BLOCK COUNT METHOD FOR ESTIMATING SEROW POPULATIONS

Abstract

The block count method was applied to serow (Capricornis crispus) populations, and its efficiency was examined in Wakinosawa Village, Aomori Prefecture, and Agatsuma-gun, Gunma Prefecture, in 1976 and 1977. Each count area covered about 200 ha and was divided about equally into the count units, which varied in size from about 5 to 50 ha at each count series. The number of serows counted increased as the unit size decreased. This relation was described as the n-s curve, a reversed S-shaped curve, with the upper asymptote in favorable visibility conditions such as unclosed coniferous stands and deciduous forests after defoliation. In low visbility conditions such as young-aged coniferous forests, densely grown sasa (dwarf bamboo) communities and summer full leaves, the n-s curve showed an incomplete shape, a reversed J-shaped curve. Using the n-s curve, it was concluded that the highest accuracy was obtained in the 5-ha unit and in 1.5-hour counts under conditions of usual visibility and also could be obtained in the 10-ha unit in two-hour counts under conditions of favorable visibility.