Role of field margins and hedgerows in maintaining beneficial insect populations in agricultural landscapes

Abstract

Intensive rice monoculture across Southeast Asian lowlands has removed habitat for natural enemies that once regulated pests. This research assessed beneficial insect abundance across four non-crop habitats—narrow grass margins (2 m), wide margins (5 m), native hedgerows, and mixed hedgerows—compared with open crop fields at UPLB, Philippines. Traps were deployed fortnightly over 24 months (2021-2023). Mixed hedgerows supported 68.4 individuals/trap/week, 5.6 times greater than controls. Parasitoids, predatory beetles, and pollinators all responded positively to hedgerow presence. Restoring even narrow vegetated margins can meaningfully enhance biological pest control.