Abstract:

Background and Aims Sampling methods were essential in the process of studying plant population spatial distribution patterns. In early time, the population pattern research method which the ecologist used was generally simple. Some comprehensive research examples indicated the transect methods could not clearly present the spatial pattern in the vision. As a result of the spatial pattern complexity, there have not a measuring method to be possible clearly to express its complete characteristic or all information. So the authors presented a new method, photography orientation method, which based on point pattern analysis and GIS.
Methods The research was taken in a fenced plot of degraded typical steppe in the Xilingole League, Inner Mongolia, which had been monitored since 1983 by the Inner Mongolia Grassland Ecosystem Research Station of the Chinese Academy of Sciences. In this research, a community block of 10 m × 10 m was chosen and divided into four hundreds of 50 cm × 50 cm sub-blocks with bamboo chopsticks. All plants in the 400 sub-blocks were then pictured by a digital camera (Nikon D100) in order, and the growing positions of each plant individuals were accurately fixed in the pictures of sub-blocks by using GIS. The feasibility of this new method was examined by Wilcoxon signed ranks test.
Key Results The results showed the method was practicable. The working efficiency was largely enhanced and the research work could be done more delicately when the method was applied to measure population patterns of degraded typical steppe.
Conclusions This study suggests that using this method, the changes in population patterns, the life histories of plant individuals, and the interactions among species could be monitored dynamically; therefore the process of community succession could be probed from the aspect of population patterns.

Key words: Photography orientation method, Camera work, GIS, Population pattern