New research shows that the lack of success in controlling weeds on agricultural and conservation land is challenging New Zealand’s position as a global leader in biosecurity.
This is despite weeds costing New Zealand billions of dollars every year.
In a state-of-the-art review* of how weeds are managed in New Zealand, Professor Philip Hulme of Lincoln University’s Bio-Protection Research Centre has called for a paradigm shift.
“Unfortunately, we have rather little to show for the vast amount of time and effort government and landowners invest in the management of weeds,” Professor Hulme said.
He said part of the problem was a reliance on short-term, underfunded, and poorly coordinated control programmes that usually only targeted the weed in question and not the underlying causes of the problem.
“Weeds may often be the passengers of wider ecosystem degradation rather than the drivers of change, so working to restore the system rather than only removing the weed may be a more sustainable approach.”
He also points to a worrying trend that spending on weed management and research is no longer a priority.
“Investment in major biosecurity initiatives such as Predator-Free NZ, kauri dieback and myrtle rust has led to fewer resources for weed eradication.”
This may explain why the Department of Conservation is managing weeds on a smaller area than it was five years ago, he said.
In addition to calling for a more holistic approach to biosecurity management, Hulme recommends shifting from a reactive response to weed control to a proactive strategy.
“We should really be looking at stopping the weeds of the future, particularly those that will become a problem under climate change but also those that, given enough time, are likely to spread anyway.”
*Hulme PE (2020) Plant invasions in New Zealand: global lessons in prevention, eradication and control. Biological Invasions, online
About Distinguished Professor Philip Hulme
Professor Hulme is Distinguished Professor of Plant Biosecurity at Lincoln University. He has been listed in the top 1% of all scientists worldwide in terms of his research impact over the past six years. In 2019, he was awarded the prestigious Hutton Medal from the Royal Society Te Apārangi for his outstanding work on plant invasions in New Zealand.