EFFECTS OF EXPLOITATION AND PROTECTION ON FOREST STRUCTURE, UNGULATE DENSITY AND WOLF PREDATION IN BIALOWIEZA PRIMEVAL FOREST, POLAND

1. The pristine part of the Bialowieza Primeval Forest (protected as B ialowieza National Park, 47.5 km(2)) is dominated by stands of deciduo us trees (mainly oak Quercus robur, hornbeam Carpinus betulus, lime Ti lia cordata, and maple Acer platanoides) (72.5% of forested area). The average age of the tree stands is 130 years. The managed part of the Bialowieza Primeval Forest (530 km(2)) has been heavily exploited for timber since 1915. Forestry practices have reduced the area of deciduo us mature stands (currently 46% of area) and have greatly increased yo ung-age coniferous stands. Pine Pinus silvestris and spruce Picea abie s are the most widely replantated species. The average age of these tr ee stands is 72 years. 2. Five species of ungulates inhabit Bialowieza Primeval Forest: red deer Cervus elaphus, roe deer Capreolus capreolu s, moose Alces alces, European bison Bison bonasus, and wild boar Sus scrofa. Their total density in winter was 13-41 (mean 28) individuals km(-2) (total biomass 1104-3338 kg, mean 2286 kg) in the pristine fore sts, and 11-24 (mean 15) individuals km(-2) (total biomass 1000-1654 k g, mean 1238 kg) in the exploited forests. In pristine forests, red de er and wild boar were dominant (on average 43% and 51% of total number of ungulates, respectively), while in the exploited forests, red deer and roe deer were the dominant species (39% and 27%). 3. Two factors, the percentage of deciduous tree stands and the percentage of mature stands (>80 years), in the 11 censused sections of Bialowieza Forest e xplained 71% of the variation in ungulate biomass per unit area. Both factors positively correlated with ungulate abundance. 4. Wolves (Cani s lupus) preyed selectively on red deer and took fewer wild boar than expected on a random basis. Roe deer fell prey to wolves relatively mo re often in the exploited forests, where it was the second most numero us ungulate in the community, than in the pristine forests. 5. Compari son of ungulate densities in the pristine and exploited forests of Bia lowieza with the data for six other woodlands in Poland showed that th e total biomass of ungulates per unit area was positively correlated w ith the percentage area of deciduous forest sites. High food availabil ity in deciduous forests (browse supply, acorn crop, soil invertebrate s) is the main factor in determining the abundance of ungulates in Pol ish lowland forests. 'Borealization' of deciduous forests due to fores try practices (favouring pine and spruce in silviculture) is diminishi ng their carrying capacity, especially for red deer and wild boar.