Proceedings of the Vertebrate Pest Conference

This one-year study focused on the impact of hedgerows of native California plants on rodents and food safety in adjacent crops in the Sacramento Valley. Deer mice, house mice, California voles, and western harvest mice were live trapped in four different walnut orchards at zero, 10, 75, 175-m transects from hedgerows. The abundance and richness of rodents was compared to control sites with conventionally managed field edges that were mowed or sprayed for weed control. Unique rodent capture data showed two peaks in activity: 1) in the middle of the orchard regardless of field border type, and 2) in the hedgerow across all seasons with winter being the most active overall. Fewer captures were recorded in the conventional field border, likely because they lacked vegetative structure. Deer mice were the most prevalent species captured throughout the study (>96% of unique captures). House mice and California voles were almost always found in hedgerows and not in adjacent crops. Fecal samples from captured rodents showed a low prevalence of Escherichia coli (non-O157 STEC 1.4%, n = 438; O157 STEC 0%, n = 434) and Salmonella (0.92%, n = 434). Giardia (28.6%, n = 210) and Cryptosporidium (23.8%, n = 210) were more prevalent in captured rodents, but the distribution was not affected by field-edge habitat.