Abstract:
The characteristics of human disturbance pattern changes of cultivated land vegetation is the spatial expression of the disturbance to changes of cultivated land vegetation under the interaction of human activities and natural conditions of cultivated land. It is an important basis to diagnose the influence of human utilization behavior on the stable crops production that mastering the dynamic characteristics of human disturbance pattern change of cultivated land vegetation on different scales. In order to explore the multi-scale dynamic characteristics of human disturbance patterns change of cultivated land vegetation, this study took Daqing, Heilongjiang Province as the research area, calculated and identified dynamic characteristics of human disturbance patterns change of cultivated land vegetation in five periods (1990-1995, 1995-2000, 2000-2005, 2005-2010 and 2010-2016) by using methods of remote sense (RS) and geographical information system (GIS). Scale effects of human disturbance patterns of cultivated land vegetation was analyzed by using methods of sliding lattice and iterative self-organizing data analysis techniques algorithm (ISODAT Algorithm). The results showed that the distribution of human disturbance of cultivated land vegetation in the research area tended to be concentrated when the human disturbance of cultivated land vegetation increased, and on the contrary tended to be dispersed. There were two main reasons for the formation of human disturbance pattern of cultivated land vegetation, one reason was that agricultural planting behavior led to the fluctuation of the physical and chemical properties of soil, which led to the change of crops prosperity. The other was that the conversion between cultivated land and other land use types, which led to the fundamental change of cultivated land vegetation. We also found that in the study period, the scale effect of human disturbance of cultivated land vegetation was not obvious in the areas that accounted for more than 50%.However, the scale effect of human disturbance of cultivated land vegetation was still obvious in the areas that accounted for 11.81% to 18.33%, these areas were the most concentrated and uneven distribution of human disturbance. Concentration of human disturbance changed the environment, vegetation and influence between the neighboring vegetation dependencies, destabilized the cultivated land vegetation habitat, therefore, in the regions where the scale effect of human disturbance was obvious, the effect of human disturbance on vegetation community habitat was significantly greater than that of other regions. In addition in the areas where the scale effect of human disturbance of cultivated land vegetation was obvious, the proportion of the area where land use type had not changed showed an increasing trend, it showed that the policy of cultivated land protection had a good effect. But agricultural production behavior was the main source of human disturbance of cultivated land vegetation. So the focus of future policy should be shifted to maintaining the stability of soil physical and chemical properties. Finally, it can be seen from the multi-scale spatial clustering types that in most regions with obvious scale effects, the smaller the scale, the more obvious the human disturbance of cultivated land vegetation. It showed that the development of moderate scale agriculture was an effective way to reduce human disturbance and improve grain yield. In this study, we proposed the theory and method which could realize the research on dynamics of cultivated land vegetation structure changes under human disturbance and rapidly monitoring of its scale effect. This research is of great significance for realizing the protection of cultivated land and stable grain production.