Abstract
I detected the lag-phase in population dynamics of sika deer (Cervus nippon) and raccoon (Procyon lotor) populations in Chiba Prefecture based on spatiotemporal changes in sex ratio of culled animals. I examined a method to catch raccoons under low density using data from the Raccoon Removal Program in Inzai-City, Chiba. In some sika deer and raccoon populations, high male/both sex ratios suggested that they were under a lag-phase with an Allee-effect in low density areas, at the edge of the distribution and within a heavy culling area. Accordingly, I propose “lag-phase management,” with the goal of achieving and maintaining populations in a lag phase, which is detectable based on the male/both sex ratio, etc., preceding whole eradication or local removal.
