[Spatial distribution and spatial association of Potentilla fruticosa populations on different slope aspects in...

The adaptation strategies of plant populations under different disturbance conditions could be reflected by the distribution pattern and correlation. Potentilla fruticosais the dominant species in alpine meadow community in south of Gansu Province, China. Based on the field investigation, P. fruticosa population spatial distribution pattern and its correlation were studied by using Ripley K function of spatial point pattern analysis. The results showed that the distribution of P. fruticosa population had significant differences on different aspects, and its species richness, diversity index and coverage showed a decreasing trend from north to south slope. The class 1 and 2 individuals of P. fruticosa population significantly aggregated at small scale in north and west slopes, and P. fruticosa clump intensity was gradually weakened with the increase of age and space scale, and finally tended to a random distribution. On south slope, the distribution patterns of all levels of P. fruticosa individuals were dominated by random distribution due to the inhibition of the habitat conditions and interspecific competition. On different slope aspects, P. fruticosa populations between class 1 and 2 individuals showed a negative correlation at certain scale, but the correlation degree decreased with increasing scale. The relationship between the class 3 and 4 individuals and the class 1 and 2 individuals had negative correlation significantly. There was no significant relationship among the large individuals, indicating that the individuals with similar age was spatially independent, which was conducive to the full use of environmental resources.