Study On Vegetation Ecology In South Luliang Mountains, Shanxi

South Luliang Mountains, Shanxi, is located in the ecotone between south warm-temperate deciduous broad-leaved forest subzone and north warm-temperate deciduous broad-leaved forest subzone according to the result of China vegetation regionalization.The ecological gradients of floral communities in South Luliang Mountains were studied by using TWINSPAN, DCA and DCCA in terms of the interactions among the plant species, communities and environmental factors. The results show that: seventy-four quadrates were classified into 18 associations by TWINSPAN, which were belong to 8 associations, 2 vegetation types, in which 4 associations are forest community and 14 associations are shrubs. These 18 associations, belonging to the secondary vegetation types in south warm temperate zone, represent the major plant communities in South Luliang Mountains. The field survey also shows that the 18 associations have been subject to human activity disturbances. DCCA ordination of the plots clearly revealed the relationships among the pattern of plant community and six environmental factors, including altitude, slop degree, soil layer depth, litter layer thickness, slope aspects, and human disturbance. It is identified that the dominant factors that the pattern of plant community depend on altitude and human activities. Besides, slope aspects and the soil layer depth also have impacts on community characteristics.By using richness, diversity and evenness indices, the relationships between plant communities and environment factors were studied combining with TWINSPAN, DCCA. The results indicated that: There were 109 species of seed plants belong to 41 families and 91 genera in the 74 quadrats. The plant communities diversity indices increased as the altitude raised. It was showed that the diversity indices in shrub layer raised, but in herb layer declined with the raising of altitude in the view of community structure ( except Simpson index ). Altitude and human disturbance were the main environment factors that influenced the diversity of plant community by DCCA.By using x~2 test , Jaccard association index, Spearman's rank correlation coefficient, the interspecific relationships of dominant species in the communities were studied. A total of 22 plant species and 231 species-pairs interspecific association were investigated. The results indicated that the species-pairs of significant and higher significant association accounted for a low proportion in all. 22 dominant species were divided into 5 groups. The species in the same groups had similar resource utilization and habitat, but in different groups had apparent differences. The results clearly showed that their interspecific relationships, community construction and their differences in resource utilization and niches.The results of the vertical distribution of plant communities was demonstrated that: (1) the vertical distribution of plant communities is clearly. ( 2 ) the vertical distribution of plant communities was divied into 3 zones: there were the dominant communities included Vitex negundo var. heterophylla shrub and Zizinhus jujuba var. spinosa shrub in the lower part of mountain and valleys from 690 to 1,100 m above sea level (a. s. l.). There were the dominant community, Quercus baronii communities, and a few Platycladus orientalis community and some Carpinus turczaniowii community in the lower part of mountain and valleys from 1,100 to 1,300 m a. s. l. on southern and semi-southern slopes. Quercus wutaishanica forest was the dominant community from 1,300 to 1,570 m a. s. l. Quercus baronii community in this area is the mainly significant of ecotone between south warm-temperate deciduous broad-leaved forest subzone and north warm-temperate deciduous broad-leaved forest subzone.