Small-scale field-margin restoration for pollination services in agriculture

Background/Question/Methods

Small-scale restoration in working landscapes can help restore ecosystem services where large-scale restoration is not feasible. However, economic incentives are often necessary to encourage project adoption and information spread to new private stakeholders. Hedgerows, field margin native plantings, are a common habitat enhancement technique in agricultural areas. Hedgerows are multifunctional, producing cultural (e.g. aesthetics) and provisioning services, including crop pollination. Hedgerows do not remove aerable land from production, making them an attractive for farmers. We evaluated the contribution of hedgerows to crop visitation and subsequent seed set in adjacent fields of hybrid sunflower, a pollinator-dependent crop. We also determined whether hedgerow presence bolstered the community of available native pollinators found within sunflower fields.

Results/Conclusions

We did not detect a difference in visitation or native pollinator abundance in fields adjacent to hedgerows versus those bordering weedy, unrestored margins. In fact, the assemblage pollinators within the field differed from the species found within the edges, suggesting that species attracted to crop resources may not be attracted to hedgerow plantings. Although previous studies have shown that hedgerows bolster the native bee community, the benefits of hedgerows may be crop specific. Further, seed set did not increase in fields bordered by hedgerows, indicating that farmers may not be able to rely on the cost of hedgerow installation to be repaid by higher yields over time. We caution against promoting hedgerows as a silver bullet agro-ecological restoration strategy for intensified farming regions until additional research on crop specificity has been conducted to allow better prescriptions of hedgerow adoption as a tool for pollination enhancement.