In European conditions and especially in Poland we can mention many potentially positive effects of hunting which facilitate the preservation of high biological diversity:
- Increased environmental knowledge and interest in nature in a big group of hunting people,
- Increase in number of disappearing species achieved by intensive protection measures,
- Regulation of game species quantity, the extensive number of which upsets balance in ecosystem,
- Reintroduction of certain species in the area where they became extinct,
- Positive changes for animals in the environment (e.g. giving additional food, improving landscape structure),
- Influencing authorities to create good living conditions for animals by making right spatial and economic decisions.
Hunting may have also negative effects on biological diversity if the following are allowed:
- Extensive exploitation of some species,
- Too great number of some species, which upsets balance in ecosystem,
- Selection of species according to some morphological features such as beauty of trophies, which may change the natural proportion of genes in a population,
- More intensive shooting of one sex in particular species,
- Introduction of alien species which may replace native species.
In Poland , there is a hunting law which specifies game species. Many traditional game species are now under strict legal protection, e.g. European bison, beaver, lynx, and wolf. Almost 100 000 hunters living in Poland have to belong to Polish Hunting Association (PZŁ). The hunters associated in PZŁ circles are responsible for game management and hunt on the land (hunting district) hired from the state. The number of annually shot animals is given in official statistical data (GUS yearbook, The Environmental Protection), but it usually contains errors.
The amount of population exploitation, if is not to upset its balance, should not surpass population growth achieved in a given year. The maintenance of specific number of big hoofed mammals (moose, red deer, roe deer) is determined mainly by the State Forests management's hunting policy. For last years, this policy has aimed at the limitation of damage in stand of trees maintaining a relatively low density of hoofed mammals.
In the 90s of the XXth century the population of moose was so reduced that it disappeared completely in many places in Poland. In 1990, its population was estimated to have 5374 animals while in 2002 only 2242 moose. That is why in 2001 moose was under all-year protection. In Poland, there is a relatively great density of roe deer, which causes much damage to the woods. The number of roe deer population is comparatively at the same level. However, the situation of wild boar is different, as its population varies according to water conditions in a given year. Another species of high variability in growth is European hare. The growth of it depends on weather and climate conditions. In last decades, the density of hare has rapidly decreased. It was caused by intensive farming, hunting and increased number of predators, especially foxes. Similar to the case of hares, the population of grey partridge fell suddenly in the second half of the XXth century. Here, it was mainly due to the changes in agriculture.
In the XXth century, many species came from the list of game species to the protected ones. Before war, among game species one could find such species as: European bison, chamois, beaver, marmot, bear, wildcat, ermine, least weasel, European otter, European mink and many species of birds. All of them disappeared from the list of game species in 1959. New list from 1975 added sika deer, moose, bebech marten, and muskrat to game species because their populations rapidly rose then. In that list there were also numerous species, which now are not game animals: lynx, wolf, wood grouse, black grouse, ruff, great snipe, common snipe, jack snipe, fieldfare and mistle thrush. In 1996, a new much shorter list of game species was established. Some species were given species protection e.g. European otter, lynx, squirrel, great bustard, wood grouse, black grouse, and many species of water birds. Wolf remained to be a game species only in three Polish provinces. At present mainly big water birds disappeared from the list of game animals. In the XXth century only one species, moose, from protected species became a game one. However, it is under all-year protection now again.
During last 50 years, two successful reintroductions, moose and beaver, took place, and presently a reintroduction of lynx is being done. These introductions have significantly contributed to the increase of biological diversity in Poland.
The population of moose developed from 6 animals brought to Kampinoski National Park and a little natural population which survived after World War II in north-eastern Poland. Thus, the gene pool of Polish moose must be very narrow. At present, the number of moose is estimated to be 2000, but this data may be overstated.
Beaver was introduced as a result of campaign conducted by PZŁ in the 70s. The animals were displaced from the endemic population near Suwalki. It was a very efficient method, in 1980 there were 1500 animals and in 2002 as many as 30153. It led to the situation that in some areas beavers do serious damage. At present, the Minister of Environment may agree to shoot a specified number of beavers in the areas where they cause the biggest damage.
Since 1993, the reintroduction of lynx to Kampinoski National Park has begun. Every year a small number of animals are freed from zoological gardens. From 1993 to 2003, 32 lynxes were introduced (18 females and 14 males). Now (2003) free-living population of lynx in Kampinoski National Park is estimated to have 15 animals, the half of which were born in freedom. In addition, the migrations of lynxes outside the park area have been observed.
The alien species in our country either introduced directly in Poland or those which came from foreign countries are: fallow deer (Dama dama),sika deer (Cervus nippon), wild sheep (Ovis ammon), ring-necked pheasant (Phasianus colchicus), Ondatra zibethicus, racoon dog (Nyctereutes procyonoides) and American mink (Mustela vison). In particular, racoon dog and American mink have a negative impact on native fauna. Moreover, American mink has almost entirely superseded Europen mink (Mustela lutreola).