Study On Picea Wilsonii Community Characteristics In North China

Picea wilsonii is the endemic species of China, located in Inner Mongolia, Hebei, Shanxi, Shaanxi, Hubei, Gansu, Qinghai, Sichuan and other provinces. The vertical distribution of it is between1500～3000m, makes it belongs to the sub-alpine vegetation. In June to August,2011, this study was composed of Picea wilsonii community types in North China, chose Mt. Xinglong National Nature Reserve, Gansu, Mt. Luya National Nature Reserve, Shanxi and Tongtian National Forest Park, Shaanxi as typical study areas. Floristic characteristics, community appearance, structure, species diversity, and population distribution patterns were investigated and analyzed. Aiming to get a systematic understanding of the Picea wilsonii community floristic composition, structural characteristics and the spatial distribution of Picea wilsonii population pattern, the results are as follows:The survey data showed that most plant of Picea wilsonii community in North China were seed plants, including gymnosperms Pinaceae, which also constitutes the dominant species of the tree layer. Families contained the most species in the community were Rosaceae, Ranunculaceae, Caprifoliaceae and Compositae. Gramineae also took an important part in the herb layer and shrub layer in communities. Flora Areal-types of North China Picea wilsonii community were mainly north temperate distribution, together with cosmopolitan distribution contributed the main floristic composition of the communities. Therefore the flora had temperate characteristics. The main genus were Picea, Fargesia, Carex, Rubus, Spiraea, Rosa etc., indicating that the plants of communities adapted to the local warm temperate mountain climate. A few tropical distribution plants and endemic distribution plants showed that although the communities were attributed to the North China flora, they had a wide connection with southwest and central flora, reflecting the characteristics of plant interaction and transition. The types of frenquency of North China Picea wilsonii community were basically in line with Raunkiaer frequency law. Large proportion of rare species indicated that community structure was relatively stable. Phanerophytes took the largest proportion of North China Picea wilsonii community, in which were mainly middle phanerophytes, small phanerophytes and short phanerophytes. Because gymnosperm species were rare,short phanerophytes were lack of needle leaf type and scale leaf type. Hemicryptophytes took the second largest proportion of the community, reflecting the plants adapted to the long, cold winter of the three regions. Chamaephytes and therophytes took a small proportion in the community. The basic characteristics of this life-form spectrum reflected the sub-humid warm temperate mountain climate in North China. North China Picea wilsonii community was divided into three layers, tree layer, shrub layer, and herb layer, sometimes also moss layer. And the community had interstratum plants.The community’s tree layer was dominated by Picea wilsonii, formed single-layer structure or continuous vertical primary forest canopy. Coverage of shrub layer and herb layer in the community were large and community regeneration was bad.Species richness index, evenness index and diversity index of tree layer of the community were less than those of shrub layer and herb layer. This was due to the tree layer was mainly composed of Picea wilsonii, the composition of dominant species was relatively simple.Picea wilsonii populations in the late stage of succession were uniform distributed, and populations in the middle stage of succession were aggregated distributed. If not being seriously interfere with, the population spatial distribution pattern will development from aggregated distribution to uniform distribution.