EN
The relative importance of various mortality factors was studied in populations of European bison Bison bonasus, moose Alces alces, red deer Cervus elaphus, roe deer Capreolus capreolus, and wild boar Sus scrofa in the exploited and protected parts of Białowieża Primeval Forest, eastern Poland. Data consisted of harvest quotas and records of ungulate carcasses found to have died from poaching, gun-wounds, traffic accidents, disease/starvation, and killed by wolves Canis lupus, lynx Lynx lynx and stray dogs. In the exploited forests, red deer suffered most from wolf predation (cause of death in 58% of deer carcasses found) and disease/starvation (22%). Important factors of roe deer mortality were disease/starvation (31% of carcasses), lynx (28%), and wolves (23%). European bison and moose died mainly from disease (79% and 52%, respectively), and poaching (14% and 32%, respectively). Wild boar suffered mostly from disease/ /starvation (61%) and wolf predation (16%). Hunters, poachers, and traffic accidents acted non-selectively on the 5 ungulate species and on the sex and age classes. Wolves positively selected red deer and took fewer wild boar than expected at random. Lynx specialised on roe deer, and stray dogs killed wild boar more often than expected. Lynx strongly selected red deer calves. Stray dogs killed more juvenile roe deer than expected. In wild boar, mortality from starvation/disease increased in the year following an abundant acorn crop. Heavy acorn crop led to an increase in the numbers of wild boar, many of which died the following year. In the other ungulates, variation in acorn crop had no effect on death from starvation and disease. Variation in snow cover did not affect ungulate mortality in mild and moderate winters, but the extremely severe winter of 1969/70 (snow depth up to 100 cm) caused mass deaths of red deer, roe deer and wild boar.