SENIOR Project Officer in our Waterways, Wetlands and Coasts team Scott Fry, (pictured), said farmers working agricultural land near important wetlands benefited if the system was healthy and functioned as nature intended.
“Weed chokes in waterways, if left untreated, can completely destroy the natural function of the wetland,” Mr Fry said.
He said neighbouring farmers often bore the consequence of that imbalance.
Typically, the first weed infestation was by floating weeds such as water hyacinth or salvinia. Once the invaders completely covered the surface of the waterway, para grass, typha, sedges and hymenachne were able to grow towards the centre of the waterway.
Sometimes the vegetation mat is so thick, even large plants like melaleuca trees (some as tall as five metres) can grow hydroponically on the framework of weeds, their roots dangling in water below the surface weeds.
Even in the windiest weather, water covered by weeds is no longer aerated by the breeze, and the population that normally inhabits the top column of the water disappears. Small fish, turtles and wader birds die out, as do the predators that normally hunt near the surface – eels and barramundi.
With no baby birds being lost to predators, populations of magpie geese grow exponentially and, because of their numbers, begin to significantly damage neighbouring sugar cane crops, rooting out billets of plant cane and attacking young cane to get at the sugar.
Overwhelming populations of native coots similarly cause enormous damage.
“A healthy wetland might include 10 pairs of coots, but they build enormous flocks very quickly, particularly following an infestation of typha,” Mr Fry said.
The coots cause havoc in sugar cane crops, picking out young cane shoots and tying growing cane tips together to nest. Coots are the third-biggest pest to sugar cane in the Burdekin and directly affect production.
He said that was why it was integral to the success of the RMAs to include local land managers in the ongoing maintenance of waterways.