Abstract: To clarify the spatial distribution and interspecific relationship of plant community in Longxiang Mountain in Jiaozuo, Henan, we investigated the species composition, diversity, niche and interspecific association of plant communities by means of interspecific association analysis, regression analysis, and non-metric multidimensional analysis (NMDS). Results showed that 172 species belonging to 128 genera and 57 families were recorded. Among those species, 28 species belonged to 24 genera and 15 families in arbor layer, 25 species belonged to 22 genera and 16 families in shrub layer, and 111 species belonged to 86 genera and 33 families in herb layer. In the arbor layer, Tamarix chinensis had the highest importance value (1.523), while Cotinus coggygria had the maximum niche width (4.763). For shrub and herb layers, Gleditsia microphylla and Carex rigescens had the highest importance value (0.483 and 0.429), and their niche width ranked 2 nd and 5 th, respectively. Total coverage (83%), Simpson index (0.605) and Shannon index (1.875) in shady slope were higher than those in sunny slope, and significantly higher than those in flat slope (P<0.05). Margalef diversity index (1.315) and evenness index (1.084) were the highest at altitude of 500-600 m. Altitude had significant power exponential and quadratic polynomial relationships with Margalef diversity index and evenness, respectively (P<0.05), while slope gradient had a quadratic polynomial relationship with Margalef diversity index and Shannon index (P<0.05). The niche overlap index of dominant plant species was positively correlated with interspecific association indices (Dice index, Jiaccard index and Ochiai index) (P<0.05), indicating that the dominant plant species in Longxiang Mountain were temporally and spatially associated, and species pairs were positively correlated with each other. Results of NMDS analysis showed that plant community composition and diversity varied among different altitudes and slopes. Our results can provide reference for the utilization, protection, and management of plant resources in mountain areas of Jiaozuo.

Key words: plant community, altitude, slope direction, niche, interspecific association