Backswamps fatten cattle, fish, birds
FLOODPLAIN graziers on low-lying North Coast backswamps who drained the areas in the past to expand grazing land are finding that allowing them to become wet-based pastures again is better for productivity and for the environment.
Department of Primary Industries is giving farmers advice on how to manage the areas.
In the Richmond catchment, more than half of the remnant freshwater wetlands are grazed - they’ve been important historically to the grazing industry but they are also important for biodiversity and the ability to influence estuarine water quality.
When the coastal floodplains were originally drained way back, some graziers noticed their carrying capacity declined once the pasture species changed from wet tolerant species to dry land types.
Now nutritional trials have shown that wetter species such as water couch can have a higher productivity value compared to dry land pastures.
The benefits of still allowing cattle access to these low lying areas far outweigh any potential impact.
The benefits of running the swamps wetter include significant reductions in the amount of acid sulfate soil discharge, where tonnes of toxic elements like iron and aluminium have in the past been carried downstream into coastal estuaries.
Instead of open slather access, grazing will now be controlled.
Cattle will be brought into the swamp on a seasonal basis.
We may increasingly find that cattle spend less time in these areas than before.
The habitat value of the swamps will also be improved by running them wetter.
Coastal floodplain wetlands are significant drought refuges for many waterbird species.
In 2001, acid sulfate soil discharge in the Richmond River caused a massive fish kill which closed the estuary to all forms of fishing for some months.
The cause of the fish kill was deoxygenated water, most of which originated from grazing land on the floodplain.
The restoration project is funded through the National Landcare Program.
Drainage affects water quality, wetland health, what pasture species will grow and the grazing carrying capacity.
Contact Chrisy Clay, Wollongbar, (02) 6626 1200.
This story appears Agriculture Today.