Effect of forest structures and tree species composition on common tick (Ixodes ricinus) abundance—Case study from Czechia

Abstract

Tick-borne diseases are a significant health problem worldwide and have become even more pervasive in Europe due to the increasing abundance of tick species, especially the common tick (Ixodes ricinus L.). Moreover, in recent years, there have been changes in tick geographical distribution, the occurrence of new tick species, and an expansion in abundance driven by changes in forest management and climate change. Therefore, this paper’s objective is to determine the effect of tree species composition and forest structure on the abundance of I. ricinus in various forest stands in Czechia. Altogether, we analyzed 4195 collected ticks on 56 monitored research plots, of which 4182 individuals were I. ricinus, 4 individuals were Dermacentor reticulatus Fabricius, and 7 individuals were Haemaphysalis concinna C. L. Koch. The average density reached 1.21 ticks per 10 m2. The highest I. ricinus abundance was observed in coniferous stands (especially in Scotch pine—Pinus sylvestris L.) and forest edges with a high incidence of wild ungulate habitat signs. Contrarily, the lowest tick numbers were in clear-cut biotopes and mixed stands. Increasing vertical structure had a significant (p < 0.05) negative effect on I. ricinus abundance, similar to tree species diversity (richness, evenness, heterogeneity) and complex stand diversity on nymph stage abundance. Close-to-nature silviculture of mixed forests, which are resistant to climate extremes, could reduce the tick abundance, as well as the presence of tick-borne diseases compared to standard coniferous monocultures, which are receding now due to climate change. Based on this knowledge, it should be possible to predict the I. ricinus abundance under changing environmental conditions in the Central European region.