Zizas, R., Mozgeris, G., Baliuckas, V., Brazaitis, G., Belova, O., Grašytė, G. and Kurlavičius, P. 2017. The Effect of Forest Landscape Structure on the Location and Occupancy of Capercaillie (Tetrao urogallus L.) Leks. Baltic Forestry 23(2): 411-422.

   Until now, forest characteristics of capercaillie habitats received very little attention in the southeastern Baltic region, including Lithuania. To fill the gap of ecological study of capercaillie we started to reveal the macro habitat characteristics in 2008. Seventy-one capercaillie leks were identified in southeastern Lithuania during about a decade ago, and these visited during the lekking seasons. Lek occupancy level and lek centre were identified by seen/heard capercaillies and/or their activity signs. The leks were divided into ones of the high (≥2 males) and low occupancy (attributed of individual males’ leks and abandoned leks). A Geographical Information System technology was used to evaluate the forest landscape in four buffer zones within the radius of 0.25, 0.5, 1.0 and 2.0 km generated around the centres of leks. Random extra points were generated within buffers of 2-5, 5-10 and 10-20 km from each lek centre (same number in total as all leks at all tree buffer zones). In order to reveal the differences between high and low occupancy leks and significant distances, leks were compared at four mentioned radii. In addition, high occupancy leks (n = 41) and low occupancy leks (n = 30) were compared with available landscapes at 1.0 km radius separately. By the results, the proportion of pine stands in high occupancy leks up to 1 km from the lek centre was bigger (p < 0.05) if compared with low occupancy leks. High occupancy leks were located about 500 m further from homesteads (the difference p < 0.0001) and 180 m further (p = 0.09) from the forest edge, if compared with low occupancy leks. Wetland proportions in high occupancy leks at all analysed distances were 2.5-3 times (p < 0.05) higher than those in low occupancy leks. The differences of stand areas of different forest types were found only when comparing the areas located 1 km and 2 km in radii from the lek centre. For capercaillies lek selection the distance of 0.5 km from the lek centre was the most significant. Lek selection in Dzūkija and Aukštaitija regions was influenced by the following variables: low (0.5), medium (0.6-0.7) and high (0.8-0.9) stocking level stands, proportion of pine, proportion of middle-age, mature-overmature pine stands, undrained Histosols (wetlands), stands of Ledo-sphagnosa and Vaccinio-myrtillosa forest vegetation types and core areas. The same forest structure variables influencing lek selection were typical for high and low occupancy leks. Our study shows that (1) capercaillie lek location in Lithuania is influenced by landscape characteristics and (2) that this influence is more pronounced for high occupancy leks compared to low occupancy leks.

Keywords: capercaillie, habitat, lek location, forest landscape, high and low occupancy.