Don’t take a shotgun to the cactus, even if it is annoying you
Posted on 22 March, 2013 by Connecting Country
Attendees at a Connecting Country education event at the Maldon Community Centre on March 13 heard two dramatically different perspectives on the grisly subject of environmental weeds.
Ecologist Geoff Carr gave a general rundown on the weed problem, which is serious. He quoted the 2007 Census of the Vascular Plants of Victoria publication, which listed all the self sustaining plants in our state [that is, plants not kept alive by gardeners or special care]. Of the 5793 species and subspecies recorded within Victoria, 1496 are exotics, the numbers of which are increasing rapidly and alarmingly.
It was clear from Geoff’s talk that ‘weed’ in this discussion isn’t just a plant you don’t like: it’s a plant which, if let go, will obliterate any competition, and render other plants in the area locally extinct. Not only that: weeds have the capacity to radically alter water catchments and affect food production. The example he gave, ironically, was from South Africa (from which a good number of our weeds originate): the Cape Town water catchment’s capacity to store water has been reduced by 30% by water guzzling Acacia weeds imported from…Australia! The problem is global.
Seventy per cent of environmental weeds started their life in Australia as garden ornamentals. Geoff posed a good question: why do we have strict control over importation of exotic animals into the country, but appear to have almost none at all over plants which could cost millions in lost production and biodiversity?
Geoff Carr’s talk was not focused on remedies, but Ian Grenda more than made up for that with a wonderfully entertaining account of his efforts at cactus control, laced with a good dose of black humour. Ian is convenor of the Tarrengower Cactus Control committee. His attacks on Wheel Cactus (Opuntia robusta) – a listed Weed of National Significance – have involved experiments with axes and shotguns (details withheld here, to protect the innocent), and the invention of a variety of deadly cactus attack weapons. The most effective weapon he highlighted, however, was community support: every month about 35 local people rock up to cactus control work parties in the Tarrengower/Nuggety area. Positive social interaction and clear practical progress keep morale high. Ian’s conclusion: ‘We’re going to beat it, using the biggest weapon in the world. That’s us—we can kill anything!’
Both speakers, interestingly, spoke admiringly of the weed enemy: attacks on weeds are motivated not by hatred for any particular plant, but by a desire to protect the variety and health of the rich native plant system we have now. Both also emphasised the need to understand how plants work, and what they do in the environment. And both made it clear that that persistence and follow up work are vital.