September 26, 2015
Just rediscovered a scribbled note from a few days in the “brousse” of New Caledonia late last year. We visited landscapes pounded by grazing, from a 600 ha cattle station turned into a horse farm and gîte in the more wild, mountainous nickel mining country around Thio, to the yellow-grass cattle and goat ranches in the semi-arid rain shadow country of Boulouparis. In these places, I found myself in the company of a variety of familiar thorny and weedy plants like mimosa bush, lantana, and coffee bush. Different bouquets of the same suite of plants decorate pastoral landscapes I’ve encountered in Fiji, Vanuatu, Madagascar, Australia, Reunion… and probably many more places too.
The thorny bush Acacia (Vachellia) farnesiana on a cattle ranch near Boulouparis, New Caledonia
Seeing these ‘old friends’ reminded me of a simple message about biological invasions that does not get enough consideration: it’s not the plant’ fault. The plants themselves – or the plant species – do not really deserve the lables as invasives and weeds. It is us humans that need to be branded: they are there because of us, because of our land uses and Read the rest of this entry »
September 27, 2014
Oil palm gets all the attention, but what about acacia? Oil palm has become synonymous with deforestation in Indonesia and resulting losses of orang-utan habitat, increased carbon emissions, and unhealthy smoke haze. But equally large areas of peatland are being converted to pulp and paper plantations of tropical salwood wattles like Acacia crassicarpa and A. magnum, trees that now cover many millions of hectares in South East Asia. In Riau province, Sumatra, the two big pulp mills (operated by Asia Pulp and Paper [APP] and Asia Pacific Resources International Ltd [APRIL]) have around 75 and 45 per cent (respectively) of their pulp plantations located on peatland. The ways in which such forestry concessions have been granted and implemented have inspired dramatic protests: 28 residents of the Meranti Islands in Riau Province stitched their lips shut while demonstrating in front of government buildings in Jakarta (Jakarta Post; Transparency Int.). Read the rest of this entry »
September 9, 2014
Invasion biology has been a remarkably active branch of the life sciences in the past two decades. My itinerary first crossed this field when I noticed, at the time of my move to Melbourne, that the ‘precious’ mimosas (acacias, wattles) of the Madagascar highlands were called ‘green cancer’ in South Africa, and in both cases were introduced from Australia. It was quite surprising to discover that this shrubby tree, so appreciated by Malagasy farmers (as a resource) and environmental managers (as ‘regreening’ barren lands), was seen so negatively across the Mozambique Channel. This observation led to a research program that (1) opened a window for me to learn about and consider the field of invasion biology, and (2), serendipitously, to collaboration with ecologist Jacques Tassin at the French research institute Cirad. I comment on some of the recent fruits of both in this blog.
- The South African approach to alien plants. Cartoon from environmental education material collected in 2006 (thanks to Rémy Kinna).
In a just-published viewpoint in the journal Land Use Policy [free official pdf until Oct. 6; pdf; link], Jacques and I argue that Read the rest of this entry »
July 17, 2014
I recently returned from my 11th trip to Madagascar in 22 years. My main goal was to scope out potential field sites for an ARC-supported research project entitled “A weed by any other name? Comparing local knowledge and uses of environmental weeds around the Indian Ocean” (with collaborators Priya Rangan, Charlie Shackleton, and Nitin Rai). I took two week-long trips from the capital, first south to my old highland stomping grounds around Antsirabe and Ambositra, and second east to the rice bread-basket of Lake Alaotra, the rainforest escarpment at Andasibe and Beforona, and the coastal plains and hills around Vatomandry. It was also a good opportunity to renew personal and professional connections, including at the University of Antananarivo’s forestry school (ESSA-Forêts), where I was invited to give a presentation. What did I find?
Neo-Australian landscapes along RN11a in eastern Madagascar: Grevillea, Eucalyptus, Acacia…
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September 25, 2013
The team of our current ARC-funded project on local knowledge and uses of environmental weeds recently assembled in Kununurra, far northwest Australia. The project will compare local people’s views of “weeds” across four case studies in four countries around the Indian Ocean – India, South Africa, Madagascar, and Australia. My Monash colleague Priya Rangan and I are collaborating with Charlie Shackleton (Rhodes University, South Africa) and Ramesh Kannan (ATREE, India), supported by Tom Bach (doctoral student on our previous ARC grant) and Pat Lowe (Kimberley-based author and environmentalist). Read the rest of this entry »
December 12, 2012
Are Australian acacias planted overseas miracle plants for rural development, or are they the worst kind of environmental weeds? The battle lines appear rather stark at times. At least when one reads environmentalist Tim Low’s rebuttal to a critique that Jacques Tassin and I wrote of his views. We thought our statement to be tempered and tried to build a reasonable case for responsible use of exotic agroforestry trees (see also previous blog). But Low calls us “in denial about dangerous aid”, flogs a misplaced example about mesquite in an argument about acacia, all the time preaching his argument to the converted in the journal Biological Invasions. Read the rest of this entry »
August 7, 2012
The landscapes that characterize different places on the earth, and from which many people earn their livelihoods and their sense of place, and which support diverse flora and fauna, are often built with a mix of local and introduced plants. Sometimes, introduced plants succeed so wildly in their new home that people come to see them as weeds or pests, crowding out crops or native species, changing soil conditions, altering fire regimes, or affecting the water table. The field of invasion biology emerged over the past few decades seeking to document, understand, and stop such “alien invasions”. But the fervour of this effort has at times crashed head-on with alternative worldviews. One of South Africa’s top weeds, for example, is the Australian native silver wattle, also naturalized in France where it is celebrated for its winter flowers and as an ingredient for Chanel No. 5 and other perfumes . Such conflicting outlooks were on stark display at a workshop I attended in October 2010 at Stellenbosch, South Africa, on Australian acacias as a global experiment in biogeography.
Picture 1: Do plants need passports? Who should control plant movements, and on what basis? Silver wattle (Acacia dealbata), native to Australia, invasive and assimilated as mimosa in the Côte d’Azur, France.
Picture 2: Do Australian acacias need passports? Australian passports specify “free passage without let or hindrance”…
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