Playing with Poison

Turkey TangentialPlaying with Poison
Spencer Shaw – Brush Turkey EnterprisesI’m sure that from the beginning of time man, in his more deluded moments, has dreamt of controlling the beast that is nature. Our fear of the silent green monster, beyond our tamed backyards, that waits to swallow you up in its verdant leafy arms, if we were to lose control, is a psychosis that many suffer from.  First there was the blade and flame to tame the wild forest and these tools gave man power to shape the landscape. Then in the 20th century herbicides were developed and became widely available. Herbicides are a group of manufactured, synthetic chemicals that either control or kill vegetation. Weeds are plants that humans deem unsuitable for growing in a particular area and are prime targets for the use of herbicides. For the purposes of this discussion the main weeds that we will cover are environmental weeds. Used wisely and as a component of a management plan, herbicides can be an effective tool in the control of environmental weeds that pose serious threats to our natural areas. However, when weed management issues are based purely around the elimination of particular plants without any understanding of the ecology that those plants are thriving in, all sorts of problems can occur.Surely removing weeds from a natural area is as simple as killing the targeted weeds by either mechanical or chemical means? Then nature will take over and fill the gaps? Well not quite. Any management technique of weeds has the potential to create more weeds if not undertaken with a level knowledge of the ecosystem you are working in. Simply put, weeds most often thrive in disturbed ecosystems. When we undertake weed management work, we create disturbance. Removal of environmental weeds has to be based around tipping the balance in favour of the growth of native vegetation, not purely based around the removal of the weed. One recent example I came across of weed control gone mad, is in river system our team have recently commenced bush regeneration works on. Salvinia (Salvinia molesta) a noxious weed of still water had become established in a series of billabongs and feeder streams adjoining a major river. When I first inspected the site I was struck by the absence of any vegetation other than the Salvinia, either in the water or on the banks up to a height of several metres. What had previously been an area with a diverse range of wetland plants, was now completely dominated by Salvinia. This monoculture was not just a result of this weed being present, but also surprisingly due to the “management” techniques undertaken. A contact herbicide had recently been sprayed on the Salvinia and everything else even remotely close to it and up to several metres on the banks. This, I would say, is the management technique that has been undertaken in this area for many years and has resulted in the elimination of all the wetland vegetation from the waters edge and eliminated everything in the water except for the Salvinia. The Salvinia was burnt by the herbicide but because of its rapid vegetative growth is able to recover and spread again. The absence of any vegetation on the waters edge, even exotic, was leading to collapse of the banks, erosion and poor water quality. The site of a fish flailing about on it’s side on the water’s surface due to the deoxygenation of the water from rotting vegetation  and the thick blanket of Salvinia, brought home to me just how far we have to go in educating some vegetation managers. Weed management through the use of herbicides is not a solution. Re-establishment of stable native vegetation communities is our objective and herbicides are but one tool we may choose to use to reach that objective.In the case of the Salvinia on this site a combination of physical removal, herbicides and most crucially, regular follow up work is required to remove this weed. The water’s edge will need replanting with suitable water plants, because the regular application of herbicides will have exhausted any natural seed bank. These edge plants will be crucial in stabilising the waters edge and provide habitat for a wide range of fauna. This site can be become a thriving healthy ecosystem not through elimination of the Salvinia, but through the management of the area as a whole, and control of Salvinia being a component of that management. This may seem like a play on words, but it’s at the heart of what Bush Regeneration is all about. A bush regenerator’s main onground practice is the control of weeds in natural areas, quite often with herbicides, but it’s so much more than the control of weeds. You must see the site’s potential, its resilience to bounce back when you step in to control the weeds.  Herbicides can be a vital component of this work, but they are not a means to an end in themselves. It’s that wonderful little bit of pink matter atop our shoulders that is our greatest tool. Like all good vegetation management tools, it must be sharp and well oiled. Unfortunately there are some very blunt, rusty models being used out there.