Abstract: The analysis of spatial distribution and association of species is an important method to study population characteristics, interspecific interaction, species and environmental relationship. Potentilla fruticosa andTaraxacum mongolicum are two major species of subalpine meadow in Gannan. We analyzed the field spatial distribution and interspecific association ofP. fruticosa and T. mongolicum on different slopes using Ripley’s K (r) function. The results showed that the distribution ofP. fruticosaand T. mongolicumwere obviously different in three slope aspects. P. fruticosa population showed a decreasing trend, while T. mongolicum population showed an increasing trend from north to south aspect. On the north aspect, P. fruticosa showed a relatively high degree of aggregation at 0-4.8 m scale and a random distribution at 4.8-5 m scale. On the west aspect, P. fruticosa showed a random distribution at 0-0.6 m scale, aggregate distribution at 0.6-1.6 m scale, and random distribution again at 1.6-5 m scale. On the south aspect, P. fruticosa showed a random distribution throughout the study scales. T. mongolicum showed aggregation distribution at 0-2.8 m scale, random distribution at 2.8-5 m scale on the north aspect, and a random distribution at the whole study scales on the west aspect and south aspect. P. fruticosa and T. mongolicum showed a negative correlation at any scale on north aspect. Both species had no association at the whole study scales on the west aspect. On the south aspect,P. fruticosa and T. mongolicumshowed no correlation at 0-2.4 m scale, and a negative correlation at 2.4-5 m scale.

Key words: probability distribution, stock density, fishing effort., northern South China Sea