Abstract: ffects of herbivorous mammal on vegetation structure in steppe region are reviewed in this pa-per,The aiinual plant inlay in grassland caued by the digging activity of Mongolian gerbils in-creases the herb productivity near gerbil burrows, and the all year digging activity looses the top soil layer near burrow.The mound soil is fertilized by faeces and urine of getbils.All of these fa-cilitates the seed germination of annual herb and delays the vegetation succession to the climax.Large and small herbivorous mammals can determine the structure of plant communities in the steppes.Climatic changes exert influences on the distribution of herbivorous mammals and their population dynamics,and thus,indirectly affect vegetation structures and their preductivity.

Key words: phytoplankton, community structure, environmental factor, canonical correspondence analysis (CCA), Beixin of Jiulongjiang River.