Setting a target for the future for sustainable Australian landscapes, we should aim for a 20:80 mix of native ecosystems alongside agricultural production. Cropping landscapes need borders and corridors of trees and bushes threading across the pattern of fields.
We are way behind the 20:80 ratio in our agricultural districts, with many locations already at 100% agricultural use, and no native plants remaining. There is no habitat left for invaluable ecosystem services to function, like filtration of water entering rivers and creeks, or habitat for birds which control insect pests. There are no migration corridors for birds and small animals, and creek banks are left exposed through lack of cover. There is little shade or shelter for grazing stock, and few windbreaks around crops.
It would be do-able to retain or restore native plant cover to 20% of the landscape, using roadsides, fencelines and creeklines. This would restore the benefits of ecosystem services while maintaining the majority 80% area for agricultural production. Single trees in a row are not enough, there needs to be multiple ages with a mix of bushes and groundcover too. Where trees are not considered suitable, say along busy roadsides, bushes would be useful. Well-established native plant communities will suppress weed species.
Farmers frequently claim to be the best conservationists, but while many individuals do a great job, this claim is not substantiated across wider landscapes. With help from regional management boards, extension officers, grants and conservation volunteers, as well as farmers, it will take a long term plan and many hands to put in place a sustainable future for our cropping and grazing lands.
With 20:20 hindsight, we can see that over-clearing in some districts has left a landscape bereft of any native habitat. The 20:80 principle suggests that a 20% portion of native cover could give up to 80% of benefits from ecosystem services like shade, shelter, insect reduction, water filtration and habitat. With a 20:80 future vision, we could have sustainable landscapes which can deliver ecosystem services to benefit the whole community, especially farmers.