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Tackling weeds in the landscape is an important focus for many in the Landcare community. This is because weeds in Australia damage our natural landscapes, agricultural lands, waterways, and coastal areas by displacing native species, contributing to land degradation, and reducing farm and forest productivity.

This damage also comes at a very significant cost, with a 2018 report[1] for the Centre for Invasive Species Solutions estimating that weeds impose an overall annual average cost of nearly $5 billion across Australia.

Given this, it’s easy to feel that we should just be getting rid of all weeds in the landscape as soon as possible. But weed management isn’t always such a black-and-white issue, as the examples of Lantana and buffel grass show.

Lantana

A lantana infestation (source: Gympie District Landcare)

However, from as far back as the first Weeds of National Significance Lantana (Lantana camara) Strategic Plan[2] in the year 2000, in which I was involved, it has been recognised that lantana can also provide important habitat for small animals such as butterflies and birds.

Some have sought to downplay or dismiss this habitat value. For example, a 1995 paper[3] in the Plant Protection Quarterly academic journal draws on the findings of three field studies to largely reject claims that lantana is generally beneficial to wildlife.

But other research finds that lantana does indeed have habitat value. For example, a 2012 paper[4] in the Journal of Herpetology reports on a study of the effects of lantana and its management on reptiles in a forest area in South East Queensland. In response to their observations, the paper authors advise that:

“The use of lantana as habitat by a number of species highlights the need to consider the importance of these habitats for fauna prior to implementing management options … Our results caution against the whole scale clearing of lantana from invaded areas, as these habitats continue to support reptile communities including threatened species.”

So, what’s the best way forward? As the authors of the reptile study suggest, the key to success is to carefully assess and consider different management options before commencing weed control activities.

Nick Clancy, Land for Wildlife Officer for Sunshine Coast Council, provides great advice on how to go about this in an article on the Land For Wildlife South East Queensland website. (Nick’s advice is also an example of the benefits of participation in the Land for Wildlife program).

Buffel grass

Like lantana, buffel grass (Cenchrus ciliaris) is considered[5] an invasive weed that poses serious threats to biodiversity, to the point where it is already a declared weed in South Australia.

However, as ABC Landline reports, buffel grass is also considered by many graziers to be the “king of pastures,” with the species supporting much of the beef industry in northern Australia. The Western Australia Department of Primary Industries and Regional Development Agriculture and Food division advises that:

“Buffel grass pastures have very high pasture value. They respond rapidly to small falls of rain, provide large quantities of good quality feed when green and, compared to native pastures, can be heavily stocked without deteriorating.”

Buffel grass pasture in the Pilbara, Western Australia (source: WA Department of Primary Industries and Regional Development Agriculture and Food division)

So, what’s the best way forward? As well as considering the ecological aspects of weed management, as highlighted in the lantana example above, social aspects are important.

A paper[6] in the academic journal Environmental Management reports that the management of contentious introduced plants like buffel grass typically involves one of two extremes. At one end of the scale, the plants are treated as weeds and their use is prohibited, which forces farmers to have to contend with negative economic and social impacts. At the other end of the scale, the plants are allowed to be used without restriction, which forces land managers such as those looking after conservation reserves to have to contend with the negative environmental impacts.

To move beyond this dichotomy, the paper authors advise building on the mutual acceptance of each others’ perspectives that those for and against buffel grass have already started to develop. The authors suggest that this provides the basis for a socially aware approach involving thorough and ongoing consultation with stakeholders, and the development of realistic goals that take into account regional differences in costs, benefits, and socio-economic and biophysical circumstances.

Collaborative learning for better environmental outcomes

The examples of lantana and buffel grass illustrate what is known as “socio-ecological complexity.” Ways of successfully navigating socio-ecological complexity are the focus of the book[7] Environmental Decision-Making: Exploring Complexity and Context, which has been written by Australian environmental researchers.

One of the approaches put forward by the book authors is “collaborative learning.” This involves all stakeholders sharing their knowledge with each other through facilitated processes that enable mutual learning, understanding, and solution planning. The ways forward suggested above for lantana and buffel grass demonstrate this collaborative learning.

In the case of lantana, the collaborative learning first involves land managers sharing their knowledge about the weed problem and potential management actions, and ecological scientists sharing their knowledge in regard to species habitat constraints that need to be considered. With this mutual understanding, everyone then works together to plan and implement management actions that are best able to consider all aspects of the situation.

In the case of buffel grass, the collaborative learning first involves those supportive of buffel grass sharing their knowledge about its value in grazing systems, and those opposed to it sharing their knowledge about negative environmental impacts and also potential alternatives. With this mutual understanding, everyone then works together to plan and implement management actions that are best able to facilitate both the prevention of environmental impacts and the continuation of economically viable grazing systems.

I discuss an example of how the collaborative learning approach works in practice in the article Case Study: Knowledge transfer and sharing through collaborative learning and governance.

Landcarer provides a great online space for facilitating collaborative learning. You can ask questions and receive valuable advice, discuss potential solutions to land management issues with a wide range of different Landcare stakeholders, and contribute your own knowledge to help others. Head over to one of the topic communities that interests you, and join the discussions!

References

1. McLeod, R. (2018). Annual Costs of Weeds in Australia. eSYS Development Pty Limited. Canberra, Australia: Centre for Invasive Species Solutions.
2. Agriculture & Resource Management Council of Australia & New Zealand, Australian & New Zealand Environment & Conservation Council and Forestry Ministers. (2000). Weeds of National Significance Lantana (Lantana camara) Strategic Plan. National Weeds Strategy Executive Committee, Launceston.
3. Swarbrick, J. T., Willson, B. W., & Hannan-Jones, M. A. (1995). The biology of Australian weeds 25. Lantana camara L. Plant Protection Quarterly, 10, 82-82.
4. Virkki, D. A., Tran, C., & Castley, J. G. (2012). Reptile responses to lantana management in a wet sclerophyll forest, Australia. Journal of Herpetology, 46(2), 177-185.
5. Marshall, V. M., Lewis, M. M., & Ostendorf, B. (2012). Buffel grass (Cenchrus ciliaris) as an invader and threat to biodiversity in arid environments: a review. Journal of Arid Environments, 78, 1-12.
6. Grice, A. C., Friedel, M. H., Marshall, N. A., & Van Klinken, R. D. (2012). Tackling contentious invasive plant species: a case study of buffel grass in Australia. Environmental Management, 49(2), 285-294.
7. Harding, R., Hendriks, C., & Faruqi, M. (2009). Environmental Decision-Making: Exploring complexity and context. Sydney: The Federation Press.