Use of a line intercept snow track index and plot sampling for estimating densities of wild boar (Sus scrofa) in southwestern Poland

In Bory Dolnośląskie Forest (southwestern Poland), in 8 forest districts with a total of 121,783 hectares (ha) of forest area, 16 sampling plots of a total area of 7,100 ha were marked. Using the block count method, the presence of 157 wild boars was found in 12 sampling plots where the population density ranged from 2.2 to 52.9 individuals/1000 ha. By counting snow tracks along 16 line transects situated within the sampling plots (total length – 70.9 km), the presence of 103 wild boars was found. In places where tracks of wild boars were found, the relative population density of this species ranged from 0.10 to 5.6 individuals/km of transect. Using non-linear regression, a mathematical formula was derived where the relative population density index (N/km) was the independent variable, and the absolute population density (N/1000 ha) was the dependent variable. A high correlation was found between these variables (R2=0.85). It is suggested that the population numbers evaluated by snow tracks of wild boars found on line transects, and the regression equation derived in this study be used in the management of this species.