Weeding out invasive species to protect our food

Global warming and severe weather events are taking a heavy toll on ecosystems and raising fears for global food security.

Invasive weeds are a growing threat to global food security.

With the world’s population expected to reach 8 to 10 billion by 2050 and food demand expected to double in that time, according to the United Nations, existing food production systems could come under significant strain.

Exacerbating food production issues, agronomic weed species across the globe are already causing significant damage as they adapt and thrive with the changing climate.

A new book, co-edited by Invasive Species and Restoration Ecologist Professor Singarayer Florentine, from Federation University Australia’s School of Science, Psychology and Sport, examines the impact of climate change on these weeds and their interactions with crops.

Professor Florentine said much work had already been done on agriculture and climate change, with this new research also considering the role of herbicides amid a warming climate.

“We looked at how these agronomic weeds are having an impact on crops under climate change scenarios, and how these things will affect food growers,” Professor Florentine said.

“We also take into consideration how the weed species are going to respond, and studies have clearly demonstrated that weeds will reduce the profitability of cropping systems, even in situations where weeds are subjected to high levels of control. In the absence of control measures, weeds have greater potential to reduce global crop production than any other type of crop pest.

“There are weed species that have formed resistance to herbicides over the last 50 or 75 years – this isn’t new – but how will these herbicide-resistant species respond under future climate change scenarios? We consider these scenarios and look at how agricultural crops are going to respond to these threats and what the mitigation measures are that we need to be taking into consideration.”

The book’s authors were asked to evaluate global findings and contribute their own research to come up with management strategies. This includes the development of new crops and changes to farming practices that have been used for generations.

Professor Florentine, who also contributed the first of the eight chapters, said research was needed to develop herbicides for climate impact-resistant varieties, in addition to the herbicides that were already used but struggled with nuisance weeds. Existing chemicals can wipe out all weeds, but these are also harmful to the crops already under pressure from the invasive species.

Measures farmers could adopt include alternating herbicides and introducing new crops into their rotation.

“Because of current agronomic practices such as no-till farming, fewer agronomic weed species are coming into their crops. But we also want to increase the crops that can withstand the extreme climatic events,” Professor Florentine said.

“Traditionally, farmers would usually plough their land after their crops were harvested, but there are issues with this. Under heavy wind, all the topsoil would be moved away.

“In some cases, farmers have been managing their land for generations and they have legacy information about climatic conditions that could go back to their great grandparents. But as scientists, what we need to do is provide answers to their concerns about what might happen in the future and how they can meet these challenges.”