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 land management instead. These landscapes are all tropical pastoral landscapes first and foremost; the weeds are a symptom of that, not an isolated problem that is attached in some way to the essence of those plants. It is how we use the land that encourages the plants’ spread. It is our aspirations for the landscape that lead us to bring the plants, and use the landscape in particular ways that makes it perfect for the plants to then spread. Biologists certainly speak of “invasibility”, but this does not get nearly as much attention as the invasive characteristics of the plants themselves.
These tropical pastoral landscapes with bouquets of weeds include:
- New Caledonia’s grazing lands with mimosa bush or cassie (Acacia farnesiana), lantana (Lantana camera), coffee bush (Leucaena leucocephala), parkinsonia (Parkinsonia aculeata), ...
- Madagascar (A. farnesiana, L. leucocephala, L. camera)…
- Fiji (L. leucocephala, A. farnesiana, , L. camera)
- Tanna island, Vanuatu (L. leucocephala)
- Broken Hill, NSW, Australia with mesquite (Prosopis)
- Mt Isa, Queensland, Australia (A. farnesiana)
- Kununurra, WA, Australia (A. farnesiana, L. leucocephala, …)
- leeward Reunion island (A. farnesiana, probably more)
This is of course from my experience and perspective; I’m sure there are plenty of other styles of such landscapes, with Chromolaena or other species.