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Don't clear native vegetation if you want high crop yields

South Australian ecologists have provided irrevocable proof why native vegetation is critical for healthy crop yields and should be protected in agricultural regions.

In the first study of its kind in South Australia, UniSA scientists evaluated the impact of native roadside (linear) vegetation and small, isolated patches of (fragment) vegetation on pollination rates and crop yields for canola and faba beans in the Yorke Peninsula.

Canola and faba bean pods within 200 meters of native vegetation—where pollinating insects live—produced more seeds and subsequently higher yields than those unpollinated by animals.

UniSA ecologist Associate Professor Sophie (Topa) Petit says the increase in seed set near vegetation, compared to the center of a field, was up to 20% higher for canola and 12% higher for faba beans. The larger patches of vegetation produced the best results.

According to first author, Ph.D. student Bianca Amato, "The results are significant, given the study area has been extensively cleared for agriculture over time, containing less than 13% of native vegetation, and roadside vegetation is often the only habitat for pollinating insects in that region."

"The findings confirm that both fragment and roadside vegetation improve pollination and crop yields. Roadside vegetation plays a strong role but is often threatened by clearance," Amato says.

"Pollinators are essential for sustainable farming, although their habitat is often overlooked in intensive agriculture. Preserving roadside vegetation and remnant patches could provide a simple way to support both biodiversity and crop production."

The research, recently in Agriculture, Ecosystems & Environment, challenges the common practice of clearing native vegetation to expand cropping areas, suggesting that such actions may inadvertently reduce long-term productivity.

In the wake of the findings, the UniSA researchers are calling on governments to offer farmers incentives to restore native vegetation, not only to boost crop yields, but also to conserve biodiversity.

"Strips of trees and bushes lining fields and roads are a familiar part of the Australian landscape. Some people assume this vegetation has little value apart from picturesque scenery, but our research shows just how important native vegetation is in supporting pollinators and increasing crop yields," Amato says.