In Kaniv Nature Reserve and its protected zone, there are meadow-steppes and areas which have become steppe land, and these have various insolation and water regimes. Communities of Orthoptera of 7 families have been observed in these areas. Original native species tend to disappear when grass is mown and plant cover is trampled down, being displaced outside the disturbed area. The ratio between species in the habitat is also changed. There are no certain dominant species on islet meadow areas or in meadow-steppe ecosystems untouched by man and on heights in the reserve. Farming activity, even when very limited in extent, changes the ratio gradually towards a complete predominance of 1 or 2 species of Acrididae with no strong habitat preference. These are usually species of Chorthippus, Omocestus and Stenobothrus, but may sometimes be the cricket, Modicogryllus frontalis. The species most sensitive to human pressure are specialized chortobionts of the Phaneropterinae (Orthoptera, Tettigoniidae), and some grasshoppers,-thamnobionts of Decticinae closely associated with high dense grasses at an early stage of their development. Their abundance decreased by 25-30% in comparison with undisturbed areas even in the case of a single mowing. To summarize, species diversity, abundance and presence of dominant species in Orthoptera communities are regularly found to depend on the level and frequency of man-made changes even when that human activity is limited.