Chin J Plant Ecol ›› 2018, Vol. 42 ›› Issue (12): 1145-1153.DOI: 10.17521/cjpe.2018.0184

• Research Articles • Previous Articles     Next Articles

Spatial distribution of male and female Populus cathayana populations and its drivers in Xiaowutai Mountains, Hebei, China

MENG Zhen-Si1,XIANG Wei2,SU Guo-Kui1,LI Da-Dong1,DONG Ting-Fa1,PENG Jin-You1,LI Xiao-Dong3,GONG Xiao-Ping3,LIANG Ning3,XU Xiao1,*()   

  1. 1 Ministry of Education Key Laboratory of Southwest China Wildlife Resources Conservation, China West Normal University, Nanchong, Sichuan 637009, China
    2 College of Land and Resource, China West Normal University, Nanchong, Sichuan 637009, China
    3 Xiaowutai Mountains National Nature Reserve, Yuxian, Hebei 075700, China
  • Received:2018-07-31 Revised:2018-09-02 Online:2018-12-20 Published:2019-04-04
  • Contact: Xiao XU
  • Supported by:
    Supported by the National Natural Science Foundation of China(31170389);Supported by the National Natural Science Foundation of China(31370596)

Abstract:

Aims Spatial segregations between male and female populations of dioecious plants has been increasingly reported in recent years. However, the drivers underlying these segregations have not been fully discussed. Here, we explored the factors driving the spatial segregation between male and female populations of Populus cathayanadistributed in Xiaowutai Mountains of Hebei Province, China.

Methods The male and female P. cathayana trees with diameter at breast height (DBH) larger than 9 cm (representing individuals with sexual maturity) were investigated and the soil physical and chemical properties of each individual were analyzed. The methods of average nearest neighbor index, kernel density estimation and analysis of variance (ANOVA) were employed to analyze the aggregation degree, population density and distribution pattern of male and female P. cathayana populations and their relationships with distance from the river, altitude and soil properties.

Important findings Firstly, P. cathayanapopulation was distributed along the Jinhegou River in a long and narrow belt, with the largest number of individuals and the highest density in the middle altitude area. Secondly, both the number and density of female and male trees increased first and then decreased with the increase of altitude, whereas the change of average DBH was opposite. Thirdly, altitude had a significant effect on sex ratio. The sex ratio was female biased in the low altitude area (1 300-1 400 m), male biased in middle-low altitude areas (1 400-1 500 m), and close to 1:1 in other areas. Fourthly, with the increase of distance from the river, the number, density and average DBH of females or males gradually decreased. Moreover, the content of organic matter and total nitrogen in the dominant distribution area of female trees was significantly higher than that of males. Lastly, because the variation of altitude and distance from the river changed soil physical and chemical properties and growth environment of P. cathayana trees in some areas, the sex ratio was biased. These results indicated that the spatial distribution, dynamic variation and sex ratio of male and female P. cathayana populations were greatly affected by altitude, distance from the river and soil physical and chemical properties. Because of the differences in resource demand and environmental adaptability between male and female populations, the sex ratio will be biased in some area.

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Key words: Populus cathayana, diameter at breast height, distance from river, sex ratio, soil physical and chemical properties