How do plants that move and spread across landscapes become branded as weeds and thereby objects of contention and control? In a chapter recently published in the International Handbook of Political Ecology, Priya Rangan and I outline a political ecology approach that builds on a Lefebvrian understanding of the production of space, identifying three scalar moments that make plants into ‘weeds’ in different spatial contexts and landscapes. Read the rest of this entry »
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.
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 »
The baobab, that iconic, majestic, and grotesquely massive roots-in-the-sky tree, teaches us something surprising about “nature”. It demonstrates that what appears to be “natural” has been – for millennia and millennia – also fundamentally “social”, for people have been important dispersal agents of these trees. Researchers like Chris Duvall and Jean-Michel Leong Pock Tsy have shown this for the African baobabs.[1,2] Our recently completed research project, led by Priya Rangan, demonstrates this in multiple ways around the Indian Ocean. Baobabs are such useful and remarkable trees , it is hardly difficult to imagine people not picking up the hard but pleasantly light and fuzzy fruit pods and walking with them.
One part of our project looked at the single species of baobabs found in Australia: Adansonia gregorii, called boab. It grows in the Kimberley region in the northwestern part of the continent. In a study just published in PLoS ONE , we combine evidence from baobab genetics  and Australian Aboriginal languages to show that humans have been the primary agents of baobab dispersal. In particular, we reveal their crucial role in dispersing baobabs inland from now-submerged areas of northwest Australia during the dramatic sea-level rises at the end of the last glaciation. (See also this article in The Conversation as well as Priya’s blog about the study)
A further question is how the baobabs arrived in Australia in the first place. Oceanic dispersal via seed pods floating in currents, several million years ago, remains the most plausible explanation, as our collaborator David Baum has shown . Yet, another one of our baobab collaborators (and veritable Renaissance man) Jack Pettigrew advances an interesting speculative argument about a possible human role in transporting the baobabs, building on evidence from rock art in the Kimberley and in Read the rest of this entry »
While a number of plants, animals, and insects in Madagascar have been called ’invasive’, the topic of invasive species has until recently received less attention here than in other island contexts. Some species, often alien to Madagascar and introduced by humans, have expanded their range rapidly and have had both negative and positive effects on landscapes, on native biodiversity, and on livelihoods. Examples include the prickly pear (raketa), the silver wattle (mimosa), and, recently, the Asian common toad (radaka boka). Building on a conceptual approach, my recent paper (link; pdf) in the journal Madagascar Conservation and Development emphasizes the importance of inclusive and deliberative site- and population- specific management of invasive species. The paper analyses three separate concepts commonly used in definitions of invasion: the origin, behaviour, and effects of particular species.
It places these concepts in their broader social and ecological context, with particular attention to local perspectives on invasive species. My co-authors and I illustrate these concepts with numerous Malagasy examples from the literature and our own experiences. Read the rest of this entry »
Just launched: a new website called Trans-Plants that asks “what can we learn about humans through plant movements, weeds, and invasive aliens?” It is a joint venture between Priya Rangan, Christian Kull, and their collaborators on three ARC-funded research projects and on all the activities that have spun-off from there.
The thorny bush Lantana camara, with its attractive pink, yellow, and orange flowerlets, covers vast areas of forest understory, fallow lands, and hedges in the hilly mountains fringing the southern end of Karnataka state, India. These upland areas are also home to several marginalized cultural groups (‘scheduled tribes’, or ‘indigenous people’) as well as a diversity of wildlife – elephants, tigers, bears, gaur, three kinds of deer, monkeys, boars, wild dogs, leopards. On our recent scoping trip to the Biligiri Ranganaswamy Hills some four hour south of Bangalore, we discovered that there were at least three ways one could talk about the lantana situation, each following familiar tropes: as a story of invasion, of dispossession, or of creative redemption. Read the rest of this entry »
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.
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?
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 »
What happens when you combine human labour, introduced plants, and particular societal histories and structures in a certain tropical landscape? You end up with anthropogenic or cultural landscapes – the “matrix” in current ecological jargon – such as the domesticated forests1 of southeast Asia, the tree gardens of Caribbean or Pacific islands, the shambas of Africa, the rice terraces of Madagascar. Despite their aesthetic and cultural attractions, these smallholder farming landscapes are directly or implicitly critiqued by many – for not being as productive as modern industrial agriculture, for trapping people in rural poverty, and for taking up space at the expense of natural habitats. In two recent papers with French collaborators, I argue instead that such landscapes can be sustainable sources of useful products, can facilitate vibrant and resilient rural communities, and can be resilient contributors to the functioning of local and global biophysical systems.