Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 8

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
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.
Population dynamics of ungulates (European bison Bison bonasus, elk Alces alces, red deer Ceruus ela.ph.us, roe deer Capreolus capreolus, wild boar Sus scrofa, non-native fallow deer Dama dama, and cattle) were analysed in the Białowieża Primeval Forest (BPF, 1250 km2), one of the largest remaining tracts of ancient mixed and deciduous forests in the lowlands of Europe. Forty percent of BPF belongs to Poland, and 60% to the Belarus Republic. Polish and Betarussian game departments inventories of ungulate numbers (1946-1993) and archival data on censuses and hunting statistics (1798-1940) are presented. The recorded ranges of densities of native wild ungutates were: European bison 0-1.5 inds/km2, elk 0-0.6, red deer 0-5.4, roe deer 0.6-4.8, and wild boar 0.2-3.8 inds/km2. Fallow deer were introduced in 1890 (maximum density reached in 1914 was 1.2 inds/km2) and were eradicated by 1920. Cattle were traditionally pastured in the Forest, and its grazing impact was heaviest in 1880-1914 (maximum recorded density 6.7 inds/km2). In 1798-1993, the community of wild ungulates consisted of three to six species, with total densities varying from < 2 to 14.4 inds/km2 (65 to 1180 kg of crude biomass per 1 km2). Roe deer, wild boar, and red deer were usually the dominants. However, in 1860-1971, cattle constituted from 15% to 80% by numbers and from 37% to 87% by biomass of all ungulates in Białowieża Forest. Data on population trends within a five-species assemblage of native wild ungu­lates were subject to multiple regression analysis to determine the roles of predation (by wolves Canis lupus and lynxes Lynx lynx), competition, food, weather variables, and humans in shaping population densities and increase rates of ungulates. Growth of the mean annual temperature had positive effect on densities of all ungulates, probably through improving food supply and feeding conditions. Bison and elk were shaped by intra- and interspecific competition for food. Bison numbers have heen significantly limited by humans, due to both uncontrolled exploitation in years of political instability and deliberate culling in years of protection. Red deer and roe deer were primarily shaped by predation from wolves and lynx, respectively. Compe­tition for food influenced red and roe deer when they had erupted after predator extermination. Wild boar was influenced predominantly by food availability, especially the highly variable crops of oak seeds.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.