Shelley's paper based on their joint research on ‘Some issues associated with the introduction of weedy species as biofuel crops’.  Echoing David Holmgren, he said that the end of cheap energy is coming, and that energy security is a rapidly emerging issue.  In order to produce large amounts of biomass for first and second generation biofuels (which includes the use of woody plants), their project needed to look at fast growing, easy to propagate, locally adapted species, i.e. plants with the potential to naturalise. He presented their research into the likely ranges of 30 plants with biofuel potential. The research looked at both current and projected climatic conditions in 2050, as part of their risk assessment.  He suggested that some declared weedy species, such as Arundo donax (Giant Reed), can be grown with minimal risk in many areas, provided basic management strategies are considered.  

Sydney-based artist, Diego Bonetto, presented on ‘Nettle, dock, dandelion and wild fennel: environmental weeds or environmental belonging’.  Diego's website highlights edible and cultural uses of weeds.  His presentation covered the connection that people from different cultures in Australia have with weeds, which in many cases are the same plants as found their countries of origin. Diego talked about people from both Australian rural and international heritages using weedy species as food plants, and of different ways of interacting with nature from the Anglo-Celtic traditions. He noted that some of this activity is actually illegal, where the transport of declared noxious weed material as food is involved, and went so far as to question if any plant should be illegal in these terms. 

Geoff Carr, of Ecology Australia and the Invasive Species Council, finished the conference with a presentation entitled ‘Conflicts in weed management: under what circumstances should we tolerate ‘beneficial’ invasive plant species?’.  He earlier characterised David Holmgren's presentation as “human-centric and old testament”.  He called for better quantification of weed control outcomes, and better monitoring.  He echoed Paul Downey's message that intelligent strategy is often missing in weed management, describing some of the War on Weeds infantry as something of a “Dad's Army”.  Whereas Downey had earlier questioned the concept of “sleeper weeds”, Geoff inferred they are certainly real, and “it's the people that should be noticing them who are asleep”. While he mentioned some cases of wildlife being dependent on naturalised weeds, he said we must take a “guilty until proven innocent” approach to weeds, and apply the precautionary principle.  He said the impact of weeds in Australia has been environmentally and economically catastrophic.  Carr said he would continue fighting this destruction even if “there is only one square metre left”.

One core philosophical divide in the conference was most readily seen between David Holmgren on one hand, and Geoff Carr on the other.  Carr is driven by conservation; Holmgren by creating sustainable human ecosystems.  Carr puts the needs of native plants and animals first and foremost.  Holmgren focuses first and foremost on limiting environmental impacts at home through productive and sustainable use of landscape.  Carr sees invaded, mixed ecosystems as catastrophes, a process which is happening constantly, even as we sleep.  Holmgren is interested in what happens after invasion, in learning from these ecosystems and using the lessons to design novel ecosystems which provide for human needs. 

They both have obviously worthy and hugely important goals.  Since conservation says nothing about human needs, we are forced to look at it in a larger framework.  If we can, as Holmgren claims (his family produces most of their own food from their own 2.5 acre property), produce for more of our needs in low input and zero pollution permaculture-styled systems, then our systems of production themselves would be biodiverse and provide ecosystem services.  From the perspective of a conservation agenda, permaculture-styled systems lower our ecological footprint, freeing up agricultural land for use by wildlife and native plants; they also produce less CO2 and pollution.  To me, it seems that the view of permaculture as “human centric” might reflect a blind spot to how one's own clothes, food, house, and transport is produced and fuelled.  If it is not from a sustainable system, then it directly and indirectly contributes to destruction of habitat. 

Holmgren's goal of a sustainable human ecosystem pre-supposes that humans are not inherently destructive to nature.  The conservation agenda, in isolation, has the danger of suggesting the opposite.  If humans − and invasive species − are inherently destructive, and inherently separate from nature, there is no hope for conservation short of human extinction and the eradication of exotic species.  Since the former is somewhat politically unpalatable, and the latter often unachievable, this would seem a defeatist agenda, resulting in tragic-heroic visions of saving the “last square metre” of untarnished native ecosystems.

That doesn't really answer the question of whether invaded ecosystems represent an unmitigated ecological catastrophe or that they might have value as “novel ecosystems”.  Does this merely come down to our perspectives and/or is it a psychological categorisation?  Or can we select a set of indicators − such as soil loss, carbon capture, water quality and overall biodiversity, value to endangered species, perhaps value to beekeepers, and so on − and monitor these novel ecosystems with the rigour of Paul Downey's work?  That would seem to be a way forward.

It was certainly a highly engaging conference.  So broad were the perspectives that it felt like the first, but at the same time certainly not the last, words to be said on the topics covered.  Much credit must go to the Weeds Society of Victoria for their bravery in providing an arena for the airing of opposing views on such an important and potentially emotive topic.  Thanks particularly to the organisers, including Rodney Jones, Ros Shepherd and James O'Brien, and to Brendan Roughead of DPI who did an excellent job in the difficult role as facilitator, concluding and summarising the major points and themes of the day.  The day would not have been a success without the participation of all the thoughtful and knowledgeable presenters who put their convictions into a potential firing line.  Thanks must also go to the conference participants who were passionate yet respectful in their interactions, both at the conclusion of each presentation and in the discussion session, on what are indeed contentious and equally important issues.