Reasons for the decrease of small game animal populations.

The main reason of a considerable decrease of small game animal populations, such as European hare or grey partridge, is intensi ed agriculture, in particular the use of chemicals in plant production. Production of chemicals for agriculture in Poland in 1990–2007 increased from 19.7 do 42.7 thousands tonnes. During this period the area of arable land decreased from 18.5 millions ha in 1990 to 16.2 millions ha in 2007. Active compounds of pesticides determine the directions of toxic effects, which are: carcinogenic effect, inheritable genetic defects, fertility disorders, effects on embryos during pregnancy. The studied group of chemicals includes: fungicides, herbicides, insecticides, desiccants, chemicals preventing lodging and seed treatments, which are applied in production of cereals, rape, maize, vegetables and fruits. If agriculture chemicals are applied over vast areas it makes dif cult or impossible for animals to nd uncontaminated food. Negative consequences of the modern agriculture practice not only affect animals living on arable land but are also dangerous for human health. S owa kluczowe: biotop, zagro enia, owiectwo, zwierzyna drobna, regres.