Diversity And Distribution Of Typical Species Under Forests Of Platycladus Orientalis And Pinus Tabuliformis In Beijing Mountainous Area

Beijing-Tianjin sandstorm source control project is an important ecological project in China,which plays an important role in building ecological protection barrier in northern China and protecting the ecological security of Beijing and Tianjin.Since the implementation of Beijing-Tianjin sandstorm source control forestry project in 2002,the ecological environment of forest land in Beijing mountainous area has been significantly improved.In order to find out the relationship between understory species and environmental factors in the forest land of Beijing mountainous area,provide more effectively guide for the planning and implementation of ecological engineering,and forestry monitoring in Beijing mountainous area,137 sample plots in the project area were investigated.The results show that:(1)The difference of species diversity is obvious between different forest types.The species diversity index under Platycladus orientalis was mainly affected by altitude,slope,organic matter,total nitrogen,total phosphorus,total potassium and available nitrogen.The species diversity index under Pinus tabulaeformis was mainly affected by altitude,slope,total phosphorus,total potassium and available phosphorus.Under Platycladus orientalis forest,the Shannon-Wiener index ranged from 0.0146 to 2.5890,Patrick index ranged from 2.6 to 36.4,which obviously affected by the distribution of mountains.Under Pinus tabulaeformis forest,the Shannon-Wiener index ranged from 0.4852 to 2.6901,Patrick index ranged from 2.2 to 23.7,which were high in the south and low in the north.(2)The species composition of shrubs under Platycladus orientalis was significantly affected by altitude,slope,available nitrogen,total potassium and organic matter.The species composition of herbs under Platycladus orientalis was significantly affected by altitude,slope,available nitrogen,available phosphorus,available potassium,total nitrogen,total potassium,organic matter and soil p H.The species composition of Pinus tabulaeformis was significantly affected by altitude,organic matter,total nitrogen and available phosphorus content.The species composition of herbs under Pinus tabulaeformis was significantly affected by altitude,slope,organic matter,total nitrogen,total phosphorus and available nitrogen content.(3)Topography factors and soil nutrient comprehensive index were used to simulate the suitability distribution of typical species under the two forest types by Max Ent model.Under Platycladus orientalis forest,the altitude of 500 m with the slope of 10 ° to 20 ° was the most suitable distribution range of Spiraea pubescens,Deutzia parviflora,Chrysanthemum chanetii,Themeda triandra,Oplismenus undulatifolius.The appearance of Spiraea pubescens,Chrysanthemum chanetii,Oplismenus undulatifolius could indicate that the soil nutrient was with a higher level.Under Pinus tabulaeformis forest,1000 m was the optimum altitude for the distribution of Ampelopsis humulifolia Bunge and Potentilla chinensis.The optimum altitude rang of Patrinia rupestris subsp.Scabra and Aleuritopteris argentea were below 700 m and 400 m,Aleuritopteris argentea could only grow on the gentle slope below 15°,Ampelopsis humulifolia,Potentilla chinensis,Patrinia rupestris subsp.scabra could still grow on the steep slope below 30°.The appearance of Ampelopsis humulifolia,Patrinia rupestris,Aleuritopteris argentea could indicate that the soil nutrient was with a higher level.