Abstract: Habitat fragmentation is defined as the breaking up of a habitat, ecosystem, or land-use type, which were distributed continuously but now become separate fragments under the disturbance of human beings and nature. This fragmentation is the main factor resulting in biodiversity loss and species extinction and threatening the existence of living creatures, and influences the gene flow among and within animal populations. Therefore, to study habitat fragmentation is of significance in keeping species genetic diversity. This paper introduced the measuring methods of fragmented degree and gene flow, summarized the research advances in these fields, and discussed the influences of fragmentation on gene flow among animal populations and the significance for the protection of species in danger.

Key words: NO emission, Seasonal variation, Diurnal variation, Automatic measurement, Wheat fields