The Research On The Change Of Plant Population's Spatial Distribution Pattern Of The Degraded Community On Typical Steppe In The Course Of Restoring Succession

This paper studied the plant population's spatial distribution pattern by means of the method, which contains both the camera work and theory-method of Geographical Information System. The point pattern, the area of "blank" and the density function of scale are analyzed in different restoring succession stages of every populations. Then the following conclusions can be drawn:1 When the change of population's pattern in the course of restoring succession is analyzed with the density function of scale, it is discovered that the population density of the community on seriously degraded steppe is bigger than that in the course of restoring succession when the scale is under a certain value. Author calls the phenomenon "Population's Adaption to Graze". Because the plant individual has miniaturized in the community on seriously degraded steppe, then intraspecific competition declines and distance among individuals diminishes accordingly.2 The Stipa grandis population's pattern in different restoring succession stages is analyzed, and as a result I think in the process of restoring succession it experienced a course that the population increased and then became steady. The pattern of Leymuschinensis population in different restoring succession stages is discussed, from which a conclusion can be drawn that in the process of restoring succession Leymus chinensis population experienced the course of increasing decreasing itself and at last becoming steady. Based on the study of the Agropyron michnoi population's pattern in different restoring succession stages, it indicates that Agropyron michnoi population decreased itself in the process of restoring succession and 6 years later became steady. According to the discussion on the pattern of different restoring succession stages, Caragana microphylla population still increases after it has restored for 21 years. After analyzing the Cleistogenes squarrosa population's pattern, we can see that the Cleistogenes squarrosa population decreased and then became steady.3. Summing up the foregoing conclusions, we can come to the conclusion that the population's spatial distribution pattern as a character of floral population changes in the course of restoring succession. So the population's spatial distribution pattern is not caused by reproductive patterns, it is a character of different succession stages about community and depends on self-organizing among individuals.