Breeding new fast-growing grass varieties that produce more seeds and are resistant to drought, pests, grazing and disease may inadvertently be creating the next generation of invasive weeds, warns an international team of researchers.
As the global demand for dairy and beef escalates, farmers are increasingly seeking ways to reap greater productivity from their pastures. The problem is that in making grass varieties more robust, they are more prone to becoming a problem for the environment. For instance, new varieties can invade adjacent areas and spread across the landscape, or they can interbreed with existing invasive weeds.
That’s according to Professor of Plant Biosecurity at Lincoln University and lead researcher at the Bio-Protection Research Centre, Philip Hulme, who has co-authored a research paper published in the latest edition of Proceedings of the National Academy of Sciences (PNAS).
“Pasture species such as ryegrass and fescue may not strike people as major threats to the environment but they are regarded by the Department of Conservation as environmental weeds,” explains Professor Hulme.
The research team have highlighted the need for government and agribusiness to ensure pasture plants are of low risk to the environment.
“Pasture is big business in New Zealand and a large part of our economic success arises from agribusiness developing ever more productive or persistent varieties,” says Professor Hulme. “As a result there is a clear conflict between economic and conservation outcomes.”
Agribusinesses do not have to assess the environmental risk of the new grass varieties they develop, but some consideration in this area might prevent the future spread of environmental weeds.
“It is probably those varieties being developed for greater persistence, especially in the face of drought, that might pose the greatest future risk,” suggests Professor Hulme.
The researchers have made four biosecurity recommendations for government, industry and researchers: governments should manage a list of prohibited varieties (not just species); develop a weed risk assessment; ensure rapid detection and control of invasive weeds; and develop an industry-pays system.