Browsing on naturally regenerated oak seedlings : the interaction between cervid browsing and light availability

Abstract: Browsing on oak seedlings and other tree species is a major problem when regenerating forest in Sweden. Several factors such as light, surrounding vegetation and season, can influence browsing intensity and browsing frequency. In this study the relationship between cervid browsing and light was examined. Five sites were selected, three in Hornsö (Kalmar county), one in Halmstad (Halland county) and one in Sösdala (Skåne county), and in each site four plots were marked in the spring of 2016. The plots were assigned two light treatments, low and high light, and one plot in each light treatment was fenced. To analyse the data a linear mixed regression model was used. Light had no significant effect on neither browsing intensity nor browsing frequency. The time of year, however, was shown to have a significant effect on browsing frequency and browsing intensity. Browsing frequency was the highest in winter and early spring. The lack of significance from light could be explained by the surrounding landscape and the low availability of palatable tree species. Habitat selection and difference in dietary choices could explain the increased browsing frequency on oak seedlings in winter and early spring. Cervids browse differently on oak seedlings depending on season and made no choice between oaks grown in high light or low light. Further studies on food quality selectivity in relation to food abundance are needed.